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An investigation on using BIM for sustainability analysis using the LEED rating system

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An investigation on using BIM for sustainability analysis using the LEED rating system

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Content AN INVESTIGATION ON USING BIM FOR SUSTAINABILITY ANALYSIS USING THE LEED RATING SYSTEM by Xin Zhao A Thesis Presented to the FACULTY OF THE USC SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE May 2011 Copyright 2011 Xin Zhao ii Acknowledgements I would like to express my gratitude to everybody who helped me to complete this work and 2 years graduate study in USC. I would like to express my deepest thanks to Professor Karen Kensek, the committee chair of my thesis, for her guidance and encouragement during the whole process. Also thanks to my committee members, Professor Edwin Woll and Ph.D. Candidate Doctor Shih-Hsin Lin, who helped me to find such a good topic, solve technical problems and work on the right direction. Thanks to Jon Mills, Timothy Smallwood and Sen Jia for their help on my case studies. Thanks to Professor Marc Schiler, director of MBS program, for being an excellent thesis coordinator. Also thanks to the Jim Brain, Tianxin Xing, Greg Otto and Todd Lukesh, for their help and ideas. And finally, thanks to my parents and families members. iii Table of Contents Acknowledgements ..............................................................................................................ii List of Tables ....................................................................................................................... vi List of Figures ..................................................................................................................... vii Abstract ............................................................................................................................. xiii Chapter 1: Introduction and Backgrounds.......................................................................... 1 1.1 Introduction.......................................................................................................... 1 1.1.1 Defining Building Information Modeling (BIM) ............................................ 1 1.1.2 Defining Leadership in Energy & Environmental Design (LEED) ................... 5 1.1.3 Connections between BIM & LEED ............................................................. 10 1.2 Objective of This Study ....................................................................................... 12 1.3 Methodology for the Study ................................................................................ 13 1.4 Conclusions......................................................................................................... 15 Chapter 2: Investigation on BIM usage in LEED ................................................................ 16 2.1 Introduction ............................................................................................................. 16 2.1.1 Scores of different types .................................................................................. 16 2.1.2 Methodology for evaluating LEED scores ......................................................... 19 2.2 Supposed software usage in different scores ......................................................... 23 2.3 Conclusions .............................................................................................................. 24 Chapter 3: Case Studies and Interviews on Existing Building ........................................... 26 3.1 Introduction ............................................................................................................. 26 3.2 Case Study 1: McKinley School ................................................................................ 27 3.2.1 Basic Information of McKinley School .............................................................. 27 3.2.2 BIM usage in design process............................................................................. 29 3.3 Case Study 2: Conrad Hotel ..................................................................................... 37 3.3.1 Basic Information of Conrad Hotel ................................................................... 37 3.3.2 Conrad’s Gold LEED Certification ..................................................................... 38 3.4 Comparison between BIM and non-BIM LEED projects ......................................... 42 3.4 Conclusions and some charts .................................................................................. 44 Chapter 4: Method 1 – Schedules and Parameters .......................................................... 47 4.1 Introduction ............................................................................................................. 47 4.2 Creating Schedules and Parameters ....................................................................... 49 4.3 Examples of Other Credits....................................................................................... 56 4.3.1 MRc1.1 Building Reuse: Maintain Existing Walls, Floors and Roof .................. 56 iv 4.3.2 MRc1.2 Building Reuse: Maintain Interior - Nonstructural Elements .............. 57 4.3.3 MRc2 Construction Waste Management ......................................................... 58 4.3.3 MRc3 Materials Reuse ...................................................................................... 60 4.3.4 MRc5 Regional Materials .................................................................................. 62 4.3.5 EAc4 Enhanced Refrigerant Management ....................................................... 63 4.3.6 SSc4.2 Bicycle Storage and Changing Rooms ................................................... 64 4.3.6 SSc4.3 Low-Emitting and Fuel- Efficient Vehicles ............................................. 65 4.3.6 SSc7.1 Heat Island Effect - Nonroof .................................................................. 65 4.4 Additional Works ..................................................................................................... 67 4.4.1 Material Libraries .............................................................................................. 67 4.4.2 Phases for different credits .............................................................................. 68 4.4.3 Creating cut sheets ........................................................................................... 69 4.5 Conclusions .............................................................................................................. 72 4.5.1 Advantages ....................................................................................................... 72 4.5.2 Disadvantages ................................................................................................... 73 Chapter 5: Method 2 – Third Party Software ................................................................... 75 5.1 Introduction ............................................................................................................. 75 5.2 Interoperability between BIM and Analyzing Tools ................................................ 76 5.2.1 IFC ..................................................................................................................... 76 5.2.2 gbXML ............................................................................................................... 77 5.2.3 DXF (Drawing Exchange Format) ...................................................................... 78 5.3 Credits Analyze ........................................................................................................ 79 5.3.1 EA c1: Optimize Energy Performance ............................................................... 80 5.3.2 WE c1-3: Water Efficiency ................................................................................ 87 5.3.3 EA c2: On-site Renewable Energy. .................................................................... 90 5.3.4 EQ c8.1 Daylight and Views - Daylight .............................................................. 90 5.4 Application Programming Interface Problem of Method 2 .................................... 93 5.5 Conclusions .............................................................................................................. 94 Chapter 6: Method 3 –Directly and Editing Families ........................................................ 95 6.1 Introduction ............................................................................................................. 95 6.2 Methods of Different Credits Types ........................................................................ 99 6.2.1 SSc1 Site Selection ............................................................................................ 99 6.2.2 SSc2 Development Density & Community Connectivity ................................ 100 6.2.3 SSc4.1 Alternative Transportation: Public Transportation Access ................. 101 6.2.4 SSc4.3 Alternative Transportation: Low-Emitting and Fuel- Efficient Vehicles ................................................................................................................................. 102 6.2.5 SSc4.4 Alternative Transportation: Parking Capacity ..................................... 104 6.2.6 SSc5.1 Site Development: Protect or Restore Habitat ................................... 104 6.2.7 SSc7.1: Heat Island Effect – Nonroof .............................................................. 105 v 6.2.7 WEp1 Water Use Reduction ........................................................................... 106 6.2.8 WEc3 Water Use Reduction ........................................................................... 107 6.2.7 EAc2 On-site Renewable Energy..................................................................... 108 6.2.8 MRp1 Storage and Collection of Recyclables ................................................. 115 6.2.8 MRc2 Construction Waste Management ....................................................... 116 6.2.9 IEQ p2 Environmental Tobacco Smoke (ETS) Control .................................... 117 6.2.10 IEQc6.1 Controllability of Systems—Lighting ............................................... 118 6.3 Conclusions ............................................................................................................ 119 6.3.1 Cut Sheet for Method 3 .................................................................................. 119 6.3.2 Conclusions ..................................................................................................... 120 Chapter 7: Using BIM for Evaluating Innovation Design and Regional Priority Credits . 122 7.1 Introduction ........................................................................................................... 122 7.1.1 Innovation Design ........................................................................................... 122 7.1.2 Regional Priority ............................................................................................. 123 7.2 BIM Used for Evaluating Existing Innovation Design Methods ............................. 124 7.2.1 Exemplary Performance ................................................................................. 124 7.2.2 Existing Methods for Achieving Innovation Credits ....................................... 125 7.3 Possibility of Using BIM to Develop New Innovation Design Methods ................ 130 7.3.1 Minimize Impact on Neighborhood Buildings ................................................ 130 7.3.2 Tracking and Reducing Embodied CO2........................................................... 133 7.3.3 Advanced Acoustic Design .............................................................................. 134 7.3.4 Integrated Process .......................................................................................... 135 7.3.5 Life Cycle Management .................................................................................. 137 7.3 BIM Used for Evaluating Regional Priority Credits ................................................ 138 7.4 Conclusions ............................................................................................................ 139 Chapter 8: Future Work and Conclusion ........................................................................ 140 8.1 What the Thesis Has Done .................................................................................... 140 8.2 Future Work .......................................................................................................... 141 8.2.1 Family and Material Libraries ......................................................................... 141 8.2.2 API of BIM ....................................................................................................... 142 8.2.3 GBCI acceptance ............................................................................................. 143 8.3 Conclusions ............................................................................................................ 143 Bibliography .................................................................................................................... 145 Appendix ......................................................................................................................... 148 Appendix A: Evaluation Table for LEED credits ........................................................... 148 Appendix B: Cut Sheets ............................................................................................... 158 Appendix C: Calculation Statement for Turbine Efficiency ......................................... 185 vi List of Tables Table 2.1 supposed software usage in different credits .................................................. 24 Table 4.1 Creating phases and material take-off for each credit ..................................... 71 Table 5.1: Some third party software that is possible for evaluating LEED credits ......... 79 Table 6.1: Credits that could be evaluated by BIM........................................................... 98 Table 7.1 Existing innovation credits for MR parts ......................................................... 126 Table 7.2 Existing innovation credits for SS parts ........................................................... 127 Table 7.3 Existing innovation credits for EA and WE parts ............................................. 128 Table 7.4 Existing innovation credits for EQ parts .......................................................... 129 vii List of Figures Figure 1.1 BIM usages in different industries ..................................................................... 2 Figure 1.2 the traditional team model and a BIM integrated design team model ............ 4 Figure 1.3 LEED NC credits checklist ................................................................................... 7 Figure 1.4 LEED template for MR credit 4 .......................................................................... 8 Figure 1.5 LEED template for MR credit 4 .......................................................................... 9 Figure 1.6 Interaction of BIM with multiple design objectives ......................................... 12 Figure 2.1 LEED template for EA Credit ............................................................................ 17 Figure 2.2 LEED template for MR Credit 5 ........................................................................ 18 Figure 2.3 LEED template for MR Credit 5 ........................................................................ 19 Figure 2.4 Possible Methods of LEED credits evaluation using BIM ................................. 23 Figure 3.1 McKinley School ............................................................................................... 27 Figure 3.2 Project Site Map ............................................................................................... 28 Figure 3.3 McKinley School Midterm LEED credit list review (partial) ............................ 30 Figure 3.4 BIM application in LEED credits of McKinley School ....................................... 31 Figure 3.5 3D rendering of Conrad Hotel .......................................................................... 37 Figure 3.6 Conrad Hotel Beijing's LEED credit list card (partial) ...................................... 39 Figure 3.7 Conrad Hotel energy simulation model ........................................................... 40 Figure 3.8 LEED matrix chart ............................................................................................. 44 Figure 3.9 Level of application in Calculating LEED Credits through BIM ......................... 46 viii Figure 4.1: Credits based documentations and calculations ............................................ 48 Figure 4.2 Simple model created for testing .................................................................... 49 Figure 4.3: LEED Documentation Template for MR Credit 4 ............................................ 50 Figure 4.4: Adding parameters to project ........................................................................ 51 Figure 4.5: Creating phases and schedules ....................................................................... 52 Figure 4.6: Adding parameters and formulas in schedule ................................................ 54 Figure 4.7: Schedule for MR Credit 4 ................................................................................ 55 Figure 4.8: Roof requirements in LEED NC Sustainable Site Credit 7.2 ............................ 55 Figure 4.9: Schedule of LEED NC Sustainable Site Credit 7.2 ............................................ 56 Figure 4.10: Schedule of LEED NC Material Resources Credit 1.1 .................................... 57 Figure 4.11: Schedule of LEED NC Material Resources Credit 1.2 .................................... 58 Figure 4.12: Schedule of LEED NC Material Resources Credit 2 ....................................... 60 Figure 4.13: Schedule of LEED NC Material Resources Credit 3 ....................................... 61 Figure 4.14: Schedule of LEED NC Material Resources Credit 5 ....................................... 62 Figure 4.15: Schedule of LEED NC Energy & Atmosphere Credit 4................................... 63 Figure 4.16: Schedule of LEED NC Sustainable Site Credit 4.2.......................................... 64 Figure 4.17: Schedule of LEED NC Sustainable Site Credit 4.3.......................................... 