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A proposal for the Indian National Lighting Code
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A proposal for the Indian National Lighting Code
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A PROPOSAL FOR THE INDIAN NATIONAL LIGHTING CODE by Kanchan Puri A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE May 1994 Copyright 1994 Kanchan Puri UMI Number: EP41440 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI EP41440 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Dissertation Publishing Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Bo. S- UNIVERSITY OF SOUTHERN CALIFORNIA THE SCHOOL OF ARCHITECTURE . UNIVERSITY PARK LOS ANGELES, CALIFORNIA 90089-0291 , W 2 . This thesis, written by under the direction of h < ~ ^ - . .... Thesis Committee, and approved by all its members, has been pre sented to and accepted by the Dean of The School o f Architecture, in partial fulfillm ent o f the require ments for the degree of A?AST& ~i ^ £ 5 ^ Date THESIS COMM! S M b r / DEDICATION I dedicate my work to the citizens of the United States of America whose adherence to Jeffersonian Principles has made it possible for me to study and grow in an atmosphere of intellectual freedom and physical comfort. I shall take back wonderful memories of your great nation to my country and try and transplant your ideals in my native soil. I also dedicate my work to my parents-in-law, Mr. M. S. Shetty and Mrs. Saraswati S. Shetty who showed a disregard for tradition and whose far sightedness and large heartedness permitted their young daughter-in-law unimaginable freedom to travel so far away and live alone so that she could fulfill her desire for learning. ACKNOWLEDGEMENTS For two years I have enjoyed the hospitality of a kind and great University whose ideals represent all that is best in the American tradition. There are hundreds of individuals who helped me in my search of knowledge and self- discovery. While it is not possible for me to thank them all individually, I shall always cherish their memories. I would like to express my individual thanks to Professor M arc Schiler who was my friend, guide and philosopher. He led me from darkness to the Light. My achievements, if any, were made possible by his encouragement. He was and will always continue to be my 'Guru'. My thanks are due to Professor Ralph L. Knowles whose scholarly advice helped me a lot. His benign presence is like a beacon to guide us all. A great debt is owed to Professor G. Goetz Schierle, our Director, whose genius has established the high standards and values that penetrate the entire Program. My thanks are also due to my sister-in-law Mrs. Vidhya S. Hegde, her husband Dr. Sadanand B. Hegde and their wonderful children, Akhil and Shilpa of North Carolina who provided me a home away from home. My thanks to all my friends in the University, both foreign and Indian who helped lighten the load of loneliness and homesickness. My thoughts turn homewards to my Alma Mater, Sir J J College of Architecture, Bombay, India which provided me a sound architectural foundation on which to build upon. My work was greatly facilitated by the running around done by my younger sister, Sonal Puri, my ‘girl friday’. My unbound gratitude to my mother, Mrs. Renuka Puri who provides the greatest requirement of a student, a comfortable and peaceful environment. She is the pivot around which the family revolves. Most of all, I acknowledge the role played by my father, Lt. Col. K. K. Puri in providing the most meaningful insights in the ‘utilization mode ‘ of the thesis from an altogether different perspective. He has taught me the love for learning. Finally I owe everything to my husband, Kiran Shetty who was a pillar of strength during these past two years. He gave me the encouragement and the freedom to dream. He funded all my ventures. All the effort and loneliness was worth it for I knew that he was waiting at the end of the rainbow. iv TABLE OF CONTENTS I. LIST OF FIGURES TABLES AND FLOWCHARTS ix IL LIST OF FIGURES xi A. INTRODUCTION 1 B. STUDY OF LIGHT AND LIGHTING DESIGN 3 1. The Eye 4 2. Light and Color 8 3. Human Vision and Perception 12 3.1 Brightness 12 3.2 Contrast 12 3.3 Glare 12 3.4 Size 14 3.5 Speed 14 4. Natural Light 15 4.1 Introduction 15 4.2 Controlling Daylight 16 5. Artificial Light and its Sources 18 5.1 Artificial Light 18 5.2 Artificial Light Sources 18 5.2.1 Incandescent Lamps 19 5.2.2 Fluorescent Lamps 20 5.2.3 High Density Discharge Lamps 22 5.2.4 Other Light Sources 25 5.3 Color Appearance of light 26 5.3.1 Color Temperature 26 5.3.2 Color Rendering Index 28 6. Lighting Controls 29 V 7. Lighting systems 31 7.1 Lighting Needs 31 7.2 Lighting for Special Groups 31 7.2 Types of Lighting Systems 31 7.3.1 General/Ambient Lighting 32 7.3.2 Task Lighting 33 7.3.3 Accent/Special Emphasis Lighting 33 8. Luminaires 35 8.1 Recessed 35 8.2 Ceiling Mounted 36 8.3 Wall Mounted 36 8.4 Suspended 36 8.5 Track mounted 36 8.6 Specially Integrated System 36 8.7 Portable Lighting Fixtures 3 7 9. Illumination Measurements 38 9.1 Illumination Measurements 38 9.2 Calculations 38 9.2.1 Zonal Cavity Method 39 9.2.2 Point by Point Method 40 B. STUDY OF CODES 41 10. An Analysis of the Californian Lighting Code 42 10.1 Introduction 42 10.2 Controls and Switching Requirements 42 10.2.1 Independent Switching 43 10.2.2 Bi-level Switching 44 10.2.3 Daylight Area Switching 45 10.2.4 Automatic Shut-off 47 10.2.5 Exterior Lights 48 10.3 Other Requirements 49 10.3.1 Tandem Wiring 49 10.3.2 Display Lighting 50 10.3.3 Certified Devices 50 10.3.4 Effective Use of Daylight Area 52 10.3.5 Effective Aperture 53 10.4 Lighting Compliance for Non-residential Buildings 54 10.4.1 Introduction 54 vi 10.4.2 The Prescriptive Approach 54 10.4.3 The Performance Approach 65 10.4.4 Lighting Trade-offs 67 10.4.5 Actual Lighting Power (Adjusted) 68 10.4.6 Automatic Lighting Control Credits 68 10.4.7 Track Lighting 70 11. A Review of the Existing Building Codes in India 71 11.1 Introduction 71 11.2 Problems Implementing the Development Controls 71 11.2.1 Impediments Inherent in the Controls 72 11.2.2 Impediments from Implementing Machinery 73 11.3 Towards a solution 76 C. THE PROPOSED INDIAN NATIONAL LIGHTING CODE 78 12. Foreword 79 13. General Aspects 81 13.1 Scope of Code 81 13.2 Lighting Vocabulary 81 14. The Physics of Lighting 91 14.1 General Principles 91 14.2 Color Appearance and Color Rendering of Light 91 14.3 Visual Environment 93 14.4 Design Process 96 15. Lamps and Control Devices 99 15.1 Types of Lamps 99 15.2 Control Devices for Lamps 105 15.3 Noise from Lighting Equipment 108 16. Luminaires 110 16.1 General Considerations 110 16.2 Classification of Luminaires 110 16.3 Luminaires for Special Environmental Conditions 112 17. Lighting Design and Criteria 114 17.1 Lighting Requirements for Various Types of Buildings 114 17.1.1 General Considerations 114 17.1.2 Industrial 116 v ii 17.1.3 Office 120 17.1.4 Selling and Display 126 17.1.5 Residential 129 17.1.6 Catering 132 17.1.7 Public Assembly and Entertainment 135 17.1.8 Indoor Sports 137 17.1.9 Educational 140 17.1.10 Library 142 17.1.11 Religious 144 17.1.12 Hospital and Health Care 145 17.1.13 Laboratories and Research Establishments 151 17.1.14 Mass Rapid Transit Stations 153 17.2 Special Lighting 154 17.2.1 Road Lighting 154 17.2.2 Outdoor sports Lighting 163 17.2.3 Security Lighting 168 17.2.4 Sign Lighting 172 18. Daylighting for Buildings 182 19. Economics and Maintenance 197 19.1 Economics 197 19.2 Maintenance for Lighting Systems 202 E. CONCLUSION 210 APPENDICES 212 Appendix A Some Recommended Illumination Levels 212 Appendix B Proposed Lighting Code Compliance Software for Commercial Buildings. 219 BIBLIOGRAPHY 230 v i i i 24 30 37 53 55 59 62 64 66 69 100 104 106 107 115 129 178 ix LIST OF TABLES AND FLOWCHARTS TABLES Types of High-Pressure Sodium Lamps and their characteristics. Types of Control Switches - their characteristics and uses. Types of Spatially Integrated Lighting Systems and their characteristics. Effective Aperture Table. Complete Building Method ~ Lighting Power Density Values. Area Category Method -- Lighting Power Density Values. Illuminance Category for Tasks. Typical Room Cavity Ratio Values with the task surface at desk height. Lighting Power Density Table. Power Savings Adjustments for Lighting Controls. Characteristics of Light Sources for General Lighting. Tubular Fluorescent Lamps . Color Appearance and Color Rendering. Ballast Losses in Tubular Fluorescent Tubes. Ballast Losses in Other Discharge Lamps. Recommended Range of Task Illuminances. Recommended Number of Socket Outlets for Lighting purposes in Private Residences. Recommended Minimum Illumination for Poster Panels, Bulletin Boards and other Advertising Signs. 178 179 180 203 204 206 212 56 58 61 199 X Relative Wattage of Colored and Inside frosted Incandescent Filament Lamps required to give signs of various colors of approximately equal advertising value. Relative Brightness Factors. Suggested Incandescent Lamps for Sign and Display Lighting. Fixture Categories for Luminaire Dirt Depreciation. Luminaire Dirt Depreciation Factors. Room Surface Dirt Depreciation Factors. Some Recommended Illuminance Levels (Appendix A). FLOWCHARTS Lighting Compliance: Complete Building Method. Lighting Compliance: Area Category Method. Lighting Compliance: Tailored Method. Life Cycle Costs of a Lighting Installation. 5 6 7 9 10 11 13 15 19 20 21 22 27 32 33 38 44 44 44 46 xi LIST OF FIGURES How the human eye functions while viewing near and distant objects. Forveal vision of the eye. Illumination levels for the aging and ‘presbyopia’ effect. The Electromagnetic Spectrum. Light source emits wavelength which object or surface reflects. Reflection of light by different sources. Direct and reflected glare. The Sun’s Orbit. Basic elements of Incandescent lamps. Different shapes of Incandescent Lamps. Basic elements of Fluorescent Lamps. Different shapes of Fluorescent Lamps. Color temperatures for electric light sources and daylight. General lighting. Task-ambient lighting. A footcandle = 1 meter / sq ft. Bi-level Switching — Alternate lamps Bi-level Switching — Dimmer (All Lamps). Bi-level Switching — Outside/Inside Lamps. Daylight Area Switching — 3-Switch position. 46 46 49 51 52 52 161 162 163 165 171 172 175 184 185 185 186 190 191 xii Daylight Area Switching — 4-Switch position Daylight Area Switching — Dimmer switch option. Tandem Wiring. Window daylit area. Skylight Daylit Area. Daylit Area Reduction. Cut-off Luminaires for Roaway areas. Staggered and One-side-only mounting pole configurations for Roadway lighting. Sports Lighting Application Angles. Avoiding Glare for Sports Lighting Applications. Protective Security Lighting — Shadow System. Protective Security Lighting -- Silhouette System. Sign Lighting: Set back distances. Section of Light Shelf. Direct beam penetration of daylight with no Fenestration Control. Vegetation and Lattice filters for Daylight. Increased Perimeter Exposure Overhang for controlling Daylight. Sidelighting Rule of Thumb for Daylighting. A. INTRODUCTION Developing countries face a major problem in converting their limited natural resources into meaningful applications. When ‘limited resources’ are juxtaposed with ‘rising expectations’, the resultant potent combination can lead to political instability and social disintegration. As a student of Building Sciences, I was faced with the dilemma of how best to fuse professional achievement with national and personal goals. At this juncture, the role played by my professors cannot be understated. They helped me identify the ideal mix. By the beginning of the 21st century, India will have a population of nearly 1 billion and an Energy demand of over 3,00,000 MW (nearly three times the present capacity). The available power is presently concentrated in ‘small islands of light’ in an ‘ocean of darkness’. Energy is drawn from hydel, thermal and nuclear resources. It is estimated that the existing coal resources of India will last for not more than a hundred years; nuclear power contributes ten percent of the total power generated, but after the Chernobyl incident and the near miss of the Three Mile Island, PA , the erection of nuclear plants has been given the ‘go slow’ signal. Hydel power generation is a costly proposition. It is estimated that more than 25 percent of the electricity produced in India is wasted due to faulty transmission, power theft by industrial and agricultural users and due to faulty or non-existent Lighting Codes. l I decided to contribute my bit to the national effort by formulating a Lighting Code for India. I am confident that the same Code can be made applicable to other developing countries as well. Methodology Research was conducted by reference to primary and secondary sources and follows the undermentioned sequence: A. Study of Light and Lighting Design. B. Study of Codes: Study of the Indian scenario and the need for the evolvement of a Lighting Code of India using the Californian Lighting Code as a benchmark. C. The Proposed Indian National Lighting Code: The Proposal addresses four questions: 1. When standards should apply? 2. What standards are required? 3. How to design and meet Standards? 4. How to start conservation? The enunciation of a Lighting Code for India is only a small step for the adoption of Standards. The acceptance of this proposal must be preceded by a public awareness and education that self discipline like eternal vigilance is the price of Liberty. It is expected that acceptance of this Code will result in power saving and consequently ensure industrial safety, lower costs of inputs and increased financial returns. 2 B. STUDY OF LIGHT AND LIGHTING DESIGN 1. THE EYE To understand the relationship between light and how well we are able to see it, it is necessary to know how the eye works. The eye can be structurally compared to the parts of a camera. A camera has components that function very much like the lens, iris, retina and many other parts of the eye. Both the camera and the eye have a lens which focuses images on the retina. The retina is the light sensitive plane at the back of the eye which relays images to the brain through a network of nerves. In the camera, this light sensitive plane is the film. The iris, or colored area of the eye controls the amount of light which passes through the lens by adjusting the opening called the pupil. The eyelid also, to a lesser degree, controls the amount of light that reaches the retina. Correspondingly, the camera has the iris diaphragm and the shutter. The ability of the eye to focus on images at varying distances is called accommodation, and is a result of changing the curvature or convexity of the lens. This process is stimulated by any shifting of visual attention resulting in blurred vision, which in turn sends a signal to the brain to contract or relax the ciliary muscle which controls the lens. By contracting this muscle the lens is allowed to assume its natural convex or spherical shape which is necessary for viewing close objects or tasks. If the lens were too flat, the projected image would be focused behind the plane of the retina and would appear blurred. The lens at its flattest - that is, when the ciliary muscle is relaxed - is focused on infinity or as far as the eye can see. 4 Lens rounded O crl iaru muscle ( M to change shap vj> during accommoi > Iris contracted O S I Cto increase z _sharpness of im ■ I E H ei;d V I > c CO -4- w b c r a m Pupil ------- Iris opened Lens -flattened strain as cilia muscle relaxed' Blind spot (no i to light as no i Choroid \ \ (pulled forwardv during near ' vision") -Fovea (highest concentration of cones) Optic nerve Retina cones a t exit to optic nerve) Fig. 1. How the human eye functions while viewing near and distant objects. The eyes’ ability to adapt to changes in light level involves a two-part process in which both pupil and retina undergo physical changes. This process is called adaptation. When the level of brightness is low, then pupil of the eye dilates or widens, to allow more light to reach the retina, and conversely, contracts in bright light to limit the amount of light on the retina. This retina is made up of tiny photo receptors - rods and cones - which send visual messages through a network of nerves to the brain. The cones perceive color and are capable of transmitting very sharp detail to the brain. The rods perceive neither detail nor color, but are extremely sensitive to very low levels of light. 5 L in e o f sight I O * b e lo w h o rifc o n + a l if * ta n d in ^ , IS* if sitting' ) latent cf vertical peripheral vision * / v /is id l sunw nd of ----- foveal vision it within 30*c*ne ( where brightnee* ratios should not enceed 3 : 1) Cone o f fo v e a l v isio n (area of sharpest focus) Visual ta sk a re a Fig. 2. Foveal vision provides the best color response because o f the concentration o f cones in the fovea, the thinnest area o f the retina Whenever a change occurs in the level of brightness, a photochemical change or bleaching takes place in the rods and cones. The amount of time required to regenerate varies, but the adaptation process is considerably longer when the change is from light to dark. The adaptation from dark to light requires only two minutes to complete. This phenomenon can be experienced when we enter or leave a movie theater. The physiological condition that affects the aging eye (generally over the age of forty) is the loss of elasticity of the lens. This condition restricts the accommodation process of the eye and is referred to as presbyopia. One means of compensating for this inability to focus is to provide higher light levels for visual tasks. Higher light levels allow the iris (aperture) of the eye to narrow, which increases the visual depth of field. Thus, accommodation, or focusing of the lens, is less strenuous. The age of the potential users of any installation should be a major factor when determining appropriate light lines. 6 20 30 40 50 60 70 80 Fgt C i(ears) 1 0 20 30 40 50 60 Ag’ e CtjesrO Fig. 3. A s age increases, normal-sighted persons need a higher illumination level as show in the left graph. The graph on the right shows the 'presbyopia ’ effect. REFERENCES 1. Egan, M. D. Concepts in Architectural Lighting. New York: McGraw-Hill Book Company. 1983. 2. Mueller, C. G. and Reidolf, M. Light and Vision. New York: Time Life Books. 1966. 3. Weston, H. C Sight. Light and Work. London: H. K. Lewis. 1962. 7 2. LIGHT AND COLOR Light is a form of radiant energy that exists in the shape of repeating wave patterns emanating from a source in straight patterns and all directions. An example of this radiant energy is the sun and its projecting rays. Light is considered to be a radiant energy wave and a part of our larger wave spectrum referred to as the electromagnetic spectrum. The visible spectrum, which is responsible for color, is a very small part of the overall spectrum of radiant electromagnetic energy. The eye distinguishes different wavelengths of this radiant energy and interprets them in different colors. The longest wavelength in the visible spectrum is red, followed in descending order by orange, green, blue and violet, the shortest visible wavelength. Wavelengths are measured in nanometers, each one millionth of a millimeter and range from 380 to 760 nanometers. Wavelength shorter or longer than this range such as ultraviolet and infrared light do not stimulate the receptors in our eyes: hence, we cannot see them. In the 1600s Sir Isaac Newton (1642 - 1727) demonstrated that color is a natural part of sunlight through a prism of transparent material. He found that as the light emerged from the prism, it had dispersed, separating the individual wavelengths into different colors. Newton carried his experiment even a step further by utilizing a second prism to mix the waves back into sunlight. This verified that color is basically made up of light and that when "colored" lights are mixed, the result is white light. Color is not a physical part of objects we see, but rather is the effect of light waves bouncing off or passing through the objects. In fact, if there were no light, there would be no color. Therefore color and light are inseparable. We perceive light because of the way it strikes objects and by the way our brain translates the messages our eyes receive. Often factors that determine how we perceive the color of a given object are the light source under which it is examined, the material the object is made of and the physical condition of the viewer's eyes. Wavelength C n rfQ Electrical p o w e r R adio Teltvtaion Mlcro .uaves 31 OOmi I m i 100 ft I ft o.o\ ft o.ooo\ ft Infrared ( IR) Visible Spectrum Ultraviole-t CUV) X ' ratjs G am m a raijs IO nm I r\m C o sm ‘ i 6, r»«,| a 0.001 rv ft 0.00001 n m 1500/ / / 1 0 0 0 / ! ift/* ' I qU / / / 7 0 0 / / / / (kfOO J / fW l > / / / 5 0 0 r S Jhk. s s \ \ \ *\QQ \ 3 W s \ \ \ 300 \ 1 6 0 . ReJ Orange Yellow Green glue V iolet <5 i) Q _ v n « _ o g > l alight Eruthemal Clauses sunoum in Iwians) Germicidal L K ills bacteria, viruses, and funguses') ---- Fig. 4. The Electromagnetic Spectrum, which contains all visible colors, occurs at about 380 to 780 nm. When a light source emits energy in relatively small quantities over the entire visible spectrum, as in the case of the sun or a bright light bulb, the combination of the colored light will appear white to the human eye. However, if a light source emits 9 energy over only a small section of the spectrum, it will produce that corresponding colored light. Examples can be seen in our electric light sources such as the high intensity discharge mercury lamp that produces a blue-green light or the deep yellow low pressure sodium lamp commonly used on freeways. Indeed, color cannot exist without light, because colors are actually other names for various mixtures of radiant electromagnetic energy. The colors that we see in objects are the result of light waves that reach the eye after the object has selectively absorbed some of the wavelengths and either reflected or transmitted the others. In other words, the color, or pigmentation, of an object absorbs all colors of light except its own color which is either reflected or transmitted to the eye. For example, if white light falls on a green surface, that surface will absorb all the wavelengths except the green ones, which are reflected back to the eye, allowing us to perceive the color green. I Fig. 5. Light Source emits wavelengths which surface (or object) reflects. 10 The material or texture of an object will also influence how much light is absorbed, reflected or transmitted. When light falls on an unpolished surface, light waves are reflected in all directions because of an overall even surface. Smooth, shiny surfaces reflect more light, and dull or matte surfaces absorb more of the light waves, thus modifying the visual appearance. Fig. 6. Reflection o f light by different surfaces. REFERENCES 1. Birren, Faber. Light. Color and Environments. New York: Van Nostrand Reinhold. 1982. 2. Bouma, P. J. Physical Aspects o f Color. London: Philips Technical Library, MacMillan Publ. 1978. 3. Faulkner, W. Architecture and Color. New York: John Wiley and Sons. 1972. 4. Grosslight, Jane. Light. Englewood Cliffs, NJ: Prentice Hall. 1984. - a - 'v Diffuse ligfht t \ ■ / y* Specular reflec+i on Polished surface (w h e re * i a i r ) l i 3. HUMAN VISION AND PERCEPTION Certain conditions must be present for the sensation of sight to take place. Light and a reflecting surface is essential. 3.1 Brightness No matter how much light falls on a black surface (one that reflects no light) there can be no visibility because there is no brightness. If there is no light, the reflectance of the object does not matter. 3.2 Contrast Contrast refers to the variations between high and low areas of brightness. The eye can adapt very well to normal contrast. However, extreme contrast can cause a strain on the muscle of the eye which will slow the visual process particularly if these conditions persist. On the other hand a certain amount of contrast is essential if seeing is to be comfortable and effective. 3.3 Glare If the contrast relationship becomes too great, it will produce an effect called glare. Glare is defined by the IES as "the sensation produced by the illuminance within the visual field that are significantly greater than the luminance to which the eye is 12 adapted and which causes no annoyance, discomfort, or loss in visual performance and visibility." Glare can be categorized into two types. One is direct glare, which refers to excessive brightness coming directly from a light source or a bright exterior exposure such as a window. The second is reflected glare, which occurs when a light source produces reflection of high luminance from a polished or glossy primary task surface. Reflected glare can be controlled by reducing the specular quality of the task or by relocating the luminance out of the offending zone. Direct Glare ted Glare UtfM’ $©ur<*e in ^ttepende-d -ffuture Im ag e litf h t s o u rc e tT veH sL js e^'vcilfc1 1 prini an epcc\i\^r materials te-g-i roga2-ir\ea) Fig. 7 . Direct and Reflected Glare. 13 3.4 Size Another necessity for vision is size, not physical but angular size. Organism too small to be seen with unaided vision become perfectly obvious under a microscope. These organism haven't become larger but their visual angle has been increased by an instrument. 3.5 Speed Because they move so fast, bullets coming out of a gun remain invisible even if there is brightness and contrast. There would be no point in lighting the area between a marksman and the target in a shooting range because there is nothing to be seen out there. REFERENCES 1. Boyce, P. R. Human Factors in Lighting. New York: MacMillan Publ. 1981. 2. Cornsweet, T. N. Visual perception New York: Academic Press. 1970. 3. Illuminating Engineering Society. Evaluation o f Discomfort Glare — The IES Glare Index System for Artificial Lighting Systems. IES Technical Report No 10. New York: IESNA. 1967. 4. Hurvich, L. M. and Jameson, D. The Perception ofBrightness and Darkness. Boston. Allyn and Bacon. 1966. 14 4. NATURAL LIGHT 4.1 Introduction Our primary source of natural light is the sun. People derive great physical and psychological pleasure from sunlight, since its our principal source of Vitamin D and fiill-spectrum light. Sunlight contains all visible wavelengths of radiant energy plus invisible infrared and ultraviolet wavelengths. Some research has proposed that a wide variety of health problem are linked to the lack of fiill-spectrum light and the absence of ultraviolet light in some artificial light sources. O rbit of Sun W a r altitud*/ / N . bearing a n g li r axim uth angle1 ) •Horiion fstn rises and &ets at east-west axis during equinoxes) West Fig. 8. The sun ’ s orbit. There has been a renewed interest in harnessing natural light. Daylight is viewed as a free source of light, offsetting escalating energy costs and health concerns. Learning to control free light is important since it is generally accompanied by excessive heat and glare. Discomfort within an interior space can be caused by too much heat or glare due to excessive contrast. 15 4.2 Controlling Daylight In order to control daylight, it is first necessary to understand the pattern of the sun's movements which is related to the time of day and year and to the latitude of the observer. In the summer in northern latitudes, the sun comes up towards northeast and arcs high in the sky, setting in the northwest. Days are longer and there is a great amount of daylight available in the summer months than the winter. The winter sun rises south-southeast, is low in the sky and appears to set quickly in the south-southwest. By understanding these solar principles, a design can utilize maximum penetration of light and heat into the interior during the winter season and constrict it in the summer. The quality of daylight is also affected by its compass direction. North light is generally a cool and consistent light that casts few shadows, making it desirable for an artist's studio. East light is strong and bright in the morning but becomes less brilliant and more neutral as the day progresses. South light is generally the most favorable in terms of brightness, pleasantness and control. It is more consistent throughout the day but may need to be controlled during the summer months. West light is usually very strong in the late summer afternoon; from the exterior it can be controlled by plants or trellises and in the interior it can be moderated by window treatments or can be filtered by tinted glass. Careful planning and control of sunlight is the basis for the design for solar energy buildings that optimally capture or repel the sun's energy. 16 Another way to maximize daylight is to manipulate it to penetrate deeply into an interior space, which can be accomplished by various types and placements of windows and skylights. By using light colors as reflectors, such as putting a high reflectance, matte white finish on ceilings and walls, the window's light will be reflected and distributed more evenly and deeply into the interiors. REFERENCES 1. Evans, Benjamin H. Daylight in Architecture. New York: McGraw-Hill Book Company. 1981. 2. Kaufman, John E. ed. Illuminating Engineering Society Handbook Re ference Volume 1. New York: Illuminating Engineering Society of North America. 1984. 3. Knowles, Ralph L. Sun Rhythm Form. Cambridge, Massachusetts: The MIT Press. 1981. 4. Lynes, J. A. Principles o f Natural Lighting. London: Elsevier Publ. Ltd. 1968. 17 5. ARTIFICIAL LIGHT AND ITS SOURCES 5.1 Artificial Light Artificial light is generally associated with electric light. When well planned, artificial illumination enables us to see at night, helps prevents accidents, and contributes to the overall ambience of an interior space. Artificial light is extremely important to the interior designers, since it affects the brightness, placement, color and quantity and quality of light in an interior environment. Varying the light can change the mood of a space from intimate to formal, as well as visually expand or shrink a space. Objects or areas within an interior can be highlighted or de-emphasized with the placement and quantity of light. When lighting is designed in relation to the architecture, activities and furnishings and people in a space, it can become more dynamic. Techniques such as dimming and increasing light, using floodlights and colored lights, and providing differing degrees of sharpness and diffusion to focus attention where it is needed create exciting effects. These techniques can also be used within many other type of interior environments. 5.2 Artificial Light Sources There are two main sources of electric light: incandescent lamps and electric or gaseous discharge lamps. Lamp is the correct term for what is commonly called the light bulb. The bulb is actual housing or enclosure of the filament and gases. Lamps come in a wide variety of types, sizes, shapes and colors. They are designs for an equally wide variety of purposes and effects. To select a correct lamp for a given 18 situation some factors must be considered like energy consumption, efficiency, length of life/ hours expected, quantity of light produced and qualitative factors such as color and brightness. Functional, decorative or psychological effects must also be considered. 5.2.1 Incandescent Lamps: The incandescent lamp produces light by passing an electric current through a filament which acts as a resistor and heats to the point of incandescence thus producing light. One of the major advantages of the incandescent lamp is the color of the light source. Most people have come to accept incandescent lighting as a standard for color rendition, to which all other light sources are compared. Filament Cusualli) tungstt,t\ wire") Argon and nitrcgen or krupton (or vacuum fo r low-u»attagB lamps) — Support wire* — Bulb (e^., clear, inside frosted ,or white finish) — torrent and lead * in u)lres ( to connect filament to base) — Mica or ceramic disc (.to deflect hot gases auau fron* the bate of a high-wattage lamp) — Fu«e C to p r o t e c t lam p a n d c irc u it bu |»|o«Jing if filament arcs) — Base CScrew base shown; not used where enact placement of filamen. is required for reflector or lens Fig. 9. Basic elements o f an Incandescent Lamp. Bulb Diameter Due to its inefficiencies, compared to some of the more recently developed sources such as fluorescent or high density discharge sources, the incandescent lamps no longer serves as a source of general illumination. However, the filament is quite small and can easily be controlled with the use of reflectors as in a reflectorized lamp 19 such as a PAR lamp. In this form, it can be used quite successfully as accent lighting or to highlight specific activities within the office. The major disadvantage of the incandescent lamp is that it typically has a relatively short life (750 to 2000 hours) and is generally inefficient as far as light output compared to wattage consumed. 5 F C Straight Flame , Conical CB-shape is similar) Q Globe R Reflector T A Tubular stan dard (or ArbitrarLj') PAR. Parabolic* Aluminiied Ref leofor E R Ell ipso id a R&f lector Fig. 10. Different shapes o f Incandescent Lamps. 5.2.2 Fluorescent Lamps The fluorescent lamp consists of a gas envelope that contains mercury at low pressure and a small amount of inert gas (argon). The inner walls of the bulb are coated with energy activated powders called phosphors. When voltage is applied, an arc is produced by the current flowing between two electrodes through the mercury. This 20 generates a small amount of visible light, but mainly produces invisible ultraviolet radiation which activates the phosphors, thus producing visible light. Cte transform U V radiation intc vifcible light; color d«per\d& on phosphors) Phosphor coaling on insidft of bulb injg on k a th o d e a t both lamp ends em it electrons') c \ e Bipin base Cto provide electrical connection* arvd m echanical Support for preheat o r r a p id - s ta rt Idm pO Low - p ressu re mencurij v ap o r e ra d ia tio n at "25^nm ) and in e rt g a s Ce g., argon, neon. K rypton) F/g. 77. Basic elements o f a Fluorescent Lamp. When the fluorescent lamp was introduced, the color of light emitted was not satisfactory. Due to the advances in phosphor coatings, its color rendition has been greatly improved and is now generally accepted as a color corrected light. A large variety of lamps allow the designer freedom of choice in color selection. However, lamps of different colors should not be used at the same installation. The fluorescent lamp, in comparison to the incandescent lamps, has a considerably longer lamp life (18000 - 20000 hours) and is more efficient as far as light output in relation to wattage consumed. What is generally considered a disadvantage is that fluorescent lamps, like most electric discharge lamps, must be used in conjunction with an auxiliary apparatus called a ballast. 21 Straight U -shaped Circular Tabular-dented C e.^., 8 f+ la m p hat cvft of xijaa«g'm jf arO T 7 /#. 