65 Figure 4.18: Schedule of LEED NC Sustainable Site Credit 7.1.......................................... 66 Figure 4.19: Material Library and Family Library .............................................................. 68 Figure 4.20 Cut sheet for SS Credit 4.3 ............................................................................. 72 ix Figure 5.1: energy cost savings percentage for each point threshold ............................. 80 Figure 5.2: Editing energy simulation settings in Excel .................................................... 81 Figure 5.3: Transfer Revit Model to eQuest by gbXML file ............................................... 82 Figure 5.4: General project information required by LEED template USGC ..................... 83 Figure 5.5: Proposed and baseline summary table required by LEED template USGC .... 85 Figure 5.6 Solar radiance studies in Revit ......................................................................... 86 Figure 5.7: Calculation table for irrigation baseline case ................................................. 88 Figure 5.8: Calculation table for water usage of flush fixture .......................................... 88 Figure 5.9: Calculation of non-portable water and irrigation baseline in Green Building Studio ................................................................................................................................ 89 Figure 5.10: Calculation of water usage of water fixtures in Green Building Studio ....... 89 Figure 5.11: Calculation formula for EQ credit 8.1 ........................................................... 91 Figure 5.12: Transfer Revit Model to Ecotect by gbXML file ............................................ 92 Figure 5.13: Using Green Building Studio to calculate daylight glazing ........................... 92 Figure 6.1: Adding parameters to control bicycle rack numbers ..................................... 96 Figure 6.2: Locate bicycle rack family with circle in site map ........................................... 97 Figure 6.3: Building with 50ft and 100ft lines in site plan .............................................. 100 Figure 6.4: Site plan with ½ mile and ¼ mile radius circles ............................................ 101 Figure 6.5: Parking family ............................................................................................... 103 Figure 6.6: Using parameter of FTE Value control the parking numbers and reserved parking numbers ............................................................................................................. 103 Figure 6.7: Tree family with shading ............................................................................... 105 x Figure 6.8: New water fixture family with parameters for calculation .......................... 107 Figure 6.9: Toilet family with parameters for calculation .............................................. 107 Figure 6.10: ROPATEC BIG STAR VERTICAL and its Revit family ..................................... 108 Figure 6.11: Parameters of the wind turbine ................................................................. 109 Figure 6.12: Parameters will change according to different turbine model .................. 109 Figure 6.13: Curve function in the calculation of energy production ............................. 109 Figure 6.14: Partial of the values of Turbine Factor and Wind Factor ........................... 111 Figure 6.15: Other parameters and calculations of wind turbine family ....................... 113 Figure 6.16: A PV panel family ........................................................................................ 114 Figure 6.17: Parameters for calculation and evaluation ................................................ 114 Figure 6.18: Trash cans families ...................................................................................... 116 Figure 6.19: Floor plans with designated smoking area ................................................. 117 Figure 6.20: Floor plans with lighting fixture information .............................................. 120 Figure 6.21: Cut sheet for sustainable site credit ........................................................... 121 Figure 7.1: Schedule for Material Resources credit 4 ..................................................... 124 Figure 7.2: Partial of Innovation in Design Credit Catalog .............................................. 125 Figure 7.3: Glaze analysis in IES-VE ................................................................................ 131 Figure 7.4: Shadow range analysis in Ecotect ................................................................. 132 Figure 7.5: Acoustic analysis in Ecotect .......................................................................... 134 Figure 7.6: Integrated design process ............................................................................. 136 Figure 7.7: Regional priority credits check list ................................................................ 138 xi Figure 8.1 Ideal work process of Using BIM evaluating LEED credits ............................. 140 Figure A.1 Evaluating chart for Sustainable Site ............................................................. 149 Figure A.2 Evaluating chart for Sustainable Site ............................................................. 150 Figure A.3 Evaluating chart for Water Efficiency ............................................................ 151 Figure A.4 Evaluating chart for Energy & Atmosphere ................................................... 152 Figure A.5 Evaluating chart for Energy & Atmosphere ................................................... 153 Figure A.6 Evaluating chart for Material Resources ....................................................... 154 Figure A.7 Evaluating chart for Material Resources ....................................................... 155 Figure A.8 Evaluating chart for Environmental Quality .................................................. 156 Figure A.9 Evaluating chart for Environmental Quality .................................................. 157 Figure B.1 Cut sheet for SS Credit ................................................................................... 159 Figure B.2 Cut sheet for SS Credit 2 ................................................................................ 160 Figure B.3 Cut sheet for SS Credit 4.1 ............................................................................. 161 Figure B.4 Cut sheet for SS Credit 4.2 ............................................................................. 162 Figure B.5 Cut sheet for SS Credit 4.3 ............................................................................. 163 Figure B.6 Cut sheet for SS Credit 4.4 ............................................................................. 164 Figure B.7 Cut sheet for SS Credit 5.1 ............................................................................. 165 Figure B.8 Cut sheet for SS Credit 7.1 ............................................................................. 166 Figure B.9 Cut sheet for SS Credit 7.2 ............................................................................. 167 Figure B.10 Cut sheet for WE Prerequisite 1 .................................................................. 168 Figure B.11 Cut sheet for WE Credit 1 ............................................................................ 169 xii Figure B.12 Cut sheet for WE Credit 2 ............................................................................ 170 Figure B.13 Cut sheet for WE Credit 3 ............................................................................ 171 Figure B.14 Cut sheet for EA Prerequisite 2 ................................................................... 172 Figure B.15 Cut sheet for EA Credit 1 ............................................................................. 173 Figure B.16 Cut sheet for EA Credit 2 ............................................................................. 174 Figure B.17 Cut sheet for EA Credit 4 ............................................................................. 175 Figure B.18 Cut sheet for MR Credit 1.1 ......................................................................... 176 Figure B.19 Cut sheet for MR Credit 1.2 ......................................................................... 177 Figure B.20 Cut sheet for MR Credit 2 ............................................................................ 178 Figure B.21 Cut sheet for MR Credit 3 ............................................................................ 179 Figure B.22 Cut sheet for MR Credit 4 ............................................................................ 180 Figure B.23 Cut sheet for MR Credit 5 ............................................................................ 181 Figure B.24 Cut sheet for MR Credit 6 ............................................................................ 182 Figure B.25 Cut sheet for EQ Credit 6.1 .......................................................................... 183 Figure B.26 Cut sheet for EQ Credit 8.1 .......................................................................... 184 xiii Abstract Proponents of building information modeling (BIM) enthusiastically tout as one of its advantages its ability to work in conjunction with other software programs to predict the performance of buildings. Theoretically this would help in the design of sustainable buildings. The U.S. Green Building Council (USGBC) through its Leadership in Energy & Environmental Design (LEED) building certification system “encourages and accelerates global adoption of sustainable green building and development practices through a suite of rating systems that recognize projects that implement strategies for better environmental and health performance.” (USGBC website 2010) Although LEED is a rating system and BIM is an information technology, there is an opportunity for them to work together with BIM serving as a depository of project information for the design team, consultants, contractor, and potentially operations and maintenance. Using BIM in this approach could allow designers to study green alternatives more quickly, make timely decisions, and communicate effectively both during design and construction. BIM could also assist in fulfilling requirements for LEED points and submitting documentation for the LEED worksheets. It could assist project stakeholders in making decisions for new and existing buildings considering the best value with regard to the applicable green building rating system score. 1 Chapter 1: Introduction and Backgrounds 1.1 Introduction 1.1.1 Defining Building Information Modeling (BIM) There are multiple definitions of Building Information Modeling (BIM). According to its name, building information modeling is a modeling process that contains building information and components’ data. The National Building Information Modeling Standard (NBIMS) gives a detailed definition: “Building Information Modeling (BIM) is an integrated, structured virtual database, informed by the AECO (architecture, engineering, construction, operations) industry that consists of three dimensional parametric objects and allows for interoperability. The National Institute of Building Sciences (NBIMS) has had a strong role in shaping its definition and standard use while also helping in the evolution and “the definition and usage to represent horizontally integrated building information that is gathered and applied throughout the entire facility lifecycle, preserved and interchanged efficiently using open and interoperable technology for business, functional and physical modeling, and process support and operations 1 .” According to the Autodesk Committee, “Building Information Modeling (BIM) is an integrated process for exploring a project’s key physical and functional characteristics digitally before it is built 2 .” This represents the industry’s view of BIM: AEC professionals say they are able to deliver projects faster and more economically while minimizing environmental impact. 1 NBIMS, 2007. National Building Information Modeling Standard V1, Part 1, Chapter 1.1, page 6, National Institute of Building Sciences, Washington DC. 2 Autodesk, 2011, Building Information Modeling, Autodesk Inc, accessed 27 March 2011, <http://usa.autodesk.com/building-information-modeling/> 2 Figure 1.1 BIM usages in different industries http://www.tekla.com/us/solutions/Pages/Solutions.aspx Tekla Corporation, 2010. (website last accessed 24-Nov-2010) According to the different definitions, at the best, BIM is an integrated, structured database, informed by the AEC industry, and consisting of 3D parametric objects. BIM is also a digital paradigm shift, in many ways similar to that of the CAD revolution of the 1980s, but potentially even more transformative of the processes used by the architecture and construction professions. BIM is often used as a method for achieving 2D /3D coordination and it can be used as a graphic interface between the building design intent and performance based software. There has been increasing sophistication and user friendliness of simulation software including day light harvesting, energy calculations, natural ventilation, and other sustainability issues. Included with this has been an increased desire and ability to provide better integration between 3 geometric and analytical models, a “complete” virtual building model that contains the necessary information to predict the behavior of a building while it is still in digital format. A BIM model can be used throughout the design, construction and facility management process. With BIM, designers create a parametric 3D model that represents a real building. From that digital model, one can automatically generate traditional building abstractions such as plans, elevations, details, sections, and schedules. When designers change their design, for example, the designer moves a wall or column in plan, this change will automatically be updated in sections, elevations, schedules, and other related views within the documentation set. This is one of the very basic advantages of BIM. In addition, the information and building data contained in a BIM model can be compressed and transferred into gbXML 3 , IFC 4 and other files format, which can be shared and used between different BIM software and AEC teams. For example, different design models (architecture, structure, and MEP) can be transformed to IFC files and then combined into one model in Autodesk Naviswork 5 . Constructors can use this model for collision detection, 4D construction simulation, and change orders. 3 Green Building XML schema, it is developed to facilitate interoperability among different building information models, and integrate numerous design and development tools used in the building industry. 4 Industry Foundation Classes (IFC) data model is intended to describe building and construction industry data. 5 A construction software program owned by Autodesk. 4 The information in a BIM model can be shared and transferred among different design teams. Project teams can work on the BIM platform and benefit from a highly coordinated and integrated project across the design phases while sharing meaningful building design information directly between applications. Figure 1.2 The traditional team model and a BIM integrated design team model Eddy Krygiel, Bradley Nies, Green BIM:Successful Sustainable Design with Building Information Modeling, page 61, 2008 Currently, there are various BIM programs in market. Revit Architecture (Autodesk) and VICO (Vico Virtual) are widely used in industry as design tools; other software, such as Ecotect (Autodesk), Solibri Model Checker (Solibri) and many other BIM tools are used as analyzing tools in industry. Chapter 2 will discuss in detail these BIM tools, their functions and their possible applications in LEED credits evaluation. 5 Currently building information modeling is mainly focused on building coordination and clash detection, but building performance simulation, 4D construction animation, and many other functions are also in use. Although it has many advantages, it is still evolving and is not yet deeply engrained in traditional design process and workflow (Timothy Smallwood, 2010.) BIM’s disadvantages will be discussed in detail for two case studies in a later chapter. 1.1.2 Defining Leadership in Energy & Environmental Design (LEED) According to Environmental Information Administration (2008), commercial construction requires the greatest amount of resources in the building industry. The impacts from commercial construction in the United States include the following:  72% of electricity use 6  39% of energy consumption 7  38% of all carbon dioxide (CO2) emissions 8  40% of raw materials use 9  30% of waste output (136 million tons annually) 10  14% of potable water consumption 11 6 Environmental Information Administration, 2008. EIA Annual Energy Outlook, US Department of Energy, Washington DC. 7 Environmental Information Administration, 2008. EIA Annual Energy Outlook, US Department of Energy, Washington DC 8 Energy Information Administration, 2008. Assumptions to the Annual Energy Outlook, US Department of Energy, Washington DC 9 Lenssen and Roodman, 1995. Worldwatch Paper 124: A Building Revolution: How Ecology and Health Concerns are Transforming Construction, World Institute, Washington DC 10 U.S. Environmental Protection Agency, 1997. U.S. EPA Characterization of Building-Related Construction and Demolition Debris in the United States, Franklin Associates, Prairie Village, KS 6 In order to reduce the building construction and operation impacts on the environment, the U.S. Green Building Council (USGBC) developed and continuously refines a building design, construction and operation guide, Leadership in Energy & Environmental Design (LEED). It is a green building certification system that provides third-party verification which encourages a building or community to be designed with cognizance of environmental impact, energy saving and human comfort. It rewards designers for using strategies that can improve performance in metrics such as CO2 emissions reduction, water efficiency, energy savings, indoor environmental quality, and other environmental impacts. Although LEED does not guarantee excellent sustainable design, it is one method to help towards this goal. According to building usages and community types, different LEED rating systems apply: LEED for New Construction and Major Renovation (LEED NC), LEED for Interior Design & Construction (LEED ID), LEED for Existing Buildings(LEED EB), LEED for Core & Shell (LEED CS), LEED for Neighborhood Development (LEED ND),LEED for Schools, LEED for Retail, LEED for Healthcare and LEED for Homes. The most frequently used LEED rating systems are LEED NC (new construction), CS (core and shell) and K-12 schools. All the three rating systems have 7 categories: Sustainable Site, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality, Innovation in Design, and Regional Priority. The total number of points in these rating systems is 110 11 U.S. Geological Survey, 2000. 200 data. USGS, Rolla, Missouri 7 (LEED for School has 79 points). If a project earns more than 40 points, it will receive LEED certified, if 50 points or above, silver, 60 points or above gold, and above 80 points a platinum rating. Figure 1.3 shows the credits checklist of LEED for New Construction and Major Renovation (2009 Edition). Figure 1.3 LEED NC credits checklist http://www.usgbc.org/ShowFile.aspx?DocumentID=5719, USGBC (2011), (website last accessed 10-Feb-2011) To achieve each credit, the ACE team must prepare required documents and then submit them on line. Figure 1.4 and Figure 1.5 show the LEED template of Material Resources credit 4 (MR credit 4): Recycled Content. This credit requires that a project 8 use materials with recycled content at least 10% or 20%, based on cost, of the total value of the materials in the project. If the materials used in the project have more than 10% recycled content, it will receive 1 point in this credit; if more than 20%, it will receive 2 points. To achieve this credit, the ACE team must list all the required materials 12 and their information in the table shown in Figure 1.4. The materials are then summed and calculated in the table in Figure 1.5 to determine whether the project meets the requirement for this credit. Figure 1.4 LEED template for MR credit 4 12 Mechanical, electrical and plumbing components and specialty items such as elevators cannot be included in this calculation. Include only materials permanently installed in the project. 9 Figure 1.5 LEED Template for MR credit 4 Most credits in LEED are like MR credit 4, which is based on documentation and calculation. Some of the credits require computer analysis and simulation, like Energy & Atmosphere Credit 1 and Indoor Environment Quantity Credit 8.1; these require energy simulation and day lighting calculation using computer programs. The remaining credits can be achieved by providing supporting documents like design drawings, photos during constructions, building site maps, etc. Although LEED has been criticized for perceived problems especially in its weighting system for points, it is an evolving system which has been helping designers create buildings that have some features leading toward a sustainable future. LEED is like a set of training wheels to help people move to higher levels of systems thinking. As Brendan Owens (2010) says, “LEED is all about focusing on multi-parameter decision making sure people are optimizing buildings as systems rather than optimizing systems of buildings.” 10 1.1.3 Connections between BIM & LEED A major aspect of LEED is documentation and calculations that must be submitted on- line in order to achieve certification. Although LEED is a rating system, and BIM is an information and modeling technology, the advantage of using BIM is that it can be a single source of all project information for team members from the design team, consultants, and facility managers and a resource for the LEED AP on the team (if applicable). Most BIM software programs have large material and component libraries. These families (to use Revit’s term for components) contain various material and component types, and they are broken up by categories. When they are put into a model, not only the information about their geometry and graphics will be put into the model, but also other parameters, such as manufacturer, cost, and even construction phases; a caveat is that this data is only as good as the person who entered it. Besides that, AEC design teams can add endless information and their own needed parameters to the components. In that case, BIM can also store all the important parameters of element information that will be needed for LEED credit evaluation and calculations. Furthermore, LEED requires that some credits use building performance simulation software; this often requires modeling separately in other programs. For example, LEED NC Energy & Atmosphere part requires energy performance simulations in a DOE-2 program. Because BIM contains not only building geometry, but also building zones, 11 facades and building openings, material types and other building information, it is possible to transfer the information to a format or a package which can be shared by the different programs. In that case, these LEED credits calculations could be assisted by use of a BIM. Last but not least, BIM, when used by an experienced user, can be a very intelligent design tool. Architects can accommodate their design to different needs, adding or deleting information or details in BIM, which can be reflected in final design outputs like plans, elevations, schedules and so on. Therefore designers can maintain currency in their LEED credit calculations as designs progress. More on this will be discussed in Chapter 7. In conclusion, if BIM can be engaged in LEED credit evaluation, it would assist project stakeholders in making decisions for new and existing buildings considering the best value with regard to the applicable green building rating system score. Moreover, using BIM in this way could allow designers to study alternatives more quickly in accumulating LEED points, to make timely decisions, and to communicate effectively both during design and construction, and when submitting documentation for the LEED worksheets. As discussed before, sharing information using the BIM model provides a work platform used by different design teams, and their information can also be integrated into the LEED credits evaluation. 12 1.2 Objective of This Study Figure 1.6 Interaction of BIM with multiple design objectives http://www.scia- online.com/eNews/en/eNewsDec06_EN.html SCIA, 2010, (website last accessed 24-Nov-2010) As has been discussed earlier building information modeling is an integrated, structured database, informed by the AEC industry, and consisting of 3D parametric objects. It can be used as an integrated process for exploring a project’s key physical and functional characteristics digitally before it is built. On the other hand, LEED is a green building 13 certification system, in which the rating is based generally on building design, construction, component and material usage, building performance and so on. As there are multiple intersections between BIM models and the LEED rating system, so it is possible to use features within the BIM software for documentation and as an evaluation tool for LEED. The purpose of this thesis is to determine if using a building information model is an effective means for predicting and documenting a building’s potential LEED score by evaluating its potential to be used in each of the LEED NC 2009 categories. The goal of this project is to produce a table listing each point, a short description, an evaluation as to whether or not a well constructed BIM could help achieve compliance, and if so, specifically how to achieve this. 1.3 Methodology for the Study The research will use Revit Architecture, one of the most frequently used BIM authoring tools , to evaluate its potential to be used in each parts of the LEED for New Construction and Renovation (2009 Edition). The research methodology includes literature reviews, case studies, simulations, and experiments trying out proposed methods. Literature reviews include the LEED rating system for New Construction and Renovation and a brief survey as to what other people have done with BIM and LEED. This is not 14 meant to be exhaustive, but instead to provide the background necessary to complete the BIM – LEED Evaluation Table. Two case studies will be evaluated to demonstrate how BIM has interfaced with LEED. The first one is the Conrad Hotel in Beijing. This is a LEED certified building that did not use BIM. The second case study is McKinley School, which is designed by LPA Inc. This is a LEED Silver project, and some of the credits were achieved by using BIM technologies. This study of existing buildings will add data to the BIM – LEED Evaluation Table. Overlooked synergies will also be explored as it is likely that most BIM projects did not fully utilize its potential for LEED. Understanding why this might have been the case is also important. Next a simple building will be used to demonstrate how specifically points could have been achieved. This experimentation will categorize points in three parts: 1. those that can be archived or documented by BIM itself; 2. scores that need to be evaluated by third party software; and 3. scores that are not helped by having a BIM. Each LEED point will be categorized into one of these three sections, and examples will be given for its implementation. Details will be discussed in Chapter 4 to Chapter 6. Finally, a comparison will be made between BIM methods and non-BIM methods, to see if BIM helps designers to evaluate LEED credits. A table will be produced listing each point, a short description, an evaluation as to whether or not a well constructed BIM could help achieve compliance, and if so, specifically how to achieve this. For each 15 credit, the table will be updated to tell which information needed for LEED documentation BIM can provide and which information BIM can’t. 1.4 Conclusions Although this research is using Revit Architecture to evaluating potential credits, it doesn’t mean that Revit is the only BIM software program or that it has all the features of other programs. Revit is a BIM tool, as are similar products from VICO, ArchiCAD, etc. These tools provide the basic 3D design, rendering, and animation of BIM and associated object technologies and have similar capabilities. In addition, this research is trying to explore possible usages when a design team has a building information model, and see how to maximize the functions of their BIM model, which can save time and money for the whole design process. It doesn’t mean that a project needs to make a building model just for LEED credit evaluation; rather this research is exploring how to better use the building information model when a project team already has one. Using a model with building information, and assuming advances in material libraries and cost estimation, it is possible for the design team to integrate information into the BIM model for LEED compliance calculations and documentation. The integrated optimization tool allows design teams to make the best decisions not only related to cost but potentially to other methods for achieving LEED certification and calculations of possible points earlier in the design process. 16 Chapter 2: Investigation on BIM usage in LEED 2.1 Introduction As discussed in Chapter 1, LEED is a green building certification system, where the rating is based on, building design and plan, construction, component and material usage, building performance and other very specific criteria. Building information modeling is an integrated, structured database, consisting of 3D parametric objects, which can be used as an integrated process for exploring a project’s key physical and functional characteristics digitally before it is built., As there are multiple intersections between BIM and LEED rating system it is possible to use BIM to evaluate a building’s possible LEED credits, and it is possible to use BIM as a documentation and analyzing tool for LEED. In this chapter, a few specific credits in LEED for New Construction will be tested to determine methods of using BIM to help achieve point compliance: by analyzing required submittal documents and LEED templates to find or complete solutions and methods which can be performed within BIM. 2.1.1 Scores of Different Types In, LEED, some of the credits require performance based simulation, for example, Energy & Atmosphere Credit 1, Optimize Energy Performance, and Indoor Environment Quantity Credit 8.1, Daylight and Views. For those credits, the submittal documents include the general information of building and the inputs of the analyzing model; these 17 are filled in on LEED templates. Figure 2.1 shows the partial LEED template of Energy & Atmosphere Credit 1: Optimize Energy Performance. The design team needs to complete the table that includes model input wall types, interior lighting power densities, HVAC systems, etc. Then the design teams need to enter the simulation results in the LEED templates and provide supporting documents that include the simulation report and a confirmation that energy simulation software meets sections of ASHRAE 90.1-2007 or CA T-24 2005 Modeling requirements. 13 For these credits, the required documentation is mostly about the simulation information in the analyzing software. Figure 2.1 LEED template for EA Credit 1 13 USGBC. Green Building Design And Construction Reference Guide. 2009. Page 277 18 Another group of credits in LEED is similar to LEED NC Material Resources Credit 4 mentioned in Chapter 1. These credits are based on documentation and simple calculations to determine if the LEED credit threshold has been met. Figure 2.2and Figure 2.3 show the LEED template for Material Resource Credit 4. The required submittal documentation includes cut sheets or manufactures’ letters to document the listed products’ names, recycled content, costs and other information 14 . To pursue this credit, the design team has to document the entire project’s material with required parameters and then calculates the total project’s material recycle content percentages. As projects are modified and revised, the credit threshold calculations need to be recalculated. Figure 2.2 LEED template for MR Credit 5 14 USGBC. Green Building Design And Construction Reference Guide. 2009. Page 374. 19 Figure 2.3 LEED template for MR Credit 5 Some credits can be directly evaluated by design or construction. They don’t need computer simulations to prove LEED requirements have been achieved. Specialized components could be created to help in demonstrating that the design is compliant. For example, LEED for New Construction Sustainable Site Credit 4.2: Alternative Transportation—Bicycle Storage and Changing Rooms. A project can earn this credit by providing qualified bicycle racks and shower facilities; no computer simulation is needed. Other credits can be achieved by providing supporting documents, like design drawings, photos during construction, and building site maps. Although a building information model can provide some of these design drawings and site plans, these are not necessarily helped by using BIM. Submitting a traditional plan would be easier. 2.1.2 Methodology for Evaluating LEED Scores Depending on the requirements of each LEED credit, different methods can be applied towards achieving it. Three categories will be discussed: interoperability with 3rd party software, schedules and parameters, and editing families (Revit’s name for components associated with data). 20 For the credits that are required by USGBC to use computer simulation, there are several existing tools that are available to analyze these credits of buildings. For example, the DOE-2 15 based programs can analyze and simulate the building energy consumption for LEED EA Credit 1, and Ecotect 16 , AGI32 17 can be used for building day lighting analyze for LEED IEQ Credit 8.2. Besides that, although for some credits it is not mandatory to use computer simulation, they can also be evaluated by software according to their features. For example, Water Efficiency in LEED can be evaluated using Ecotect or Green Building Studio, because credits in this part are based on water consumption calculations, and these programs have the function to calculate it. It should be mentioned that, while not all information that is needed in the simulation program may be available in the BIM, it is possible to evaluate these credits through intelligent interoperability. This means using BIM to give information to analyzing software for LEED point calculations. However, it doesn’t mean these tools are specifically linked to a credit in order to evaluate whether the projects has been achieved. As stated by Krygiel and Nies (2008), “many of the tools used to measure the impact of sustainable design strategies are not directly accessible within a BIM model itself; therefore, data needs to be exported to another application or imported from a 15 DOE-2 is an energy simulation program intended to aid in the analysis of energy usage in buildings. 16 Ecotect is an environmental analysis tool that allows designers to simulate building performance right from the earliest stages of conceptual design. It is developed by Autodesk, and it is also BIM software. 17 AGI32 is a lighting calculation and visualization software for day lighting and electric lighting prediction. 21 data source.” Therefore, in the third party software method, integrated optimization tools for LEED decisions will be explored that look at a different set of data and building characteristics to test the ability of this integration and what information a BIM model can provide to third party software. For credits in LEED which are evaluated by calculations and submitted with additional documentation, one could create relevant parameters in BIM and store useful information; then use the schedules and formula functions in Revit Architecture to achieve them. As discussed before, these credits require the design team to list the project’s materials, components or facilities with relevant parameters, and then to sum all to calculate if the qualified materials or facilities reach the required percentage. Each time the design change, the list needs to be updated and recalculated. It is possible to put these parameters inside BIM; then one can create schedules that contain all the materials or facilities applied to each credit and apply custom, user-defined formulas to calculate the required percentage. When the design changes, the schedules will also automatically change, will the calculated percentage. Therefore the designers can see how their decisions influence pursuing LEED credits. It doesn’t mean that Revit will automatically validate the LEED certification; however, Revit does take care of the constant recalculation that most project teams do during the course of a LEED project. By reading the internal Revit database, a project team can use ‘what if’ scenarios to investigate different options and review the point qualification outcome. 