72. Different shapes o f Fluorescent lamps. The ballast starts the lamp and limits the passing current to the value for which the lamp is designed. The disadvantages are that the ballast increases power consumption, which increases the heat build up in the fixture. The ballast also increases the size of the fixture and the cost. Noise may also be contributed by the ballast. Developments in lamp and ballast technology have resulted in more efficient choices. Lamps with greater light output (lumens/watt) can be coupled with high efficiency ballasts to reduce energy requirements. New developments in solid state ballasts have improved their efficiency as well as allowed some dimming capability and moved the sound frequencies generated to level above human hearing. 5.2.3 High Density Discharge (HID) Lamps HID lamps have grown in popularity due to their efficiency. However, they are usually found in indirect lighting applications rather than ceiling mounted downlight 22 systems. HID sources include mercury vapor metal halide and high pressure sodium lamps. The following are all HID lamps: 5.2.3.1 Mercury Vapor The mercury lamp is constructed of two glass envelopes. The inner envelope contains mercury vapor and a small amount of argon under pressure. The outer envelope acts as a shield from drafts and temperature changes and produces a surface for the phosphor coatings that help correct the source color. An electric current striking an arc creates heat which causes the mercury to vaporize, producing ultraviolet energy which then activates the phosphors. The lamp does not reach its full light output until the mercury has entirely evaporated. The slow start ranging from 5-14 minutes should be a major consideration in its application. 5.2.3.2 Metal Halide Lamps The metal halide lamp is a modification of the mercury vapor lamp. In addition to mercury, the arc tube contains metallic vapors which are responsible for its improved color rendition. Phosphor coated or color corrected lamps are available for areas requiring more improved color qualities. The metal halide lamp has considerably higher initial light output than the mercury lamp, but light output decreases at a faster rate and the lamp generally has a shorter life. Due to heat problems, the lamp also has restriction on the positions in which it can be used. Because of the small size of the metal halide lamp, and the fact that it is not always a phosphored lamp, precise optical control is more easily attained with the use of properly designed reflector systems. 23 5.2.3.3 High Pressure Sodium (HPS) HPS is also constructed of two glass envelopes, but light is produced by electricity passing through sodium vapor. Its very thin arc tube provides excellent optical control conditions. This is the most efficient of the HID sources. However its severely distorted color output limits its use. This color distortion can be overcome by the use of high pressure sodium in conjunction with other sources such as daylight and/or metal halide. The different types of High pressure sodium lamps are listed in Table 1. TABLE 1 Types of High-pressure Sodium Lamps and their Characteristics. Type W attage Efficiency lumens/watt Characteristics Mercury Vapor 40-1000 22-60 Blue green color rendition; deluxe white and warm deluxe white have improved color but still low in red rendition. Mainly used for exterior landscape lighting. Metal Halide 30-1500 100 Well balanced color rending properties. Higher light output and smaller size for precise light control. Used in office, retail and public interiors. High Pressure Sodium 50-1000 50-127 Most efficient HID lamp: provides excellent optical control due to linear shape. Light output is yellow tinted, thus affecting color rendition qualities. 24 5.2.4 Other Light Sources Other light sources have been developed for specialty and decorative lighting needs. These types permit to create a variety of special effects and a type of light not possible with the above mentioned types. 5.2.4.1 Neon Neon lights are another type of low pressure electric discharge lamp used primarily for display or decorative purposes. They have a very long life, are available in a full range of colors, can be bent to any shape, and can be mounted on walls or ceilings. Neon lamps are low energy consumers and can be dimmed and flashed but are fragile, requiring a special ballast for starting at high voltage and for staying lit. The ballast for a neon lamp is about 1.5 to 2.0 times bigger than that of a fluorescent and can be noisy unless mounted in a remote or concealed area. Neon lamps have endless potential for creating interior lighting, since they can be shaped to any contour. They can be used for special visual effects, decoration, highlighting and dramatization. 5.2.4.2 Cold Cathode They operate like instant start fluorescents but are similar to neon in that the tube can be bent to conform to any shape. Cold cathode lamps have a veiy long life and are generally useful where long continuous light is required, such as in built-in structural lighting. 25 5.2.4.3 Fiber Optics Fiber Optics are thin, cylindrical glass or plastic fibers that do not produce light by themselves. However, when a ray of light is passed through one end and emerges from the other in a process called total internal reflection, intense pinpoints of light are produced. Fiber optics are used to create decorative effects, such as starlight patterns in the ceiling, under the treads of a staircase or interlaced with plants. Because the light from fiber optics diffuses rapidly, once it has left the fiber, this type of lighting has been used in decorative, rather than functional ways. 5.2.4.4 Laser Light Laser means light amplification by stimulated emission of radiation. A laser is a device containing a crystal, gas or other substance in which the atoms are stimulated by focused light waves, amplified and concentrated, then emitted in a narrow, very intense beam. Laser light offers the opportunity to produce and direct a cast of light beam, creating physical planes or sheets of light in mid air. Laser light opens up a whole new field of visual experience and communications. 5.3 Color Appearance of Light The perceived color of materials and finishes within an exterior space varies depending on the type of light source used. The best choice of lighting is one with good color rendering properties and a moderate color temperature. 26 The measures of light source color have been established and are commonly used to describe color characteristics of lamps. These are: 5.3.1 Color Temperature 5.3.2 Color Rendering Index (CRI) 5.3.1 Color temperature measured in Kelvin degrees, describes the actual appearance of the light produced in terms of its visual warmth or coolness. Kelvin range from 9000K (which appears blue) down to 1500K (which appears as orange red). Color temperature is related to the tasks that will be performed in an interior. o c « 2 • _Q £ Q i * 1 1 1 — ^rtific-ial U f e W t Sources Color Temperature (iO Pa^l^ht O ne blue and one ddijlight %&ooo l^poo £*tremelu blue, clear Northwestern ekj One blue -and T iuo daylight - 1,0,000 \ 6,000 11,000 <6000 3 dlue sKu| with 3r - Thin clouds Daij light la< np i Uniform overcast s|u{ Cool luhiteCor ( 6 000 <6000 cool ujhite delune) |‘ / 2.h\ after damn .* > £ c 5 Daum or dusK in ^ Warm white» . 4 ooo -2,000 •%ooo 1 ooo Incandescent or H P 5 Candle flame Fig 13. Color Temperatures fo r electric light sources and daylight. 27 5.3.2 The color rendering index is a measure of how well colored objects appear under different light sources. The CRI is a number (from 0 to 100) representing how color samples appear when compared to a reference light source with the same color temperature. Generally the higher the CRI number, the better the color appearance. REFERENCES 1. Cayless, M. A. and Marsden, A. M. Lamps and Lighting. Baltimore: Edward Arnold. 1983. 2. Egan, M. D. Concepts in Architectural Lighting. New York: McGraw-Hill Book Company. 1983. 3. McCrowan, T. K. “ A ll about Sources” . Progressive Architecture. Sept. 1993. 28 6. LIGHTING CONTROLS The use of controls can play a major role in energy conservation. The need for control is dictated by rising electrical costs due to depleting natural resources used in producing electrical energy. Artificial illumination can be manually controlled by the user or by automatic systems. In the latter, the illumination level of a task will automatically be adjusted to accommodate light depreciation factors or the supplements of daylight. The use of manual control systems, where the occupant is responsible for energy conservation is not as effective as automatic systems, since slight variation in illumination levels are not easily detected. The most common method of switching control is the manually operated light switch; however other types such as the push button, slide plates, photocells, occupancy sensing systems and electronic control are available. Dimming an electric light source when other light is present is an excellent way to provide the required amount of light within a space without wasting energy. Good lighting control in residential applications requires every space or area to have a light switch adjacent to the door or access. Depending in the type of space or activities, more than one switch is sometimes required for lighting flexibility. For safety purposes stairs should have switches at the top and bottom and hallways should have them at both ends. The mounting height of switches should be no higher than 48 inches. However, for better access by the handicapped, some codes recommend that switches should be mounted 30-40 inches above floor. 29 TABLE2 Types of Control Switches, their Characteristics and Uses Type of Switch Characteristics Common Uses Toggle/Snap Most common and least expensive. Connection made by snapping one one metal contact to another. Typical for most residential and commercial applications. Momentary Contact Switch operates or closes a circuit. Actually a push button switch. Often used as elevator call button. Generally accompanied with an integral light to indicate if circuit is on or off Dimmer Allow variable voltage to a to a lamp circuit, producing dimming effect. Used in most residential and commercial applications to dim light fixtures. Electronic Variety of switching methods triggered by heat, sound, touch, motion, radio waves and light. Used for security installations, switching for daylight/night time phases. Mercury Vial of liquid mercury is tilted and conducts electricity between contacts. Used in thermostat controls and as silent action switches. REFERENCES 1. McGraw Edison Company, Halo Lighting Division. The Language o f Lighting; Illinois: McGraw Edison. 1983. 30 7. LIGHTING SYSTEMS 7.1 Lighting Needs As human vision differs widely, a designer must analyze user needs according to age, experience and perception in terms of brightness, color and satisfaction. 7.2 Lighting for special groups As a person's eyes age, the individual's color vision, depth perception, visual acuity, peripheral vision, glare and flicker tolerance, and size of the visual field all change. When these changes occur, generally more light is needed for performing detailed visual tasks. Designers can help compensate for visual loss through creative and flexible lighting design such as adding special accent lighting to keyholes, public phones, switches and electrical outlets and by providing dimmers so individuals can adjust levels of light for their particular situation. Aging eyes cannot distinguish colors very well. The sensitivity to contrast declines and the ability to discern simultaneous contrast which is important in distinguishing color vibrancy is decreased. The elderly need highly saturated primary hues in contexts of high contrast. Also blues should be used sparingly because the ability to see blue and mixtures containing it is reduced with aging. 7.3 Types of Lighting Systems Lighting for visual activities or functions can be categorized as: 31 7.3.1 General/Ambient Lighting General/Ambient lighting brightens an entire space fairly uniformly. It provides a comfortable level of light, allowing people to find their way around, locate objects, etc. General or Ambient lighting can be produced by either a direct or indirect way: 7.3.1.1 Direct Method: Direct lighting means that light shines directly from the luminaire downward, generally from recessed, ceiling mounted or suspended fixtures. 7.3.1.2 Indirect Method: Indirect light shines against a surface, usually the ceiling and is reflected down to the space indirectly. It produces a softer effect than direct light and can be provided by suspended fixtures, wall sconces or built in lighting systems. General lighting can also be achieved by perimeter lighting that outlines the perimeter of a space. Lominairt (uiith fluore*c*rt+ lamps') Illumination gradient C d ro p s off near mails) Desk Fig. 14. General Lighting provides uniform illumination over the entire area o f the room, allowing flexibility. 32 7.3.2 Task Lighting Task lighting is direct functional lighting that provides illumination for specific visual tasks or activities. Typical tasks that require special lighting considerations include reading, writing, drafting, preparing food, eating and grooming. Direct lighting is the best type of task lighting. However, proper placement is also very important so as to avoid the generation of shadow and glare. Task lighting can be placed high or low and can be mounted or portable, such as on floor, desk, or table lamps. Fig. 15. Task-Ambient Lighting provides high illumination on the ‘ task ’ supplemented by ‘ ambient ’ illumination, usually from indirect light sources. 7.3.3 Accent or Special Emphasis Lighting Accent lighting is used to highlight art objects or special structured features within a space. Low voltage halogen lamps or other types that produce narrow beam spreads are a good choice for these effects. Special effects can also be created by fixtures that break light into many small bright spots. Accent lighting can take the form of a candle on restaurant table. Valance (provide* — lig h t on ah e lf and on ceiling’) Display ahfelf------- ^S u ep en d ed luminaire t-Por general lighting) — Illumination gradient (built- up bij general lighting') — Illumination gradient (built- up near uuatl bq local light) 33 Special emphasis lighting can be used to create interesting pools of light within a space and attract people to certain areas or to break up a large room into smaller islands of space. It can also be used to direct traffic or to set a mood or illusion. REFERENCES 1. Boer, J. B. and Fischer, D. Interior Lighting. Antwerp: Philips Technical Library, MacMillan Publ. 1978. 2. Helms, Ronald N. and McGovern, John M. Lighting Design Handbook 4681, Gordon Drive, Boulder, CO 80303. 1978. 3. Pritchard, D. C. Lighting. London: Longman Group Ltd. 1978. 34 8. LUMINAIRES The lighting fixture, called a luminaire is the housing for the lamp and is an integral part of a buildings electrical system, transforming energy into usable light. Luminaires are available in a variety of shapes and sizes that can determine the shapes and direction of the light beams. The form of the light beam can be generally classified as point, linear and volumetric sources. Point sources are used to give focus to a space by providing areas of brightness. They are also used to highlight an area or object of interest and can be arranged to create a rhythm or sparkle. Linear sources can be used to emphasize contours of a space, outline an area or provide direction. If linear sources are placed parallel to one another, they create a plane of illumination. Volumetric sources are diffused point sources that have been expanded by the use of translucent materials to create illumination patterns in the form of spheres, globes or other three dimensional forms. Five common types of mounting methods for luminaires determine the direction of light beams: 8.1 Recessed: Recessed luminaires provide direct light. They are mounted above the ceiling line, the bottom generally flush with the ceiling. They can also be used for small washing or accent light. 8.2 Ceiling Mounted: Ceiling mounted luminaires produce direct light and are very efficient, impeding neither light nor heat. This type is mounted directly on the ceiling, its light beam can be directed in a pattern. Installation and relamping are 35 generally easy and relatively less expensive. One disadvantage is that they can lower the effective height of ceiling. 8.3 Wall Mounted: Often called scones, provide, direct, indirect, diffused or direct/indirect light. Fixtures are mainly used for decorative purposes and tend to bring down the line of sight in a space with a very high ceiling. Some fixtures incorporate a reflector plate against a wall to reflect any lost light and to create a focal point of brightness. 8.4 Suspended: Suspended fixtures can produce direct, indirect, diffused or direct/indirect light beam. These fixtures are suspended below the ceiling and can be adjustable depending on ceiling light. One major advantage of these fixtures is their appearance, they become lighted ornaments when suspended in a interior space. 8.5 Track Mounted: Track mounted luminaires can provide direct, indirect or direct/indirect light. A track mounted system primarily consists of two parts, i.e., the track and the luminaire. This type of lighting system is very popular because it offers optimum flexibility in a vast range of lighting effects and can economical. The track can be surface mounted, recessed in ceiling or attached to a wall or can have pendant fixtures hanging from it. 8.6 Spatially Integrated Lighting System: They can be defined as lighting that is built in and integral to the construction of a building. This type is relatively invisible and can be controlled to enhance the brightness within a space without providing glare in the field of view. 36 TABLE 3 Types of Spatially Integrated Lighting Systems and their Characteristics. Type Characteristics a. Comice Light fixture is mounted behind opaque shield and attached to ceiling. Light washes down the wall. b. Cove Light fixture mounted behind opaque shield attached to wall and near ceiling. Light washes up and deflects off the ceiling c. Valence d. Wall Bracket Light fixture with opaque shield mounted above drapes. Light washes drapes and sometimes upwards. Similar to Valence but not above windows or drapes; can be mounted high or low on wall; can shine up, down or both. e. Soffit Light fixture built into soffit, i.e. above counters in a kitchen Light is directed downward. f. Specialty Light fixture is mounted in a variety of specialized locations such as at stairs, handrails, inset into floor, etc. 8.7 Portable Lighting Fixtures To provide working light close to the task. REFERENCES 1. Bean, A. R. and Sunors, R. H. Lighting Fittings. Performance and Design. Oxford: Permagon. 1968. 2. Nuckolls, James L. Furniture Integrated Lighting. Michigan: The Shaw Wallace Company. 1969. 37 9. ILLUMINATION MEASUREMENTS AND CALCULATIONS 9.1 Illumination Measurements A quantity of light is measured in foot-candles which is defined by the IES as "the unit of illumination when the foot is taken as a unit of length". It is the illumination on a surface of one foot square in an area on which there is a uniform distributed flux of one lumen or the illumination produced on a surface all points of which are at a distance of one foot from a directionally uniform point source of one candela. The definition of foot-candle fc = 1 meter/sq.ft., is the basis of all lighting calculations. Spherical surface ( I ft* area a t illumination level of I f O * Ug'ht source------ of I C3r\dlepoiutr C P Cor I candela ,cd; Fig. 16. A foot-candle is the quantity o f light on one square fo o t o f surface area one fo o t away from the light source. In the metric system, a lux is the quantity o f light on one square meter o f surface area one meter away from the light source. 9.2 Calculations In designing a lighting layout, we must be able to calculate the quantity of illumination for each particular space. This may be done by manual methods using the m me Spherical surface C I area at illumination level of I lux) 38 Zonal Cavity or the Point by Point Methods or by any number of computerized calculation methods. Methods for Calculating Illumination 9.2.1 Zonal Cavity Calculation Method This type of calculation is used primarily to determine foot-candle levels in large areas with an equally spaced grid of fixtures throughout and will compute an average foot-candle level for the space. This method is applicable only to empty rectangular spaces. It does not account for furniture, modular systems, screens and partitions. Using standard methods, it does not account for non-uniform surface reflectances. One of the keys to the calculation is the Coefficient of Utilization (CU) which is an index of how well the fixture can be expected to perform within a particular space. The CU value varies with the size and reflectance values of the room and can be obtained from manufacturers' testing data. The Light Loss Factor (LLF) is a percentage of the light still available from a system after a given period of time before lamp replacement and luminaire cleaning. The LLF is a combination of Lamp Lumen Distribution (LLD) which accounts for loss of efficiency with the age of the lamp and Luminaire Dirt Depreciation (LDD) as loss of efficiency due to dirt accumulation on the fixture. Since each type of luminaire has its own characteristics for dirt depreciation, it is necessary to check manufacturers' test data for recommendations. 39 The computation uses the following equation: (No of luminaires)x(lumens per luminaire)x(CU)x(LLF) Average fc = --------------------------------------------------------------------- Area in square feet 9.2.2 Point by Point Method This is a more involved method of calculating illumination which can be used for non-uniform layouts or task-oriented lighting. It uses the following equation: Candlepower x Cosine of Angle of Incidence Illumination = --------------------------------------------------------- Square of the Distance Candlepower is a measurement of light emitted from the luminaire at a particular angle. This information can be obtained from the manufacturers' test data. With this method of calculation, all contributing luminaires must be added together to find the total foot-candles on a task. This method is more accurate than the previous one. However it does not include illumination reflected from the surfaces within the room. By point by point calculation, the distance of the source must be at least five times the maximum luminous dimension away to obtain accurate results. Interreflected contributions of light from each surface within the room can also be calculated using point by point method, although it is a long process. REFERENCES 1. Kaufman, John E. ed. Lighting Handbook. New York. IESNA. 1981. 2. Keitz, H. A. Lighting Calculations and Measurements. London: MacMillan Publ. 1971. 40 STUDY OF CODES 10. AN ANALYSIS OF THE CALIFORNIA LIGHTING CODE 10.1 Introduction The California Energy Commission establishes lighting standards for both residential and non-residential buildings. The Standards encourage efficient use of lighting in buildings by: * Limiting the maximum power allocated for lighting i.e. setting a Power Budget. * Requiring automatic lighting control devices. * Requiring manual switching or controls to allow turning off or dimming of lights. * Requiring Certified lighting products. * Providing for the use of daylighting. The energy used for buildings must not exceed allowed lighting power density requirements, expressed in watts per square foot, and lighting systems must meet the mandatory measures required by the energy efficient standards. These mandatory measures have proven to be cost effective over a wide range of building and occupancy types. The lighting mandatory measures require design provisions for switching (manual and automatic) of lighting systems that permit efficient operation of the system. 10.2 Controls and Switching Requirements All lighting systems must have switches or controls that allow lights to be turned off when they are not needed. 42 10.2.1 Independent Switching Independent Lighting controls are required for each area enclosed by ceiling- height partitions. These controls can be any of the following: * A switch located so that the person using the device can see the lights or area controlled by the switch. * A switch with indication of whether the lights are "on" or "off1 when viewing that area from the switch is not possible. * An occupant sensing device. Exceptions to this mandatory measure are: * Lighting in areas within a building that must be continuously illuminated for reasons of building security or emergency egress are exempt from the switching requirements for a maximum of one-half watt per square foot. These lights must be designated as security or emergency egress areas on the plans, and the lights must be controlled by switches accessible only to authorized personnel. * Switches for lights serving public areas such as building lobbies or retail stores may be located in areas accessible only to authorized personnel. Individual switches that operate in conjunction with any other lighting device must be able to. * override the action of the other control device * automatically reset the mode of any automatic system to normal operation without further action. 43 10.2.2 Bi-level Switching: Lighting in buildings must be switched so that the connected lighting load of the switched space may be reduced by at least 50 percent in a reasonably uniform illumination pattern. The bi-level switching requirement may be met by: a. Switching the output of every other luminaire in a row or every other row of luminaires (see Figure 17). b. Using dimming controls on all lamps or luminaires (see Figure 18). c. Separately switching half of the lamps in each luminaire, or two lamps in three-lamp luminaires (see Figure 19). d. Designing an efficient lighting system that uses less than 1.2 watts per square foot. e. Providing separate switching for each luminaire. Fig. 17. Fig. 18. Fig. 19. Outside lamps on 'A ’ Alternate Lamps Dimmer (All Lamps) Inner Lamps on ‘ B ’ Bi-level switching is not required if: * The area has only one luminaire. * The area is less than 100 square feet. 44 * The necessary lighting power density is less than 1.2 watts per square foot. * An occupancy sensing device controls the area. * The area is a corridor. * An automatic time switch control device with a timed manual override switch serves only that area. 10.2.3 Daylight Area Switching The standards encourage turning off lights in areas where natural light from windows and skylights provide sufficient lighting. Daylit areas must be switched so that these areas can be controlled separately from the non-daylit areas. It is acceptable to achieve control of the daylit area by shutting off at least 50 percent of the lamps within the daylit area. This must be done by a control dedicated to serving only luminaires in the daylit area. If there are separate daylit areas for windows and skylights, they must be controlled separately. ( Refer to "Effective use of daylit area ") The daylit area switching area requirements are in addition to the bi-level switching requirements. The daylit switching requirements may be met by one of the following: * Switching at least 50 percent of the lamps in the daylit area separately from the rest of the lamps in the enclosed area (see Figure 20). * Using bi-level switching in the daylit area, separate from the non-daylit area (see Figure 21). * Using dimming controls on all lamps in the daylit area (see Figure 22). 45 Fig. 20. 3- Switch Option 1 5 f t 1 5 f t Fig.21. 4- Switch Option © f. 1 5 f t Fig. 22. Dimmer Switch Option 46 Daylit switching is not required if the enclosed area containing the daylit area is less than 250 square feet or if effective use of daylighting is not feasible for one of the following reasons: * Windows or skylights are so obstructed by adjacent structures, trees, or other natural objects that usable daylight is not available to the space. * The size of the glass and/or the transmission properties of the glass prevent usable daylight from entering the area.( Refer to "Effective aperture") 10.2.4 Automatic shut-off An effective way to control lighting energy is to automatically turn off all the lights in the building during non-business hours. The Standards require all buildings or separately metered space greater than 5,000 square feet of conditioned space to have a certified automatic shut-off control. Additionally, if the building has more than one floor, each floor shall have all the lights on the floor controlled by a separate automatic control device or control point if a multiple point control system. All interior lighting systems must have a separate automatic shut-off control incorporating an override switching device. The control can be an automatic shut-off system or an occupancy sensor. Areas exempt from automatic shut-off include: * Buildings or separately metered spaces less than 5,000 square feet. * Areas that must be continuously lit or require manual operation of the lighting system. 47 * Continuously lit security or emergency egress lighting not exceeding one-half watt per square controlled by switches accessible only to authorized personnel.(The security or egress area must be documented on the plans.) * Corridors, guest rooms an lodging quarters of high rise residential buildings, hotels and motels. The standards provide for the manual override of the automatic shut-off controls. The override switching device shall: * Control an area not exceeding 5,000 square feet on a single floor. * Be readily accessible. * Allow the operator to see the lights or area controlled, or be enunciated (indicate whether lights in the area are "on" or "off'). * Be limited to no more than a two-hour override. 10.2.5 Exterior Lights Automatic controls are required for all exterior lights served from a panel located within the building. The control may be a directional photocell, an astronomical time switch, or a building automation system with astronomical time switch capabilities that automatically turns off exterior lighting when daylight is available. Lights in parking garages, tunnels and other large covered areas that require illumination during daylight hours are exempt from this requirement. 48 10.3 Other requirements 10.3.1 Tandem Wiring Since two lamp ballasts are the most efficient conventional ballast type, the Standards require that pairs of the following types of one-lamp or three-lamp fluorescent fixtures are tandem wired: * Pendant or surface-mounted luminaires in continuous rows. * Recess-mounted luminaires located within 10 feet of each other and served by the same switch (see Figure 23). Ir'vxSUn+afcJ CV ( W o u r v f e d f - Fig. 2 3. Tandem Wiring Exemptions to the tandem wiring requirement include: * Luminaires that use electronic high frequency ballasts. * Luminaires not on the same control or not in the same area. 49 10.3.2 Display Lighting Display lighting must be separately switched on circuits that are 20 amps or less. Because most display lighting uses high lighting power density, the Standards require switching of display lighting separately from general lighting to allow for turning off display lighting when it is not needed. 10.3.3 Certified Devices The Energy Commission publishes directories of approved lighting-related devices based on manufacturers' documentation of Commission-required features. Designers should specify that these devices are Commission-approved. Two directories that are helpful in choosing lighting devices are the Directory of Certified Luminaires and Ballasts and the Directory of Automatic Lighting Control Devices. This Directory lists: * Automatic time switches * Occupant-sensing devices * Automatic daylighting controls * Lumen maintenance control devices * Interior photocell sensors 50 10.3.4 Effective Use of Daylight area Areas that can effectively use daylight as a lighting source require separate switching in the daylit area. The daylight source can either be windows or skylights. For areas adjacent to the windows, the daylight area is defined as an area the width of the window plus 2 feet on each side and extending into the room 15 feet, (see Figure 24) For areas beneath skylights, the daylit area is defined as the footprint of the skylight, plus the floor to ceiling height in each of the lateral and longitudinal dimensions. (see Figure 25) All daylit areas must be reduced if either of the following conditions exist (refer to Figure 26). tta4, IjgggS. — 1„------------ , 1 1 r^ f ir T f|£- Fig. 24. Window Daylit Area 51 c £>*VLtr A. E& EA. Fig. 25. Skylight Daylit Area s' 1 ^ - - »j * e - —H a W W PHPytfftWiBIWWIBJt “ O / * / ; « # X J : V / » j \ irr- ! , , ' f ' .. l— r S aL . 1 -»\ f r .1 Day 3 5 a y l« + r t r t t e X , Fig. 26. Daylit Area Reduction * A 60 inch or higher opaque partition, in which case the daylit area extends only to the partition. * An adjacent daylit area, in which case the daylit area extends only half the horizontal distance to the edge of the adjacent window or skylight. 52 10.3.5 Effective Aperture Effective aperture (EA) is a value calculated to determine if adequate daylight is available for lighting purposes. If the EA of a window is less than 0. l(or of a skylight is less than 0.1) then separate switching for the daylight area is not required. For each room the effective aperture for windows is the visible light transmittance (VLT) of the windows times the window wall ratio. The visible light transmittance is the amount of visible light that passes through the glazing. This value should be obtained from the glazing manufacturer. The window wall ratio is the total window area to gross exterior wall area in a room. TABLE 4 Effective Aperture table Is adequate daylight available? Windows (Vertical Glazing) Window wall ratio Glazing Type <0.10 VLT >0.60 NO VLT 35% to 0.59 NO VLT <0.35 NO 0.10 to 0.20 MAYBE MAYBE NO 0.20 to 0.40 YES MAYBE MAYBE >0.40 YES YES MAYBE Skylights (Horizontal Glazing) Skylight-to-roof ratio Glazing Type <0.10 0.01 to 0.03 >0.03 VLT >0.60 NO MAYBE YES VLT 0.35 to 0.59 NO MAYBE YES VLT <0.35 NO MAYBE MAYBE 53 The Effective Aperture Table for windows and skylights indicates if the effective aperture is low enough for exemption from daylight switching requirement. If the table indicates NO, the exemption applies. If it indicates MAYBE, the effective aperture must be calculated to determine if the exemption applies. If the table indicates YES, daylight switching is required. For windows, the calculation described in the paragraph above to determine if the effective aperture is less than 0.1, should be used. 10.4 Lighting Compliance for Non-residential Buildings 10.4.1 Introduction The California Energy Commission has established standards that encourage efficient lighting. Lighting must not exceed allowed power density requirements (watts per square foot) and mandatory measures must be installed in all buildings, regardless of the approach used to show compliance with power density requirements. There are four methods available to show compliance for lighting power density with the new standards. With the exception of high-rise residential and hotel/motel buildings, all non- residential have the same options for showing compliance. 