22 Some credits don’t need documentation or computer simulations as proof of achieving LEED requirement,and can be directly evaluated by design or construction. Some settings or changes inside BIM can also help designers directly evaluate these credits. Take the Sustainable Site Credit 4.2, for example. This credit requires that a project has bicycle storage and changing rooms for occupants. In addition, the bicycle racks and changing rooms should be within 200 yards radius circle of the project’s main entrance. So it is possible to change some components’ characteristics to help designers. For example, a circle with a radius of 200 yards can be added in the family of the entrance gate or the bicycle rack. When designer choose the location of bicycle rack or building entrance, they can know whether their decision will qualify for this credit. Actually, method 3 can differ according to different situations and credits. Details will be discussed in a later chapter. 23 Figure 2.4 Possible Methods of LEED credits evaluation using BIM 2.2 Supposed Software Usage in Different Scores For the third party software method, it is important to know about the different ways that file information can be transferred between programs, including gbXML, IFC, and other fiel transfer protocols. See the chart below for specific examples. 24 Table 2.1 supposed software usage in different credits 2.3 Conclusions As discussed in this chapter, building information modeling design and documentation system in some cases is ideally suited to deliver the kind of information that can be used to improve design and building performance. Much of the data needed for supporting LEED evaluation can be captured or input during the design process and is extracted from the building information model as needed. 25 In Chapters 5 through 7, work will be continuing on evaluating the 110 LEED points to see if building information modeling can make the compliance path easier and if other methods should be utilized besides the three discussed: interoperability, schedules, and customized components. In chapter 8 it will also be questioned whether BIM can assist designers pursuing Innovation points in LEED. 26 Chapter 3: Case Studies and Interviews on Existing Building 3.1 Introduction To better understand how the ACE industry deals with their LEED credits evaluation process and their building information model (if it exists), two case studies will be evaluated. This evaluation will give guidance to this study before discussing the detailed methods using BIM evaluating LEED credits. The first case study is the Conrad Hotel in Beijing. This is a LEED certified building designed without BIM usage. The second case study is McKinley School designed by LPA Inc. This is a LEED Silver project, and some of the credits used BIM technologies. This study is expected to assist the author in adding more data to the BIM – LEED Evaluation Table. Overlooked synergies will also be explored, as it is likely that most BIM projects did not fully utilize its potential for LEED. Understanding why this might have been the case is also important. The case studies focus on the credits in which LPA used BIM for evaluation, and compare this with the non-BIM project (Conrad Hotel Beijing.) Several interviews have been conducted with design team members in the two projects, seeking their views on BIM potential usage in LEED certification and the advantages and disadvantages in doing this. The existing methods will be added into the final BIM-LEED chart. The reason why ACE teams don’t use BIM will also be considered in order to give guidance on improving the interoperability between BIM and LEED. 27 3.2 Case Study 1: McKinley School 3.2.1 Basic Information of McKinley School Figure 3.1 McKinley School Picture provided by LPA, Inc. The first case study is McKinley K-8 School. McKinley is an arts-focused K-8 school in the Pasadena Unified School District, in Pasadena, California. LPA Inc. has just begun schematic design. McKinley is a historic campus that was recently reopened. LPA Inc will be restoring the academic buildings and designing a new gymnasium, band room, and science wing. The new construction will include the school's quad, play space, and streetscape. In partnering with the City of Pasadena, the school district desires the school to be designed to LEED Silver. LPA, Inc. did most of the design, including architecture, civil engineering, structural engineering, mechanical/ plumbing engineering, and landscape architecture. For that 28 reason it was easy for the author to interview and talk with multiple people in different design teams. The image showed in figure 3.1 was created in Sketchup, the team found that compared with BIM, Setchup is easier to use and provides graphic feedback very quickly. It also has interesting rendering effects. In the design process, the architects are using the traditional 2D techniques to generate the architectural drawings, but using the conceptual design in Revit to research the building’s orientation, daylighting, solar radiation, and other environmental impacts. Figure 3.2 Project Site Map Picture Provided by LPA, Inc. At the beginning of the design, a building information model is usually used for the coordination between different design models, detecting if there is any conflict between 29 structural components and MEP components. The engineer design team also uses the BIM model for the construction 4D simulations and construction budget estimation. Finally, when the design and construction is finished, this BIM model will also serve as a documentation tool for this project. The building information model of McKinley School is mainly used for the coordination between different design models, budget estimates and 4D simulations. At the beginning of the design process, BIM was used as a schematic and conceptual design tool to analyze the environment impact and the relationships between McKinley School and its neighbors. Besides that, the building information model was also used for evaluation of 2 credits that total 20 points (in LEED for Schools 18 .) This will be discussed in further detail in the next section. 3.2.2 BIM Usage in Design Process McKinley School is aiming for LEED silver certification and at the midterm evaluation; McKinley has earned 55 points, which has reached the LEED Certified Level. The design team used their building information model to evaluate two LEED credits: Energy & Atmosphere Credit 1: Optimize Energy Performance, and Indoor Environment Quality Credit 8.1: Daylight & Views. 18 The LEED for Schools Rating System is based on LEED for New Construction but recognizes the unique nature of the design and construction of K-12 schools. Most credits in LEED for Schools are same as those for LEED for New Construction. 30 LEED for New Construction Energy & Atmosphere Credit 1 concerns optimizing energy performance; and there are 3 options to archive this credit. Option 1 is the most common method design teams are using because it can earn a much higher score than Option 2 and Option 3 (Option 1 can earn up to 19 points, while Option 2 and Option 3 at most can only earn 3 points). In this credit, the design team used the third party software method. Figure 3.3 McKinley School Midterm LEED credit list review (partial) Charts provided by LPA, Inc. 31 Figure 3.4 BIM application in LEED credits of McKinley School The analyzing process can be divided into 2 steps. The first step is conceptual design. During the primary design phase, the design teams set a goal in this credit to earn 9 points (saving 28% energy compare to the baseline 19 ). They made a conceptual model in Revit Architecture and then used Solar Radiance 20 to analyze the solar gains and day lighting of building; it helped architects to optimize their design by seeing its 19 Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007 gives the baseline of building energy performance . 20 This is a Revit Plug-in program which can analyze day lighting of building and solar gains. 32 environmental impact. In additional it also helped the design team to decide whether to use PV panels to help cut down the energy consumption of building and determine where to put the PV panels. This analysis also indirectly contributed to Energy & Atmosphere Credit 2: On-Site Renewable Energy; because seeing the solar gain of a building can help design teams approximately estimate if solar energy can be attributed to this credit. In addition, the design team also exported this conceptual model to Green Building Studio to do conceptual energy analysis, seeing how design changes contribute to building energy savings. In addition, the team can view building water consumption in Green Building Studio, which informs them for making decisions for earning Water Efficiency credits. The second step was taken during the design phase. In this phase, architects, structural engineer, and mechanical engineer worked on the same building information modeling platform. The energy simulation team also used the geometry provided by Revit and imported it into EnergyPlus. Before importing the Revit model to EnergyPlus, they first defined the rooms and space types in Revit, modifying room bounding objects and verifying analytical volumes. They then exported the Revit model as a gbXML file (which has been described in Chapter 1.) This gbXML file was then imported to Ecotect; Ecotect was used to release the information package as a gbXML file and transferred this information into an IDF file, which can be directly used in EnergyPlus. The geometry, 33 constructions and HVAC operation information can be viewed and edited in EnergyPlus. The final calculation will be done in EnergyPlus 21 . The modeling process in EnergyPlus is not the traditional way to build a model, which would have virtualized 3D or 2D geometry guides; all the modeling and settings are done by writing programming code. Therefore there is no virtual 3d model that looks like the building. The advantage of this modeling method is that, it will make the results more accurate, because all the building details are described in text. The disadvantage is that designers can’t view their model in EnergyPlus; it will take time for designers to check if their building geometry is right. Especially when design changes, they will need to update the building geometry. With the help of BIM, all the geometry information can be transferred from Revit to EnergyPlus via a gbXML file. In that case, design teams can directly use the geometry information provided by BIM. Regarding the information other than geometry, they still need to input in EnergyPlus manually or make modification accordingly. For this project the design team is using EnergyPlus because, besides EA Credit 1, they will also pursue IEQ Credit 8.1: Daylight and View. EnergyPlus can do both the energy and Daylight simulations. In IEQ Credit 8.1, the design team uses the same method as EA Credit 1 to analyze McKinley’s day light; in both the conceptual design phase and the design phase analyses. In addition, they will also export their conceptual model to 21 To follow these steps, it is required Revit 2010 or higher version, and EnergyPlus v3.0 or higher version. 34 Ecotect to analyze the annual shadows, seeing how surrounding buildings influence McKinley School. When talking about the benefits of using BIM in evaluating LEED credits, Timothy Smallwood, the Project Coordinator of LPA, said that one of the most time-consuming aspects of EA Credit 1 and IEQ Credit 8.1 is the setup required to carry out the analysis. This is a process of re-creating the building geometry as well as setting the conditions necessary to properly represent the environment both inside and outside of the building. Especially when a building has an irregular shape or a complicated curtain wall system, it is difficult to model inside the energy simulation tool, and it is time consuming to re- create the building geometry when design changes. The integration between Revit and EnergyPlus makes it easier the design team to update the energy model; it saves about 60% to 80% of time needed to model inside Energyplus. In addition, the building’s volumetric representations are more accurate, and it is easier to model complicated building shape and different window shapes, which will make the calculation results more accurate. When talking about the disadvantages, Timothy Smallwood said BIM now can only provide geometry information to the 3rd party software; other settings must be done in EnergyPlus. For some 3rd party software, like eQuest, settings can be made inside BIM and gbXML, DOE2 file, but to ensure the correctness of the simulation results, the design team also only uses geometry information provided by BIM. LPA’s principal Jon 35 Mills explained that, before the McKinley School, they tried to do everything within BIM and the energy program, but they failed. They transferred their Revit file to gbXML file and then used Green Building Studio to open it and transferred the information to a DOE-2 file. They defined the space and zone information inside Revit and edited the HVAC settings inside DOE-2 file. eQuest was used only for the final calculation. But the result of energy consumption was wrong; it differed from the result obtained by editing the HVAC and other operations inside eQuest, which was the same as the running results in EnergyPlus. They can’t figure out why this happened. As a consequence they are now only using the geometry and space information provided by BIM; other information is edited in the energy simulation tool. Timothy said that, for a project using building information modeling, LPA has adopted the following as the standard energy modeling workflow: starting with its Revit architectural model, data flows to Green Building Studio, back to Revit, then to Ecotect Analysis and to eQuest or EnergyPlus. However, with most tools, they have to make changes to their models to adapt to the analyzing software system, because models from Revit are more and more complex, but the analyzing tools are not keeping up with the development of BIM technology. For example, during the process of importing Revit file into EnergyPlus, the design team firstly has to simplify the model, deleting all the detailed components, remaining only the main structure, rooms and zonings of building. EnergyPlus can’t read all of the detailed information sent from Revit. When analyzing 36 McKinley School’s sustainability performance, they integrated the Revit model with Ecotect and EnergyPlus. However, those models are not always able to exchange data. The lack of a fully integrated approach can be frustrating. That’s why LPA only uses their building information model to provide geometry information when simulating a project’s energy performance, and finishes the rest of the work in EnergyPlus or eQuest. Timothy says sometimes he feel that the true promise of BIM isn’t really there yet. So far, however, LPA has seen the benefits of using BIM in evaluating LEED credits, which is saving time and providing better coordination between different design teams. LPA is looking forward to seeing the improvement of BIM tools and other analyzing tools, and better interoperability, sharing data abilities between them. 37 3.3 Case Study 2: Conrad Hotel 3.3.1 Basic Information of Conrad Hotel Figure 3.5 3D rendering of Conrad Hotel Picture Provided by China Construction The second case study is Beijing Conrad Hotel, which is located in Beijing’s Central Business District, close to the newly built China Central TV Tower. It is designed by JR Hong Kong, constructed by China Construction, Beijing Institute of Architectural Design is the Structural and Mechanical Engineer. It has a site area of 7779 square meters and constructed area of 56994 square meters. The building height is 106 meters. Beijing Conrad Hotel is scheduled to be open in 2012. 38 This is a complicated design. The façade element, which looks like the nervous system in a body, is planted onto a simple cubic. It is described as “the toxin that destroys and transforms the surface into an organic envelope.” 22 The whole building is transformed into a melting box; a starting point for the urban grid to change from solid efficiency into a liquid idea. Because BIM technology is quite new in China, the design team didn’t introduce BIM to this project. They are using Sketch Up for their 3D modeling, Tangent 23 for their architectural and mechanical design and PKPM 24 for their structural design. The design team also hired a consultant firm to do the energy, daylighting and thermal analysis, which used Ecotect, eQuest and Airpak. The building has at least 6 models for different usages. 3.3.2 Conrad’s Gold LEED Certification Conrad Hotel Beijing is going to pursue a LEED gold certification, and they have already earned 43 points in the mid-term evaluation, while their final goal is 64 points. To pursue LEED gold certification, the design team followed the USGBC’s documentation guide, gathering, filling, updating all the required documents as the project progressed, 22 NoéMie Schwaller, 2009, http://www.dailytonic.com/conrad-hotel-by-mad/, website last accessed 11- Feb-2011 23 Tangent is a popular architectural and mechanical design tool in China, which is developed by Tangent, Inc. This software is based on Auto CAD platform. 24 PKPM is a popular structural design tool which developed by China Academy of Building Research Architectural Design Institute. This software is also based on Auto CAD platform and the Chinese structural design code. 39 and submitting the documents on line. (This is how most design team evaluates and achieves their LEED credits.) Figure 3.6 Conrad Hotel Beijing's LEED credit list card (partial) Chart provided by China Construction This section focuses on the Conrad Hotel, comparing the difference of using and not using BIM technology in evaluating these two credits. In Energy and Atmosphere, the design team of Conrad Hotel commissioned a consultant firm, EMSI Beijing, to do the whole building energy simulation. EMSI used eQuest for Conrad Hotel’s energy simulation. Because the building has a really complicated shape, and the building façades are particularly irregular, it was very difficult for the consultant to model the building. Figure 3.7 shows the final modeling of the Conrad Hotel in eQuest, 40 EMSI has simplified the building as a rectangular shape. They also simplified the windows as rectangular, but kept the percentage of windows to wall the same as the design. Each time when architects change their designs, the consulting firm has to update the model to the latest design. It takes much time for the consult firm to communicate with architects and update energy model. Originally the design team had planned to pursue 10 points in EA credit 1, but during the midterm review, they could only earn 2 points. Figure 3.7 Conrad Hotel energy simulation model Picture provided by EMSI The same situation also happened with IEQ Credit 8.1: Day Lighting. This credit requires a project to have 75% or more of all regularly occupied spaces achieve daylight 41 luminance levels of a minimum of 25 foot-candles and a maximum of 500 fc in clear sky conditions on September 21 at 9 a.m. and 3 p.m. 25 . There are different options to achieve this credit: the first option is computer simulation and the second option is to calculate visible light transmittance and window-to-floor area ratio of the daylight zone (LEED provides calculation methods for this credit.) A third option is to measure the actual daylight foot-candles after building has been occupied. Initially the design team is planned to use the first option, using Ecotect to simulate Conrad Hotel’s day lighting. However the complicated shape and the irregular building façades make it very difficult to model inside Ecotect, so they choose the second option to achieve this credit: using formulas provided by LEED to calculate the project’s day lighting. When talking about this method, the design manager in China Construction, Sen Jia, said it really takes a long time for the design team to calculate visible light transmittance and window-to-floor area ratio, because the project has many daylight zones. Also each time the design changes, they have to recalculate. To be fair, it would also have been difficult to model the building in Revit, but then changes would have been easier to make. 25 USGBC. Green Building Design And Construction Reference Guide. 2009. Page 549. 42 3.4 Comparison between BIM and Non-BIM LEED Projects Comparing the two case studies, if a project is a BIM project, the design team can use their building information model to provide geometry information for some simulations in analyzing software. During the conceptual design phase, design team can integrate their building information model with plug-in or third party software to see how top take advantages of environmental impacts. For EA credit 1, Conrad Hotel design teams are mainly improving their HVAC systems and using renewable energies to save energy. By contrast the McKinley School design team uses the BIM model to analyze the building’s solar gains, day lighting, natural ventilation, and other environmental impacts. During the design phase, they will take advantages of those impacts to earn more credits in EA credit 1. So for some credits BIM can definitely help the design team better evaluate and more easily achieve LEED credits. However ACE teams haven’t yet taken full advantages of BIM. For example: LPA design teams use their building information model for project budget estimation and 4D construction simulation. To accomplish this they need to put in construction information for each component and material; for example: material cost, construction time, demolition time and other construction details. Actually, the design team can also put LEED template required information into their building information model. The reason they didn’t do that is that there is no guideline for using BIM to evaluate a project’s LEED credits. They are using BIM in evaluating of EA Credit 1 and IEQ Credit 7.1 because 43 this method has been used by several firms and have mature guidelines. 26 For other credits, although there are other methods, which may be more convenient than the traditional methods, they don’t use them because there are no mature guidelines for using BIM to evaluate other LEED credits. A project’s budget and time is limited and exploring new methods requires extra time and money (which was supposed to be avoided with the use of BIM.) Therefore, comparing exploring new methods with traditional ones, they prefer using the traditional methods to document project information and evaluate LEED credits. When the author was interviewing Jon Mills and Timothy Smallwood, he asked them if they would switch to a BIM based method if it was proved useful over time as a method for evaluating LEED credits. Their answer is yes. Jon Mills said LPA has their own chart of LEED credits evaluation methods. The chart contains requirements for each credit, how to achieve this credit, conditional cost to achieve this credit, preparation, documentation guide, and a lot more information. When they want to achieve a certain credit, they will refer to this chart and follow instructions on it. Figure 3.8 is a LEED matrix chart provided by Todd Lukesh of Webcor Construction. This is the LEED guidance, progress, responsibility and coordination chart for project Taube-Koret Campus for Jewish Life that might be similar to what LPA could develop. Jon Mills also said when there is a more convenient method for evaluating a certain credit they will 26 GLUMAC is a pioneer in using BIM integrated Energy Modeling: they have detailed guideline for doing this. 44 update their table. For example, before BIM was widely used, they built energy models separately to achieve EA Credit 1. Now, they find the integration between BIM and energy software is more convenient and faster to evaluate this credit, so they have updated their chart, using BIM in this credit when a project has a building information model. The method of achieving each LEED credit is based on many years’ experience of many architects, engineers and contractors. Jon Mill said BIM is a quite new tool, it is just getting started. If it develops well and people find better and more convenient ways to document LEED project information, they will definitely consider using BIM for potential LEED credits evaluation. Figure 3.8 LEED matrix chart Picture provided by Todd Lukesh 45 3.4 Conclusions and Some Charts From the two case studies and interviews with people in ACE industry, currently, the market does not have a high level of application for BIM to LEED credit calculation. According to the Green BIM Smart Market Report by McGraw-Hill Construction (2010), there are challenges in using BIM for LEED credit calculations. 42% of firms currently practicing Green BIM are not using BIM for LEED Credit calculation because they find existing tools easier to use, and another 36% do not believe they have a need. Figure 3.9 shows the level of application in “Calculating LEED Credits through BIM” (according to Green BIM practitioners) and reasons behind not using BIM to calculate LEED credits (according to Non-Green BIM companies). From the two charts, it can be seen most designers don’t use BIM as an evaluation tool is because they lack relevant BIM tools to this and they have other ways to calculate LEED credits. For some simple projects there is no need and it’s complicated to build a BIM model which will usually cost more money and spend more time. For those complicated project where BIM can show advantages, the design team has began to try using their building information model to calculate and evaluate potential credits. And in cases where a BIM model already exists, it can be leveraged for this purpose. However it is still at a beginning level. Only 5% of the design teams are at a high level in associating BIM and LEED. Nearly 80% are at a low level or didn’t use their BIM model in evaluating LEED credits at all. 46 Figure 3.9 Level of application in Calculating LEED Credits through BIM Picture from McGraw Hill Construction Mike Opitz (2010), USGBC’s vice president of resource development, explains the goal of future versions of LEED online, which will allow project teams to have their BIM software, automatically send in their data to LEED online, rather than laboriously upload it into the system 27 . 27 McGraw-Hill Construction. Green BIM Smart Market Report, page 43. 2010 47 Chapter 4: Method 1 – Schedules and Parameters 4.1 Introduction As discussed in chapter 2, there is a group of credits that are achieved based on documentation and simple calculations, such as LEED NC Material Resources Credit 4. To pursue these credits, the design team has to document the entire project’s materials or components with required parameters; then based on the documented parameters, use equations provided by LEED NC, and calculate a certain percentage or a certain value, to determine if the LEED credit threshold has been met. As projects are modified and revised, the credit threshold calculations need to be recalculated. The required submittal documentations of these credits usually include cut sheets or manufactures’ letters to document the listed products’ names, costs and required parameters. There are about 20 points in LEED that are based on documentation and calculation. Figure 4.1 shows these credits, their requirements, submittal documents, and the parameters need to be documented. The numbers in red in this figure are the requirements of each credit the project need to achieve. To evaluate these credits, AEC teams usually use Excel or other forms of tabulation to store building component data and then make calculations on the data according to formulas provided by LEED. The disadvantage of this method is that, each time the design changes, the designers have to go back to their documentation to change the data, and recalculate them. 48 Figure 4.1: Credits based documentations and calculations. Theoretically, a building information model can be a single source of all project information. When a project is using building information modeling, instead of traditional building documentation, designers can add the data required by LEED into a BIM model and then use schedules and calculation functions of BIM to document these components. When design changes, BIM software can automatically detect changes, 49 and will adjust the schedules. In that case, time will be saved in updating the documentation. 4.2 Creating Schedules and Parameters Figure 4.2 Simple model created for testing To test the possibility of using BIM to provide LEED information, a simple BIM model is created. It contains all the material and component types which might be documented in LEED credits evaluation, such as different sloped roofs, water fixtures, refrigeration systems, wood components and so on. All the credits in group of parameter and schedule will be researched and evaluated by using this model. 50 Figure 4.3: LEED Documentation Template for MR Credit 4 At first, we will discuss the method of using BIM documenting LEED NC Material Resources Credit 4. This credit requires that the project use materials with recycled content to at least 10% or 20%, based on cost, of the total value of the materials in the project. In LEED, the AEC teams need to document the following information to achieve this credit: Material Name, Manufacturer, Material Cost, Post Consumer Recycled Content, Pre-Consumer Recycled Content, and Recycled Content Information Source (see figure 4.3). AEC teams can get these values of from the materials’ manufacturer’s data. To use BIM to provide the information required by LEED first the LEED information needs to be added into the model. Revit and all the other BIM softwares allow adding new parameters to the project. To do this in Revit, designers can go to the “Manage” tab and select “Shared Parameters”; a command window will show as in the left panel of Figure 4.4. Then new parameters can be typed and added to a project. Before adding parameters, parameter groups can be created for ease of management. For example, in 51 this thesis 6 groups are created according to different LEED categories, and the parameters of this credit are settled in group “LEED NC MR”. For this credit 3 new parameters are created: Post Consumer Recycled Content, Pre-Consumer Recycled Content and Recycled Content Information Source. The other 3 parameters required by this credit are initially contained in materials and components. Figure 4.4: Adding parameters to project Now designers have the new parameters for the project, and they need to provide values for these new parameters into each material and component. To do this, they can select a certain component; for example, a column. Then choose the “Edit Family” command and types and edit information in this column. By clicking “Element Properties”; a command window will show as in the right panel of Figure 4.4. Here, designers can add the parameters they created to this column, and type in the values of 52 parameters according to the manufacturer’s data, just as in the traditional LEED documentation procedure. Now, the column contains the LEED required parameters. Not only this column, but also the whole same column type has these parameters; this is because in Revit the material and component types are organized by categories and families. When we change a single component’s properties, all the component’s properties of this family type will be changed. This saves time when designers want to make changes to their designs. The same method applies for other component types, like beams, windows, doors, etc. Figure 4.5: Creating phases and schedules After all the components have the required parameters, a schedule can be created. Because not all materials are qualified for this credit, before creating a schedule, different phases should be created and defined for each component and material. For this credit, as described for credit requirements in LEED NC: “mechanical, electrical and plumbing components and specialty items such as elevators cannot be included in this 53 calculation. Furniture may be included if it is included consistently in MR Credit 3: Materials Reuse through MR Credit 7: Certified Wood.” So before creating schedules, we need to group materials. There are two methods: one method is going to “Manage” tab, in “Phases”, creating a phase for materials which qualify for MR Credit 4 (see left picture of Figure 4.5). Then go to each element’s property to define its phases (Actually phases are created before starting a model, details will be discussed in Chapter 4.4). A second method is to sort the components which are not qualified for MR Credit 4 as a phase, and exclude these components when creating a schedule. There are many loops of the qualified components for MR Credit 4 and other credits. Details will be discussed in Section 4.4, after all credits have been discussed. After defining phases, a material takeoff schedule can be created by selecting different material categories and phases; then the material group that is qualified for the credit can be selected (see right panel of Figure 4.5). The “material takeoff” command is under the “View” tab, “Schedules”. Then the “Material Takeoff Properties” command window will appear as shown in figure 4.5. In the command window, the specific parameters, as required by LEED template, can be added to the schedule along with a few simple formulas to calculate the recycled content value. For this credit, two parameters need to be calculated, which are Recycled Content Value = Percent Postconsumer Recycled Content × Material Cost + 0.5 × Percent Preconsumer Recycled Content × Material Cost, 54 and Percentage Recycled Content = Total Recycled Content Value / Total Materials Cost. Using these formulas calculate values for the parameters.. Figure 4.6: Adding parameters and formulas in schedule Figure 4.7 shows the completed schedule. In order to better track the change of the whole project’s recycled content percentage, I added another two parameters. One is “% Cost”; this is the percentage of each component’s cost relative to the whole building cost. Another is “Total Recycled Content Percentage”; this is “% Cost” multiplied by each component’s recycled percentage. So the grand total of “Total Recycled Content Percentage” is the project’s final recycled content percentage which is used for evaluating MR credit 4. Comparing with the LEED template, this schedule contains all the information needed for the LEED template, and it can calculate the recycled content value and percentage recycled content. When the design changes, for example, a 55 concrete wall is added or a steel column is removed, the schedules and calculations will automatically update. Figure 4.7: Schedule for MR Credit 4 Sometimes it is not easy to select the components group by simply selecting the component category and phases. It should be predetermined whether components or materials qualify for credit requirements. LEED NC Sustainable Site Credit 7.2 is about minimizing the heat island effect caused by dark roofs. To earn this credit, roofing materials for low and steep slopes with a solar reflectance index (SRI) equal to or greater than the values in the figure 4.8 below for a minimum of 75% of the roof surface. Figure 4.8: Roof requirements in LEED NC Sustainable Site Credit 7.2 For this credit, the qualified roofs can’t be easily selected by component categories and phases, because first one needs to determine the roof’s slope and then compare it to 56 the required SRI value of the roof. To solve this problem, similar to the method used for LEED NC MR Credit 4, shared parameters that are required by LEED template should be created and added to the project. The schedule is created and a slightly more complex formula given. The final schedule is shown in figure 4.9. SRIcounts = if(or(and(Roof Slope, SRI>29), and(not(Roof Slope),SRI>78)), %totalroof,0) Figure 4.9: Schedule of LEED NC Sustainable Site Credit 7.2 4.3 Examples of Other Credits In this section two credits are shown as examples of the method of editing parameters and creating schedules. There are 14 credits, which account for20 points which can use this method. 4.3.1 MRc1.1 Building Reuse: Maintain Existing Walls, Floors and Roof Requirement: Maintain the existing building structure at least 55% (by area) of the completed building. (55% 1 point, 75% 2 points, 95% 3 points) Documentation: Structural Name, Existing Area, Reused Area Calculation: Reused Percentage = Reused Area / Total Area 57 Methods: The parameters of “Structural Name” (Family and Type) and “Existing Area” (Material: Area) are already existing in Revit and have values in each element. Only “Reused Area” needs to be added into project. Because the reused area of each structure element varies, so a new parameter called “MR C1 Reuse Percentage” is created. This inputs the percentage of reused area of each structure element; then total reused area and total percentage will be calculated using the same method discussed in MR Credit 4. A phase can be created and structure walls and floors added to this phase. This will help selecting qualified elements when creating the schedule. Figure 4.10: Schedule of LEED NC Material Resources Credit 1.1 4.3.2 MRc1.2 Building Reuse: Maintain Interior - Nonstructural Elements Requirement: Use existing interior non-structural elements in at least 50% (by area) of the completed building 。 