10.4.2 The Prescriptive Approach The prescriptive approach for lighting involves a comparison of the building's Allowed Lighting Power with its Actual Lighting Power (including adjustments). The Allowed Lighting Power value determined by these calculations sets the upper limit for the building. The Actual Lighting Power(adjusted) may not exceed the Allowed 54 Lighting Power. The procedures and methods for using the prescriptive approach, and when each method is applicable, are described below. Three methods are available to determine the Allowed lighting Power using the prescriptive approach: Complete Building, Area Category, and Tailored. TABLE 5 Complete Building Method Lighting Power Densities Values Type of use Watts/sf General commercial and Industrial Work Buildings 1.2 Grocery Store 1.8 Industrial and Commercial Storage Buildings 0.8 Medical Buildings and Clinics 1.5 Office Buildings 1.5 Religious Worship, Auditorium, and Convention Centers 2.0 Restaurants 1.5 Retail and Wholesale Store 2.0 Schools 1.8 Theaters 1.5 All Others 0.8 55 10.4.2.1 Complete Building Method The Complete Building Method for determining the Allowed Lighting Power (expressed in Total Allowed Watts) can only be applied when all areas in the entire building are designed under the same permit and are the same type of use. There cannot be any unfinished areas such as unoccupied tenant improvements. This method is the easiest of the three prescriptive approaches. Flowchart 1 shows the Complete Building Method. To determine the Allowed Lighting Power, multiply the complete building conditioned floor area times the lighting power density(LPD) for the specific type of use, as given in the Table 5. Complete Permit for Complete% No \ Bmldmg? i ; ; Find Watt$ sf ( from Table) Watt& Conditioned Floor area (sfj Use Another Method Flowchart 1. Complete B uilding M ethod 56 10.4.2.2 Area Category Method The Area Category Method is more flexible than the Complete Building Method because it can also be used for buildings with multiple types of use or with partially completed buildings. Areas not covered by the current permit are ignored; to be dealt with when lighting in those areas is completed under a new permit. This method makes compliance of tenant improvement spaces much cleaner and easier to document. Flowchart 2 shows how to calculate the Allowed Lighting Power expressed as Total Allowed Watts for the various areas in a building. The Area Category Method divides the building into primary function areas defined by occupancy type. Each function area in the building must be treated separately. Table 6 shows Lighting Power Densities for the only occupancy types allowed under this method. The most common case for using this method is one where there are clearly separate functions enclosed by floor to ceiling partitions. Multiple function areas of the same type, such as private enclosed offices, may be grouped together even if they include floor to ceiling partitions, in this case the partition around the perimeter of the group of similar function areas (the offices) defines the boundary. Areas separated by this perimeter partition, such as corridors, must be accounted for separately. If an area includes different functions, but no floor to ceiling partitions, such as an open office plan with movable partitions and corridors, it may all be 57 included as one function area defined by the ceiling height partitions around the perimeter. In this case, the corridor areas would be included in the function area of the office. ^ Find Watts perjsjf (;£rom lf|ble):|;i; Find Watts per sf (from Table) Watts per: sfitintes; Watts per sf times Floor area (sf) Conditioned Total "Allowed Watts Flowchart 2. Area Category M ethod. Finally, in some cases, the function areas are clearly defined by separate, permanent, architectural details and shall be treated as separate areas even though no floor to ceiling partitions exist. The function area is calculated by multiplying the width times the depth, as measured from the inside of the bounding floor to ceiling partitions in a function area. The floor area beneath interior partitions is included in the floor area of the function area, and the area beneath the boundary partition is not. TABLE 6 Area Category Method LPD Values Primary Function Watt/sf Auditorium 2.0 * Bank/financial Institution 1.8 Classrooms 2.0 Convention, Conferences, & Meeting Centers 1.6 Corridors, Restroom, and Support Areas 0.8 Dining 1.2 Exhibit 2.3 General, Commercial, and Industrial Work 1.3 Grocery 2.0 Hotel Function 2.3 * Industrial and Commercial Storage 0.6 Kitchen 2.2 Lobbies: Hotel Lobby 2.3 * Main Entry Lobby 1.6 * Mall, Arcades, and Atria 1.2 * Medical and Clinical Care 1.8 Office 1.6 Precision Commercial and/or Industrial Work 2.0 Religious Worship 2.2 * Retail Sales, Wholesale Showrooms 2.2 Theaters. Motion Picture 1.0 Performance 1.5 * * additional chandelier/sconce allowance available. 59 The Allowed Lighting Power(Total Lighting Watts) is determined by multiplying the number of square feet of each function area times the LPD, in watts per square foot, for that function. Table 6 lists the LPDs to be used for various types of function areas. The Total Allowed Lighting Power is the sum of the Allowed Lighting Power in watts for those areas covered by the permit application. 10.4.2.3 Tailored Method The Tailored Method, based on task activities, is used to determine the maximum Allowed Lighting Power for each space or activity in the building. This method requires the most detail on the plans, and in some cases, requires documentation of the actual lighting tasks. Unless there are special lighting needs in a substantial portion of the building, the Tailored Method may actually result in less Allowed Lighting Power than other methods. The task allotments are defined in terms of the illuminance categories for each task. The Illuminating Engineering Society(IES) provides illuminance category and foot-candle levels for determining design lighting levels. Since the task allotments are based on the same categories as the IES design lighting levels, this method allows designers to translate their design parameters directly into Allowed Lighting Power levels. Flowchart 3 shows the calculation procedure for the Total Allowed Watts with the Tailored Method. 60 Tailored Method Illuminance Categories A »D 1 Calculate Room Cavity Ratio Find Allowed Watts per sf Total Allowed Watts (all rooms) Illuminance Categories E -1 Find Wattage % Show Actual AUowan 1 1 Watts Total Allowed Watts (all tasks) Total Allowed Watts 1 Flowchart 4. Tailored M ethod. The first step in identifying the Allowed Lighting Power is to determine the illuminance category for each task. Illuminance categories are determined according to the task activity that will be performed. For each task the appropriate category is found in the Table 7, or in tables and procedures found in the IES 61 Handbook, Applications Volume, 1987. Selection of each illumination category must be supported by a justification on the plan. TABLE 7 Illuminance Categories for Tasks Task Area Illuminance Category Dining D * Office D Public Area Displays G Sales Feature Displays (floor or wall) Churches: G Alter, Ark, Reredos E Choir and Chancel D Pulpit and Rostrum E Main Worship Area D All Others IES Handbook * Special criteria if higher illuminance category is needed. Illuminance categories A, B, C, and D are used for general lighting, and may be assigned within spaces without detailed supporting documentation or whether the actual task areas are not yet defined based upon general plan designations such as: "office," "hallway," or” rest room." Selection of illuminance categories E through I requires specific identification of the task area and of the luminaires and wattage assigned to that area. Category E can only be applied in offices which have visually difficult tasks requiring extra illumination. 62 The criteria for determining if a task is visually difficult is based on the duration of the time spent on the more difficult task. This means that the illumination category shall not be based upon visual tasks requiring a total of less than two hours per working day at the higher lighting level. Poor quality tasks that are capable of being improved are not permitted to be the basis of an increased power allotment. Lighting Power Density: The next step is to find the Lighting Power Density (LPD). The LPD depends on the illuminance category and the Room Cavity Ratio(RCR) for categories A through E, and on the illuminance category and the task area and throw distance for categories F through I. Once the lighting power densities are found for each room or activity, they are multiplied by the area for that space; then added together to obtain the Total Allowed Watts for the entire permitted space. LPD for Categories A through D: A room’s lighting level is affected by the amount of light provided by fixtures and by the room configuration, expressed as the Room Cavity Ratio (RCR). The first step in determining the lighting power density for categories A through D is to calculate the RCR. The RCR is based on the entire space bounded by floor to ceiling partitions. If a task area within a larger space is not bounded by floor to ceiling partitions, the RCR of the entire space must be used for the task area. 63 Table 8 shows typical RCR values for rooms with the task surface at desk height (2.5 feet above the floor). For values not listed in the Table 8, one must either calculate the RCR or use the lighting power densities listed for RCRs of 0 - 3.5. The RCR combined with the illuminance category, enables one to use the Table 9 to find the lighting power densities for illuminance categories A through E. For categories A through D, the LPD is multiplied times the entire area of the space to determine the Allowed Lighting Power. TABLE 8 Typical RCRs Room Length 8 12 (Task height 2.5ft above floor) Room Width 16 20 24 Room Cavity Height = 5.5ft (eight foot ceiling) 5 8.9 7.8 7.2 6.9 6.6 8 6.9 5.7 5.2 4.8 4.6 12 — 4.6 4.0 3.7 3.5 16 — — 3.4 3.1 3.0 20 — — — 2.8 2.5 24 — — — — 2.3 Room Cavity Height = 7.5 ft (ten foot ceiling) 5 12.2 10.6 9.8 9.4 9.1 8 9.4 7.8 7.0 6.6 6.3 12 — 6.3 5.5 5.0 4.7 16 — — 4.7 4.2 3.9 20 — — — 3.8 3.4 24 ——— ——— — ——— 3.1 LPD for Categories E through I: The use of illuminance categories E through I are limited to those areas with tasks having specific lighting needs. If the 64 design does not include tasks with these high lighting levels, one cannot take credit for these amounts by adding them to the Total Allowed Watts. When included in the design, the allotted lighting watts are limited to either the value calculated using the Table 9 or the actual watts of design lighting (whichever is less). The lighting must be assigned to the task area. Adjacent non-task areas must be assigned on illuminance category between A and D. The LPD for illuminance category E depends upon the room cavity ratio. In categories F through I the LPD is based on the task area and the throw distance. When category E is used for private offices or work spaces, it must not be applied to more than 50 percent of the space, and the remainder of the area must be allotted 0.5 watt per square foot. Throw Distance: For illuminance categories F through I, the LPD allowance is higher when the throw distance from the lamp location to the display is greater than eight feet. When tasks are illuminated by lamps with different throw distances, the shortest throw distance is used to determine the LPD allowance from Table 9. 10.4.3 Performance Approach The performance approach provides an alternative to the prescriptive approach for establishing the Allowed Lighting Power for the building. The performance approach requires the use of a Commission certified computer program to model the energy use of the building. In this energy analysis, 65 the Standard Lighting Power Density is used to determine the energy budget for the building. TABLE 9 Lighting Power Density Illuminance Categories Room Cavity Ratio 0 to 3.5 3.5 to 7 7+ A 0.2 0.3 0.4 B 0.4 0.5 0.8 C 0.6 0.8 1.2 D 1.2 1.5 1.8 E 2.8 3.6 4.7 Task Area < 2sf Task Area >2sf or and Throw Distance Throw Distance > 8 feet < 8 feet F 10.0 5.0 G 26.0 13.0 H 63.0 33.0 I 130.0 65.0 When a lighting permit is sought under the performance approach, the applicant uses a Proposed Lighting Power Density to determine whether or not the building meets the energy budget. If met, this proposed Lighting Power Density is automatically translated into the Allowed Lighting Power for the building (by multiplying by the area of the building). If the building envelope or the mechanical systems are included in the performance analysis, then the performance method allows energy trade-offs between systems that can let the Allowed Lighting Power go higher than any other method. Alternatively, this approach allows lighting power to be traded away to other systems, resulting in a lower Allowed Lighting Power. This makes the performance approach very flexible in determining Allowed Lighting Power. It may only be used to model the performance of lighting systems that are covered under the building permit application. The Actual Lighting Power(adjusted) may not exceed the Allowed Lighting Power determined by the performance approach. 10.4.4 Lighting Trade-ofTs The Actual Lighting Power is restricted to the Allowed Lighting Power as determined by the various methods in the Standards. In most cases there are no restrictions as to "where" or "how' the lighting power is used. This means that as long as the Total Allowed Watts for the permitted space is not exceeded, the installed lighting power may be allocated to each space as desired. This ability to make trade-offs applies primarily to general area lighting. The exceptions to trade-offs are the so-called "use it or lose it" categories of lighting. These are specific task or display lighting applications, such as chandeliers under the Area Category Method or display lighting under the Tailored Method. 67 10.4.5 Actual Lighting Power (Adjusted) The designed or Actual Lighting Power (adjusted) is the sum of the wattage of all of the lighting fixtures in the building. It is based on the same conditioned floor area used to calculate the Allowed Lighting Power determined by one of the Prescriptive or Performance methods. 10.4.6 Automatic Lighting Control Credits The Actual Lighting Power may be adjusted by lighting control credits if optional automatic lighting controls are installed. A list of the controls qualifying for these credits is shown in Table 10. These controls may be installed in some spaces to reduce the Total Actual Lighting Power to a level in compliance with the wattage allowed by the Standards. The credit is determined by multiplying the Actual Lighting Power for the controlled fixtures by the Power Savings Adjustment Factor. This credit is subtracted from the Total Actual Lighting Power to determine the Actual Lighting Power (adjusted). To qualify for the power savings adjustment credit the control system or device must be certified and must control all of the fixtures for which credit is claimed. At least 50% of the light output of the controlled luminaire must fall within the type of space listed in Table 10. Except as indicated, control credits may not be combined. 68 TABLE 10 Power Savings Adjustments for Lighting Controls Type of Control Type of Space Power Saving Adjustment Factor Occupant Sensor With separate sensor Any space < or =250 sf, enclosed by 0.20 for each space ceiling to floor partitions; any size classroom, conference or waiting room. Rooms of ant size that are used 0.60 exclusively for storage. Rooms >250 sf. 0.10 Dimming System Manual Hotels/Motels, Restaurants, Auditoriums, Theaters. 0.10 Multi-scene Hotels/Motels, Restaurants, Auditoriums, 0.20 Programmable Theaters. Lumen Maintenance Controls Any Space 0.10 Tuning Any Space 0.10 Autom atic Time Room < 250 sf. and with a timed manual 0.50 Switch Control override at each switch location and Device controlling only the lights in the area enclosed by ceiling height partitions. Combined Controls Occupant sensor with a Any space < or = 250 sf. and enclosed 0.37 separate sensor used in by opaque floor to ceiling partition. conjunction with lumen maintenance controls. Occupant sensor with Hotels/Motels, Restaurants, Auditoriums, 0.35 programmable multi Theaters. scene dimming system. Occupant sensor with a Any space < or = 250 sf. within a daylit 0.10* separate sensor for each area and enclosed by opaque floor to space used in conjunction ceiling partitions. with day-lighting controls, and separate sensor to each space. * factors that can be added to others. 69 10.9.7 Track Lighting Track lighting presents a special situation while calculating Actual Lighting Power, because the number and types of luminaires can be easily changed at any time. The wattage for track lights is calculated as the larger of the two values, either a) the total luminaire wattage proposed to operate on each track; or b) 45 watts per square foot, which is 50 % of the lighting power rating of the track by National Electric Code (90 watts per square foot). Tracks serviced through permanent installed transformers for low voltage lighting may use the volt ampere(VA) rating of the transformer as the Actual Lighting Power of the track. In some situations, extra length of track is desired to provide greater flexibility in locating light fixtures. T n these eases, the designer can limit the Actual Lighting Power by providing interlock switching that limits the circuits and therefore the electrical capacity of track lighting that can be operated simultaneously. REFERENCES 1. California Energy Commission. The California Energy Code. Sacramento, CA: Building and Appliance Efficiency Office. 1992. 70 11. A REVIEW OF THE EXISTING BUILDING CODES IN INDIA 11.1 Introduction Building Codes are defined as a series of standards and specifications designed to establish minimum safeguards in the erection and construction of buildings to protect the human beings who live and work in them from fire and other hazards and to establish regulations to further protect the health and safety of the public. There are two types of codes, i.e. the National Building Code and the Local Building By-laws. The National Building Code represents the national awareness and goals and is only a recommendatory document for adoption in the local building by-laws, the basic characteristic of local building bylaws is that they are to be adhered mechanically and no discretion is allowed. The total number of building codes may be as numerous as the number of local governments. 11.2 Problems connected with Implementation of Development Controls: The problems of implementing development controls are multi-dimensional. National and regional factors which impinge on city growth cannot be dealt with at a local level. In the light of this, the strategy open to local governments is to do what they can within the given resources or urban limits. Basically, then the impediments to implementation of development controls are : 71 11.2.1. Impediments which are Inherent in the Controls 11.2.1.1.Lack of synthesization within Regulatory Bodies: Each agency vigorously implements its regulations disregarding its impact on the total situation. Even at formulation stage, the interrelation is ignored. Each principal participant or expert draws particular regulations and then these are left for execution by different agencies in their own way. Engineers and architects continue to formulate and enforce the building codes. In the absence o f proper training in ‘enforcement constraints’ the specialists create more problems than they solve for themselves, for the organization or for the community. Each building agency, each developer refers to multiplicity of codes and deals with multiplicity of authorities and in the process, the level of housing activity suffers. 11.2.1.2.Technical viability of the codes: A number of expert committees have gone into detail and the conclusions that have emerged all point to the fact that the standards (apart from affordibility criterion) are even technically prodigal and in a or country like India these need to be made more realistic. For example, the fire safety standards, room size requirements, floor space indices are all too prodigal and expensive. 72 11.2.1.3. Intricate variations in regulations: A variety o f bylaws are in operation in various cities. Even within the same city depending upon the number of local governments, variety of codes create administrative conflicts. Lack of uniformity in Standards is a big problem. 11.2.2.4. Rigidity of Standards: A number of experts have referred to the deterrent role of rigid and fossilized development standards. The National Building Code which represents the national aspirations of low cost housing, has yet to be adapted in local building bylaws. Similarly the standards applied to the planning of sites and to the interrelationship of placement of building site tend to be particularly inflexible. 11.2.2. Im pediments which emerge from the Implementing M achinery 11.2.2.1. Ineffectiveness of local government to deal with problems: The problem is: a. that most local governments are too small to provide effective solutions to urban explosion; b. extensive overlapping layers of government controls cause further confusion; c. popular control over local government is ineffective; d. policy leadership is typically weak, if non-existent; 73 e. archaic administrative organizations are totally inadequate to the enforcement demands, and f. the professional services of highly qualified personnel are typically not attracted to local governments. 11.2.2.2. Local political factors and ineffectiveness of development controls: Frequent changes in the development controls like zoning , subdivisions are made to suit the interests of some groups. Inspire of statuary regulations large tracts of land are subdivided in a substandard manner and extensive public and private lands are squatted upon in connivance with the local influential pressure groups. 11.2.2.3. Poverty and Enforcement constraints of development controls: The abyss of poverty in India is so deep that not only the majority of the people cannot construct as per codes but cannot even afford to pay the penalties. As a result large scale slum settlements come up. Most of the public authorities at many places adopt ‘demolition’ as a solution and have found that their enforcement program has run into jeopardy. Despite this, public agencies during the last one decade must have demolished more houses than they have constructed. 11.2.2.4. Practices and procedures for enforcement: Enforcement of development control is in the hands of particular specialists who lack experience in 74 administrative work of what is purely a legal exercise. Frequently the cases are taken to courts by the affected parties and years lapse before even partial enforcement is adhered to. 11.2.2.5. Lack of proper state or central government support to local enforcement machinery: Since enforcement of development controls is basically a police function, local governments, it is seen, do not adequate support from higher governments. 11.2.2.6. Lack of agencies for resolving local conflicts: Master plans by the time they are completed get dissociated from realities and become a source of local conflicts in the city. In the absence of any institutions which these conflicts at a local level, the stalemate continues. 11.2.2.7. Discretionary powers of the enforcement agencies are iniquitous in practice: Provision of discretionary powers in various enforcement codes creates seeds of inequity right at the formulation stage. Special exceptions on this basis are made with abandon for the benefit of vested interests. 75 11.3. Towards a Solution A cursory look at the problem being faced by the enforcement agencies is enough to convince that drastic changes are required in — a. Revising the strategy for standards or codes. b. Strengthening the enforcement agencies and changing their practices and procedures. The following steps can help to mitigate the problem: 11.3.1. Giving a layman’s orientation to the codes: By making various standards fairly easy to comprehend and affordable, we can make them enforceable. 11.3.2. Controls though can be formulated cannot be enforced at the Local level: More of the national approach is needed to solve the local problem. Many local agencies have found to their dismay that codes have been broken because the other local agencies has permitted it. Law gets determined at the national level but leaving enforcement to local level cannot work. In the process national authorities rarely get subjected to pressures and continue to remain in blissful ignorance. It is therefore essential that the responsibility is shared by all concerned authorities. National Codes should be evolved from grass-roots, upwards. 11.3.3. Maintaining inter-relation between the regulations: There is need for consistency in theory and implementation of Codes. Even if formulation of each set 76 of codes or regulations is treated as a specialist’s job, enforcement of these regulations, which is a legal job, need not be left to the same specialist. 11.3.4. Im proving the effectiveness of enforcement agencies: Some of the listed constraints of enforcement agencies can be easily overcome if we strengthen the enforcement agencies. 11.3.5. Periodic Review of all th at is form ulated and w hat is enforced: Environmental, social and political changes demand a periodic review o f all regulations. Static plans to deal with a dynamic situation have little chance of success. REFERENCES 1. Crossette, B arbara. India: Facing the Twenty-first Century. Bloomingdon: Indiana University Press, 1993. 2. Ghosh, Arun. Planning in India: The Challenge for the Nineties. Newbury Park, CA: SagePubl. 1992. 3. India, Planning Commission. Sixth Five Year Plan. New Delhi: Govt, of India Planning Commission. 1981. 4. National Committee on Science and Technology. An Outlook for India's Future. New Delhi: NSCT. 1978. 5. Jha, Prem Shankar. India: A Political Economy o f Stagnation. New Delhi: Oxford University Press. 1980. 77 D: THE PROPOSED INDIAN NATIONAL LIGHTING CODE 78 12. FOREWORD The Indian National Lighting Code is being prepared by the Indian Society of Lighting Engineers (ISLE) under the authority of the Bureau of Indian Standards (BIS). ISLE is a professional body of Lighting Engineers in India and covers a cross section of experts from all fields associated with lighting like architects, interior designers, engineers, contractors, builders, educationists, traders and manufacturers. The responsibility of preparing a first draft has already been taken up and a panel of 15 members has been appointed. A provisional index o f chapters to be covered has been prepared. I have attended one meeting of the National Lighting Code and have had prolonged discussions with the cross section of the assembled experts. My effort in this thesis is to address these chapters and attempt to draft them to the best of my abilities. The purpose of the proposed Indian National Lighting Code is to establish criteria for the design, installation and maintenance of lighting so as to provide sufficient lighting for indoor as well as outdoor activities and to provide energy efficiency targets appropriate for each function. Illumination levels for different tasks should be achieved either by daylighting or artificial lighting or a combination of both. This proposed Code recommends a range of illuminance levels as well as optimum illuminance. The higher and lower values provide flexibility for designers to cater to particular 79 situations where higher and lower illuminances may be used to advantage as elaborated in the included chapters. The process of preparation of the proposed Code has thrown up a number of problems; some of them have been answered fully and some partially. Therefore, a continuous program is envisaged by which additional knowledge that is gained through technological evolution, users' view over a period of time pinpointing areas of clarification and coverage and results of research in the field, would be incorporated in to the Code from time to time to make it a living document. It is proposed to introduce changes to the Code periodically. The revisions of the Standards are proposed to be announced through the issue either of amendment slips or of revised editions. Provision of the proposed Code will serve as a model for adoption by Public Works Department and other Government construction departments, local bodies, other construction agencies, builders, architects, interior designers and lighting designers. Existing municipal by-laws and other regulatory media could either be replaced by the proposed National Lighting Code or suitably modified to cater to local requirements in accordance with the provisions of the Code. Compliance with the Proposed Indian National Lighting Code does not exempt users from legal obligations. 80 13. GENERAL ASPECTS 13.1 Scope This Code deals with the design, installation and maintenance of artificial lighting systems and daylighting strategies. It covers the requirements relating to realization of aims of good lighting. Artificial lighting provisions have been amplified to cover step wise guidance for the design of interiors and exteriors to meet the recommended levels of illuminance. 13.2 Lighting Vocabulary A daptation The process which takes place as the visual system adjusts itself to the brightness of the color of the visual field. The term is also used to denote the final state of this process. Candela (cd) The SI unit of luminous intensity, equal to one lumen per steradian. Chrom aticity The color quality of a stimulus, usually defined by coordinates on a plane diagram or by the combination of dominant wavelength and purity. Color rendering A general expression for the appearance of colors when illuminated by light from a given source compared, consciously or unconsciously, with the appearance under light from some reference source. 81 Color rendering Index Coefficient of Utilization (CU) Color temperature (unit: Kelvin) Contrast Contrast rendering factor Daylight area Daylight Factor A measure of the degree to which colors of surfaces illuminated by a given light source conform to those of the same surface under the reference illuminance, usually diffuse skylight. Percentage of lumens emitted by the lamp that eventually reaches the work plane. The temperature of a full radiator which emits radiation of the same chromaticity as the radiator considered. A term that is used subjectively to describe the difference in appearance of two parts of a visual field seen simultaneously or successively. The difference may be one of brightness or color or both. A measure of the contrast of a task under a given lighting installation in comparison with its contrast under reference lighting conditions. The superficial area on the working plane illuminated to not less than a specified daylight factor, i.e. the area within the relevant contour. The ratio of the illuminance at a point on a given plane within an interior due to the light received directly and indirectly from a sky of assumed or known luminance 82 Diffuse reflection Diffuse lighting Direct lighting Direct ratio Directional Lights Disability glare Display lighting distribution, to that on a horizontal plane due to an unobstructed hemisphere of this sky. Direct sunlight is excluded from both values of illuminance. Reflection in which the reflected light is diffused and there is no significant specular reflection, as from a matte surface. Lighting in which the flux comes from many directions, none of which predominates. Lighting in which the greater part of flux from the sources reaches a surface (usually the working plane) directly, i.e. without reflections from surrounding surfaces. The proportion of the total downward flux from a conventional installation of luminaires which is directly incident on the working plane. Lighting designed to illuminate a task or surface predominantly from some direction. Glare which impairs the ability to see detail without necessarily causing visual discomfort. It is lighting confined to the area of a display that provides a higher level of illuminance than the level of surrounding ambient illuminance. 83 Discharge lamp Discomfort glare Downlighters Downward light Output ratio Flicker General lighting Glare A lamp in which the light is produced either directly or by the excitation of phosphors by an electric discharge through a gas, a metal vapor or a mixture of several gases and vapors. Glare which causes visual discomfort without necessarily impairing the ability to see detail. Luminaires from which light is emitted only within relatively small angles to the downward vertical. The ratio of the total light output of a luminaire below the horizontal under stated practical conditions to that of the lamp or lamps under reference conditions. A visible oscillation in luminous flux. Lighting designed to illuminate the whole of an area uniformly, without provision for special local requirements. When designed for lower-than-task illuminance used in conjunction with other specific task lighting system, it is also called 'ambient' lighting. The discomfort or impairment of vision experienced when parts of the visual field are excessively bright in relation to the general surroundings. 84 Illuminance Illumination Incandescent lamp Indirect lighting Initial light o u t p u t(unit: lumen) Isolux diagram Lamp lumen maintenance factor Light loss factor The luminous flux density arriving at a surface, i.e. the luminous flux incident per unit area. Lux = Lumens per square meter. The process of lighting. A lamp in which light is produced by a filament heated to incandescence by the passage of an electric current. Lighting in which the greater part of the flux reaches the surface (usually the working plane) only after reflection at other surfaces and particularly at the roof or ceiling. The luminous flux from a lamp after 100 hours of operation. A diagram showing contours of equal illuminance. Proportion of the light output of a lamp after a set time to its initial output at 100 hours. The ratio of the illuminance provided by the installation at some stated time, with respect of the initial 100 hour illuminance. The light loss factor is the product of the lamp lumen maintenance factor, the luminaire maintenance factor and the room surface maintenance factor. 85 Light output factor Lighting design lumens(unit:lumen) Local lighting Lumen Luminaire Luminaire maintenance factor The ratio of the total light output of a luminaire under stated practical conditions to that of the lamp or lamps under reference conditions measured at 25'C ambient temperature. The lighting design lumen is a nominal value which is representative of the average output of each type or size of lamp throughout its life. Lighting designed to illuminate a particular small area which usually does not extend far outside the visual task, e.g. a desk light. The SI unit of luminous flux, used in describing the quantity of light emitted by a source or received by a surface. A small source which has a uniform luminous intensity of one candela emits a total of 12.566 lumens in all directions and emits one lumen within unit solid angle. An apparatus which controls the distribution of light given by a lamp or lamps and which includes all the components necessary for fixing and protecting the lamps and for connecting them to the supply circuit. The lumen output from a luminaire declines with time because of dirt deposition on and in the luminaire. The luminaire maintenance factor quantifies this decline. 