Documentation: Structural Name, Existing Area, Reused Area Calculation: Reused Percentage = Reused Area / Total Area 58 Methods: The method of using BIM for documenting this credit is same as for MR Credit 1.1. A phase needs to be created, and the non structural elements, such as doors, ceilings, and roofs added to this phase. Figure 4.11: Schedule of LEED NC Material Resources Credit 1.2 4.3.3 MRc2 Construction Waste Management Requirement: Recycle and/or salvage ≥ 50% of construction and demolition (C&D) debris Documentation: All construction waste Calculation: Volume of recycled materials / Total material waste volume Methods: Material volume is one of the properties that is originally assigned for each material. A “percentage” parameter called “Recycled” in the schedule will be created to determine what percentage of each material is recycled. To present the user has to manually put in this percentage. As the software gets more sophisticated and the material definitions more exact, it is hoped that eventually the schedule will just query 59 the database and determine this itself; then calculate the percentage of the reused material. Obviously, this simple example does not take into account the nuances of percentage of material to be recycled. For example, the wall should be broken into components such as framing and sheet rock and the percentage of construction waste separately tabulated. A more sophisticated schedule could do this. In Revit, a phase for construction waste could be created to make it easier to track. Actually, there is another method to evaluate this credit by editing families. It will be discussed in Chapter6. 60 Figure 4.12: Schedule of LEED NC Material Resources Credit 2 4.3.3 MRc3 Materials Reuse Requirement: Use salvaged, refurbished or reused materials totaling ≥ 5% or 10% of the project materials total value. (5% 1 point, 10% 2 points) 61 Documentation: Material Name, Vendor, Cost Calculation: Cost of reused materials / Total material cost Methods: Material Name and Cost is originally contained in each material’s properties, but the Cost needs to be given values according the real cost. A “yes/no” parameter called “ReusedMaterial” will be created in the to input whether a material is reused. As with MR credit 2, the user has to manually put input the yes or no; then calculate the percentage of the reused material. Because this credit applies to all of the project’s materials no new phase needs to be created; all materials will be included in the schedule. Figure 4.13: Schedule of LEED NC Material Resources Credit 3 62 4.3.4 MRc5 Regional Materials Requirement: Use building materials or products extracted, harvested or recovered , as well as manufactured, within 500 miles of project site for ≥ 10% or 20% (based on cost) of the total materials value. (10% 1 point, 20% 2 points) Documentation: Material Name, Manufacturer, Cost, Harvest Distance, Manufacture Distance, Location Info. Calculation: Cost of regional materials / Total material cost Figure 4.14: Schedule of LEED NC Material Resources Credit 5 Methods: The new parameters that need to be created for this credit are Harvest Distance, Manufacturer Distance and Location Info. A Yes/No parameters will be created to determine if the material qualifies for MR Credit 5: if both harvest and manufacturer distances are within 500 miles from project location this parameter is yes; otherwise it is no. Then a calculation parameter needs to be added to calculate the percentage of materials which are marked “yes”. Because this credit applies to all of the project’s 63 materials no new phase needs to be created; all the materials will be included in schedule. 4.3.5 EAc4 Enhanced Refrigerant Management Requirement: To provide for the ongoing accountability of building energy consumption over time. Documentation: ODPr,Lr,Life,Mr,Rc,GWPr Calculation: •LCGWP + LCODP x 105 ≤ 100 • LCODP = *ODPr x (Lr x Life +Mr) x Rc+/Life • LCGWP = *GWPr x (Lr x Life +Mr) x Rc+/Life Methods: Adding new parameters to project, and defining the values according to refrigerant manufacturr’s data. According to the 3 formulas provided above, create 3 calculation parameters, then see if the LCGWP + LCODP x 105 is lower than 100. The user should create a schedule of specialty equipment to group the refrigerators. Figure 4.15: Schedule of LEED NC Energy & Atmosphere Credit 4 64 4.3.6 SSc4.2 Bicycle Storage and Changing Rooms Requirement: Provide secure bicycle racks and/or storage within 200 yards of a building entrance for 5% of all building users; Provide shower and changing facilities for 0.5% of the FTE occupants. Documentation: Bicycle storage quantity, Full-time equivalent (FTE) Calculation: Bicycle storage quantity>FTE*0.05 Methods: Add new parameters to the project; then create schedules to see if the quantity of bicycle racks meets the requirement. A new phase needs to be created to group the bicycle racks or, alternately, the designers can place these in the category of specialty equipment when creating schedules. Although bicycle racks and refrigerators are in the same category, because they are entered in different phases, the parameters of refrigerants won’t appear in the schedule of bicycle racks. Other than by schedule, there is another method to use BIM evaluate this credit; and, in addition, the designer needs to locate the bicycle rack within 200 yards of the project entrance. These will be discussed in more detail in chapter 6. Figure 4.16: Schedule of LEED NC Sustainable Site Credit 4.2 65 4.3.6 SSc4.3 Low-Emitting and Fuel- Efficient Vehicles Requirement: Provide 5% of the total parking for low-emitting and fuel-efficient vehicles or provide 20% discount for 2 years for such vehicles in lieu of preferred parking. Documentation: Total Parking, Preferred Parking Calculation: Preferred Parking>Total Parking*0.05 Methods: Adding a yes/no parameter in project to determine if the parking space is reserved for the low emitting and fuel efficient cars. Calculate the grand total of parking spaces and spaces reserved, to determine if it meets the requirement. Besides documenting method, there is another way to evaluate this credit; it’s about editing the parking space families. This method will be detailed discussed in chapter 6. Figure 4.17: Schedule of LEED NC Sustainable Site Credit 4.3 4.3.6 SSc7.1 Heat Island Effect - Nonroof Requirement: Provide at least 50% Percent shading or qualified SRI materials for site hardscape. 66 Documentation: Site hardscape, Parking, Shading facilities, open-grid pavement system Calculation: Area of qualified spaces>Total hardscape area*0. 5 Methods: There are more than 4 types of elements that need to be documented, and they are not in the original Revit family libraries (except for parking facilities.) So some families including specific parameters need to be created especially for this credit (see Chapter 6), like planting with shading areas, site hardscape and open-grid pavement. Designers can directly use those families for this credit, and they can easily change and duplicate them by editing their properties. A yes/no calculation parameter will be created to automatically determine if an element qualifies for this credit; then calculate the qualified percentage. Figure 4.18: Schedule of LEED NC Sustainable Site Credit 7.1 67 4.4 Additional Works 4.4.1 Material Libraries The modeling process in Revit is based on Revit’s materials, families and detail components libraries. These libraries contain arrays of material and family types classified by categories. When a material or a component, such as a column, is chosen to be put into a model it comes with information that determines size and graphics and also other parameters, such as manufacturer and the respective construction phase, to define the item. In addition the design team can also input as much information as desired to be carried with this column. To better correspond with design intentions, designers can add their own components and materials family in libraries. They can even create their own libraries which include their most frequently used design features. In that case, the libraries currently in Revit can be expanded to consist of specific popular brands or LEED certified materials. Furthermore, new sustainable finishes that are discussed in the LEED reference guide, along with their important parameters, can also be added in. So when building a model, designers can directly select materials and components from the libraries; they don’t need to add LEED parameters one by one. 68 Figure 4.19: Material Library and Family Library 4.4.2 Phases for different credits Because different credits apply to different materials, and the schedule function in Revit is not enough to sort these different groups, different phases need to be created to group the materials. Phases are distinct periods of time. Revit Architecture lets designers create phases and phase filters to group building elements called categories. By the phases and phase filters, designers can track views or elements that are created or demolished, seeing how the project appears during various stages of work. The function of phase can also control the schedules; it allows designers to create phase-specific documentation. Designers can create as many phases as necessary and assign building components to specific phase. Although not their major use, phases can also be used to separate different families that happen to be in the same category (for example bicycle racks and refrigerators that are both in the same category of “specialty equipment”). 69 According to the features of different credits, a table is made to show what phases need to be created, and how to group the materials. As shown in Table 4.1, the first column is the credit name, and second column describes the documentation objective, which means the type of materials that need to be grouped. Then the table will explain what phases need to be created for each credit, and what they are applying to. The last two columns describe how to use the phases and the category in schedule to sort the materials, and a short description of each credit, which can give clear guidance to designers how to use the phases function in Revit. 4.4.3 Creating cut sheets A cut sheet can be created in Revit for each credit. In this cut sheet, designers can add basic description for this credit and the schedules in it; then save the file with these schedules and cut sheets as a template. For every new project, they can use this template to start their design, and use the materials and components from the library they created. With the progress of the model, the schedules will also automatically update. By viewing the cut sheets, designers can easily know the credits and their progresses. Figure 4.20 shows the cut sheet for Sustainable Site Credit 4.3, Low-Emitting and Fuel- Efficient Vehicles. From this cut sheet, designers can see the general information of this credit, and the options to get points. For each option, there is a method for achieving it. Take option 1 for example: designers can either load parking spaces which have been 70 edited with parameters, or directly use the parking family created for this credit (this method will be discussed in Chapter 6). A schedule for method 1 in option 1 is also included in this cut sheet, so when designers are at work they don’t need to create a new schedule by themselves; they can directly use the template and the schedule will automatically update, telling designers at which step they have arrived. Other cut sheets will also be created, which include all the credits in LEED NC. The template including these cut sheets will be saved so that architects can directly use this template for their design. All the cut sheets will be shown in Appendix B. 71 Table 4.1 Creating phases and material take-off for each credit 72 Figure 4.20 Cut sheet for SS Credit 4.3 4.5 Conclusions 4.5.1 Advantages This method of schedules and parameters is easier to keep updated than relying on hand calculations. Each time the design changes information is automatically updated in BIM schedules. AEC teams can add all the shared parameters into building components and then create different schedules according to different credits. They can also save these schedules as BIM templates with customized tabs for each applicable LEED credit and can also create their own material library in which the materials 73 themselves contain all the information needed for LEED. These BIM templates and material libraries can be used for future designs. This method can apply to other BIM programs besides Revit. Because all building information modeling is based on the “information”, designers can add LEED information to any BIM program and use BIM to document the LEED information. 4.5.2 Disadvantages Although Revit can automatically generate schedules, not all parameters can be added into a schedule. For example, roof slope is a parameter of roof families, but it can’t be added into roof schedule because Revit regards all the dimension parameters as annotations shown in plans and sections. If designers do want dimension parameters in a schedule, they have to text them into it, or they can use some tricks. For example: if a designer wants to add a project’s length into schedule, he or she can create a shared parameter and provide a formula to it, which is the actual length multiplied by 1; then this shared parameter which represent the actual length can be shown in schedules. However, for most complicated parameters, like slope or angles, Revit can’t automatically provide their value, so the user must manually enter Yes/No parameters created in MR Credit 1.1 and MR Credit 1.2. However, other BIM programs, like ArchiCAD and VICO, they can automatically include the dimension parameters in schedules. So this disadvantage is not inherent to BIM; it depends how the developers 74 develop the BIM program. It is hoped that the developers can design BIM software that is better suited for LEED documentation. Another disadvantage is that the UCBI still hasn’t accepted the documentations generated by BIM. This means that, before the final submission, the designers still have to manually input the documentation to LEED templates. However the technicians of LEED have seen the power of using BIM for evaluating LEED credits. As the vice president for LEED technical development, Mike Opitz, said (2010) future versions of LEED online will allow project teams to have their BIM software automatically send in data, rather than laboriously upload it into the system. 75 Chapter 5: Method 2 – Third Party Software 5.1 Introduction In LEED for New Construction, some credits require design team do simulations using computer programs. For example, the Energy & Atmosphere prerequisite and credit 1, their implementation option 1 requires that the design team do energy simulations using the DOE-2 engine. For some credits, although they do not required computer simulations, firms have developed computer programs based on the credit’s features to help architects make decisions. For example, Autodesk designed Green Building Studio that can calculate a project’s water consumptions based on the calculation guide of credits in the Water Efficiency part. There are about 32 points that potentially can be evaluated by third party software. To achieve these points, usually the design team would make separate models in each simulation program to evaluate these credits. For example, a design team may make a model in eQuest to evaluate the energy credit, and another model in Ecotect for day lighting analysis. As discussed in two case studies in Chapter 3, the disadvantage of making separate models in simulation program is re-creating the building geometry and setting the conditions necessary to properly represent the environment both inside and outside of the building. When a building has a complicated shapes, it is often difficult and time consuming to model inside the simulation tool. 76 Theoretically, a building information model can share data with other programs, so it is possible that the use of the BIM affords the opportunity to reuse data in simulation programs. This chapter will detailed discuss sharing information between different BIM software and other programs. All the credits that are possible to be evaluated by third party software will be discussed in this chapter. 5.2 Interoperability between BIM and Analyzing Tools Before discussion the specific credits, the potential for interoperability between the BIM and analysis tools needs to be discussed. This interoperability can be defined as the ability of sharing and exchanging information between different programs. As Kumar (2008) said, “the ideal interoperability should be a seamless exchange of data among software tools, eliminate the need for duplicating data generation, and allow the bidirectional updates, the changes in one program should be able to flow between the programs.” The interoperability of BIM and other tools is usually accomplished by generating a shared data model. The most popular data models include IFC, gbXML, and DXF which are represented different types of interoperability, such as geometric, syntactic, organizational, they will be discussed below. 5.2.1 IFC IFC stands for Industry Foundation Classes. It is a data model that is intended to storage the building and construction data which includes the building geometry, objects, 77 events, timeline. It is developed by buildingSMART and used for the interoperability between different building industry applications, especially building information modeling software, permitting information to be shared and maintained throughout the life cycle of a project, such as, design, analysis, construction and occupancy (Khemlani 2004). The information contained in a building information model can be documented and packaged into an IFC file. It consists of tangible components such as walls, beams, furniture, doors, etc, as well as the more abstract concepts of space, materials, finishes, geometry, etc. Although two programs may use different file format, IFC make it possible that different programs share the same building information. Graphisoft, the developers of ArchiCAD, was the first software company that world widely allows designers to export and import their BIM files as the IFC format28. 5.2.2 gbXML The file format gbXML, “green Building XML schema”, is a data structure which initially was developed to transfer information related to energy simulation, and now it can also facilitate the transfer of building information stored in building information models, enabling integrated interoperability between BIM models and different types of engineering analysis tools. It can transfer the building information including building geometries, product characteristics, room and space relationships, and building type, etc. It carries a detailed description of a single building or a set of buildings for 28 IFC Support, Graphisoft’s website, website last access: http://www.graphisoft.com/support/ifc/ 78 engineering analysis and simulation. This file format is widely used by manufacturers such as Autodesk, Graphisoft, and Bentley for data exchange. 5.2.3 DXF (Drawing Exchange Format) Drawing Exchange Format is a CAD data file data that is for interoperability between AutoCAD and other programs, enabling primarily geometry information transfers between different programs. It was developed by Autodesk and was intended to provide a detailed representation of the data in the AutoCAD native file format. It is one of the first interface data file for computer building design tools. Although it can’t provide as much information as IFC and gbXML, it is more powerful in geometry information transformation, and the interoperable programs of DXF are much more than that of IFC and gbXML, even non-BIM programs can read the data contains in DXF file, such Rhino, SketchUp, etc. 79 5.3 Credits Analyze Table 5.1: Some third party software that is possible for evaluating LEED credits Table 5.1 shows a list of common software that can be used in conjunction with BIM software. Some of the software list above just help architects evaluating LEED credits, the evaluation results won’t be accepted by USGBC, such as Green Building Studio, it can estimate the building’s energy consumption during the design phase, the result can’t be accepted by USGBC, further simulation works should be done in eQuest and other simulation tools. 80 5.3.1 EA c1: Optimize Energy Performance This credit requires that design teams demonstrate a percentage improvement in the proposed building energy performance rating compared with the baseline building performance rating. The building energy performance calculation baseline is the Appendix G of ANSI/ASHRAE/IESNA Standard 90.1-2007, which requires a computer simulation model for the whole building project. Figure 5.1 shows the energy cost savings percentage for each point threshold: Figure 5.1: energy cost savings percentage for each point threshold USGBC, LEED for New Construction and Renovation, Page 35, 2009 81 To use a building information model to evaluate this credit, the information contained in the model must be transferred to a file that can be used in DOE-2 software. In industry, there are some existing tools, such as Ecotect and Green Building Studio that can export an information model to a DOE-2 file. Designers can compress and transfer the information and building data contained in a BIM model into gbXML, IFC files. This can be opened in Ecotect or Green Building Studio and translated again to a DOE-2 file. The DOE-2 file can be opened in Excel; all the information and design data will be listed in Excel. One could edit the HVAC, internal heat load, and other information in Excel and save it (see figure 5.2). Then the design team could re-open it in a DOE-2 software, like eQuest, to calculate the final results. Figure 5.2: Editing energy simulation settings in Excel 82 Before using DOE-2 tool, the BIM model should be simplified, such as deleting the detail components inside. If a Revit model includes all interior spaces such as mechanical rooms, janitor closets, and other small spaces the DOE-2 model will become unnecessarily complex. In addition, before exporting BIM model to gbXML and IFC files, rooms and spaces should be defined in Revit, because the DOE-2 engine needs the room and space information for calculation. Using the Room/Space names in Revit is also because it simplifies navigation in the DOE-2 tool. In summary, one potential workflow for the design team is to transfer their BIM model into gbXML, open it in Green Building Studio, and export it to a DOE-2 file. The DOE-2 file can be opened in Excel; although a bit cumbersome, this method is often easier than creating the model directly in eQuest. Figure 5.3: Transfer Revit Model to eQuest by gbXML file 83 Figure 5.4: General project information required by LEED template USGBC, Green Building Design and Construction Reference Guide, Page 279, 2009 Figure 5.4 and Figure 5.5 shows parts of the templates required by EA Credit 1. Comparing the information required listed in templates, it is apparent that BIM can provide some general project information, like geometry, building usage, room area and space. However, other information, like climate information, R value 29 of walls, HVAC settings, etc. have to input during the process of transferring data from BIM to DOE-2 engines. So this workflow has the potential to save time in the process and might have fewer inconsistencies with the original design geometry. 29 The R-value is a measure of thermal resistance used in the building and construction industry. 84 The potential influence of BIM on EA credit 1 is far beyond that. Before the final transfer from BIM to the DOE-2 engine, designers can use the interface of BIM and other third party software to create designs to explore achieving EA credit 1 during the primary design phase. For example, the design team can make a conceptual model in Revit Architecture and then use a third party plug in program, Solar Radiance, to analyze the solar gains and day lighting of building. The simulation results can help architects to optimize their design to gain more solar power and also help them to decide whether to use PV panels to generate electricity and determine where to put the PV panels. This analysis also indirectly contributes to Energy & Atmosphere Credit 2: On-Site Renewable Energy. As figure 5.6 shows, by seeing the solar gain of a building can help design teams approximately estimate if solar energy can be attributed to this credit. 85 Figure 5.5: Proposed and baseline summary table required by LEED template USGBC, Green Building Design and Construction Reference Guide, Page 279, 2009 In addition, during the primary design phase, the team can also export their conceptual model to Green Building Studio via gbXML, to perform a conceptual energy analysis. Each time the design changes, the architects can immediately see how those changes contribute to building energy savings. Besides Green Building Studio, there are many 86 other programs that can do conceptual energy analysis, like IES VE Ware 30 , Autodesk Conceptual Energy Analysis 31 , Revit MEP, etc. Figure 5.6 Solar radiance studies in Revit Course project of ARCH-507, Xin Zhao, 2010 In conclusion, using BIM to evaluate EA Credit 1 is not just simply transfer the information from BIM to a DOE-2 engine; it can be used throughout the whole design process. Starting with the conceptual design, Revit allows users to study solar, shading, and site issues. Then designers can combine Revit with Green Building Studio for early schematic studies. Finally, at later stages of design, designers can export their BIM to analysis tools. 30 IES VE Ware is a free whole-building annual energy and carbon usage tool which is developed by IES. It is accessed by plug-ins to Google SketchUp and Autodesk Revit 31 It is a energy analysis software which developed by Autodesk. It can convert conceptual design models into rich analytical energy models, and conduct integrated whole building energy analysis within Autodesk Revit Architecture 2011. 87 5.3.2 WE c1-3: Water Efficiency This part has 3 credits, which require designers reduce potable water use for building by using high efficient water fixtures, captured rainwater, and recycled gray water. To achieve these 3 credits, designers need to calculate the water use baseline using the formulas provided by LEED, then fill the water fixture and non-portable water usage schedules in the LEED template, calculated the expected actual water usage after occupation (see figure 5.7 and figure 5.8). These schedules are similar with schedules of credits that be evaluated by method 1, parameters and schedule, which means designers can create schedules in Revit and use Revit calculate actual water usage. Indeed there already have some existing tools that designers can directly use, like Green Building Studio and Ecotect. 88 Figure 5.7: Calculation table for irrigation baseline case LEED template for WE credit 1 Figure 5.8: Calculation table for water usage of flush fixture LEED template for WE credit 3 89 In Green Building Studio, for example, when designers export their model to Green Building Studio, it will automatically calculate the design base line of irrigation, flush fixture and total water consumption, based on basic project information from Revit, like building type, building footage, site area, location, etc. Then as figure 5.9 and figure 5.10 show, designers can input the basic fixture information and rainfall harvest information, and GBS will calculate the actual annual total water and portable water consumptions. Compared with design baseline, GBS will tell designers how much water they are saving. Figure 5.9: Calculation of non-portable water and irrigation baseline in Green Building Studio Figure 5.10: Calculation of water usage of water fixtures in Green Building Studio 90 5.3.3 EA c2: On-site Renewable Energy. This credit requires that the project use on-site renewable energy systems to offset building energy costs. The on-site renewable energy includes solar power, wind power, geothermal, etc. Designers are required to use the building annual energy cost calculated in EA credit 1, and calculate the energy produced by the renewable systems as a percentage of the building’s annual energy cost. In DOE-2 simulation engines, designers can input the information about PV panels, geothermal heat pumps and other renewable energy systems, and then DOC-2 will simulate and calculate the energy offset by renewable energy. So this credit is quite similar with EA credit 1. BIM provides building geometry and other general information, other settings are done in the DOE-2 engines. Actually, this credit can also evaluate directly by BIM, using the method 3: editing families. It will be discussed in chapter 6. 5.3.4 EQ c8.1 Daylight and Views - Daylight There are two ways to achieve this credit. One is using computer simulations to demonstrate that 75% or more of all regularly occupied spaces achieve daylight illuminance levels between 25 footcandles (fc) and 500 fc in a clear sky condition on 91 September 21 at 9 a.m. and 3 p.m. 32 . Another option is using the formula in Figure 5.11 to calculate manually to see if each room meets the requirement. Figure 5.11: Calculation formula for EQ credit 8.1 USGC, Green Building Design and Construction Reference Guide, Page 550, 2009 Both the two options can be evaluated by third party software. The work flow of option 1 is similar with that of EA credit 1. Designers can transfer their building information from Revit to daylight simulation tools via gbXML file (see Figure 5.12). Besides that, there already have existing tools that contained formula in option 2. After importing BIM model, it will automatically calculate each room’s daylight level to determine if it reaches requirement. Figure 5.13 shows using Green Building Studio to evaluate this 32 USGBC. Green Building Design And Construction Reference Guide. 2009. Page 549 92 credit. Similar with EA credit 1, designers can also see how their design influences building’s daylight during the conceptual design phase, by using Green Building Studio, VE-Toolkit, etc. Figure 5.12: Transfer Revit Model to Ecotect by gbXML file Figure 5.13: Using Green Building Studio to calculate daylight glazing 93 5.4 Application Programming Interface Problem of Method 2 Method 2 is based on interoperability between BIM and simulation software. At its most basic implementation, only geometry would be exchanged and the additional information would have to be added in the analysis software. In the best situation, all information needed by the simulation software would be exported from the BIM. For example, the calculation of EA credit 1 needs the wall information of R-value. In BIM, a model does have detail information about walls, such as layer, material, thickness, etc. That information is enough to calculate a wall’s R-value. However, during the interoperation of BIM and third party software, it can’t be transferred; designers have to redefine the wall’s R-value. Another problem is that most third party software can only show the analysis results, but they don’t specifically inform the designers whether they have meet the requirements; they have to refer to the LEED guidelines. Although some third party software can tell designers if they meet the requirement, they can’t feed back the result directly to the required LEED documentation. An application programming interface (API) between the analysis results and BIM could be created that would make the BIM more intelligent in transferring information to third party software, reporting analyzing results and credits, and making best use of the parameters already existing in the BIM. This is an ideal situation, and it is an excellent area for future work, but beyond the scope of this study. 94 5.5 Conclusions In this method, the third party software does the specific task that it is designed for; all the other information needed by simulation is generated and stored inside the BIM or added during the process of interface. This method has the potential to save time in the process and might have fewer inconsistencies with the original design geometry. Besides the tools discussed above, there are many other third party software that can be used for LEED credits evaluations, for example, VE-Ware, 3DS Max, DesignBuilder, and more will probably be developed over time. In some cases, the process has been made even more simple and automated by the simulation software. For example in IES VE-ware and Green Building Studio, not only will they give the simulation results for daylighting, but the software will declare if the requirements for LEED have been met. Although interoperability between BIM and analytical software is beneficial for helping establish LEED compliance, one major disadvantage to this method for sustainable design iterations is that currently “round tripping” is impossible, as one cannot make changes to the model in the simulation software and update the building information model. 95 Chapter 6: Method 3 –Directly and Editing Families 6.1 Introduction Some credits can be evaluated directly; no calculations or computer simulations are required. Take LEED NC Sustainable Site Credit 4.1 for example. This credit is about the number of bicycle racks and distance to changing rooms. In order to comply with this credit, the design must provide secure bicycle racks and/or storage within 200 yards of a building entrance for 5% or more of all building users (measured at peak periods). Table 6.1 shows credits that are similar with SS credit 4. As shown on table 6.1, there are some common features of these credits. First, most of the sustainable design features should be within a certain distance from project. Second, the requirements of the sustainable features are varies according to project itself, like FTE (full time equivalent) building user, or a total of other types components. Third, most of the submittal documents for the LEED credit are the design description and plans showing how they achieve credits. Essentially, a simple calculation is made (this could be a parameter or attribute of a object), and a graphic sympol is created to put on the drawing. One could make some changes to the sustainable feature families, or add the parameters inside families, to make it possible to change families according different project’s situations, then generate documents including the cut sheet of the description and plans of those families. 96 SS credit 4.2 is a good example. A circle with a 200 yard radius can be added in to the bicycle family. When it is imported into project, the circle can be shown in project site plans, as the small circle shown in figure 6.2 (The larger circle is used for SS credit 4.1). With the guidance of these circles and GIS maps or data, designers learn if they project might be eligible for these credits early in the design process. Besides that, designer can also add peak period users and bicycle rack numbers as parameters into the bicycle family, setting a formula: Bicycle Rack Numbers = Peak Period Users * 0.05, to control the number of bicycle racks. Designers can easily change the value of peak period users to adjust their design with different projects. Figure 6.1: Adding parameters to control bicycle rack numbers 97 Figure 6.2: Locate bicycle rack family with circle in site map Project of ARCH-507, Xin Zhao, 2010 This credit can also be evaluated by method 1, parameters and schedules. Method 1 gives more priority to design; designers design their project, and then using the schedule to see if it qualifies this credit. Method 3 is to make design adjust the LEED requirements. Each method has its own advantages, it depends how architects want to work. 98 Table 6.1: Credits that could be evaluated by BIM 99 6.2 Methods of Different Credits Types 6.2.1 SSc1 Site Selection Requirement: Do not develop the land that is within 100 feet of any wetlands or areas of special concern and land that is within 50 feet of a water body Submittal documents: Narrative(s) for special circumstances regarding compliance with the site selection criteria Methods: Designers can directly draw a subregion with the edge 50 feet and 100 feet beyond building in the site plan (see figure 6.3). Or designers can draw the property lines in site plan. They can use the subregion or property line in site to determine if the location of project meets the requirements, but to achieve scores, building needs to overlay with GIS information. 100 Figure 6.3: Building with 50ft and 100ft lines in site plan 6.2.2 SSc2 Development Density & Community Connectivity Requirement: Locate project within 1/2 mile of a residential area with an average density of 10 units per net acre and within 1/2 mile walking distance of 10 basic services. Submittal documents: Preparing a site plan that highlights the 1/2 mile radius, locations and types of services and location of residential areas Methods: Create a door entrance family that includes a ½ mile radius circle line on it, and load it into project. The circle can be drawn in plan views by using Detail Line in Annotation Tab. After finishing circle, designer should “Convert Lines”; otherwise it won’t be shown in other views. With the guidance of these circles and GIS maps or data, 101 designers learn if they project might be eligible for these credits early in the design process. (See figure 6.4). 