86 Lum inance (unit: candela/sq meter) (old unit: lambert) Luminosity Luminous efficacy (unit: lumen) Luminous flux Luminous intensity (unit: candela) Luminous intensity distribution The physical measure of the stimulus which produces the sensation of luminosity, in terms of the intensity of light emitted in a given direction by unit area of a self-luminous or transmitting or reflecting surface. It is measured by the luminous flux density leaving a surface. A term which expresses the visual sensation associated with the amount of light emitted from a given area. It is the subjective correlate of luminance. Colloquially, the term ’ brightness' is used in this sense. The ratio of luminous flux emitted by a lamp to the power consumed by the lamp and its per control watt)gear. It is also known as circuit efficacy. The light emitted by a source or received by a surface. A quantity which describes the power of a source of surface illuminated to emit light in a given direction. It is the luminous flux emitted in a very narrow cone containing the given direction divided by the solid angle of the cone. The distribution of the luminous intensities of a lamp or luminaire in all spatial directions. Luminous intensities are usually shown in the form of a polar diagram or table for a 87 Lux Metamerism Multi-scene dimming system Occupancy sensor Reflectance Room cavity ratio Room index single vertical plane, in terms of candelas per 1000 lumens of lamp flux. The SI unit of illuminance, equal to one lumen per square meter. The phenomenon which makes two samples to appear the same under one light source but different under another. A lighting control device that has the capability of setting light levels throughout a continuous range, and that has pre- established settings within the range. A device that automatically turns lights off soon after an area is vacated. The ratio of the flux reflected from a surface to the flux incident on it. The value is always less than one. Proportions of a space determined from its length, width and height: RCR = 5H(L + W)/(L x W). An index related to the dimensions of a room and used when calculation the utilization factor and other characteristics o f the lighting installation. 88 Room surface maintenance factor Sconce Skylight Skylight area Spacing/height ratio Stroboscopic effect Uniformity ratio Upward light output ratio The proportion of the illuminance provided by a lighting installation in a room after a set time compared with that which occurred when the room was clean, allowance having been made for the depreciation in lumen output of lamps and the effect o f dirt deposition on luminaires. A wall mounted decorative light fixture. A glazing having a slope less than 60' from the horizontal. The area of the surface of the skylight, plus the area of the frame, sash and mullions. This ratio describes the distance between luminaires in relation to their height above the working plane. An illusion created by oscillation in luminous flux, that makes a moving object appear as stationary or as moving in different manner. The ratio of the minimum illuminance to the average illuminance. The ratio of the total light output of a luminaire above the horizontal under stated practical conditions to that of the lamp or lamps under reference conditions. 89 Utilization factor The proportion of the luminous flux emitted by the lamps which reaches the working plane. Ventilation factor A factor by which the Light Output Ratio of a luminaire/ Utilization Factor is to be multiplied, to account for the change in the light output of fluorescent tubes used in luminaires. This factor will vary with the design of each luminaire and is to be furnished by the manufacturer as part of the photometric data for the luminaire. W orking plane The horizontal, vertical or inclined plane in which the visual task lies. Unless otherwise indicated the plane may be assumed to be horizontal and 0.75 m above the floor. REFERENCES 1. Boylan, B ernard R. The Lighting Primer. Iowa: Iowa State University Press. 1987. 2. H arris, C. M. Dictionary o f Architecture and Construction. New York. McGraw- Hill Book Company. 1975. 3. K aufm an, John E. Lighting Handbook. 1981 Reference Volume. New York: Illuminating Engineering Society of North America. 1981. 4. Nuckolls, Jam es L. Interior Lighting for Environmental Designers. New York: John Wiley & Sons, Inc. 1983. 90 14. THE PHYSICS OF LIGHTING 14.1 General Principles The main functions of lighting, whether electric or daylighting or a combination of both are as follows: a. To provide sufficient visibility of the environment to enable occupants of a building to move around and to perform their intended activities easily, safely and efficiently; b. To satisfy the need for visual comfort of the occupants and to provide mental and physical health and performance-attitude. The quality of lighting required for visual satisfaction will often exceed that of the lighting required purely for visibility. The potential relationship between daylighting and electric lighting should always be considered at an early stage in the design of the building. Decisions on the respective roles of daylighting and electric lighting can have an important bearing on the ultimate form of the building. 14.2 Color Appearance and Color Rendering of Light The color of daylight as a source is beyond human control. For daylighting of interiors the color of light can be affected by the orientation of the windows and by the spectral transmission characteristics of the glazing. In order to avoid unnatural visual environments, it is recommended to use only glazing with natural 91 spectral transmission characteristics, even when using heat absorbing or heat reflecting material. Electric light sources are available in a great variety of colors. The color of the light usually is characterized by two different quantities-- color appearance and color rendering. The color rendering of a light source may be specified by its Color Rendering Index (CRI) which is a measure of the extent to which color of objects seen under that light are natural. Both the color appearance and the color rendering of a light source are determined by the spectral composition of the light emitted. Completely different light compositions, however, can result in similar color appearances and yet can produce great differences in color rendering. It is impossible, therefore , to draw any conclusion regarding the color rendering properties of a lamp from its color appearance. In combination with other factors of the environment the color appearance of the light, through control of the metabolic state of the human nervous system, greatly influences the mood of the people. This well known phenomenon is used in application fields ranging from psychiatric therapy to places of entertainment. For many applications it is of great importance to select the appropriate color of light. Cooler colors of light for working, warmer colors for relaxing; cooler colors for hot climates; warmer for cold climates, etc. The degree of'warmth' or 'coolness' of the visual atmosphere is related to the correlated color temperature of the light source. 92 The color rendering of a light source determines the extent to which the surface colors of objects and skin colors of occupants look natural and these influence the visual satisfaction of the occupants. For tasks where color selection, color matching or color grading is involved the color of light in combination with the surface color of the background are important factors. However, a color selection should also be checked under lighting conditions in which the materials will ultimately be used. For color matching of basic materials, two light sources of widely different color should be used to detect metamerism. The higher the CRI, the better and more natural the color of the object. The CRI of fluorescent lamps ranges from about 85 for lamps with accurate color rendering properties down to about 50 for some lamps with relatively poor color rendering. The index does not give any guide to the color appearance of the lamp. 14.3. Visual Environment A high illuminance is not itself a guarantee of good lighting. Indeed, the advantages of high illuminance in terms of visual performance will be lost, unless they are accompanied by comfortable visual conditions. Recommended levels of illuminance are given in Appendix A which deals with locations in which specific visual tasks are to be performed. 93 An important factor affecting visual comfort is the range and distribution of luminance in the field o f view. The eye appears to adapt to its assessment of the average brightness of the field of view. In parts of the visual field, contrast harshly with the apparent average brightness, visual discomfort and/or reduction in ability to see may result. Thus glare may occur if luminaires are seen against a background that is relatively dark. The remedy is to reduce the apparent brightness contrast by lowering the luminance of the luminaires as seen from normal positions of view, or to raise the luminance of the background, or both. This is one reason why light-colored walls and ceilings are used in many working interiors. The degree o f discomfort glare is affected by: a. the luminance of the source; b. the luminance o f the background; c. the apparent size of the source; d. the position of the source within the field of view; e. the reflectance o f ceilings and walls, and f. the proportions o f upward and downward light from the luminaire. The role to be played by daylight should be established. The color of the artificial lighting should blend acceptably with daylight. Tubular fluorescent lamps o f color temperatures exceeding 4000 Kelvin are often used as a useful compromise between efficacy and optimum blending of light. 94 The reflective characteristics of the main surfaces, furnishings and contents of a room contribute to the luminance pattern and may have a marked effect on visual comfort and, therefore should also be considered at an early stage in the lighting design. Glare may also be caused by the specular reflection of light sources in polished surfaces, such as table tops and floor. Matte surfaces are generally preferable where there is a risk of this occurring. For the same reasons matte surface are recommended for walls and ceilings. Although contrasts in luminance between illuminated surfaces in a working interior in excess of a 10:1 ratio are generally to be avoided, complete lack of contrast is also undesirable as it can lead to a lifeless and soporific effect. To create an interior that has a lively and stimulating appearance, variety in the visual scene is required, with contrast in light and dark, highlight and shadow, as well as variations in texture and color. Luminous ceilings may give the interior a dull appearance if they provide for illuminances of 400 K or less. If these lower values are required, it is preferable to reduce the overall area of the visible luminous ceiling. Overall diffusing luminous ceilings, where there is little control of the brightness o f the ceiling at normal angles of view, are not advised for any environment where glare has to be low. For other working environments, the luminance of the ceilings from normal directions of view should not exceed 500cd/sqm. These recommendations apply 95 strictly only to working environments and not to reception areas, displays, museums, etc., where other factors may make these limitations undesirable. An appropriate distribution o f luminance can also help to concentrate attention on specific parts of the interior. The eye is attracted involuntarily to that part o f the field of view which appears the brightest or has the strongest local brightness contrasts. For example, in a library it helps the reader if the pages o f the book he is reading appear rather brighter than the surface o f the table and in turn the table surface appears brighter than the floor behind it. This can be achieved by appropriate lighting and the choice o f materials with suitable Munsell value and chroma. 14.4. The Design Process It will be seen from the preceding proposed sub-clauses that decisions about methods o f lighting need to be taken at an early conceptual stage in the design of building by the architect in consultation with the lighting engineer. The first step is to establish the general requirements for artificial lighting in terms o f the main visual tasks to be carried out in the building. The next step is to determine the lighting requirements in terms of revealing the form of the interior space and helping to create the right character for the interior. The possibility of changes in the use of the building should also be considered at this stage. There are 96 task or function related requirements. This can be fulfilled by task or ambient lighting. The artificial lighting should be considered as a part o f the design o f an energy efficient interior as a whole. It needs to be related to a lighting power budget, to daylighting and to the thermal and acoustic requirements of the building. The proportion o f the building cost to be allocated to the artificial lighting installation should be decided as early as possible and cost checks should be made as the design proceeds. A correct balance should be struck between capital and running costs. Detail aspects o f the lighting design may be considered under the following headings: a. artificial lighting/daylighting; b. 'work lighting' and 'building lighting'; c. required illuminance distribution throughout the interior; d. discomfort glare in terms o f the whole visual environment; e. directional lighting to give modeling effects and to reveal form and texture; and f. color scheme o f the interior in terms o f hue, value and chroma and any particular requirements for color rendering. 97 Particular considerations such as siting, weight and access for maintenance of luminaires and electrical control equipment should be taken into account at an early stage. On completion of the building the building owners or tenants should be given drawings showing the layout of the artificial lighting, installation and clear instructions for its operation and maintenance (including a reminder of the need to replace lamps with those of the type originally specified). REFERENCES 1. Egan, M. D. Concepts in Architectural Lighting. New York: McGraw-Hill Book Company. 1983 2. Lam, William M. C. Perception and Lighting as Formgivers for Architecture. New York: McGraw-Hill. 1977. 98 15. LAMPS AND CONTROL DEVICES This proposed clause gives a brief review of lamps and control devices necessary for their operations. (See Table 11) 15.1 Tungsten Filament or Incandescent Lamps Tungsten filaments lamps operate on the principle of an electric current through a tungsten wire filament thereby raising its temperature to incandescence. The lamps for General Lighting Service (GLS) have a rated life o f 1000 hrs. Some of the lower wattage lamps are available with either coiled-coil or single-coil filament, the former having a higher luminous efficacy. Many other tungsten lamps are available for special applications, including low-voltage lamps for display spotlights, tungsten halogen lamps (which have increased life and efficacy compared with their GLS equivalents) and lamps with internal reflectors to control their light distribution. The cost of GLS lamps is low, they need no control gear and their installation is simple, their relatively short life means that replacement costs can be high if labor charges are high. Because their luminous efficacy is low, the electrical loading and running costs are high. Due to high power drain, their use is to be avoided, where possible. The spectral distribution of the light from tungsten filament lamps is deficient in blue and 'rich' in red light. The 'warm' light emission is particularly suitable for social applications, as it flatters the skin tones. 99 TABLE 11 Characteristics of Light sources for General Lighting Lam p Luminous Efficacies (lm/W)* # W attage Range (W) Nominal Life (h)* Correlated Color Temp. Tungsten Filament 8-18 25-1500 1000 1800-3000 Tungsten Halogen 17-22 300-2000 2000 2800-3400 Low-pressure Sodium 100-200 10-200 10000 N/A High-pressure Sodium 80-130 35-1000 7500 2500 High-pressure 40-60 M ercury Fluorescent 50-2000 7500 4000 Hot Cathode Tubular 45-95 Fluorescent 4-125 7500 2700-6500 Compact Fluorescent 50-65 5-35 5000 2800-5000 Metal Halide 65-85 70-10000 2000-6000 3600-4000 * For up-to-date information on these characteristics, reference should be made to manufacturers' catalogues. # Efficacies vary considerably within the given range and are based on initial (100 h) exclude controls devices. 100 Other Characteristics Lam p Available with internal Reflection Coating O perating Position Color Rendering Need for Control Device Tungsten Filament Yes Any Good No Tungsten Halogen No Various Good No Low-pressure Sodium No Horizontal© Bad Yes High-pressure Sodium Yes Any Bad Yes High-pressure Mercury Vapor Yes Any Fairly Good Yes Hot Cathode Tubular Fluorescent Yes Any See Table 12 Yes Compact Fluorescent Yes Any Good Yes Metal Halide Yes Some Restrictions Fairly Good Yes @ Certain o f the low-wattage lamps can be used vertically. As these lamps dissipate most of their energy in the form of infra-red radiation, heating problems arise with high lighting levels. For example, a 100 W lamp will emit about 91 W of heat energy of which 84 W is radiated as infra-red and 7 W is released as conduction/convection losses. 101 15.2 Discharge Lamps 15.2.1 General Principles Discharge lamps operate on the principle of passing an electric current through a gas or vapor, thereby producing a luminous arc. Control device to initiate the discharge and to stabilize it is essential for all discharge lamps. The control device is normally located within or near the luminaire. Discharge lamps take several minutes (according to their type), to run-up to full light output from switch-on. Many types will not restrike immediately after switch-off, without the use o f special control device. Discharge lamps (described further) and their control devices will initially cost more than incandescent lamps but this can be offset by cost reduction resulting from their high luminous efficacy and longer life (5,000 to 10,000 hrs). 15.2.2 High-pressure M ercury Discharge Lamps A high-pressure mercury discharge lamp has a compact discharge tube within an outer glass envelope, which may have an internal coating of fluorescent powder. Some lamps have internal reflectors to modify the light distribution. Mercury lamps are available in the ratings from 50 W to 2000 W. A few lamp types are available wit internal ballasts in the form o f tungsten filaments (self ballasted or blended light lamps). The spectral energy distribution o f plain mercury lamp consists o f radiation at particular wave-lengths in the blue, green and yellow regions. The color rendering properties of these lamps is poor, restricting their use 102 to industrial interiors and to exterior lighting unless they are mixed with other sources. A better spectral distribution is obtained by the use, on the inside o f the outer envelope, o f fluorescent powders, which convert ultra-violet radiation into visible radiation. Fluorescent powders are chosen to add light throughout the visible spectrum, but particularly in the red end where mercury lamps are most deficient. Recent improvements to these powders make the lamp suitable for many commercial applications. Metal Halide lamps improve the color rendering and have a higher efficacy some 25% above that of other mercury lamps. The range of ratings currently available is 150 W to 10000 W. Some lamps have clear glass envelopes and some employ a fluorescent powder coating. 15.2.3 T ubular Fluorescent Lamps (Hot Cathode) Tubular fluorescent lamps are low-pressure mercury discharge lamps with an internal fluorescent coating. They are available in ratings from 4 W to 125 W. A wide range o f different colored lamps is available. For general lighting there are 'whites' and 'daylights'. With the availability o f triphosphor coated tubes, high luminous efficiencies can now be achieved with high color rendering index. About 25% o f the input energy is radiated as infra-red radiation for fluorescent tubes. 15.2.4 Com pact Fluorescent Lamps A new generation of compact fluorescent lamps has come into use in recent years. Such lamps are available with and without 'built-in' control device. The 103 former can be substituted in many applications in the form o f straight replacements of incandescent lamps. The latter need to be wired through appropriate ballasts. They are designed to reduce electrical loadings by some 75% compared to incandescent lamps but produce the same warm color impression with a high color rendering quality and possess an average life of 5000 hours. Compact fluorescent lamps radiate 30% o f input energy as infra-red (compared to some 85% for incandescent lamps) and hence contribute to reduced air-conditioning load as well. TABLE 12 T ubular Fluorescent Lamps: Color appearance and Color Rendering Color Correlated Color Color Guide Design- color Appearance Rendering to ation Tem perature of lamps Application Daylight 6500 K approx. Bluish cool, similar to north sky light. Medium fidelity 75-80* Homes, shops, offices. Cool White 4000 K approx. Neutral white but not as cool as daylight. Low fidelity 50-70* Industrial and commercial areas. Tri phosphor types 3000 K 4000 K 6000 K Warm Neutral white Bluish cool High fidelity 85* Commercial areas (offices, factories, hotels and shopping areas) * CIE color rendering index. 104 15.2.5 Low-pressure Sodium Discharge Lamps The common forms o f low-pressure sodium discharge lamps are either a U- shaped discharge tube with a bayonet lamp-cap (BC) at one end or a straight (linear) tube with a bi-pin lampholder at each end. Lamps are available in ratings from 10 W to 200 W. These lamps produce yellow light that is virtually monochromatic. Poor color rendering limits their use to streetlighting and floodlighting, and to security lighting in unoccupied interiors at night. 15.2.6 High-pressure Sodium Discharge Lamps High-pressure sodium lamps have shorter and thinner arc tubes than low- pressure sodium lamps and are available in ratings of 35 W to 1000 W. These lamps have a continuous spectrum resulting in a much better color rendering than that o f the low-pressure sodium lamp, but their light emission is deficient in blue and deep red. The color rendering is acceptable for industrial uses, for streetlighting, floodlighting and interior sports areas. In commercial interiors , their use is limited, but is increasing mainly in circulation areas such as internal atria. 15.2 Control Devices For Lamps Other than incandescent and self-ballasted lamps, every gas-discharge lamp requires a ballast which is an essential accessory to limit the current and also administer optimum voltage to the lamp. Certain lamps also need starting devices, ranging from a simple starter for a fluorescent lamp, to electronic igniters for high- pressure discharge lamps. 105 TABLE 13 Ballast Losses (Tubular Fluorescent Tubes) S/No Lam p Type Ballast Type Ballast loss Total input w atts/ lamp 1. 600 mm 16 W High Frequency Electronic Quickstart 3 19 2. 600 mm 18 W/20 W Switchstart 5-12 23-32 3. 600 mm 20 W Preheat/Semi Resonant Quickstart 10-17 30-37 4. 900 mm 30 W Switchstart 8-12 38-42 5. 900 mm 30 W Preheat/Semi Resonant Quickstart 13-17 43-47 6. 1200 mm 32 W High Frequency Electronic Quickstart 3.5 36.5 7. 1200 mm 36 W/40 W Switchstart 5-12 41-52 8. 1200 mm 40 W Preheat/Semi Resonant Quickstart 10-17 50-57 9. 1500 mm 50 W High Frequency Electronic Quickstart 5 55 10. 1500 mm 58 W/65 W Switchstart 12-15 70-80 11. 1500 mm 65 W/80 W Preheat/Semi Resonant Quickstart 17-20 82-85 106 TABLE 14 Ballast Losses (O ther D ischarge Lam ps) S/No Lam p Type/W attage Ballast Loss (W) T otal input W atts/lam p (W) AI A) High-pressure Mercury 50 W 10-12 60-62 A2 80 W 8-10 88-90 A3 125 W 13-15 138-140 A4 250 W 20-22 270-272 A5 400 W 25-28 425-428 A6 700 W 30-35 730-735 A7 1000 W 40-45 1040-1045 B1 B) High-pressure Metal Halide 70 W 12-14 82-84 B2 150 W 14-16 164-166 B3 250 W 20-22 270-272 B4 400 W 25-28 425-428 B5 1000 W 40-45 1040-1045 C l C) High-pressure Sodium 50 W 11-12 61-62 C2 70 W 15-17 85-87 C3 150 W 25-27 175-177 C4 250 W 30-33 280-283 C5 400 W 40-45 440-445 C6 1000 W 100-110 1100-1110 D1 D) Low-pressure Sodium 10W 5-6 15-16 D2 18 W 7-8 25-26 D3 35 W 13-15 48-50 D4 55 W 13-15 68-70 D5 90 W 20-22 110-112 D6 135 W 25-28 160-163 D7 180 W 40-45 220-225 107 The power dissipated in starting devices is quite negligible. But the power dissipated in the ballast can be quite significant. Such copper and iron losses in ballasts are inevitable and are dissipated as heat and they reduce the overall efficiency o f the system in terms o f lumens/watt. Hence the necessity to minimize such losses in control device is understood by manufacturers and users. Table 13 and 14 show common lamp wattages and their ballast losses to enable calculation of the total input watts into a lighting installation. These tables serve only as a guideline to assist in calculating the electrical loading for lighting. Exact details on power losses in control device are available from manufacturers. The choice o f low-loss control gear is always desirable so long as life-cycle costs are favorable. 15.3 Noise from Lighting Equipm ent An inherent characteristic of all inductive control devices in operation is the generation of noise. In the case o f control device for use with tubular fluorescent lamps, the noise level should not exceed 30 dB under certain prescribed conditions and when suspended in free air. This, however, is not a safeguard against excessive noise as the luminaire can amplify the noise from the control gear and the final noise depends upon the extent of this, the ambient noise level and the acoustic properties o f the room. Increasing the number of the lamps in a room will also tend to increase the noise level. Where noise is likely to be a source of annoyance: 108 a. the luminaire should not have loose parts that may vibrate; b. the control device should be mounted rigidly or resiliently depending on the type o f casing; c. a resilient suspension for the luminaire should be used to reduce the transmission o f noise to the structure; and d. the ceiling and, where possible, other surfaces should be sound- absorbing. Manufacturers advice should be sought if it is anticipated that the problem o f noise will be critical. R E FER EN C ES 1. Cayless, M. A. Lamps and Lighting. Baltimore: Edward Arnold. 1983. 2. E lanbass, W. Light Sources. London: MacMillan Publ. 1972. 3. Schiler, M arc. Simplified Design o f Building Lighting. New York: John Wiley & Sons, Inc. 1986. 4. Stein, B enjam in; Reynolds, John S. and M cG uiness, W illiam J. Mechanical and Electrical Equipment for Buildings. 7th Edition. New York: John Wiley & Sons, Inc. 1986. 109 16. LUMINAIRES 16.1 General Considerations Luminaires should be constructed from such materials and be so finished that their safety, performance or appearance does not deteriorate significantly during normal life when they are operated in the conditions for which they were designed. They should comply with the requirements and tests for insulation, ingress o f moisture and dust and resistance to corrosion as defined by the Indian Standards. The user should select with care or consult the manufacturer to ensure that the luminaire and the service conditions are compatible. 16.2 Classification 16.2.1 Classification by Light Distribution Luminaires are classified by the manner in which their light is emitted. Previously they were broadly classified according to the proportion o f light emitted upwards and downwards as below: 16.2.1.1 Direct 0 - 10% 100 - 90% upwards downward 4.2.1.2 Semi-direct 10 - 40% 90 - 60% upwards downwards 4.2.1.3 General diffusing 40 - 60% 60 - 40% upward downwards 4.2.1.4 Semi-indirect 60 - 90% 40 - 10% upwards downwards 4.2.1.5 Indirect 90 - 100% 1 0 -0 % upwards downwards 110 16.2.2 Classification by Position of Mounting Luminaires are often described in relation to the manner in which they are designed to be mounted when in use. 16.2.2.1 Recessed: The luminaire is housed above the ceiling, or in a wall or floor, so that any visible projection is insignificant. Sometimes this is called a 'flush fitting1 . If the dimensions of a luminaire are related to the building module, then the luminaire may be described as 'modular'. The method of fixing recessed luminaires in ceilings should be related to the building structure and weight of the luminaire. For example, the weight of a 1200 mm x 600 mm modular recessed luminaire, designed to house four lamps, may be 20-25 kg. If the suspended ceiling cannot support the luminaire, separate suspension members should be adjustable to allow for the luminaire to be aligned flush with the suspended ceiling. The trimmings in the opening made in the ceiling for the suspension of luminaires should be designed to minimize the leakage of light and dust. The ambient temperature within the ceiling void and the thermal insulating effect of the ceiling are likely to raise the temperature within the luminaire. 16.2.2.2 Semi-recessed: The luminaire is partially recessed into the ceiling or wall. 16.2.2.3 Surface Mounted: The complete luminaire, sometimes called a 'ceiling fitting', is fixed directly to the ceiling or wall surface. Due to the poor thermal conduction properties o f ceilings, the luminaire may increase in temperature. It may be necessary to use heat-resisting cables between the mains wiring and the 111 luminaire terminals. Luminaires should not interfere with the operation o f the sprinkler heads and the designers o f the sprinkler system should be consulted. 16.2.2.4 Pendant: The lumianire is suspended below the ceiling level by means o f a flexible cable, chain or rod. The ceiling plate for fixing the luminaire to the ceiling is a separate component from the lamp enclosure. The overall drop o f a suspended luminaire should be taken as the vertical distance from the ceiling to the lowest point o f the luminaire. Multi-light branched luminaires or those based on crystal glass are often called 'chandeliers'. In the case o f the former, the term 'spread' is taken to apply to the diameter of the circle passing through the center lines o f the lighting units at the extremities o f the arms. 16.2.2.5 Wall Bracket: A luminaire designed for mounting on a wall. Generally, restrictions applicable to surface mounted luminaires should be considered. 16.2.2.6 Portable: A portable luminaire is one that can easily be moved from one place to another. Other terms in common use are table lamp, floor standard and reading lamp. 16.3 Lum inaires for Special Environm ental Conditions Atmospheric conditions: Presence o f hostile atmospheric conditions in industrial areas such as humidity, dust and inflammable gases may impose special requirements on luminaires in order to ensure: 112 a. the safety of the personnel with regard to electric shock; b. the proper functioning of the equipment; c. protection against damage to equipment or property. In general for industrial areas, a distinction is made between hazardous and non-hazardous atmospheres depending on the presence or absence of inflammable dusts, vapors or gases in explosive concentrations. For hazardous atmospheres luminaires must additionally meet the requirements regarding protection against explosions, which are generally laid down in national regulations. In order to meet the requirements for the hostile industrial environments mentioned above, in general enclosed gasketed luminaires must be used. Severe corrosive conditions necessitate knowledge o f the atmospheric content to permit selection of appropriate material for the luminaire and its enclosure. REFERENCES 1. Boylan, B ernard R. The Lighting Primer. Iowa: Iowa State University Press. 1987. 2. Egan, M. D. Concepts in Architectural Lighting. New York: McGraw-Hill Book Company. 1983. 3. Schiler, M arc. Simplified Design o f Building Lighting. New York: John Wiley & Sons, Inc. 1992. 113 17. LIGHTING DESIGN AND CRITERIA 17.1 Lighting Requirements for Various Types of Buildings 17.1.1 General Considerations The range of types of buildings and their visual requirements is so great that this proposed clause will consider only the principal design features and refer to other recommendations where relevant and consistent with these features. Table 15 shows the values of illuminance range applicable to the specific types of visual tasks . Appendix A which has been drafted by the Indian Standards gives recommended illuminances for a selection of areas and activities. Because circumstances may be different for different interiors used for the same application or for different conditions for the same kind of activity, a range of illuminances is recommended for each type of interior or activity, instead of a single value of illuminance. The recommended design value can be used with confidence in most situations. A higher than recommended design value can be justified when: * unusually low reflectances or contrasts are present in the task; * errors are costly to rectify; * the visual task is critical; * accuracy or higher productivity is important; * the visual capacity of the worker makes it necessary; * safety is a prime consideration. 114 TABLE 15 Recommended Illuminance Range in lux Recommended Design Type of Space/Task Value 5 0 - 100 100- 200 75 150 Circulation areas, e.g. corridors, staircases. Rooms not used continuously for working, e.g. industrial surveillance, storage areas, cloakrooms, entrance halls. 2 0 0 - 500 300 Tasks with simple visual requirements e.g. rough machining, lecture theaters. 3 0 0 - 750 500 Tasks with medium visual requirements e.g. offices, control rooms, shops. 5 0 0 - 1000 750 Tasks with demanding visual requirements, e.g. inspection and testing, drawing offices, supermarkets. 750 - 1500 1000 Tasks with difficult visual requirements, e.g. fine machining, color discrimination. 1000 - 2000 1500 Tasks with special visual requirements, e.g. inspection o f very fine work, hand graving. 2000 and above — Performance o f very exacting visual tasks, e.g. micro electronic assembly, surgery. A lower than recommended design value may be permitted when: * reflectances or contrasts are unusually high; * speed or accuracy is not influenced by lighting level; * the task is executed only occasionally. 115 The types of buildings discussed within this proposed clause are: 1. Industrial 2. Office 3. Selling and Display 4. Residential 5. Catering 6. Public Assembly and Entertainment 7. Indoor Sports 8. Educational 9. Library 10.Religious 11.Hospital and Health Care 12.Laboratories and Research Establishments 13.Mass Rapid Transit Stations 17.1.2 Industrial 17.1.2.1 General This covers the lighting o f manufacturing processes. The requirements will vary with the severity of the visual task and the environmental conditions that surround the task. 116 17.1.2.2 Lighting layouts A regular overhead array o f luminaires is usually installed to provide general lighting o f an area. For situations where more exacting work is done within limited sections, the illumination of such areas can be raised to an appropriate level by using sources of greater power or by reducing the luminaire spacing, or both. 17.1.2.3 Relation to N atural Lighting It is important that artificial lighting be planned with full regard to the provision made for natural lighting. In the case of multi-storied factories, where natural lighting comes predominantly from side windows, the artificial lighting should be capable o f being used to supplement the natural lighting and should be separately switched in sections parallel to the window. For work places, it will be usually the working plane. The working plane is assumed to be a horizontal plane limited by the walls of the interior at a height of 0.90m above the floor for standing workers and 0.75m for those who are seated. In the case of general lighting, the ratio o f the minimum to the average illuminance should normally be less than one-third o f the task illuminance. 17.1.2.4 M ounting height The choice o f layout and lighting equipment will be affected by the available mounting height. Below 8m, dispersive reflectors are normally used. For higher mounting, it may be more economical to use reflector systems giving a 117 more concentrated light distribution. In either case, some upward light is desirable to prevent a tunnel effect. 17.1.2.5 Environmental conditions The choice of equipment will be affected by the conditions under which it is operated. These conditions are either 'normal' where no special treatment of the lamp and equipment is necessary or 'hostile' requiring lamps and equipment to be protected against such conditions. Hostile environmental conditions include a. dust; b. water; c. corrosive liquids and vapors; d. explosive dusts and vapors; e. high and low temperatures. 17.1.2.6 Practical considerations a. Installations. While full use should be made of roof trusses for mounting luminaires, consideration should be given to trunking systems that provide for subsequent variations of layout or the addition of luminaires. b. Light sources. The choice will depend upon the location and the mounting height. Up to about 7m, the tubular fluorescent lamp is most commonly used for general lighting, but the range of high pressure discharge lamps with improved color rendering should also be considered, particularly if the mounting 118 height allows one of the higher wattage ratings to be used, thus reducing the number of luminaires required. c. Lighting equipment. Lighting equipment should comply with the Indian Standards appropriate to the conditions of use. Luminaires should also be designed so as to facilitate installation or removal, maintenance and lamp changing. d. Switching. Switching of luminaires should be flexible, to facilitate individual areas of work to be lit adequately and switched off or reduced in unwanted areas. Programmed lighting with microprocessor controls (including sensing of daylight penetration) should be considered at the time of design. e. Accessibility. Lamps and luminaires should be accessible without interference with tasks. For very high interiors, consideration should be given to the use of catwalks or similar means of obtaining access. The extra capital cost of this provision will often be justified by reduced maintenance charges, better lighting service and conditions of safety. f. Critical color requirements. In situations where critical color matching is required, an illuminance of 1000 lux is recommended and the light sources should have a spectral quality in accordance with the requirements o f the Indian Standards. These sources have a luminous efficacy than those commonly used for general lighting, but it may only be necessary to provide this form of lighting over the inspection area and not in any adjacent general manufacturing areas. 119 17.1.3 Office 17.1.3.1 General The provision made for lighting will depend on the type of office, e.g. general office, executive's office, drawing office, etc., and the subdivision o f the floor space. Where areas are to be used without further division, or the precise requirements are known, fixed lighting and switching outlets can be installed. Where the layout of partitioning is unknown or subject to alteration, provision should be made for a flexible installation that will allow luminaires to be placed in proper relation to any arrangement of partitioning. This flexibility can be achieved by either: a. providing fixed outlets on a modular system sufficient in number to ensure that luminaires can be located satisfactorily irrespective of how the interior is partitioned; or b. by using continuous lines of trunking or lighting track along which luminaires can be located as required. Both the above mentioned can facilitate group and individual switching of luminaires to suit workstations which may carry on working, outside the general office hours. 17.1.3.2 Lighting requirem ents General overall lighting will normally be satisfactory but, in relatively deep offices, integration of daylight and artificial light may be required in order to give 120 properly balanced seeing conditions while still retaining the effect of natural lighting. The minimum illuminance recommended for general offices is 300 lux. The layout should be designed to limit glare and care should be taken to avoid specular reflection of the light sources from polished furniture, glossy paper, machine surfaces or glazed partitions. 17.1.3.3 Integration with other services Wherever possible the layout and operation of the lighting system should be designed in conjunction with other services. This involves dimensional coordination with the building module and positional coordination with the air input and exhaust terminals. The electrical power o f the lamp and the control devices contribute to the heat input o f a building and allowance should be made for this in the design o f the heating and cooling system. Air conditioning and lighting can be combined in such a way that the return air is exhausted through the luminaires. This is done primarily to: a. reduce heat radiation from lamps and luminaires; b. reduce temperature of the air surrounding the lamps thereby increasing their luminous flux and hence their efficacy; c. minimize openings in the ceiling to the extent that air-exhaust can be effected through some luminaires. 121 The data (from luminaire manufacturers) concerning luminaires for use in an integrated system should provide information on the rate of heat removal, increase in luminous flux, air distribution and level of noise (due to exhaust air), apart from the usual lighting characteristics. 17.1.3.4 Lighting layouts The three main types of installation are as follows: a. Individual luminaires; ceiling-mounted or suspended, supplied from fixed outlets or from continuous trunking or track; b. Recessed luminaires, usually modular, which may be inserted in suspended ceiling; c. A combination of localized lighting with (a) or (b) above. (Sometimes referred to as task lighting in conjunction with ambient lighting of a lower level). Recessed modular luminaires do not provide any appreciable light on the ceiling and may be unsatisfactory in interiors having surfaces of low reflectance. 17.1.3.5 Decorations and furnishings For good utilization of light, interior finishes should have reflectances of not less than 70% for ceilings and 50% for walls. Dark floors and furniture should be avoided. Where it is desired to use strong colors, their effect will be enhanced by directing light onto them. 122 17.1.3.6 Lamps For economic and practical reasons, tubular fluorescent lamps should normally be used for general office lighting. For difficult visual tasks, tungsten filament or compact fluorescent lamps may be used locally to supplement the general lighting. The choice o f tubular fluorescent lamps as regards 'color' depends on the importance placed on good and attractive color rendering. Where the decorations and furnishings are o f a high standard, e.g. executive suites and conference rooms, then lamps with 'good' color rendering are to be preferred. If the artificial lighting is being fully integrated with the daylight then a lamp with a color temperature of 4000 K or more is often preferred. 17.1.3.7 Drawing offices An illuminance of 750 lux or more is required on the surfaces o f all drawing boards including those of the adjustable type. This may be achieved by providing a high illuminance throughout, with tubular fluorescent lamps in luminaires installed in continuous or near continuous lines preferably oriented to give the draftsmen an end view of the luminaire. Alternatively, local luminaires may be attached to drawing boards to supplement the general overhead lighting, but in such cases care should be taken to ensure that they do not cause glare to other draftsmen. Compact fluorescent lamps often provide an economic solution, with no attendant heat. 123 17.1.3.8 Lighting for Visual Display Terminals (VDTs) The aspects of the visual environment which are likely to cause problems for VDT operators are basically: a. the reflection of high luminance surfaces; b. an excessive range of luminance reflections within the field of view especially between the screen and documents on the desk. The other area of high luminance reflection on the VDT is the keyboard. High luminances reflected from shiny keys can produce a twinkling effect when the keyboard is used, which can be distracting. High luminance reflections occurring on the VDT screen can have three effects. First they can be distracting. Second they can reduce the contrast of the characters making up the display which may make some parts difficult to read. Third they can give misleading cues as to the distance at which the eyes should be focused which, if allowed, will make the display blurred. The most common source of high luminance in an interior are windows and luminaires, although the effect of a white blouse/shirt worn by the operator seated immediately in front of the VDT cannot be ignored. As for the range of luminances, the basic problem is that the human visual system cannot cope with a wide range of luminances simultaneously. For any average luminance to which the eye is adapted then relatively high luminances will be seen as glaring and relatively low luminances will be seen as black shadows. 124 One relevant situation in which an excessive range of luminances is likely to occur is when the luminance of the documents from which the VDT operator is working is much higher than that of the screen. Another example is when the operator can see a window or a high luminance luminaires close to the sight line to the VDT screen. The illuminance on the horizontal plane in the room used mainly for VDT work should be in the range of 300 to 700 lux. This range generally takes care of the illuminance necessary for reading working documents and a comfortable setting for operating the VDT. A very high illuminance will produce difficulty because of the difference in luminance between the documents, especially since the eye alternates between documents and the screen. It is important to note that when either direct lighting or low luminance luminaires are used, the surface reflectances of the walls, ceiling and floor should be moderate or high if an impression of gloom is to be avoided. The suggested reflectances are ceilings Rc = 0.7(minimum), walls Rw = 0.5, floor R f = 0.3. This has beneficial effects on better utilization of artificial lighting as well. Discomfort Glare. The quality aspects of a lighting installation for VDT operation deserve special consideration, particularly with regard to minimizing the degree of discomfort glare from the luminaires. Brightness Ratio. The brightness ratio between the VDT and its immediate surroundings, particularly the table top, is very important. If these table 125 surfaces are shining and bright, usually due to a high value of horizontal illuminance, (more than 700 lux) there is a risk of visual discomfort. Optimum character contrast of picture background should be within a range of 5:1 (light screen) and up to 10:1 (dark screen). Luminance ratio of documents to screen luminance should be within the range of 5:1 (light screen) and up to 20:1 (dark screen). 17.1.4 Selling and Display 17.1.4.1 General Most selling areas do not receive a significant amount of natural light and reliance is placed on artificial sources. While adequate general lighting should be provided for safe movement over the whole area used by the public, higher illuminances are needed for selling and display. 17.1.4.2 Lighting layouts There are two quite separate lighting techniques: a. An overall high illuminance of 600 - 1000 lux, as used in supermarkets and multiple stores; b. An illuminance of 100 - 200 lux from a general lighting system with additional highlighting of display areas, as in a boutique or jeweler’s shop. This requires a more flexible electrical installation than (a) to permit frequent changes of display 126 layouts. Systems incorporating a light track with busbar connection for spotlights and pendant luminaires are suitable, including dimming of certain sections. 17.1.4.3 Lighting requirem ents for shop interiors A combination of tubular fluorescent and tungsten filament lamps is normally used for the lighting of shops and stores. Tubular fluorescent lamps have advantages for general lighting, as they combine a high luminous efficacy with minimum heating effect. High-pressure mercury lamps with improved color rendering are also being used. Supplementary lighting from tungsten filament lamps will give improved modeling and emphasis to the display and will produce highlights and sparkle. In open selling areas, it is often advantageous to direct light on the walls in order to enhance the display and define the perimeters of the selling area. 17.1.4.4 Lighting requirem ents for shop windows The lighting should primarily enhance the merchandise, and the display treatment and the level of illuminance should be chosen bearing in mind the immediate surroundings. If window displays are to be lit during the day, a very high value of illuminance is usually needed both to compete with the general daylight illumination and to minimize reflections of the street seen in the front glass. For single aspect windows, the main lighting should be from the front, and interest may be added by using limited back lighting. The avoidance of glare is no problem 127 provided that bare lamps are not exposed to the public view. Multi-aspect windows always present a problem if glare is to be avoided from opposing viewpoints. Large scale louvers or baffles over the ceiling can be used to screen luminaires and, in general, the light should be directed more vertically than in single aspect window displays. Spotlights with optical systems giving reasonably precise cut-offs are usually the necessary components of this type of installation. It is common practice to use a variety of light sources within a single window. The general lighting will often be provided by tubular fluorescent lamps, but accent lighting will invariably be from tungsten filament lamps housed in appropriate luminaires. Low voltage lamps are used where small areas of very high illuminance are required. Color filters are also used for special effects. 17.1.4.5 In many windows the lighting arrangements have to be changed frequently to suit new displays, so a light track system should make this both possible and convenient. 17.1.4.6 Provision should be made for adequate ventilation in order to avoid overheating the lighting equipment and merchandise. 17.1.4.7 Window lighting may be required after the shop has closed and this is normally achieved by controlling the light circuit with a time switch. Solar switches are available if the lighting is required to come on only after dark. 128 17.1.5 Residential 17.1.5.1 General This proposed clause deals with the lighting requirements of kitchens, bathrooms, living rooms, entrance halls, landings, stairs, bedrooms, garages, workshops and the external lighting of houses, flats and apartment houses, study/bedrooms of hostels and guest rooms and lounges of hotels. It is recommended that a switch at the entrance-door to the room should control a fixed lighting point and that the installation of all lighting points should be in accordance with the Indian Standards. 17.1.5.2 Private (individual) residences In addition to the fixed lighting points, domestic lighting requires a flexibility that can be achieved by the provision of an adequate number of switched socket outlets. The following table gives the suggested provision: TABLE 16 Recommended Num ber of Socket Outlets for Lighting purposes in Private Residences A rea to be lit locally Num ber of outlet socket Dining area 2 Living area 4 Double bedroom 4 Single bedroom 2 Single study room 4 Single bed sitting room in family dwelling 4 Store/workshop/garage 2 129 17.1.5.3 Illumination Unlike industrial and commercial interiors, the uniform illumination of domestic areas is seldom necessary or even desirable. Low-key general lighting plus supplementary lighting, where needed is usually acceptable. Lighting can also be used primarily for decorative effect. a. Kitchen and dining areas General lighting should be provided by at least two luminaires, one of which should be arranged to give higher local lighting over the main working areas, i.e. sink unit and cooker. The luminaires should preferably be switched separately. Tubular fluorescent lamps are particularly suitable for kitchens in view of the reduced shading effect. The lamps should have a color rendering index greater than 80 to enable the proper color of foodstuffs to be seen. b. Main living areas Although individual requirements will vary widely, more than one light source will always be required to provide a range of illuminance. Consideration should be given to the wiring points for the lighting of pelmets, pictures, etc. c. Bathrooms Lighting should be switched from outside the room or by a pull-cord inside the room. All luminaires should be earthed or double-insulated. A luminaire should be provided for the bathroom mirror for facial illumination. 130 d. Bedrooms Lighting control with local switches is normally required near the bed-head position. A high illuminance is required for the dressing table; in the absence of information regarding its position, one solution is the use of portable luminaires. e. Hallway and stairs Two way switching is required at the top and bottom of staircases and also for large hallways. In the latter case, one switch should be near the main door entrance and the other switch close to the staircase. The staircase luminaire should be positioned so as to illuminate all stair treads and glare should be avoided. 17.1.5.4 Special requirem ents Provision should preferably be made for: a. lighting in the loft or in cellars with a switch close to the trap door; b. lighting outside all external doors; c. an illuminated house number and bell push; d. lighting in the garage switched from the normal exit door (two-way if necessary); e. lighting in deep cupboards with door-operated switches. 17.1.5.5 M ulti-story residences Separate 'landlord' lighting circuits are required for corridors, lobbies and exterior paths. An all night lighting system should be installed in these areas and 131 this can be provided economically by the use of miniature tubular or compact fluorescent or other low wattage discharge lamps or possibly an occupancy sensor. 17.1.5.6 Hostels and hotels Bedrooms should have desks, bedheads and wash basins. General lighting in the lounge should be sufficient for casual reading. Desks should be provided with local lighting luminaires; care should be taken to ensure that these do not cause glare elsewhere in the room, i.e. adjustable luminaires may need to have a limited range of movement. Special attention should be given to the illumination o f fire escape routes. 17.1.6 Catering 17.1.6.1 General There is a great diversity in the lighting requirements of hotels and catering establishments ranging from the illumination of public rooms such as ballrooms and large dining rooms, where the emphasis is on lighting o f a decorative character — to the more modest requirements of hotel bedrooms and private sitting rooms. The latter are dealt within 17.1.5 under residential lighting. 17.1.6.2 Hotel dining rooms and restaurants In hotel dining rooms and restaurants, the character o f the lighting is often more important than the illuminance. A minimum illuminance of 100 lux on dining room tables is recommended, but this should be applied with discretion. 132 In many schemes, the lighting is often required to be subdued and intimate in character. Tungsten filament or compact fluorescent lamps in table luminaires are often used for this purpose and these can often provide satisfactory 'highlights' on the silver and glassware, and at the same time diffuse sufficient general light to reach the faces of the diners. One alternative is to use 'downlights' to light tables, and in this case wall-lights may be required in addition, to give the necessary subdued general lighting and to improve modeling. Where a room is required for a variety of functions, it may be necessary to provide for a high illuminance with suitable switching and dimming facilities. Reduced lighting should not be obtained by switching off some of the lamps in a multi-lamp luminaire if this gives rise to a patchy appearance. In large rooms, where daylight alone may be adequate only in some parts of the room, it may be necessary to supplement the daylight permanently with artificial lighting. Separate lamp circuits and control switches maybe required to provide the necessary flexibility for both day-time and night-time use. 17.1.6.3 Canteens When lighting canteens, an attempt should be made to give the interior a more relaxing character than is obtainable by a purely functional approach, even if the installation is confined to overhead lighting. A suitable average illuminance is 200 lux and if tubular fluorescent lamps are used, they should have a color rendering index of not less than 80 and give a reasonably warm color appearance. 133 17.1.6.4 Hotel bars In lounges and public bars a minimum average illuminance o f 70 lux is recommended. Focal points, such as tables and bar counters, however, should have a higher illuminance than the remainder o f the room. In cocktail bars, provision should be made for two values o f illuminance, low for normal use and higher for use by cleaners, etc. In all bars, particular attention should be given to lighting the till and the sink in the service areas with local luminaires, in addition to providing a well diffused illumination for the whole service area. A typical arrangement includes low wattage tungsten filament or compact fluorescent lamps in 'downlights ' over the counter, recessed tubular fluorescent lamps over the service area, and enclosed local luminaires to light the sink. Attractive lighting o f bottles on display, either from behind or from the front can be attempted. 17.1.6.5 Hotels and restaurant kitchens In kitchens of catering establishments, the lighting has to be designed to cater for the wide range o f activities associated with the preparation and serving of food. A general illuminance o f 200 lux is recommended and working areas should have an illuminance of 300 lux. In kitchens where there are hoods over the cookers and other equipment, the luminaires may be installed within the hoods themselves and consequently, they should be suitable for the higher temperature and humidities involved. 134 All luminaires should be so designed as to exclude moisture and to facilitate cleaning. Lamps that have a satisfactory color rendering should be chosen. Food service areas should be treated in the same way as the kitchen, with lamps having the same color rendering. 17.1.7 Public Assembly and Entertainment 17.1.7.1 General This proposed clause deals with assembly halls, concert halls, theaters, cinemas, dance halls and exhibition halls and parts of such buildings to which the general public have access, e.g. foyers, corridors, stairways, auditoria and service areas. Safety lighting is required to be provided to assist members of the public to leave the premises if the normal lighting is switched off. Emergency lighting is also required to be immediately available in the event o f failure of the mains supply. 17.1.7.2 Foyers In foyers, the lighting should be such that visual adaptation can be satisfactorily achieved when entering or leaving the building during both night and day. The necessity for visual adaptation coupled with the advertising value of bright surroundings, has often led to the adoption of higher illuminances than the minimum recommended. Tungsten filament, compact fluorescent and tubular fluorescent lamps can be used for these areas, the choice generally depending on aesthetic considerations. The problem of visual adaptation between the brightly lit 135 foyer and the darker auditorium should be solved by progressively reducing the illuminance in the connecting corridors. In cinema and theater foyers the luminaires should be decorative, but at the same time provide adequate illuminance. 17.1.7.3 Auditoria In multi-purpose halls the lighting system should be as versatile as possible. If a substantial reduction in illuminance is required, the lighting should be capable of being dimmed smoothly or switched in stages. Cinema and auditoria may be provided with direct or indirect lighting, or a mixture of both, but all visible luminaires should be decorative and compatible with the interior design. 17.1.7.4 Stage areas In assembly and concert halls a means should be provided to highlight the performers either by increasing their illuminance or by subtly dimming the auditorium lighting in order to focus the attention in the required direction. To enhance modeling, some light may be directed onto the stage from the sides of the auditorium and from as high up as possible. 17.1.7.5 Dance halls Dance halls require good general lighting, usually capable of being dimmed, over the dance floor and adjacent areas. Although this may be provided by tubular fluorescent lamps, it is usual to add a degree of sparkle and modeling by the use of luminaires with incandescent lamps. In addition, the provision of special effects, 136 produced by colored lighting or ultra-violet radiation is often a permanent feature of dance hall installations. 17.1.7.6 Exhibition halls Exhibition halls should be uniformly illuminated by general lighting having reasonable color rendering properties. Provision should be made for additional electrical outlets for the directional lighting of exhibits. 17.1.7.7 Special lighting requirements Recommended systems of lighting in cinema premises and other similar public premises, are as follows: a. In auditoria during the entertainment: both safety lighting and subdued general lighting; b. In auditoria during intervals: both safety lighting and normal general lighting; c. Passages, stairs, etc., and exterior exit ways: in the absence of adequate daylight, both safety lighting and general lighting. (F o r Recommended Illumination levels, refer to Appendix A) 17.1.8 Indoor Sports 17.1.8.1 General Every sport has its own particular lighting problems; nevertheless, the main aim of the designer should be to meet the visual needs o f the players. If, however, 137 spectators are present, it will be necessary to consider their visual needs and any additional requirements for color TV coverage. Sufficient light should be provided to allow players and spectators to follow the intricacies of the game: this will vary widely according to the class and speed of the game, size and color of the detail, degree of background contrast, and the distance of the spectators from the game and, it may, in some installations, be necessary to satisfy the requirements of television. Recommended illuminances are given in Appendix A. If there is a danger of damage to fittings due to impact, luminaires should be protected types. 17.1.8.2 Glare Artificial lighting should be designed to minimize glare as far as possible. In most sports this presents obvious difficulties, since players will have to see equally well in all directions and often upwards. 17.1.8.3 Background of a moving object The background against which the sport is played by day or by night should be carefully considered. It should not embody glare sources and should present an appropriate contrast to the game itself. In this respect the type and position of windows and skylights (if any), luminaires and reflectances of ceilings, walls and floors are all vital factors in the lighting design. 17.1.8.4 Lighting requirem ents Categories of indoor sports: For the purpose of illumination, sports may be divided into four major groups: 138 a. ball games, e.g., tennis, badminton; b. combat games, e.g., boxing, wrestling, fencing; c. target games, e.g., archery, rifle range; d. agility sports, e.g., athletics, swimming, skating. a. Ball games. In these games because both players and spectators may be required to observe the 'ball' against the ceiling and walls for much of the playing time, the luminaires should be carefully cited and adequately screened. The 'ball', throughout its flight should be uniformly lit. b. Com bat sports. The lighting should be confined to, and concentrated on, the relatively small combat area, yet adequately screened from the spectators. c. Target games. The illumination of the target area should be supplemented by the use o f well-screened directional lighting. This additional accent lighting should be superimposed on the shielded general lighting, so that the target is the brightest point in the visual field. d. Agility sports. In these sports areas good general lighting is necessary. In the case of'track' sports, the spectacular effect can be increased by separately lighting the perimeter track, swimming pools can be lit both from above and by underwater luminaires. The diving areas should receive additional lighting. Luminaires external to the pool should withstand conditions o f high humidity and chlorine. 139 17.1.8.5 Multi-purpose halls In order to cater for a wider range of sporting activities, multi purpose sports halls will require both general lighting and special lighting for particular sports, the special lighting either being used alone or to supplement the general lighting. 17.1.8.6 Gymnasia The requirements here are to give adequate general lighting without glare. Where, in addition to their normal function, gymnasia also serve as concert, dance and assembly halls, consideration should be given to the addition of a flexible supplementary lighting system. Alternatively, the basic general lighting should be adequately provided with switch controls to give a choice both in the types of lighting (side and top) and in the illuminance. Glare will be reduced and the lighting increased by using light colors for all the room decorations. Luminaires should be chosen from those designed to withstand impact. 17.1.9 Educational 17.1.9.1 General The detailed design of the artificial lighting should commence with a close study of the wide range of visual tasks that occur in school and college buildings. These may range from normal reading and writing, to close and detailed work such as dissection in biology, fine needlework or technical drawing. 140 Each teaching room may be used in different ways, sometimes with all the groups working on different activities. The room is normally planned to allow for this variety of use, and the lighting should be arranged to give an adequate general illuminance over the whole room including the walls. Local lighting, as necessary, on chalkboards, display areas and fixed working positions, that are at a distance from the windows will also be required. In lecture theaters of the type found in colleges, attention has to be given to providing unobstructed sight lines and satisfactory distribution of brightness and dimming of lights for the use of various visual aids. 17.1.9.2 Illummation An illuminance of 300 lux is recommended for teaching areas. Higher illuminances should be provided for more exacting visual tasks, e.g. 500 lux for laboratories. 17.1.9.3 Quality of lighting Special attention should be given to designing for visual comfort. Direct glare from the lighting system should be avoided, as students will often have to look across the room, as well as down at their own desks. Luminaires should have a limited brightness from normal angles of views, and ceilings should be bright enough to allow the luminaires to be seen against a light background. 141 17.1.10 Library 17.1.10.1 General Reading, both casual and sustained, of a wide variety of printing types and styles, examination of drawings and maps, writing and binding are among the more common visual tasks that have to be performed in the modem library. The accommodation may range from the small private library, modestly equipped, to the large town or country library with a multiplicity o f requirements. The latter may have records and picture loan departments necessitating the critical examination of returned items. As in the case of offices, particular attention should be paid to the avoidance of direct and indirect glare, and the use of decorations and furnishings with a non-gloss finish is recommended. 17.1.10.2 Installation Modem ideas on library design favor the open plan with provision for rearrangement of furniture as needs change. There is much to be said, therefore, for a general lighting system designed specifically to avoid the need for providing local lighting of tables and desks. In practice, it is not always possible to do this as the positioning of the luminaires and the general distribution may be indicated by the form of the building and the predetermined positions of book stacks and tables, and a compromise has often to be accepted. 142 In reference rooms and reading rooms which are infrequently used or rarely fully occupied, local lighting combined with general lighting giving a lower illuminance may be an economic solution. A further exception is in book storage areas where restricted height and width of aisles may necessitate a system of lighting more directly related to the individual book stacks. If local luminaires are used, their positioning will be largely influenced by the design of the desks and tables and the physical size of the literature to be read. Particular attention should be paid to avoid direct glare. Reflected glare from glossy paper will be minimized if the luminaires are placed on each side o f the reader rather than being mounted directly in front o f the reader. Indirect lighting by means o f concealed lamps, placed on the tops of symmetrically arranged book stacks, is sometimes adopted, as it avoids the presence o f visible luminaires unless augmented with local lighting. However, running costs (energy and maintenance) will be relatively high and the ceiling may become a source o f discomfort glare or distraction. 17.1.10.3 Book stacks Although the visual task encountered in book stack areas is relatively simple, factors such as labeling, lettering and book positioning may affect ease of seeing. The restricted width o f the aisle between the stacks makes the achievement o f constant illuminance from top to bottom of shelving impracticable. The material or finish o f the shelving and the floor covering should be of light color to help 143 inter-reflection of light at the bottom of the stack. If the minimum illuminance on the vertical plane is about 50 lux, however, and the luminance contrast between the book titles and their background is good, visual performance will be of an acceptable standard. Continuous line sources, such as tubular fluorescent lamps, housed in louvered or prismatic luminaires which control the light so as to minimize glare when looking along the aisle, represent one method of solving this problem. The luminaires should be mounted centrally between the stacks at a height that does not interfere with the removal of books. Depending on the layout and frequency of use, it may be advisable to install local switching for each 'row' of book stack luminaires. 17.1.11 Religious 17.1.11.1 General The lighting of places of worship usually has to comply with two requirements: a. there should be sufficient illuminance for devotees to congregate, read prayer and hymn books; b. the lighting should be designed to blend with the architectural character of the interior and contribute to the ceremonial aspects of the 'service'. 144 The architectural features of buildings designed for public worship (churches, mosques, temples, etc.) vary widely in respect of each building. Because of this diversity, there is great scope to relate the lighting to each o f those architectural designs and it is not possible to do more than mention a few of the possible lines of approach. For churches, lighting equipment can usually be concealed behind roof trusses, in windows, in recesses in vaulted roofs and in arches. Luminaires positioned behind the chancel arch can be concealed from the congregation and be so mounted as to illuminate the chancel, choir and sanctuary. For temples or mosques with vaulted high ceilings, a similar procedure can be adopted. A simple and effective method of general lighting is the use of pendants and wall brackets which should be aesthetically harmonious with the building. Luminaires should be so positioned that they are not within the normal line of vision of the congregation and pleasing in appearance when the interior is viewed as a whole. Direct downward lighting will result in dense roof shadows and so a proportion of upward light is recommended. 17.1.12 Hospital and Health Care 17.1.12.1 General: The complex nature of a hospital layout and its requirements introduces conflicting considerations that have to be reconciled. For convenience, the accommodation can be divided into four main groups: 145 a. Rooms occupied by the patients, e.g. wards, sick rooms, day spaces and visiting rooms; b. Special rooms, e.g. operating theaters, recovery rooms, diagnostic centers, laboratories and examination rooms; c. Service areas, e.g. kitchen and dining rooms, sterilizing rooms, laundry and maintenance rooms; d. Administration rooms, e.g. offices and staff rooms. This proposed clause refers to those rooms that exist only in hospitals, i.e. groups (a) and (b). Areas (c) and (d) can be lit as per general recommendation for similar areas (see 17.1.6.5 and 17.1.3). 17.1.12.2Wards a. General: The lighting of a hospital ward should satisfy the often exacting clinical requirements of medical staff, yet create a reassuring and pleasing atmosphere for patients. Ward lighting is also complicated by the fact that patients may be in different stages of recovery. It is essential to provide lighting which, while not restricting the activities of convalescent patients, does not disturb those who are less well. The present concept in ward planning tends towards small units of not more than six beds, and it is a growing practice to wheel patients out to separate examination rooms thus obviating the need for special examination lighting in the wards themselves. 146 b. Installation: The mounting height of the luminaires, for general lighting, should be determined by the geometry of the viewing angle and the provision for upward light. Inward 3.0 m high and greater, it will usually be possible to suspend luminaires from the ceiling, but in wards of less than 2.5 m in height, recessed or surface-mounted luminaires are recommended. It is now generally possible to light a multi-bed ward by the use of wall mounted luminaires alone using their indirect component for aisle lighting. c. Glare: The glare in hospital wards should be limited, on the assumption that the patient may get a direct view of the luminaire when in a recumbent position. With the exception of recessed luminaires the amount of light directed on to the ceiling by any luminaire should, in general, be between 40% and 10% of its total light output. The luminaires selected should not harbor dust and should be easy to clean. d. Bed head: A bedhead luminaire should be mounted over each bed and be capable of being controlled by the patient in such a way that adequate illumination is provided on reading matter, etc., without causing visual discomfort to other patients. The luminaire should be designed to allow for reading, whether as patient is sitting up or lying down, and it should be capable of being swung back to allow beds and apparatus to be moved. To permit continuous and adequate observation of seriously ill patients, after the general lighting is switched off, 147 provision should be made for night 'watch' lighting. The most convenient arrangement is an additional small wattage lamp housed in the bed-head luminaire dimming circuit controlling the normal reading lamp. An illuminance o f 5 lux is considered adequate for this purpose. e. Night lighting: During the night time, when patients are sleeping, there should be sufficient general lighting for the night nurse to move around the ward, but light should not fall directly on to the beds. A maximum illuminance on the beds o f 1 lux for children and not more than 0.2 lux for adults, is recommended. In some cases, stray light from the adjoining corridors will be sufficient for this purpose. 17.1.12.3 O perating th eater a. G eneral requirem ents: The main visual problems are the detailed examination o f human tissue and organs and the manipulation o f surgical instruments at the site o f the operation. The size of critical detail can be exceedingly small and the contrast very low. The required illuminance ranges between 10000 lux and 50000 lux. Operating table lighting equipment can be divided into two main categories: i. Adjustable luminaires, containing one or more tungsten filament lamps, with cantilever suspension from the ceiling, operated locally by the surgeon or an assistant. A vast majority o f luminaires are within this category. They have the 148 advantage o f being simple to control and easy to maintain and relamp. The main criticisms are that it is difficult to ensure that such luminaires are thoroughly hygienic and that they produce local concentration o f radiant heat. ii. A number o f sealed and adjustable projectors installed in the ceiling o f the theater or located outside so as to direct their light through a transparent ceiling. They are operated by remote control and thus require skilled manipulation. Such systems are highly versatile and are very useful in teaching hospitals, as they do not obscure the views to observers. They are more complex than (i). iii. Provision should be made for the dimming o f the general lighting in operating theaters. To prevent interference to sensitive medical equipment high frequency filters and shielding, bonded to earth should be considered for fluorescent lighting in operating theaters. Portable floor standing lighting equipment is normally required for supplementary use with systems (i) and (ii). To ensure a satisfactory gradation o f brightness between the high illuminance at the site of the operation and the surrounding areas, a minimum general illuminance o f 300 lux is recommended and this is normally adequate for staff operating the ancillary equipment, b. Standby lighting: Failure o f the electric supply or lamps during an operation may have serious consequences and it is necessary therefore to provide a permanent, reliable and safe emergency lighting system for the operating theater, anesthetic room, sterilizing sink and recovery rooms. The emergency lighting o f 149 the operating table should be equal in all respects to the normal lighting of this area, and should be of the 'no-break' type to ensure continuous illumination. c. Luminaires: Luminaires should meet the requirements of hygiene and should be totally enclosed to provide adequate mechanical protection to the lamp to prevent hot particles falling into the danger zone in the event of lamp breakage d. Light sources: For the general lighting of the operation theater suite, tubular fluorescent lamps that have the color temperature about 4000 K and CRI over 90 are recommended. One advantage in the use of tubular fluorescent lamps is that they radiate appreciably less heat than tungsten filament lamps. For lighting the operating table, however, tungsten filament lamps are generally preferred because of their suitability for optical control. e. Other rooms: The general lighting throughout the operating theater suite including recovery rooms, laboratories, plaster rooms, endoscopy rooms and anesthetic rooms, should be similar in type to that of the theater. The recovery room requirements are similar to those of the general wards, but provision should be made for connecting an examination lamp and separate switching should allow the illuminance over each bed to be raised to 400 lux. In view of the proximity of the anesthetic room to the operating theater, a general illuminance of 300 lux is recommended with provision for dimming to enable anesthetists to provide suitable environmental conditions. Provision should also be made for a fixed or portable spotlight. 150 The color rendering properties of the light sources should be the same as those used for the general lighting of the theater. f. Primary light sources. Color rendering of skin and tissue is a critical aspect of hospital lighting and primary light sources should have an emission spectrum that provides clinically acceptable color rendering. 17.1.13 Laboratories and Research Establishments 17.1.13.1 General The relationship between daylight and artificial light in laboratories requires special consideration. Some laboratories require a degree of environmental control that may be difficult with large windows. In others, black-out may be required. Wall space is often at a premium in respect of storage. For these and other reasons, design solutions with smaller windows and the integration of daylight and artificial light may be favored. Work in laboratories ranges from reading and writing and other simple visual tasks where the detail is fairly large and the contrast good to very exacting tasks with minute detail and low contrast. Typical of the latter tasks are the reading of vernier scales or pipette marks, the identification of substances by their color or texture, dissection work or the identification of fast moving objects. Other important considerations are as follows: 151 a. More scientific work involving the use of apparatus is done more easily when there is a fair degree of modeling. In practice, it is usually possible to achieve this, as well as to comply with the relevant recommended limiting glare indices. In cases where a high degree of modeling is required, adjustable local luminaires are necessary. b. Deep cupboards may require internal lighting with door-operated switches. c. In some laboratories, because of the presence o f corrosive or explosive atmospheres, luminaires designed to withstand these conditions should be used. d. Cleanliness is essential in many laboratories, and the luminaires should not harbor dust or insects and should be easy to clean. 17.1.13.2 Dlumination A research laboratory should have a uniform illuminance of not less than 600 lux. Tasks requiring higher illuminances should have additional local lighting. In many instances instruments such as microscopes or balances are provided with 'built in' lighting. Elsewhere, adjustable bench luminaires will be satisfactory for supplementing the general lighting. In order to compensate for the complexity of the equipment and the wide range of visual tasks, walls and other large background surfaces should be as plain as possible. Although in some instances the preferred bench top materials are inevitably dark, it is desirable to keep other main surfaces as light as possible so as to avoid introducing excessive brightness contrast. 152 17.1.13.3 Light sources In some laboratories, accurate color rendering will be needed for the identification o f materials or stages in a process and, in such cases, light sources that may distort the relationship of colors should be avoided. Color rendering is not always critical, but where it could be, a source having a color temperature of about 4000 K and with a color rendering index greater than 90 should be used. Preferably the illuminance should not be less than 1000 lux. 17.1.14 Mass Rapid Transit Stations 17.1.14.1 General Considerations a. Visibility b. Guidance c. Emergency d. Safety e. Vandalism 17.1.14.2 Public areas Public areas should be lighted by a general lighting system providing illuminance at floor level in concourses, passageways and at the platforms enabling people to move around safely and to find their way easily. During peak hours however with dense pedestrian circulation, most parts of the floor are invisible and visual information is obtained from the ceiling and upper parts of the walls only. 153 Special consideration shall be given to illumination of directional and informative signs. The layout of the luminaire should provide optical guidance in those cases and the upper parts of the walls should be sufficiently lighted, optical guidance can be achieved by using continuous rows of fluorescent luminaires at a mounting height above the floor between 3 m and 5m to follow the run of the main streams of circulation, by a distinct disruption of the regular pattern as seen in the perspective view at junctions and by a concentration of luminaire above locations of special interest. Illuminance of about 200 lux with increased luminance at platform edge is recommended. When screen doors are adopted at the platform edge (for air- conditioning reasons), the illuminances in the car and platform should be about the same to prevent either side acting as mirror. 17.2 Special Lighting 17.2.1 Road Lighting 17.2.1.1 Introduction The purpose of roadway lighting is to promote improved traffic safety, effective traffic movement, and adequate pedestrian safety under all types of weather conditions. A number of key factors which directly affect a person's ability to see must be taken into consideration when designing lighting systems for roadways and traffic. These include: 154 a. The brightness of the roadway background. b. The ratio of the pavement brightness to the surrounding brightness as seen by either the pedestrians or the motorists. c. The size of objects viewed and their detail. d. The brightness of objects viewed on or near the roadway. e. The brightness contrast between the object viewed and its general surroundings (the roadway and its adjacent areas). f. The time available to the motorist or pedestrian to view the object. g. Direct glare from the luminaire. h. Reflected glare from the pavement surface. I. The visual capability of the motorist or pedestrian. Road lighting includes normal street lighting, associated illumination of traffic signs, special pedestrian crossing lights etc. but not the traffic signals or painted boards. 17.2.1.2 Illumination requirements Roadway lighting systems must conform to the required illumination level and uniformity ratios set by the Indian Standards(IS). The illumination levels increase as traffic density, traffic speed, and peripheral areas requiring lighting increase. IS 1994 has specified an illumination level ranging from 30 lux for main arterial roads to 4 lux for secondary roads, these values were specified in 1970. As compared to that, the number of vehicles in the country have increased from 18 155 lakhs(1800000) to 213 lakhs and is estimated to go up to 400 lakhs in a period of a decade As compared to the phenomenal increase in the number of vehicles, the extent of night driving has not increased. Heavy night driving is restricted in some suburban or selected inner city roads. Much higher level of illumination is required in the city roads at the evening peak hours. However, this improved appears to be a waste at night and can be avoided by a developing nation like ours. The classification of roads recognized by the Indian Standards 1944 are listed below. 17.2.1.3 Classification of roads as per the area: The roads include those used for vehicular or pedestrian traffic which are in residential areas, city centers, shopping areas etc. but excluding those which are covered in the other parts of the code, i.e. the roads in the vicinity of airports, docks and other hazardous areas which are not covered herein, the rest of the roads are classified on the basis of vehicular traffic. An additional parameter of evening peak traffic as well as the average vehicular traffic after midnight are taken into consideration. The groups therefore evolved are: a. Group A As classified in Indian Standards (IS) 1944 (P2), this group covers two sub categories — I) G roup A l: This covers main roads with very heavy mixed traffic throughout the day and the night and/or roads catering to very heavy traffic in the 156 evening hours but noticeably lesser traffic at late night hours, such roads are therefore sub divided into group Al 1 and A12 in this code. While doing this, some guidelines about the density of the vehicular traffic are also proposed to be included. Group A ll: These include main city roads with very heavy mixed vehicular and pedestrian traffic. The number of vehicles passing at the peak evening time should be over 5,000 per hour with noticeably heavy pedestrian activity at that time. The group anticipates about 40% to 50% vehicular traffic after midnight with less than 25% pedestrian traffic at that time. Group A 12: These include the same traffic conditions and vehicles per hour as in group A l 1. The extent of vehicular traffic would, however, reduce to less than 15% after midnight. The pedestrian traffic at that time would also be low. Considering the variation, it is necessary to have separate values of recommended illumination levels during that time. ii) Group A2: This covers the city roads which cater to comparatively lower traffic than the roads in group A l. the number of vehicles passing at the evening peak traffic time should be between 3000 and 5000. It is assumed that the pedestrian traffic would be quite high. The change in intensity of vehicular traffic after midnight may be considerable. However no separate criterion is intended for the lighting level after midnight. 157 b. Group B The roads under this group are defined as secondary roads which do not require lighting levels as high as group A roads. i) Group B l: This includes main city roads in shopping streets etc. where the number of vehicles at peak traffic times would be between 1000 to 3000 per hour. Such areas attract relatively heavy volumes of night-time heavy vehicular and/or pedestrian traffic on a frequent basis. It is expected that the traffic, both vehicular and pedestrian, would reduce considerably after midnight. It is desirable to have dual standards of recommended illumination levels. ii) Group B2: This group includes roads where the number of vehicles at peak traffic times would be less than 1000 per hour. These areas are characterized by a moderately heavy night-time pedestrian activity level. Even though the vehicular and pedestrian traffic would reduce considerably after midnight, dual standards of illumination levels are not recommended. c. Group C This includes roads in residential areas as well as unclassified roads including the ones in private residential colonies. In either case these areas are characterized by light night-time pedestrian traffic. Lighting for such roads is primarily required for security. 158 d. Group D This covers bridges and flyovers. These roads essentially form parts of main arterial roads falling under category Al or A2. There may also be bridges which fall under category B l and B2. The considerations which are taken into account in designing the illumination of roads under the respective sections are also relevant here. 17.2.1.4 Uniformity Ratios The illuminance vales will only provide effective visibility when combined with the proper average /minimum and maximum/minimum uniformity ratios. The recommended average/minimum uniformity ratio is 6:1 and maximum/minimum is 12:1 for all applications excepting local roadways i.e. group C. 17.2.1.5 Glare control Glare control is of utmost importance in roadway lighting. Most light related problems occur when the motorist's or pedestrian's view is partially or completely impaired due to direct or reflected glare. 17.2.1.6 Aesthetics Two types of aesthetics are important in roadway lighting: a. Day-form Appearance: This relates to the actual physical appearance of the luminaire and the pole. When selecting a luminaire type, it is important that the overall architectural standard of the community is met. 159 b. Night -form Appearance: This relates to the luminaire's capacity to control glare and unwanted light distribution. It is closely related to glare control. 17.2.1.7 Economics Three types of costs must be taken into consideration when designing roadway layouts. In order of their importance, they are: a. Energy costs b. Maintenance costs c. Initial equipment and installation. 17.2.1.8 Lamp Selection Due to their high efficacy(lumens of light produced per watts of energy consumed), high pressure sodium lamps are the primary lamps selected for roadway lighting. They have an effective lamp life of up to 24,000 hours(say 5 to 6 years of operation time) and they also have the finest lumen maintenance characteristics of all high intensity lamp types. They do not pose any problems of color rendition too. 17.2.1.9 Luminaire Selection Both cutoff and non-cutoff luminaires can be used with resulting advantages and disadvantages in each case, a. Cutoff Luminaires A cutoff luminaire is best defined as one which shields light being emitted from the luminaire at angles above 72 degrees from vertical. 160 The main advantage is light and glare control. These luminaires produce highly distinctive and predictable light patterns and virtually eliminate spill light from occurring behind the luminaire. They are also aesthetically pleasing in day- form appearance. While cutoff luminaires have no true disadvantages, extremely close attention must be paid to mounting heights and pole spacings otherwise it could result in the formation of dangerous pockets of darkness. Fig. 27. Cut-off luminaires can restrict the light to the actual roadway areas. b. Non-cutoff Luminaires These do not restrict the visible light emitted from the luminaire to any specific angle away from the vertical, a fact resulting in several performance characteristics. The main advantage is increased flexibility in mounting heights and pole spacing. When compared to similarly lamped cutoff luminaires, these produce more uniform light patterns when mounted at lower heights on greater pole spacing. The reason for this is the use of a unique combination o f reflector and refractor optics. 161 The lack of light control constitutes the main disadvantage of these luminaires. There is no regulation of beam spread or spill light, since these luminaires do not shield light above the recognized glare angle of 72 degrees, they could provide visual discomfort and are recommended only for residential areas where traffic concentration and speeds are reduced. 17.2.1.10 Roadway Lighting Design Three factors contribute to good roadway lighting design: a. Correct lamp and luminaire selection b. Corresponding mounting height c. Corresponding pole spacing The designer must decide if the system will employ staggered pole spacing or one-side-only pole spacing. Staggered pole spacings provide better light uniformity and also are more economical. One-side-only pole arrangements are applicable when there are physical obstructions on the other side and are advantageous because they need a single electrical wiring system unlike the staggered system. _ J » /*. L < — — 'A- U_ * I . 1 ' ~ \ r ~-----------------------'-------------" — * I \/ 4 - I I I 1UUUM. I I U-LUM.f !■£& TH : s&i -- i— y --------------------------- 2 1 P —W SR^INSi 5^ K---- SP A dK K S ; 5 P A c /M < ^ M OML.V SPA c-V N G i Fig. 28. (A) Staggered and (B) One-side-only mounting pole configurations. 162 17.2.2 Outdoor Sports Lighting 17.2.2.1 Introduction The primary objective of any sports lighting design is to provide adequate visibility for both the participants and the spectators. Good visibility is obtained by controlling the brightness of the playing object and the background it is viewed against. Regardless of its size, location, trajectory, or travel speed, the playing object must be visible from any normal viewing position. In most cases, this visibility is achieved through the illumination of vertical as well as horizontal surfaces. w i d t h w i d t h o f p l a y i n g a k e a - ^ » Fig. 29. For any sports lighting application, the angle created by the ground and a straight line passing through the luminaire and a point one-third across the playing fie ld should not be less than 30 degrees. 17.2.2.2 Illumination Levels The illumination level required is solely dependent upon the type and classification of sport that the lighting layout will serve. Regardless of the sport, 163 the lighting level must be sufficient to allow the participants to comfortably and accurately perform their tasks and to allow the spectator to follow the course of play. Often times, the skill level of the player or the classification of play must be taken into consideration. The visual needs of the spectator also affect the illumination requirements. The lighting levels needed for clear television broadcasting may also affect the lighting design of larger stadiums and playing fields. Illumination levels in sports lighting are most often stated in horizontal values maintained in service. The only time vertical values are of significance is in sports like archery and golf. All aerial sports like football, cricket and tennis require illumination in the open space at the 36’ level above the playing surface. 17.2.2.3 Light Quality Light quality in sports applications can be broken down into three distinct areas: glare control, light uniformity, and light direction. 17.2.2.4 Glare control Glare occurs when the luminance within a particular visual field is sufficiently greater than the illuminance to which the viewer's eyes have become accustomed. Because floodlights are designed primarily for lighting efficiency and not lighting control, the floodlight luminaires employed in many sports lighting designs are inherently glare sources. Therefore, one of the primary tasks of a 164 lighting designer is to reduce the objectionable effects of this glare to the minimum. This task involves four factors: a. Proper beam spread b. Adequate mounting height c. Proper luminaire location d. Proper floodlight aiming techniques. Fig. 30. Viewing at angles away from the beam axis decreases glare. 17.2.2.5 Light Uniformity Reasonable uniformity of illumination is also a prime design consideration. Expressed in terms of horizontal illumination, acceptable uniformity occurs when the ratio of maximum/minimum illumination within the specified area does not exceed the desired. For example the recommended maximum/minimum ratio for tennis is 2:1. A maximum/minimum ratio for other sports in which the play is fast posrho .LUMINAIRE. a t iirvM Jnri 165 paced or requires great hand-eye coordination is 3:1. A 3:1 ratio is also recommended for any sports application which includes spectators. Problems in light uniformity generally occur when there is an inadequate overlap o f beam spreads. To help alleviate potential uniformity problems, the beam spreads of floodlights should overlap by no less than 50%. Of course, correct floodlight aiming is essential to ensure maximum light utilization. 17.2.2.6 Light Direction Adequate light direction is closely related to light uniformity and proper aiming. In order for the eye to see, there must be a difference in the illuminance of an object and its surroundings. There must also be a difference in the illumination of various surfaces in the object itself In all cases, some type of lighting contrast is necessary for the eye to see clearly. Since the visual task of spectators and participants involves viewing both vertical and horizontal surfaces, it is essential to provide adequate illumination on both the horizontal and vertical surfaces of the ball or object of play. This is not the same as uniform illumination on all the surfaces of the playing object. In fact, semi-directional illumination provides the shading and modeling necessary for clear seeing. To eliminate harsh shadows and permit good visibility at all points on the playing surface, it is generally necessary to provide each point on the playing surface with light from several directions. 166 Since the very nature o f floodlighting tends to produce shadows, good directional quality in outdoor sports lighting application is not characterized by an absence o f shadows but by reduction in the number and severity of the shadows produced. For unidirectional sports, such as archery and golf, it is desirable to produce a much higher illuminance level in one direction or plane(in this case, the vertical plane). In such sports , it is possible to locate luminaires so that they are completely shielded or removed from the normal lines o f sight. 17.2.2.7 Economics The major economic factors pertinent to outdoor sports lighting are: a. Energy costs b. Maintenance costs c. Initial equipment and installation costs. 17.2.2.8 Lamp Selection Two types o f high intensity discharge lamps, metal halide and high pressure sodium, are used in modern sport applications. These two lamps provide an efficacy that no incandescent lamp can match. A superior color rendering qualities o f metal halide lamps make them the logical choice over high pressure sodium lamps in sport installation where video broadcasting is common; however, high pressure sodium lamps should be used where maximum efficacy is desired or color rendering is o f secondary importance. 167 17.2.2.9 Luminaire Selection Luminaires used in sport lighting can be broken down into four major classifications: round spun floodlights, cast heavy duty floodlights, architectural sharp cutoff lights, and a new entry-sharp cutoff floodlight luminaires. 17.2.2.10 Combination Fields Lighting systems designed to allow the playing of several sports on the same playing surface are never as satisfactory as individual sports lighting systems, but many institutions find combination fields the only solution to land space and monetary limitations. Most fields are designed to accommodate a two- or three- game combination which may include sports as football and hockey. While the specific lighting requirements of the individual sports involved must be taken into consideration, many compromises will inevitably be necessary. For example, the relative position of the various fields and their boundaries will have a decided effect on the mounting pole positions. Minimizing glare for all sports is the main design criteria when working with combination fields. 17.2.3 Security Lighting 17.2.3.1 Introduction There are two basic classifications of security lighting: a. Surveillance security lighting b. Protective security lighting 168 17.2.3.2 Surveillance Security Lighting Surveillance is a part o f an overall security system employed to visually observe potential intruders or escapees. This is done by guards positioned at certain check-points or stations or on patrol. Closed-circuit televisions may also be used, whereby a single guard can monitor the area. These systems are used where there are large open areas protected by barriers or a fence or in smaller confined areas like walkways between buildings. These systems are often used for prisons, storage depots, nuclear stations, and other facilities which run a high risk of sabotage or theft. The lighting for such systems is uniquely fitted to the needs and physical dimensions of each individual facility, and no standard guideline can be drawn. 17.2.3.3 Protective Security Lighting Most buildings and facilities that have open access to public and can be vandalized or entered by intruders employ protective security systems. In most cases, this system constitutes the entire building's security system. An effective protective security lighting system has the following features: a. It makes the intruder believe that detection by the building occupant, passing pedestrian, or regular night watchman or police patrols will be inevitable. b. It makes detection inevitable if entry into the area occurs. c. It offers its users complete reliability, and failure of a lamp or lamps does not create a dark spot vulnerable to intrusion. 169 d. It does not create glare or spill light which will annoy pedestrians or motorists or neighboring residents. 17.2.3.4 Economics The three main economic factors in the order of their importance are: 1. Operating Costs 2. Maintenance Costs 3. Initial equipment Costs 17.2.3.5 Lamp Selection The type o f lamp selected has a strong influence on operating and maintenance costs, therefore, the HID high pressure sodium lamps are recommended for all protective security lighting systems. HPS lamps have the highest efficacy and life and lumen maintenance are also the finest available. Since color rendition is no problem in security lighting, the golden-white color of HPS causes no problem. 17.2.3.6 Lum inaire Selection The luminaire selected should produce highly efficient asymmetrical patterns to fully utilize the light producing capabilities of an HPS lamp. 170 17.2.3.7 Protective Security Lighting Systems The illumination surrounding a building's perimeter can be provided in two ways: from ground mounted luminaires or from luminaires mounted on building itself. Each method produces a different lighting effect, a. The Shadow and Silhouette System In this system, the building facade is illuminated from ground mounted luminaires located away from the building. Any intruder passing between the luminaire and the building will cast a large shadow onto the building surface.. Fig. 31. An intruder passing between a ground-m ounted luminaire and an illum inated building exterior w ill cast a long obvious shadow. Also if the intruder is approaching, and has not yet entered the area of illumination, his or her silhouette will stand out against the illuminated wall. These shadows and silhouettes are easily detected by passing pedestrians, night watchmen or police patrols. The major drawback of this system is that its ground mounted luminaires are easy targets for intruders and vandals. 171 I - - ' Cl Fig. 32. A s an intruder approaches the perim eter o f a ground-m ounted protective lighting system, his or her silhouette w ill stand out against the lit background o f the building. b. Building Facade or Parapet-Mounted Systems This preferred method involves mounting luminaires on the building itself. A recommended value of 0.5 horizontal foot-candles should be provided throughout the illuminated area. The width of this perimeter area will vary, but it is recommended that the illumination level should extend out from the building a minimum of 20'. It is also accepted field practice to provide a maximum/minimum uniformity ratio of 6:1 or less for visibility. The recommended minimum lighting level of 0.5 fc should extend up the building face for a distance of not less than 3'. 17.2.4 Sign Lighting 17.2.4.1 Introduction: An illuminated sign has the widest application as a communication. In this case application of light as a selling agent -- the dominant 172 consideration is effect, cost of light may be a secondary consideration. The purpose may be to give viewers information or direction, advertise a product or service, or create a striking light-produced visual effect. This category of lighting includes: a. Any group of word(s), letter(s), model(s),sign(s), placard(s), board(s), and notice(s) employed wholly for the purpose of advertisement. b. Any sign post, bus sign, name plate, warning sign etc. not being on a vehicle. Since they both involve the purpose of lighting of vertical surfaces, building and sign floodlighting are best discussed together. The design techniques used for lighting these vertical surfaces are among the simplest and most accurate of all the outdoor lighting designs. 17.2.4.2 Illumination requirements Illumination levels, uniformities and surrounding brightness contrasts vary according to the sign or building and are arbitrary factors assigned according to their function and the conditions in which they are viewed: a. High - Downtown locations with high circulation and high illuminations from street lighting, store windows and high sign concentration. b. Medium - Suburban areas with significantly lower illumination levels from street lighting, store windows and only moderate sign concentration. c. Low - Rural areas with low circulation with very little lighting competition. 173 17.2.4.3 Types of Illuminated Signs a. Exposed lamp signs b. Enclosed Lamp Signs c. Silhouette Signs d. Drifting Signs e. Gas discharge tube Signs f. Floodlighting Signs 17.2.4.4 Design of Signs There are three main characteristics of a sign which together make up its usefulness: a. attracting the passers by b. legibility - which enables them to read the message clearly. c. power of expression - which enables them to remember the message. 17.2.4.5 Factors Affecting Recognition a. Size f. Location b. Distinctiveness c. Color d. Brightness e. Spacing of letters g. Motion h. Contrast i. Legibility 174 / / / / 4 J A * o = » 4o J C f e c f * c o i n d l e 5 . 2 H 2J> Ax A re « iMurYk'neatz^ 4e> V <se»«slle® SgL „ Z7g. 53. ^45 set back distance increases, the area covered w ill increase and illumination level on the vertical surface w ill decrease. 17.2.4.6 Lamp Selection Lamps for sign work present certain special problems. They must be capable of burning horizontally in all kinds of weather and often under conditions of severe vibration. They should have maximum intensity in the direction of the axis of the lamp, i.e., in the direction they are generally viewed, the lamps adopted for most signs are of usual supply voltage and are generally spiraled vacuum lamps in both, clear and colored types. For high speed motion effects, gas filled clear lamps of 15 watt ratings are generally used. The filament heats and cools very rapidly producing a clean, sharp, on-off action. It's used for special effects, running borders and traveling message signs. 175 17.2.4.7 Hoardings Hoarding is a flat surface having a matte finish. It can be illuminated by a comparatively short offset. If long offsets are to be used, for proper illumination, in most cases, lighting fittings are placed below to give upward throw. Hoarding reflectors are of two types ~ symmetric and asymmetric, the latter used for both downward and upward throw. The main advantage of the asymmetric ones is the variation in the form of cut-off angle and they also give even illuminance on a surface which varies in distance from the source. For hoardings, variation brightness though not recommended, is tolerable in practice. Average illumination of 100 lumens per sqm (lux) with a diversity not exceeding 10:1. A hoarding 3 meters high using reflectors at the top fitted with 200 watt lamps, each of the following values are expected: Average illumination 100 lux Maximum illumination 200 lux Minimum illumination 50 lux whereas on the same hoarding with reflectors top and bottom each fitted with a 100 watt lamp, these figures are improved to Average illumination 110 lux Maximum illumination 150 lux Minimum illumination 60 lux. 176 17.2.4.8 Recommended Illuminance Levels a. Externally lit signs Ambient Light Level Sign Illuminance in lux Low 100 - 200 Medium 200 - 400 High 400 - 600 Based on maintained reflectance of 70% for white sign letters. A maximum to minimum uniformity ratio o f 5:1 is recommended as an acceptable ratio of illuminance on the sign face. Lower ratios will produce a more pleasing appearance and a more legible sign. b. Lighting Signs which are lit from the inside surface of the Sign: Ambient light level Sign Illuminance in lux Low 1100 Medium 2300 High 4500 These luminance values are for a white translucent material on the legend and the border. Where color is present, higher illuminance values are required to obtain equivalent legibility. The maximum to minimum luminance ratio for the sign background should not exceed 5:1 luminance. 177 TABLE 17 Recommended Minimum Illumination for Poster Panels, Bulletin Boards, and other Advertising Signs. Average Reflectance of Recommended Illumination Levels Advertising Copy Bright surrounding Dark surrounding Low 1000 500 High 500 200 TABLE 18 Relative wattage of colored and inside frosted Incandescent Filament Lamps required to give signs of various colors of approximately equal advertising value Clear or inside Colored Lamp rating watts frosted lamp Daylight Yellow Orange Green Red Blue rating watts 15 15 05 05 25 25 40 25 25 25 25 40 40 40 178 TABLE 19 Relative Brightness Factors (AB) Lamp Size Watts Watts Size of Sign Total Watts Values of A x B When the general surrounding illumination is Dark is Medium is Bright 100 110 230 350 15 500 160 310 450 1000 210 380 550 2000 250 450 650 100 90 210 325 25 500 140 280 420 1000 175 340 510 2000 225 420 600 100 70 170 275 40 500 115 230 350 1000 160 290 425 2000 200 350 500 100 65 150 250 60 500 100 200 320 1000 140 250 375 2000 170 310 450 100 50 125 200 100 500 75 160 250 1000 100 200 300 2000 125 240 350 179 TABLE 20 Suggested Incandescent Lamps For Sign and Display Lighting For districts of high circulation Surrounding illumination DARK MEDIUM BRIGHT Small exposed 15w 25w 25w 40w lamp signs inside inside blue inside 8m or less frosted frosted sign frosted from ground. Exposed lamp 15w 25w 25w 40w 40w signs 8-25m inside inside blue blue inside from ground. frosted frosted sign sign frosted Large or roof 25w 25w 40w 40w 60w lOOw exposed lamp blue inside blue inside daylight inside sign 25m or sign frosted sign frosted bulb frosted higher. Enclosed lamp 25w 25w 40w 40w 60w lOOw signs blue inside blue inside daylight inside sign frosted sign frosted bulb frosted For districts of low circulation Small exposed 15w 15w 25 w lamp sign clear inside inside 8m or less bulb frosted frosted from ground Exposed lamp 15w 15w 25w 25w signs 8-25m clear blue inside blue from ground. bulb sign frosted sign Large or roof 15w 15w 25w 25w 40w 40w exposed lamp clear blue blue inside blue inside sign 25m or bulb sign sign frosted sign frosted higher. Enclosed lamp 25w 25w 40w 40w signs. blue inside blue inside sign frosted sign frosted 180 REFERENCES 1. Fischer, D. A Luminance Concept for Working Interiors. Journal o f the Illuminating Engineering Society. Vol. 2. New York: Illuminating Engineering Society of North America. 2. Frier, John and Frier, Mary. Industrial Lighting Systems. New York: McGraw-Hill Book Company. 1980. 3. Gilliatt, Mary and Balm, Douglas. Lighting your Home. A Practical Guide. New York: Pantheon Books. 1979. 4. Hopkinson, R. G. and Kay, J. D. The Lighting o f Buildings. London: Faber and Faber. 1969. 5. Illuminating Engineering Society. Code for Interior Lighting. New York: Illuminating Engineering Society of North America. 1977. 6. Illuminating Engineering Society. Lighting ofArt Galleries and Museums. Technical report No 14 of the British Illuminating Engineering Society. 1970. 7. McGraw Edison Company, Halo Lighting Division. The Language o f Lighting. Illinois: McGraw Edison. 1983. 8. Schiler, Marc. Simplified Design ofLighting Buildings. New York: John Wiley & Sons, Inc. 1992. 9. Stein, Benjamin; Reynolds, John S. and McGuiness, William J. M echanical and Electrical equipment for Buildings. 7th Edition. New York: John Wiley & Sons, Inc. 1986.. 181 18. DAYLIGHTING FOR BUILDINGS 18.1 Introduction The relation between people, daylight and architectural form is intimate. Daylight can introduce life, variation, drama into otherwise banal spaces. Throughout the history of civilization, buildings have articulated this relationship. Daylight as a design variable, can be profoundly influenced by building orientation, form and scale and effect the character of interior spaces, and the way the interior space is perceived. The following paragraphs address the more pragmatic issues of daylighting, such as how daylighting strategies impact a building's electric lighting system as well as the total connected electrical load. Although the potential for improved efficiency and energy savings is significant, effective daylighting design requires that time and effort be expended to solve the series of problems and issues which currently act as obstacles to the widespread use of daylighting. The building designer can add to the design palette, technical information about daylight with which the client may make cost effective decisions. Architecture is the masterly correct and magnificent play o f masses brought together in light. Our eyes are made to see forms in light; light and shade reveal these forms; cubes, cones, spheres, cylinders or pyramids are the great primary forms which light reveals to advantage. — Le Corbusier 182 18.2 Design Issues Creativity and sensitivity to daylighting fundamentals will guide most designers to achieve an aesthetically pleasing space, several specific goals should be identified and realized during the design process. 18.2.1 Veiling Reflections Avoid creating conditions within the building where disabling veiling reflections may occur, particularly in spaces where there are critical tasks. There are many types of visual tasks with various degrees of criticality. A receptionist may not require the same level of illumination as a graphic designer. Many spaces in a building can be lighted which do not require a high degree of illuminance. 18.2.2 Quantity Get as much daylight as possible, and as deeply as possible, into the building interior. Generally, the human eye can adjust to high levels of luminance without producing discomfort. Veiling reflections and excessive brightness differences should be avoided. 18.2.3 Brightness Control the brightness of the surfaces within the field of view. Brightness differences will result in uncomfortable spaces. Consideration should be given to controlling brightness in a space and also external to the building. 183 18.2.3.1 Reflect daylight in a space to increase room brightness. Although the source of daylight is the sun, surfaces and objects within a space reflect and scatter this light. Increased visibility and comfort is achieved through increasing brightness by spreading and evening out brightness patterns. This reduction in intensity occurs from reflecting and partially absorbing light throughout a space. A light shelf, if properly designed will increase room brightness and decrease window brightness. (Figure 34 ) Fig. 34. Section o f Light Shelf. 6.2.3.2 Avoid direct beam daylight on critical visual tasks. Poor visibility and discomfort for occupants will result if excessive brightness differences occur in the vicinity of critical visual tasks. It is a fallacy to believe that good daylighting design merely entails adding large apertures of glazing to a building design. Fenestration controls should be considered if direct beam illumination is undesired for the building type being designed. 184 18.2.3.3. Allow daylight penetration high in a space: With the location of an aperture high in a wall, deeper penetration will result. There will be less likelihood of excessive brightness in the field of view by reflecting and scattering light before it gets to task level. 18.2.3.4 Slope ceilings to direct more light into space: Sloping the ceiling away from a fenestration area will help increase the ceiling brightness deeper in a space. (Fig. 35.) Fig. 35. Direct beam penetration with no fenestration control 18.2.3.5 Filter daylight: When harshness of direct light is a potential problem, filtering can be accomplished by vegetation, curtains, or louvers. This can help to soften and distribute light more uniformly.(Figure 36) Fig. 36. Vegetation and Lattice filter. 185 18.2.3.7 Increase perimeter daylight zones. Extending the perimeter of a building may improve the building's performance by increasing the total daylighting space. The trade offs between this increased perimeter exposure and a compact building form are shown in Figure 37. Careful attention should be given to these strategies in terms of the thermal impacts of turning off electric lights due to available daylight and increasing the linear footage of window wall. IT1 T y p i c ^ 1 1 B .L-itr- ' Ur-4 Fig. 37. Increased perimeter exposure. 186 18.2.3.8 Consider other building environmental concerns. Fenestration systems can potentially allow light and/or air into the space. Ventilation, acoustics, views, and electric lighting systems all need to be considered in the design process. 18.2.4 Design Elements There are several design considerations impacting light which affect a building in terms of form and shape. Probably the most significant design determinant when implementing daylighting strategies is the geometry and surface reflectance of the building's walls, ceilings, floors, windows and how each relates to the other. An understanding of the effects of various building elements will provide the basis for manipulating form to achieve adequate lighting levels. It is important to understand geometric relations in terms of lighting functions. It is also important to comprehend the quantitative relationships which accompany various geometric forms. A review of measured or calculated illumination levels for various designs will be helpful as will the experience. Designers need to manipulate the configurations and measure the results before they can really understand the quantitative relationships. This can be accomplished through physical model tests and/or computer simulations. 18.2.4.1 Exterior Elements a. Aperture Location The window size and height above the work plane are very important variables in daylighting design. As the window increases, the amount of daylight received in a 187 space increases. The height of the window from the finished floor will dictate the depth of penetration. The higher the window, the deeper the daylight will penetrate. b. Overhangs Overhangs can be useful fenestration controls for direct beam sunlight, they will reduce the amount of sky seen from within a room in addition to blocking the direct beam. Reflected light from the ground can be caught and directed back into the interior of a space, the result will be a more even distribution of light in the space. c. Skylights Skylighting is an excellent toplighting strategy where large quantities of light can be let into a building with relatively small openings. They are effective for delivering daylight deep into interior zones of single story buildings or into top floors of multi-story buildings. Light wells can be implemented with reflective components to bring daylight into the lower floors of a multistory building. Skylights come in a variety of sizes and materials, these include glazing of acrylic, glass or fiberglass. Probably, the most common skylight is the acrylic dome. These are vacuum formed and housed in aluminum frames, these skylights are relatively inexpensive, easy to install, and durable. The performance of skylights depends on the various transmittance values available. Clear, bronze, gray and several ranges of translucent white are available. The transmittance value selected will depend on the application. For a warehouse where you have bulk storage, quality of tight may not be critical and a high transmitting skylight may be acceptable (visible transmittance = 0.80). In a manufacturing space, 188 you may need as much light and as little glare as possible. Here a diffusing skylight would be more appropriate because it will scatter the direct beam and create a more uniformly lighted space. Skylights will reduce energy consumption of buildings by admitting daylight and reducing the need for electric lighting systems. d. Clerestories Clerestories have many of the attributes of skylights except they have a vertical instead of a horizontal aperture. They typically are exposed to less quantities of daylight and can be oriented to prevent the penetration of direct sun. Clerestory apertures located high in the building will produce deeper penetration of daylight. e. Louvers There are many varieties of louvers for daylight control. Interior applications may be small and movable such as Venetian blinds. Exterior designs may be larger and fixed. Venetian blinds are effective because they can be fixed to block direct beam sunshine or they can be partially closed so light would be reflected in the space and still allow a view to type outdoors. They offer versatility and tend to increase the ratio of ground reflected light to direct sky contribution. Disadvantages, or perhaps, inconveniences of manual louvers include the need for a human operator to adjust them to respond to changing sky conditions. Deterioration of cords and straps may occur and they might become unsightly. 189 Exterior louvers and overhangs are effective methods of blocking direct beam light at high sun angles. Vertical louvers are advantageous for east and west orientations to block direct beam and also reflect light into the interior. Fig. 38. Overhang. f. Glazing Materials A variety of glazing materials is available in the market. Glass with lower transmittances will help reduce bright windows. Selective transmitting material will admit a maximum amount of visible radiation (light), while reflecting or absorbing the non-visible portions of the spectrum which produce heat, but not light. Tinted and reflective glazing are also available in several colors and treatments. 6.2.4.2 Interior Elements a. Room Geometry: The depth daylight will penetrate is dependent on the ceiling height relative to the top of the window. If a space is modeled keeping the floor to 190 ceiling height and the area and location of the window constant, changing the room depth will cause a change in light intensity. With deeper rooms, the same quantity of incoming light is spread over a larger area. A rule of thumb for the sidelighting strategy (unilateral) is that the location of an opaque partition from the window should not be more than two and a half times the height of the window. (Figure 39). I h 1 Fig. 39. Sidelighting Rule o f Thumb. b. Reflectance of Room Surfaces: The reflectance values of room surfaces will greatly impact performance of a daylighted space. The ceiling is the most important surface in controlling the daylight coming into a space to reach the task, the next most important thing is the back wall, followed by the side walls, and finally, the floor. This should mean two things to the designer: keep the ceiling as light as possible and use the floor for patterns or deep colors. Dark colors on the floor will have the least negative impact on the daylighted space. c. Fenestration Controls: Several daylight control devices can be used to eliminate excessive spots and also get daylight is needed. These controls can be static or 191 dynamic. Dynamic controls have an advantage of adjusting for changing sky conditions. A disadvantage is that they require someone to operate them or an automatic device which may be expensive. Static controls are often, however, less responsive and efficient. These fenestration controls can be internal or external, such as movable shades. d. Drapes: Drapes are often used as control devices because they can add texture, color and flexibility to a space. Fabrics are available in a range of weaves with varying Shading Coefficients. The degree to which a window needs to be softened can be accomplished with these weaves. 18.3 Integration with Electric Lighting A complete daylighting system includes automatic photoelectric controls for the electric lighting system. There are many manufacturers producing controls that respond to visible radiation. Two generic types of daylighting controls are available: 18.3.1 On/off Daylighting Controls 18.3.2 Dimming Daylighting Controls These controls both have components which will sense daylight and in response, either dim or switch the lighting system on or off. Controls are essential to a daylighting design if energy savings are to be achieved. Automatic photoelectric controls are recommended as manual controls rely on occupants who are not as reliable. 192 The design professional should select the proper control based on the characteristics of the space. Selection consideration for a daylighting control should include: a. Type of space (industrial, office, retail) b. Types of lamps and/or ballasts c. Layout of fixtures d. Size of the room The optimal control system will reduce the electric lighting system without adversely affecting the illumination quality of the space. Time delays to reduce rapid responses in light intensity are necessary. Control units should be equipped with these to accommodate this capability. 18.3.1 On/Off Controls On/Off (also known as switching) controls simply turn off electric lights when the required foot-candle design level is met. Task switching devices control one or two fixtures by sensing the light level at the task. This device will sense two light levels to compensate for electric lighting. When enough daylight is available, lights will be turned off. when the amount of illumination drops below what is required, the lights will be turned on. Source switching is another type which senses daylight at the area source(i.e. window, skylight). These devices are typically capable of reading higher levels of 193 illumination up to a range o f3000 - 4000 foot-candles(fc). Both switching devices can be installed to control one luminaire or ganged with relays to control several circuits. 18.3.2 Dimming Controls Dimming controls reduce the electric lighting proportionately with increases in the amount of available daylight. Dimming controls installed on fluorescent lamps with standard ballasts are available in a variety of configurations. Two generic types are available: 18.3.2.1 Single Fixture Dimmers Single fixture dimmers will control one or two ballasts. Typically, a fiber-optic tube senses available daylight and transfers this to a control box mounted on a fixture. Each fixture in a daylighted zone will have a control. An advantage to this type of system is that variations in illuminance design levels can be accounted for. Therefore, this may be more appropriate when an office space with a south orientation has drafting stations with a conference room adjacent to it. The drafting space may require 80 foot- candles, while the conference room needs only 30 foot-candles. The controls for the luminaires in each space will respond to a room's specific task instead of uniformly dimming a complete circuit. 18.3.2.2 Multiple Fixture Dimmers Multiple fixture dimmers are useful when a large number of fixtures are dimmed. This a common strategy when all the spaces along a single building orientation have similar tasks occurring in them and are consequently considered one 194 daylighting zone. One sensor is used to read the daylight level, which produces an electronic signal to a controller and dims the lights. In this type of system, one sensor and one controller can dim several hundred watts of lighting. To ensure good economic feasibility, the maximum allowable watts should be connected to a control. Be sure that areas not receiving daylight, such as curtain walls interrupted by a structural column, are not on the same controlling switch loop. Dimmed spaces should all receive equal amounts of daylight. Not all fluorescent lamps can be dimmed. Product literature should be matched before specifying dimmers with energy saving lamps. Controlling HID lamps is currently limited to on/off strategies and dimming with transformers. Concerns being investigated include the impacts on the life of the lamp and ballasts and on the color rendition. Some electronic dimmers exhibit undesirable characteristics such as flickering and waveform distortion. Careful product evaluation is required to assure the acceptability of these devices. 18.3.3 Quality of Space Photoelectric controls are essential to realize energy savings, however, sensitivity to the occupants of the space is critical. An office building, for example, with an on/off control used on a three lamp fixture is best wired switching only two of those three lamps off. The reason is that most people are accustomed to seeing a lighted ceiling. Even though foot-candle design level is maintained completely with available 195 daylight, it is recommended leaving one lamp on. Users of daylighted spaces tend to feel more comfortable in that type of environment and the probability for a successful daylighted space is much higher. Other building types such as industrial spaces with toplighting strategies implementing skylights, will probably be perfectly acceptable using on/off controls turning all the luminaires in a daylighted space off. 18.3.4 Control Schemes The selection of automatic controls should be carefully approached. The foresight taken in schematic design to use various daylighting strategies can be completely negated with an ill-conceived electric lighting control system. Reductions in electric lighting energy consumption without adversely affecting the quality of the space is an important objective of the design. REFERENCES 1. Evans, Benjamin H. Daylight in Architecture. New York: McGraw-Hill Book Company. 1981. 2. Lynes, J. A. Principles o f Natural Lighting. London: Elvesier Publ. Ltd. 1968. 3. Moore, Fuller. Concepts and Practice ofArchitectural Daylighting. New York: Van Nostrand Reinhold. 1991. 4. Schiler, Marc. Simplified Design ofBuilding Lighting. New York: John Wiley & Sons, Inc. 1992. 196 19. ECONOMICS AND MAINTENANCE 19.1 Economics Although the initial cost of lighting equipment and associated wiring is an economic factor, it should not be the sole criterion in the design of a lighting installation. To make a fair comparison between the economics of various lighting systems giving equal lighting conditions, the annual cost should take into account the following: a. Amortization of the initial cost of lamps, luminaires and installation; b. Cost of electrical energy and replacement lamps; and c. Maintenance costs, including labor costs of lamp replacements and cleaning of luminaire. It should be borne in mind that accounting procedures vary and the relationship between capital and revenue may influence any decision. However a "Life cycle" comparison which takes into account prevalent financing costs and amortization period of choice, gives a fairly accurate picture of relative economics. Flowchart 4 shows the procedure for ‘Life cycle costs of a lighting installation’. 197 Life Cycle Cost for a Lighting Installation Procedure 1 a. Room Index (K) L x W K = H (L x W) where: L W H Room length (meters) Room width (meters) Difference between luminaire mounting height and working plane height (meters) b. Utilization Factor For given Reflectances of Ceiling (Rc), Walls (Rw) and Working Plane (Rf) depending on the interior, read offUtilization Factor (UF) from the Light Distribution data and UF table for the luminaire published by the luminaire manufacturers. Light Distribution data are also published as bar codes by manufacturers. c. Number of Luminaires E x L x W N = LPFxNLxM xUFxV where: E L W LPF NL M UF V Required illuminance (lux) Room length (meters) Room width (meters) Lamp flux (lumens) Number of lamps per luminaire Light loss factor Utilization factor Ventilation factor (published by Luminaire Manufacturer and mainly relevant to fluorescent luminaires) 198 Procedure 2 a. Investment (Inv) Inv= N x (LPR + INSTC + LAPR + NL) where: N = Number of luminaires LPR = Luminaire price INSTC = Installation costs per luminaire LAPR = Lamp price NL = Number of lamps per luminaire Procedure 3 a. Capital Annuity Cost (CC) CC = (Inv-N xNLx LAPR) x AF where: Inv AF Investment Annuity Factor based on amortization period and interest rate (For N, NL, LAPR and AF) R/100 AF = -------------------------- 1 1_(-----------) A 1 + R/100 where: Procedure 4 a. Energy Cost (EC) Ec = N x LWATT x KWHPR x BRNH where: AF R A Annuity factor Interest rate (%) Amortization Period (years) N LWATT KWHPR BRNH Number of luminaires Total luminaire wattage Kilowatt-hour price Burning hours per year 199 Procedure 5 a. Lamp Cost (LC) N x NL x LAPR Lc = RP where: N NL LAPR = RP Number of luminaires Number of lamps per luminaire Lamp price Relamping period (years) Procedure 6 a. Maintenance Cost (MC) NxMCL MC = --------------- RP where: MC = Maintenance costs per year N MCL RP Number of luminaires Maintenance cost per luminaire Relamping period (years) b. Total Cost (TC) TC = EC + CC + LC + MC where: EC CC LC MC Energy costs per year Capital annuity costs Lamp costs per year Maintenance costs per year 200 Flowchart 4. Life Cycle Costs of a Lighting Installation Select luminaires in lux for the application Select possible types of Luminaire(s) and Lamp(s) based concerned from Code o f on Electrical, Mechanical, Practice Optical a n d Aesthetic Criteria as Alternatives A C, D. Compute Ho. o f Luminaires for Schemes A,B,C,D, Adjust Quantity to suit a rational layout. Scheme A Scheme B ; Scheme C Scheme t > Luminaire A Luminaire B LxaninaireC Luminaire D Lamp A Lamp B Lamp C Lamp I > Compute investment (INV) Compute Capital Annuity Cost(CC) Computi Energy Cost (EC) Compute Compute jjjj TOTAL M aintenance ANNUAL Cost ■ COST MC) I I (TC) Go to Schemes B, C, & D Life Cycle Comparison 19.2 Maintenance of Lighting Systems 19.2.1 General Principles Good maintenance of lighting systems reduces deterioration of the equipment, the interior, promotes safety, keeps the lighting performance within design limits, and helps to minimize the electrical load and capital costs. Maintenance includes renewal of failed or faulty lamps and control gear, and cleaning of luminaires and room surfaces at suitable intervals. 19.2.2 Light Loss Factors Throughout the life of a lighting system, the light available in the working place progressively decreases. The factors contributing to this depreciation are many and called Light Loss factors. Light loss factors, often expressed in terms of percentages, indicate the expected amount of uncontrollable depreciation and the amount of projected effort that will be necessary to overcome this depreciation. A number of these light loss factors are discussed below: 19.2.2.1 Light Source Depreciation The light output of a lamp decreases with time and the rate of depreciation (Lamp Lumen Depreciation) generally depends on the type of lamp but can vary between lamps of the same type produced by different manufacturers. The useful life of a discharge lamp can be regarded as that period during which the lumen output does not fall below 75% of the rated initial value. The lamp should therefore be replaced 202 when this life is reached. For any calculation concerning lamp lumen depreciation, the lamp's mean lumen value should be taken. 19.2.2.2 Luminaire Depreciation and Maintenance A significant amount of light loss can generally be attributed to dirt accumulation on luminaire surfaces and permanent discoloration of its optical control caused by age, by radiation from the lamps or by corrosion in some atmospheres, etc. The rate of accumulation of dirt depends on luminaire design and location. Luminaires should therefore be cleaned and serviced at regular intervals. Luminaire Dirt depreciation(LDD) is the multiplier used to relate the initial illumination provided by a clean luminaire to the reduced illumination provided by a dirty luminaire at the time of anticipated cleaning. TABLE 21 Fixture Categories for Lamp Dirt Depreciation Category Top Enclosure Bottom enclosure I 1. No top enclosure 1. No enclosure n 1. No top enclosure 1. No enclosure 2. transparent, translucent or opaque top with 15 % or more uplight through apertures. 2. Louvers or baffles m 1. Transparent, translucent, or 1. No enclosure opaque top with less than 15 % uplight through apertures. 2. Louvers or baffles. IV 1. Transparent or translucent with 1. No enclosure no apertures. 2. Louvers V 1. Transparent or translucent with 1. Transparent or translucent with no apertures. no aperture. VI 1. No enclosure. 1. Transparent or translucent with 2. Transparent or translucent with no apertures. no aperture. 203 L D D (LUMINAIRE D IR T DEPRECIATION FACTOR) CATEGORY I 1.0 0.9 0.8 0.7 0.6 05, M ONTHS CATEGORY. IV W 0.9 VC 0.8 0.7 CATEGORY II VC VD MONTHS CATEGORY V V C VD MONTHS CATEGORY III VC D. VD M ONTHS CATEGORY V I % " V t N ^ ‘ > ^ v c V s . \ N.,' X s t x v 0 3 6 9 1? 1 5 1 8 2) 24 27 3 33 36 M ONTHS ro o TABLE 22 Luminaire Dirt Depreciation Factors (LDD) 19.2.2.3 Room Surface Depreciation Generally in commercial and industrial buildings, wall and ceiling finishes with high light reflectance values are used, these are particularly important in indirect lighting application The illuminance of a work place is a mixture of direct light from the luminaires and diffused light reflected back from ceilings and walls. Dirt accumulation on these surfaces tends to reduce the amount of reflected light. Room surfaces should therefore be cleaned at regular intervals and the use of light colored walls and ceilings is recommended. TABLE 23 Room Surface Dirt Depreciation Factors MONTHS Luminaire Distribution Type Direct Semi-Direct Direct-Indirect Semi-Indirect Indirect 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 10 20 30 40 .98 .96 .94 .92 .97 .92 .89 .84 .94 .87 .80 .76 .94 .87 .80 .73 .90 .80 .70 .60 .98 .96 .94 .92 .96 .92 .88 .83 .94 .87 .80 .75 .94 .87 .79 .72 .90 .80 .69 .59 .98 .96 .93 .90 .96 .91 .87 .82 .94 .86 .79 .74 .94 .86 .78 .71 .90 .79 68 .58 .97 .95 .92 .90 .95 .90 .85 .80 .94 .86 .79 .73 .94 .86 .78 .70 .89 .78 .67 .56 .97 .94 .91 .89 .94 .90 84 .79 .93 .86 .78 .72 .93 .86 .77 .69 .89 .78 .66 .55 .97 .94 .91 .88 .94 .89 .83 .78 .93 .85 .78 .71 .93 .85 .76 .68 .89 .77 .66 .54 .97 .94 .90 .87 .93 .88 .82 .77 .93 .84 .77 .70 .93 .84 .76 .68 .89 .76 .65 .53 .96 .93 .89 .86 .93 .87 .81 .75 .93 .84 .76 .69 .93 .84 .76 .68 .88 .76 .64 .52 .96 .92 .88 .85 .93 .87 .80 .74 .93 .84 .76 .68 .93 .84 .75 .67 .88 .75 .63 .51 .96 .92 .87 .83 .93 .B6 .79 .72 .93 .84 .75 .67 .92 .83 .75 .67 .88 .75 .62 .50 Per Cent Expected Dirt Depredation Room Cavity Ratio 1 2 3 4 5 6 7 8 9 10 205 19.2.2.4 Voltage Drop: Voltage drop can seriously lower light output. In addition to the drop in the wiring system, there are possible drops in the service voltage too. 19.2.2.5 The Ballast factor: Light loss due to the operational characteristics of the lamp's ballast is usually a problem only in systems employing fluorescent lamps, the accepted factor is 0.90, resulting a light loss roughly up to 10%. 19.2.2.6 Luminaire Ambient Temperature: Cold weather can seriously reduce the light output of fluorescent lamps, and use of special protective jackets and special ballasts should be considered in cold places, cold ambient temperature does not effect the output of HID and incandescent lamps, but exceedingly high temperatures can adversely effect all three lamp groups. This can lead to ballast overheating and malfunction, or lamp failure, or adversely effect luminaire finishes. 19.2.2.7 Luminaire Surface Depreciation: The reflective surfaces or lenses of luminaires can be adversely effected by exposure to certain chemicals or cleaning agents and scratching and marring of these surfaces during cleaning or servicing can also lower the distribution of light. 19.2.2.8 Lamp Burnouts: As lamps within a system bum out, the average system illuminance decreases proportionately. It is recommended that a regular schedule of group lamp replacement is conducted in which all the lamps are replaced at on time. 19.2.3 Group Replacement of Lamps The most economical cleaning interval for a given lighting installation will depend on the type of the luminaire, the rate at which dirt accumulates, and the cost of 206 cleaning. For maximum economic advantage, the luminaire cleaning interval should be related to the lamp replacement interval. Lamps may be replaced individually as they bum out, or the entire installation can be relamped at one time. The latter method is known as group replacement. For large installations, money is saved by organized group replacement rather than by replacing lamps individually. Moreover this will entail a higher maintenance factor to be applied. As the calculation of the lighting installation depends on the knowledge of the planned maintenance schedule, the latter must be adhered to if the design illuminance levels is to be maintained. A maintenance factor should be allowed for in the design stage to cater for dirt and dust accumulation and light source depreciation, its values depending on the environment and types of lamps and may have to be scheduled in dirty industrial environments and each case should be based on an individual basis. REFERENCES 1. Illuminating Engineering Society. Depreciation and Maintenance o f Interior Lighting. IES Technical report No 9. New York: IESNA. 1967. 207 E. CONCLUSION On gaining Independence, India introduced centralized planning for social and economic development and established a series of scientific and research bodies to provide the infrastructure for such development. This vast development effort was widely noted by all developing countries as a role model. After more than forty-five years, considerable development has taken place, but certainly, problems have not disappeared. India is now more than ever on the threshold of a new phase of development based on the experience of the last so many years both in science and technology. The coming phase may be marked with greater self- reliance as well as closer co-operation with the other nations. It has been emphasized time and again by the Government of India that it is trying to bridge, in a matter of decades, the gap created by a century and more of stagnation. India has considerable experience in technology transference in its development program. Over time and particularly since we achieved independence, the countries with which we have concluded agreements as well as the range of knowledge import has been enlarged. We have been attempting of late, a critical review of what has been achieved by the intake. This has thrown up a number of issues for both Policy and Planning for consideration by the Government. Some of the major concerns are perhaps shared by other developing countries in the Asian Continent. 208 It is always mentioned that the developing countries have a particular advantage of being latecomers in the sense that technology and policies have already been developed in the advanced countries. The situation is not so simple. There are well known difficulties of importation of raw knowledge. In many cases, it has to be modified and adapted to a certain level of understanding and scale of application in the recipient countries. However, on the other hand, the developing countries indeed are at a disadvantage compared with the now developed nations when they started their effort. The consumption and applicability pattern is conditioned by that of the advanced country through the demonstration factor. This factor creates demand and pressures of an economic and social nature inside the developing country which leads to the import of ideas which do not correspond to the economic, social and cultural system. It may be that for more rational implementation, consumer and applicability patterns and inputs shown be more conditioned to the basic requirements of the masses of the population at the lower income levels and partially isolated from the impact of social and consumption patterns of the developed countries. Given the early start achieved by the more advanced nations, it is only natural that their patterns assist in the development of the developing nations. Reinventing the wheel can be a costly, time-consuming and an inappropriate endeavor for the poorer countries considering their present phase of development. 2 0 9 One of the most significant factors affecting transfer of knowledge is based on local development in the interaction between scientific and political communities. The politicians must especially identify the socio-economic objectives and the scientists should be appraised of them promptly and in clear terms. Where technocrats have attempted to bridge the gaps of generations of ignorance, they have taken recourse to a doctrinaire policy of rigidly applied Standards. Standardization has the advantage of harmonizing under-development and modem technology. It is agreed that Standardization stultifies innovation and impedes progress. It could also be argued that non-application of Standards in a growing economy coupled with a lower level of technical education could lend to chaotic conditions. There is much merit in both arguments and this thesis , I hope, has addressed this dilemma and attempted to redress the imbalance between the literature and ground realities. An environmentally harmonized and ecologically friendly global energy policy demands optimum utilization of all natural and artificial sources. Technological advances have helped develop more efficient devices that will provide more ‘Bang for the Buck’. Energy production consumes most of the world’s available fossil fuels and it is estimated that the existing known reserves of fuel may provide for about a 100 years of energy production at existing consumption levels. What is required therefore is a search 210 for newer sources of energy and concurrently an attempt at optimum utilization of existing resources. At the heart of the matter is the ‘technological tyranny’ of Standards and the profligacy of individualism which may more often than not be based on lack of technological inputs. An attempt has been made at the harmonious blend of the two approaches. At first the Standards have been enunciated and then an attempt has been made to spell out the factors that lead to establishing the parameters of the Code. The reader has been left with the option to either use the Standards as a ‘rule implement’ or to intelligently use the Code. With existing traditions, cultures, availability of resources, technological infrastructure and ‘state of art’, Lighting Codes will then become a responsible and responsive Art. 211 APPENDIX A TABLE 24 SOME RECOMM ENDED ILLUMINANCES Area O r Activity niuminance Lux Recommended Design Value WORKING INTERIORS Bakeries: General working areas 200-500 300 Decorating, inspection 300-750 500 Breweries 200-500 300 Canning And Preserving Factories 300-750 500 Carpet Manufacture: Winding, beaming 200-500 300 Production processes 300-750 500 Weaving, mending 300-750 500 Inspection 500-1000 750 Chemical Works: Interior plant areas 200-500 300 Grinding, mixing, calendering, injection 300-750 500 Control rooms 300-750 500 Laboratories 500-1000 750 Color matching 750-1500 1000 Chocolate Factories: General working areas 200-500 300 Decorating, inspection 300-750 500 Dairies: Bottling milk 200-500 300 Electrical Industries: General working areas 200-500 300 Assembly work: - Medium 300-750 500 - Fine 500-1000 750 - Very fine 750-1500 1000 Adjustment, inspection 750-1500 1000 Electronic Equipment Manufacture: Printed circuit boards manufacture 300-750 500 Silk screening 300-750 500 Insertion of components 500-1000 750 Inspection 500-1000 750 212 Area Or Activity Illuminance Lux Recommended Design Value Assembly of wiring harness 500-1000 750 Chassis assembly 750-1500 1000 Soak test 100-300 200 Safety and functional tests 200-500 300 Founderies: Rough molding, pouring 100-200 150 Fine molding, core making, inspection 300-750 500 Furniture Manufacture: Raw material stores 50-100 75 Finished goods stores 75-150 100 Wood matching and assembly, rough sawing, cutting 200-500 300 Machining, sanding and assembly, polishing 200-500 300 Finishing 200-500 300 Upholstery Manufacture: Cloth inspection 750-1500 1000 Filling, covering 300-750 500 Slipping, cutting, sewing 300-750 500 Mattress Making: Assembly 200-500 300 Tape edging 500-1000 750 Pharmaceutical And Fine Chemicals Manufacture: Grinding, mixing, tableting, filling, wrapping 200-500 300 Inspection Exterior plant Soap Manufacture: 200-500 300 Tobacco Processing: Preparation, making, packing 300-750 500 Hand processes 500-1000 750 213 Area Or Activity Illuminance Lux Recommended Design Value Glass Works: Furnaces, annealing 100-200 150 Mixing rooms 100-200 150 Cutting, forming, grinding, polishing 200-500 300 Decorating, etching 200-500 300 Leather Factories: General 200-500 300 Pressing, glazing 300-750 500 Cutting, sewing 300-750 500 Grading, matching 750-1500 1000 Machine Shops: Rough bench and machine work, welding and soldering 200-500 300 Medium bench and machine work 300-750 500 Fine bench and machine work 300-750 500 Very fine work, gauge rooms 500-1000 750 Very fine precision work, inspection 750-1500 1000 Mechanical Engineering: Structural steel fabrication 300-750 500 Sheet Metal Works: Pressing, punching, shearing, stamping, spinning, folding 300-750 500 Benchwork, scribing, inspection 300-750 500 Die Sinking Shops: General 300-750 500 Fine work 750-1500 1000 Paint Shops And Spray Booths: Dipping, rough spraying 200-500 300 Preparation, ordinary painting, spraying and finishing 300-750 500 Fine painting, spraying and finishing 300-750 500 Inspection, retouching, matching 500-1000 750 Plating Shops: Vats and baths 200-500 300 Buffing, polishing, burnishing 300-750 500 Final buffing and polishing 300-750 500 214 Area of Activity Illuminance Lux Recommended Design Value Rubber Products: Preparation-plasticising, milling 100-200 150 Calendering, cutting, extruding, molding, etc. 300-750 500 Inspection 500-1000 750 Printing Works: Type foundries: - Matrix making, dressing type, hand and machine casting 200-500 300 - Assemble and sorting of font 300-750 500 Composing room: - Proof presses and reading 300-750 500 - Retouching, etching 500-1000 750 - Color reproduction and inspection 750-1500 1000 - Printing machine room 300-750 500 Binding: - Folding, pasting, punching, stitching 300-750 500 - Cutting, assembling embossing 500-1000 750 Textile Mills: Washing, spreading 200-500 300 Reeling, spinning 300-750 500 Weaving plain cloth 500-1000 750 Weaving fine worsteds, linen, synthetics 500-1000 750 Inspection, mending 750-1500 1000 Warehouses And Bulk Stores: Storage 100-200 150 Automatic High-bay Racks: Gangway 20-50 30 Control station 150-300 200 Packing and dispatch 200-500 300 Cold Stores 100-200 150 Woodworking Shops: Rough sawing, bench work 200-500 300 Sizing, planing, sanding, medium machining and bench work 300-750 500 Bench and machine work, fine sanding, finishing 300-750 500 Inspection 500-1000 750 OFFICE AND SCHOOLS Offices: Conference rooms, executive offices 300-750 500 215 Area of Activity Illuminance Lux Recommended Design Value General offices: - Normal 300-750 500 - Deep plan 500-1000 750 Computer work stations 300-750 500 Computer and data preparation rooms 500-1000 750 Filing print rooms 200-500 300 Drawing office(general) 300-750 500 Drawing boards 500-1000 750 Schools: Classrooms, lecture theaters, libraries 200-500 300 Laboratories, reading rooms, art rooms 300-750 500 Chalkboard, whiteboard ----- 300(vertical) SHOPS, STORIES AND EXHIBITION AREAS Shops: Conventional shops 300-750 500 Self-service shops 300-750 500 Supermarkets 500-1000 750 Shopping precincts and arcades 100-200 150 Departmental stores 300-750 500 Show Rooms 300-750 500 Museums And Art Galleries: General: - Lighting sensitive exhibits 100-200 150 - Exhibits insensitive to light 200-5000 300 - Workshops 300-750 500 PUBLIC BUILDINGS Entrance Halls, Lobbies, Waiting Rooms 100-200 150 Enquiry Desks 300-750 500 Gatehouses 100-200 150 Lifts(Interior), Corridors, Escalators, Travellator 100-200 150 Car Parks: Floors and outdoors #10-20 15 Ramps and comers #50-100 75 Entrances and exits #50-300 100 216 Area O r Activity Illuminance Lux Recommended Design Value Cinemas: Auditoria 50-100 75 Foyers 100-200 150 Multi-purpose Sports Halls(recreation) 150-300 200 Multi-purpose Sports Halls(tournament) 300-750 500 Color TV coverage 750-1000 1000 Theaters And Concert Halls: Auditoria 75-150 100 Foyers 150-300 200 Sacred Buildings: Nave 75-150 100 Choir 150-300 200 Hospitals: General level in operating theaters* 200-500 300 Recovery room, laboratories, anesthetic rooms, endoscopy room 200-500 300 HOMES AND HOTELS: Homes: Bedrooms: - General 50-100 75 - Bed head 150-300 200 Bathrooms: - General 75-150 100 - Shaving, make-up 300-750 500 Living rooms: - General 75-150 100 - Reading, sewing 300-750 50 Stairs 75-150 100 Kitchens: - General 150-300 200 - Working areas 300-750 500 Workroom 200-500 300 Nursery 100-200 150 Hotels: Entrance halls 200-500 300 Dining rooms 200-500 300 2 1 7 Area of Activity Illuminance Lux Recommended Design Value Kitchens 300-750 500 Bedrooms, bathrooms: - General 75-150 100 - Local 200-500 300 MISCELLANEOUS Indoors: Circulation areas, corridors and stairs 100-200 150 Lifts 75-150 100 Enquiry desks 300-750 500 OTHER WORKING INTERIORS: Paper Mills: Paper and board making 200-500 300 Printing, inspection, sorting 300-750 500 Ceramics: Firing 200-500 300 Molding, pressing 300-750 500 Enamelling, decorating 500-1000 750 Plastics And Rubber: Automatic plant 50-100 75 (Plant with manual control) 200-5000 300 Non automatic plant 200-500 300 Mixing, extrusion, injection, molding etc., trimming, cutting, polishing, cementing 300-750 500 Printing, inspection 500-1000 750 # Daytime levels will be on the higher side and night levels will be on the lower side as the latter has to match street lighting levels only. * Excluding special operating light. 218 APPENDIX B THE PROPOSED CODE FOR LIGHTING * The maximum allowable load for lighting is proposed not to exceed 2.5 watts/sf. * For building spaces larger than 200 sq ft, circuiting and individual switching is proposed to be provided so that Lighting energy can be reduced by at least one half. Lighting can be turned off. * Exterior decorative lighting is proposed not to exceed 2 % of the total lighting load. PROPOSED LIGHTING CODE COMPLIANCE SOFTWARE FOR COMMERCIAL BUILDINGS Introduction A computer program is proposed to be designed to simplify the task of determining whether or not a commercial building complies with the Code. The program is expected to enable: * Creating an information file for a building. * Entering the design data for the building. * Calculating compliance using one of the two methodologies, namely Method A: Whole building Performance Method. Method B: Component Performance Method. * Printing a suitable report for submission to the Permit Office. 2 1 9 Although the procedure for calculating Code Compliance is different for each method, one should be able to enter the information the same way for either method. In each case, the program is proposed to evaluate the building data, display the results and issue a Pass or Fail grade regarding the building’s lighting performance. After the program calculates compliance, one should be able to print the results. Depending on the choice of compliance method, the form should be produced which can be submitted to the Permit Office. It is proposed that the same program provide a means for evaluating each of the various systems like electrical, cooling , heating, air handling, air distribution systems etc., as well as an evaluation of their interaction with one other. Definitions and required information should be described in the Help area of the program. Overview FILE EDIT CALCULATEREPORT HELP New Project Data Method A Results of Alt key Open Walls chosen functions Save Fenestration Method B calculation Save as Doors methodologies Buttons Exit Roofs Print Floors Lighting About- HVAC Systems Water Heating 220 _____________ Project/Building Data Screen__________ Project Title Project Number Project Owner Project Permit Number Project Address Project Type (New Construction/Existing Construction) Building Type (Assembly, Office etc.) Building Location (Climatic Location) Building Gross Floor Area Building Gross Lighted Area Building Net Conditioned Area Total Number of stories Total Number of Zones Walls (Orientation, Length, H eight, Area) Lighting Screen The screen allows the user to enter the lighting information for the building according to the type of internal space. When the lighting screen is accessed, the top of the screen should display ‘New Entry in Zone 1’. An individual lighting screen should be completed for each specific internal space of a particular size, activity type and lighting configuration. A single zone can be broken down into any number of activity spaces but every zone must have at least one space type identified in it. Up to 50 separate spaces can be entered. Space Type: Select Space Type from the Space Type Description option table (Pg up/Pg dn). Descriptions of activities in spaces are very precise. For example, Office space is first broken down into closed or open (Low, Medium or High Partition) 221 and further broken by general activity in space— reading, drafting, accounting etc. If actual activity in a particular space is not listed, select a space type which most closely describes a activity. Right hand column of the Space Type Description Table displays lighting Unit Power Density allocated to each space type. This value is set at default, but defaults must be the most restrictive case. Lighting Screen New entry in Zone 1 Space Type Space Width Space Depth Space Height Space Area Number of spaces Total Space Area Lighting Type 1 Number of Fixtures Fixture wattage Single Space Wattage Total Type 1 Wattage Control Type 1 Numbers of Controls type 1 Lighting Type 2 Number of Fixtures Fixture Wattage Single Space Wattage Total Type 2 wattage Control Type 2 Number of Controls Type 2 OK NEXT PREY CLEAR CHGZONE DAYLIGHT 222 Space Width, Depth, Height and Area: When width and depth is entered, area is calculated automatically. The value may be overridden by manually typing a new value. Height is the average ceiling height. Number of Spaces and Total Space Area: Determines number of spaces within the zone that have same activity usage, dimensions, lighting type and control, the number is entered. The number is then multiplied by space area value to complete Total Space Area line. If necessary, this value can be manually changed. Details concerning Unit Power Density: The right hand column displays UPD which may be increased by an area factor (AF) which is a combination of the activity area and ceiling height to produce Lighting Power Budget. LPB’s for all the spaces plus an unlisted space allowance results in Interior Lighting Power Allowance. The program is proposed to determine the amount of unlisted space by subtracting all the areas that the user specifies o n the lighting screen from the Building Lighted Floor Area of building originally enclosed on Project/Building Data screen. The Lighting Power Budget for these unspecified areas is proposed to be set at 0.2 Watts per square foot, which is less than LPB of any specified activity area. The user should describe space activities throughout as much of the building as possible so that ILPA is not exceeded due to improperly defied building spaces. On the floor plan of the building, the user should mark out block layouts of 2 2 3 different activity areas so that no area is left unaccounted. Also the drawing scale should be checked to make sure spaces are of proper sizes. Lighting Type: Type section refers to all permanently installed and wired lighting fixtures within the space. Type 1 and 2 are identical. Type 2 should be used when space contains different kind of lighting or if the space has one type with two different controls, control Type 2 should be used to describe the second lighting control components. Lighting Type 1: Select appropriate lighting type from Description Option Table. Lighting Type None Incandescent Recessed Fluorescent Suspended fluorescent etc. Single Space W attage and Total W attage: This identifies number of lighting watts installed in one of the described spaces. The single space wattage line is then multiplied by number of space line to calculate Total Wattage which can be modified manually if required. Control type : Describes type of lighting controls: Type of Control None Manual Automatic Security (continuous) 2 2 4 1. Manual: Manual Lighting Control Type Equivalent number of Control Points On/Off 1 Stepped 3 Level 2 Stepped 4 Level 3 Continuous Dimming 3 2. Automatic If your select Automatic, another table appears offering a combination. The right side of both Manual and automatic Control Types lists equivalent number of control points that each control or combination of controls represent. The control points range from a minimum of 1 for a manual on/off switch to a maximum of 8 for a combination of an automatic 4 step on continuous dimming daylighting control with lumen maintenance and a timer or an occupancy sensor. Automatic Lighting With no Daylighting Control Options Control Type(s) daylighting On/ 3 4 Continuous Off Step Step Equivalent Number of Control Points Daylighting N/A 1 2 3 3 Programmable Timer 2 3 4 5 5 Occupancy Sensor 2 3 4 5 5 Lumen Maintenance 3 4 5 6 6 Occupancy Sensor/ 4 5 6 7 7 Timer 225 Daylighting controls or Daylighting serving controls reduce the artificial lighting needed to illuminate a space where natural light is available. The proposed Code allows a Lighting Power Control Credit that reduces the Connected Lighting Power of the building. Credit is given for installation of automatic lighting controls such as Lumen Maintenance, Occupancy Sensor, Daylighting Sensing and Programmable Timer. If the building lighting exceeds ILPA, the program calculates these credits from information provided. Num ber of Controls Type 1: While the electrical lighting specification may call for multiple switches on the same lighting circuit (3-way or 4-way), each of these switches is not to be counted separately as a control. A single fixture controlled by 2 different switches would be counted as having a single control. Therefore, number of controls refers to number of times that lighting in the described space has been divided into separately controlled lighting batches. Moving to Next Space in a Zone: The Next button proceeds to next internal space. Yes at prompt window (asking to add a new space) displays 2 of 2 in Zone 1. Minor modifications can be done in the new space. Clear will give fresh lighting screen if space is substantially different from previous screen. The user has to continue the process describing each internal space in every zone. If automatic daylight sensing controls have been entered in any space, select D aylight button after Lighting Section. 226 Daylighting Screen Daylighting screen allows to enter information about any automatic daylighting serving control used in the building. Daylighting Screen New Daylighting Entry in Zone 1 Glazing Orientation Space Glazing Width Space Glazing Height Visible Transmittance Design Lighting Level % of Lights controlled Sensor Location Dimming Control Minimum Foot-candles % of Power at minimum Foot-candles Step Control Step 2 Artificial Foot-candles Step 2 Lighting Watts Step 3 Artificial Foot-candles Step 3 Lighting Watts Step 4 Artificial Foot-candles Step 4 Lighting Watts Glazing Orientation: Just four lines used to determine amount of Natural Light available to space. Glazing orientation selected from Orientation Option Table which lists 8 compass points. 2 2 7 Space Glazing Width, Length and Visible Transmittance: Provides width and length in feet and tranmittance values. Design Lighting Level: Contains amount of light (in foot-candles) which is required from either natural or artificial sources at task surface within the space. Percentage of Lights Controlled: This refers to percentage of total lighting watts in space that are under daylighting control. Sensor Location Within 5 feet of glazing Middle of Space Within 5 feet of back wall Sensor location establishes location of photocell or similar sensing device. When automatic daylighting controls restrict lighting output of fixture, the fixture power consumption is not necessarily reduced in direct proportion to illumination. For example, a light producing 50% of its full illumination level may still require 60 % of its full capacity power. The remainder of daylighting screen will be used to establish this relationship between artificial lighting output and lighting power for daylighting sensing controls. These lighting and power values specifications are available from lighting control suppliers. Dimming Controls: One can identify the daylighting control system as one of the four options: On/Off (2 step) 3 Step 4 Step 228 Continuous Dimming: If it is a continuous dimming system, the user has to enter only the first two lines under Dimming Control. M inimum Foot-candles: Provide minimum lighting output in foot-candles. % of Power: Enter percentage of maxim power that is used to maintain this minimum light level. 2, 3, or 4 Step: Skip the Dimming Control and finish lighting and wattage data for applicable number of steps. Step 1 is Off. Provides actual power consumption (Lighting watts) at different lighting levels (artificial foot-candles) rather than percentage approach for dimming controls. 2 2 9 BIBLIOGRAPHY Bean, A. R. and Sunors, R. H. Lighting Fittings. Performance and Design. Oxford: Permagon. 1968. Birren, Faber. Light. Color and Environments. New York: Van Nostrand Reinhold. 1982. Boer, J. B. and Fischer, D. Interior Lighting. Antwerp: Philips Technical Library, MacMillan Publ. 1978. Bouma, P. J. Physical Aspects o f Color. London: Philips Technical Library, MacMillan Publ. 1978. Boyce, P. R. Human Factors in Lighting. New York: MacMillan Publ. 1981. Boylan, Bernard R. The Lighting Primer. Iowa: Iowa State University Press. 1987. California Energy Commission. The California Energy Code. Sacramento, CA: Building and Appliance Efficiency Office. 1992. Callender, J. H. ed. Time Saver Standards. New York: McGraw-Hill Book Company. 1974. Cayless, M. A. and Marsden, A. M. Lamps and Lighting. Baltimore: Edward Arnold. 1983. Comsweet, T. N. Visual Perception. New York: Academic Press. 1970. Crossette, Barbara. India: Facing the Twenty-first Century. Bloomingdon: Indiana University Press, 1993. Daylighting Committee of the Illuminating Engineering Society. “ Recommended Practice o f Daylighting” . Lighting Design and Applications: Vol 9. New York: Illuminating Engineering Society of North America. 1979. 2 3 0 Elan bass, W. Light Sources. London: MacMillan Publ. 1972. Egan, M. D. Concepts in Architectural Lighting. New York: McGraw-Hill Book Company. 1983. Evans, Benjamin H. Daylight in Architecture. New York: McGraw-Hill Book Company. 1981. Faulkner, W. Architecture and Color. New York: John Wiley and Sons. 1972. Fischer, D. A Luminance Concept for Working Interiors. Journal of the IES, Vol 2. New York: Illuminating Engineering Society of North America. Fischer, R. E. ed. Architectural Engineering— Environmental Control. New York: McGraw-Hill Book Company. Frier, John and Frier, M ary. Industrial Lighting Systems. New York: McGraw-Hill Book Company. 1980. Ghosh, Arun. Planning in India: The Challenge for the Nineties. Newbury Park, CA: Sage Publ. 1992. Gilliatt, M ary and Balm, Douglas. Lighting your Home: A Practical Guide. New York: Pantheon Books. 1979. Grosslight, Jane. Light. Englewood Cliffs, N.J.: Prentice Hall. 1984. Harris, C. M. Dictionary o f Architecture and Construction. New York. McGraw-Hill Book Company. 1975. Halse, A. O. The Use o f Color in Interiors. New York. McGraw-Hill. Book Company. 1978. 231 Helms, Ronald N. and McGovern, John M. Lighting Design Handbook 4681, Gordon Dr., Boulder, CO 80303. 1978. Hopkinson, R G. and Kay, J. D. The Lighting o f Buildings. London: Faber and Faber. 1969. Hopkinson, R G. Architectural Physics: Lighting. London: Her Majesty’s Stationary Office. 1963. Hurvich, L. M. and Jameson, D. The Perception ofBrightness and Darkness. Boston: Allyn and Bacon. 1966. Illuminating Engineering Society Depreciation and Maintenance o f Interior Lighting. IES Technical Report No 9. New York: Illuminating Engineering Society of North America. 1967. Illuminating Engineering Society Evaluation o f Discomfort Glare — the IES Glare Index System for Artificial Lighting Installations. IES Technical Report No 10. New York: Illuminating Engineering Society of North America. 1967. Illuminating Engineering Society Code for Interior Lighting. New York: Illuminating Engineering Society of North America. 1977. Illuminating Engineering Society Lighting o f Art Galleries and Museums. Technical Report No 14 of the British Illuminating Engineering Society. 1970. India Planning Commission. Sixth Five Year Plan. New Delhi: Govt, of India Planning Commission. 1981. . Jha, Prem Shankar. India: A P olitical Economy o f Stagnation. New Delhi: Oxford University Press. 1980. Kaufman, John E. Illuminating Engineering Society Handbook. Reference Volume 1. New York: Illuminating Engineering Society of North America. 1984. 2 3 2 Kaufman, John E. ed. Lighting Handbook. 1981 Reference Volume. New York: Illuminating Engineering Society of North America. 1981. Keitz, H. A. Lighting Calculations and Measurements. London: MacMillan Publ. 1971. Knowles, Ralph L. Sun Rhythm Form. Cambridge, Massachusetts: The Massachusetts Institute of Technology Press. 1981. Kohler, W. and Luckhardt, W. Lighting in Architecture. New York: Reinold Publ. Corp. 1959. Lam, William M. C. Perception and Lighting as Formsivers for Architecture. New York: McGraw-Hill Book Company. 1977 Larson, Leslie. Lighting and its Design. New York: Whitney Library of Design. 1964. Lynes, J. A. Principles o f Natural Lighting. London: Elsevier Publ. Ltd. 1968. McCrowan, T. K. “ A ll About Sources Progressive Architecture. Sept. 1993. McGraw Edison Company, Halo Lighting Division. The Language o f Lighting. Elk Grove Village, H : McGraw Edison. 1983. Moore, Fuller. Concepts and Practices ofArchitectural Lighting. New York: Van Nostrand Reinhold. 1991. Mueller, C. G. and Reidolf, M. Light and Vision. New York: Time Life Books. 1966. National Committee on Science and Technology. An Outlook for In d ia ’ s Future. New Delhi: National Committee on Science and Technology. 1978 Nuckolls, James L. Furniture Integrated Lighting. Michigan: The Shaw Wallace Company. 1979. 233 Nuckolls, James L. Interior Lighting for Environmental Designers. New York: John Wiley & Sons, Inc. 1983 Olgyay, Victor. Design with Climate. Princeton, N. J. : Princeton University Press. 1963. Phillips, D. Lighting in Architectural Design. New York: McGraw-Hill. 1964. Pritchard, M. D. W. Environmental Physics: Lighting. New York: American Elsevier Publ. Co. Inc. 1969. Pritchard, D.C. Lighting. London: Longman Group Ltd. 1978. Schiler, Marc. Simplified Design ofBuilding Lighting. New York. John Wiley & Sons, Inc. 1992. Stein, Benjamin; Reynolds, John S and McGuiness, William J. Mechanical and Electrical Equipment for Buildings. 7th Edition. New York: John Wiley & Sons, Inc. 1986. Weston, H. C. Sight. Light and Work. London: H. K. Lewis. 1962. 2 3 4
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A proposed wood frame system for the Philippines
PDF
Interactive C++ program to generate plank system lines for timber rib shell structures
Asset Metadata
Creator
Puri, Kanchan
(author)
Core Title
A proposal for the Indian National Lighting Code
Degree
Master of Building Science
Degree Program
Building Science
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
engineering, architectural,OAI-PMH Harvest
Language
English
Contributor
Digitized by ProQuest
(provenance)
Advisor
Schiler, Marc (
committee chair
), Knowles, Ralph Lewis (
committee member
), Schierle, Gotthilf Goetz (
committee member
)
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-c20-300738
Unique identifier
UC11258983
Identifier
EP41440.pdf (filename),usctheses-c20-300738 (legacy record id)
Legacy Identifier
EP41440.pdf
Dmrecord
300738
Document Type
Thesis
Rights
Puri, Kanchan
Type
texts
Source
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Access Conditions
The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...
Repository Name
University of Southern California Digital Library
Repository Location
USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA
Tags
engineering, architectural