6.2.3 SSc4.1 Alternative Transportation: Public Transportation Access Requirement: Locate the project within 1/4 mile walking distance of 1 or more stops for 2 or more public bus lines; or locate project within 1/2 mile walking distance of an existing or planned rail or subway station Submittal documents: A description table for rail or bus lines indicating name of line/route and distance to station. Develop a site plan to scale and label walking paths between main entrance and 1/2 mile of rail stations or 1/4 mile of bus stop. Figure 6.4: Site plan with ½ mile and ¼ mile radius circles 102 Methods: The method for this credit is similar with SS credit 2. A circle with a 1/2 mile or ¼ mile radius added in the entrance door family. Then import it into project. The circle can be shown in project site plans, as shown in figure 6.4. 6.2.4 SSc4.3 Alternative Transportation: Low-Emitting and Fuel- Efficient Vehicles Requirement: Provides 5% preferred parking of the total parking capacity for low- emitting cars; or provide 1 LE/FE vehicle per 3% of FTEs; or provide low-emitting vehicles for 3% of the FTEs. Submittal documents: A site plan showing total parking and preferred parking or refueling locations, including the calculation of FTEs. Methods: The method of this credit is similar with the SS credit 4.2, bicycle racks. Create a parking family and then add FTE parameter in this family. Create two new parameters, one is total parking numbers; the second is parking spaces reserved for efficient cars. Using the formulas included with these parameters (see Figure6.6), designers can type different FTE values to control the number of parking spaces. This credit can also be evaluated by method 1, parameters and schedules; it has been discussed in Chapter 4. 103 Figure 6.5: Parking family Figure 6.6: Using parameter of FTE Value control the parking numbers and reserved parking numbers 104 6.2.5 SSc4.4 Alternative Transportation: Parking Capacity Requirement: Provide preferred parking for carpools or vanpools for 5% of the total parking capacity Submittal documents: A site plan showing parking, carpool/vanpool information and parking space quantities, including the calculation of parking spaces for building type. Methods: This credit is similar with SS credit 4.3. Designers can add a new parameter for carpool parking and assign a formula to it. In addition, this credit can also be evaluated by method 1, parameters and schedules. 6.2.6 SSc5.1 Site Development: Protect or Restore Habitat Requirement: Limit all site disturbance 10 feet beyond hardscapes, 40 feet beyond the building perimeter, 15 feet beyond primary roadway curbs and main utility branch trenches, and 25 feet beyond constructed areas with permeable paving areas, storm water detention and play fields. Submittal documents: A site development and landscaping plans showing extent of development, protection & planting Methods: Designers can draw a subregion with the edge 10 feet and 40 feet beyond building in the site plan. Actually comparing with directly draw lines in tradition 2D plans, this method doesn’t make it easier. Designers spend more effects using BIM than using traditional method; this will be further discussed in Appendix A. 105 6.2.7 SSc7.1: Heat Island Effect – Nonroof Requirement: Provide at least 50% Percent shading or qualified SRI materials for site hardscape. Documentation: Site hardscape, Parking, Shading facilities, open-grid pavement system Calculation: Area of qualified spaces>Total hardscape area*0. 5 Methods: This credit has been discussed in Chapter 4. To make the hardscape available to be documented in schedules, some families need to be edited. For example, as figure 6.7 shows, a “shadow” can be added into the tree family, and using this “shadow” to calculate the shading area the tree can provide in schedule. Same method, other families can be created make them possible to be documented. Details see Chapter 4. Figure 6.7: Tree family with shading 106 6.2.7 WEp1 Water Use Reduction Requirement: Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building. Submittal documents: Manufacturers’ data that has information of the water consumption rates, manufacturer, and model of each fixture and fitting. Provide a list of plumbing fixtures by usage group. Methods: This credit has been discussed in Chapter 5. Although there already exists third party software to evaluate this credit, designers could use water feature families that contain required parameters and create schedules to roughly determine fixture water consumptions. Figures 6.8 and figure 6.9 show two example models that were created for this credit including the parameters used for water consumption calculation. Designers can directly load the families into their design and use the schedule that was created in chapter 4 to see the total water consumption. The ideal situation for this credit is to create a water fixture family library, which contains most popular water fixture products and the manufacturers’ information. A more ideal situation is that each water fixture supplier will have their products’ Revit family with product data that can be downloaded from their website. 107 Figure 6.8: New water fixture family with parameters for calculation Figure 6.9: Toilet family with parameters for calculation 6.2.8 WEc3 Water Use Reduction Requirement: Using less water than the water use baseline calculated for the building. Points vary from 2 to 4 by saving water from 30% 40%. Submittal documents: Manufacturers’ data which has information of the water consumption rates, manufacturer, and model of each fixture and fitting. Provide a list of plumbing fixtures by usage group. 108 Methods: See WE prerequisite 1. 6.2.7 EAc2 On-site Renewable Energy Requirement: Using on-site renewable energy systems to offset total building energy costs. Points vary from 1 to 7, based on percentage energy saving from 1% to 13%. Submittal documents: Documenting the on-site renewable energy source types, total annual energy generation, and calculating the energy generated from each on-site renewable energy source. Methods: This credit requires designers use renewable energy systems and calculate how many power they can generate. Usually this credit is directly evaluated in third party software as discussed in chapter 5 or manually calculated. In addition to these two options, method 3 can also be applied to this credit. Figure 6.10: ROPATEC BIG STAR VERTICAL and its Revit family Product of ROPATEC http://www.ropatec.com/admin/Referenze/img/UK%2020kw.jpg website last access 2/23/2011 109 Figure 6.10 shows an existing wind turbine product, which can generate green energy that is qualified for achieving this credit. And figure 6.11, figure 6.12 and figure 6.13 show the parameters and conditions for calculating wind energy production. Figure 6.11: Parameters of the wind turbine table from manufacture menu of ROPATEC Figure 6.12: Parameters will change according to different turbine model table from manufacture menu of ROPATEC Figure 6.13: Curve function in the calculation of energy production table from manufacture menu of ROPATEC 110 The calculation of energy production is difficult because the value of the parameters and the final result will vary in for different turbines and wind speeds. For example, as figure 6.12 shows, the value of “Surface” varies in different turbine models. To present this parameter and its value, first, the parameter of turbine model and surface will be created in this turbine family, and then a conditional statement should be added in the formula of this parameter, as shows below: if(Turbine Model = 1, 2.07, if(Turbine Model = 2, 6.6, if(Turbine Model = 3, 9.9, if(Turbine Model = 4, 11.5, if(Turbine Model = 5, 16.1, if(Turbine Model = 6, 34.4, if(Turbine Model = 7, 46.4, 0))))))) This statement will help Revit automatically generate the value of “Surface” according different turbine model. Using the same method, the parameter of “Wind Power” which varies in different wind speed, can add a similar conditional statement in its formula, as shows below: if(Wind Speed = 4, 697, if(Wind Speed = 5, 1508, if(Wind Speed = 6, 2774, if(Wind Speed = 7, 4672, if(Wind Speed = 8, 7173, if(Wind Speed = 9, 10213, if(Wind Speed = 10, 14010, if(Wind Speed = 11, 18648, if(Wind Speed = 12, 24438, if(Wind Speed > 12, 24438, 0)))))))))) 111 These two statements are relatively easy; some calculations are more difficult. For example, turbine efficiency‘s value is related to both wind speed and turbine model. The formula is below: Turbine Efficiency = Turbine Factor / Surface / Wind Factor Figure 6.14: Partial of the values of Turbine Factor and Wind Factor table from manufacture menu of ROPATEC All the 3 parameters are not fixed parameters; before calculation, one should first determine the wind speed and turbine model type, and then determines the value of Turbine Factor and Wind Factor which are related to wind speed and turbine model type. How to calculate surface value has just been discussed, figure 6.14 shows the different values of Turbine Factor and Wind Factor based on different turbine model. The statement below is a part of the calculation formula in Revit to calculate Turbine Factor and Wind Factor; this statement will let Revit automatically select values 112 according to different situation. The complete statements of the formula and other statements for this credit will be shown in appendix C. (if ( and (Wind Speed = 4 , Turbine Model = 7), 713.44 , if ( and (Wind Speed = 4 , Turbine Model = 6), 241 , if ( and (Wind Speed = 4 , Turbine Model = 5), 157 , if ( and (Wind Speed = 4 , Turbine Model = 4), 112 , if ( and (Wind Speed = 4 , Turbine Model = 3), 96 , if ( and (Wind Speed = 4 , Turbine Model = 2), 64 , if ( and (Wind Speed = 4 , Turbine Model = 1), 17 , if ( and (Wind Speed = 5 , Turbine Model = 7), 1542.734 , if ( and (Wind Speed = 5 , Turbine Model = 6), 500 , if ( and (Wind Speed = 5 , Turbine Model = 5), 314 , if ( and (Wind Speed = 5 , Turbine Model = 4), 224 , if ( and (Wind Speed = 5 , Turbine Model = 3), 191 , if ( and (Wind Speed = 5 , Turbine Model = 2), 127 , if ( and (Wind Speed = 5 , Turbine Model = 1), 33 , 0))))))))))))))/Surface)/ (Wind Speed ^3*1.225*0.5) Other parameters and calculations are shown in figure 6.15. The complete formula and statements are shown in Appendix C. 113 Figure 6.15: Other parameters and calculations of wind turbine family Another easy example is the PV panel. A general PV family was created, and the photovoltaic cell’s equation for wattage of peak power calculated: (Solar Panel Area / 1 SF) * Solar Cell Efficiency * Solar Radiation Watts per Square Foot 33 . The solar efficiency is based on the type of solar panels and the solar radiation, which is based on where the sun is located and how much direct sunlight the solar panel collects. 33 Sustainable Parametric Objects A Professor’s Challenge, Karen Kensek, 2009, AUGI AEC EDGE 114 Figure 6.16: A PV panel family Xin Zhao, Homework from ARCH-507, 2010 Figure 6.17: Parameters for calculation and evaluation After defined these parameters, it is possible to calculate the energy generated by solar systems. Although it is possible for the designer to create the model families and write the formulas, it would be preferable if this information is instead provided by the supplier. 115 This is especially applicable for equipment such as the solar panels and turbines where the manufacturer has a much more thorough grasp of the information. 6.2.8 MRp1 Storage and Collection of Recyclables Requirement: provide an easily-accessible area for the collection and storage materials for recycling during the construction. Materials to be recycled must include at least paper, corrugated cardboard, glass, plastics, and metals. Submittal documents: Floor plans or site plans that highlight recycling storage areas. Designers provide a record of the material recycling plan including its size and accessibility to facility staff. Methods: To achieve this credit, designers and contractors must determine the recycling collection area that is easily accessible to all the people, and submit plans showing the implementations. A trash bin family that contains different types can be created, and designers can locate it in the project file (see figure 6.17). Designers can submit the plan that shows the location of trash bins and the 3D views to LEED online. 116 Figure 6.18: Trash cans families 6.2.8 MRc2 Construction Waste Management Requirement: Develop and implement a construction waste management plan that identifies the 50% to 75% materials to be diverted from disposal and whether the materials will be sorted on-site or comingled. Submittal documents: Track and document of all construction waste generated by type and its quantities, and the total percentage of waste diverted from landfill disposal. Methods: This credit is related with MR prerequisite 1. Although BIM can’t generate documents that could be submitted for this credit, load different trash families in project can give contractors the basic information of construction waste management, like the location of waste disposal, types of waste that will be handled, capacity of landfill, etc. 117 6.2.9 IEQ p2 Environmental Tobacco Smoke (ETS) Control Requirement: Prohibit on-property smoking within 25 feet of entries, outdoor air intakes and operable windows. Submittal documents: A detail sheet showing the unit separations, and the site plans and descriptions. Methods: A circle with a 25 feet radius can be added in the entrance door family. Or designers can add a designated smoking area with 25 feet lines offset from the walls in the site plan, as figure 6.19 shows. Figure 6.19: Floor plans with designated smoking area 118 6.2.10 IEQc6.1 Controllability of Systems—Lighting Requirement: Providing individual lighting controls for at least 90% of the building occupants to enable adjustments to different task needs and preferences. Submittal documents: A floor plan that shows the location, zoning, and type of lighting controls. Design information on task lighting, sensors, and lighting controls. Method: Editing the lighting fixture families, adding circles around each lighting fixture to show the lighting zones. Then load the lighting fixtures into the project, create a floor plan that includes the information about the task lightings, and enter the information about the sensors and lighting controls. 119 Figure 6.20: Floor plans with lighting fixture information Xin Zhao, homework of ARCH-507, 2010 6.3 Conclusions 6.3.1 Cut Sheet for Method 3 Same with method 1, parameters and schedules, a cut sheet can also be created in Revit for credits using method 3, directly and editing families. Figure 6.21 shows the cut sheet for sustainable site credit 2 (SS C2), development density and community connectivity. This credit requires designers submit a site plan that highlights the ½ mile radius circle, project’s location, and the types of qualifying services. So a site plan with the circle and 120 marks of service buildings is added in this cut sheet, designers fill the table of service information. Cut sheets for other credits will be shown in Appendix B. Actually, cut sheet for SS C2 meets the requirements as a submittal document. But it is unknown if GBCI will accept it. Perhaps someday GBCI will accept documents generated directly by the BIM, including calculation results of green power, water consumption, etc. 6.3.2 Conclusions This method of creating custom components is flexible because designers can change the family according to different situations and credits and help create the submittal documents. Compared with the traditional method, this method takes no less effort to evaluate most credits. For example, designers can evaluate their project locations by using a door entrance family in site plan; they can also evaluate directly in Google Map; or they can use the PV panel or wind turbine families to assume the green power generation, and they also directly use the data from the manufacture menu to manually calculate them. Depending on the office, using custom families in BIM might be more difficult or easier than doing the work manually. But BIM provides the advantage that all the information can be contained within the model. Designers can make all the decisions and evaluate most of the credits in a single model if it contains the appropriate information; they don’t need to go through different tools to evaluate each credit. BIM has the potential to save designers time. 121 Figure 6.21: Cut sheet for sustainable site credit 122 Chapter 7: Using BIM for Evaluating Innovation Design and Regional Priority Credits 7.1 Introduction 7.1.1 Innovation Design In addition to the 100 standard LEED points, there are 6 points for innovative design and 4 points regional priority in LEED for new construction. The innovation design points are intended to encourage design teams to perform above the requirements set or not specifically addressed by the LEED. It includes 3 parts, one is exceptional performance, and it is awarded for exceeding the regular credit requirements and achieving the next percentage threshold. For example, Material Resources credit 6 requires project using minimum 2.5 % rapidly renewable materials, which can earn 1 point. If the project achieves a threshold of 5%, it can earn 1 more point for innovative design as exceptional performance. Not all the credits are available for exceptional performance points. The second part is innovative performance. It rewards innovative and sustainable building designs that improve performance beyond the LEED requirements as specified in each credit. GBCI has accepted many innovative performance submittals and lists them on its website as a reference for future innovations. For example, Green 123 Housekeeping (IDc1.1 inquiry 4-8-04), High Volume Fly Ash (IDc1.1 inquiry 12-6-02) 34 , etc. The third part encourages better coordination towards achieving LEED certification by requiring that a LEED Accredited Professional be a principal participant in the project. 7.1.2 Regional Priority Because some environmental issues are unique to a locale, LEED allocates six credits that identify distinct environmental areas to encourage design teams to focus on regional priorities. Each Regional Priority credit is based on an existing credit; if a project earns a Regional Priority credit, it will automatically earn an additional point beyond that already awarded. Essentially, “bonus” points are given for earning specific LEED credits; which credits receive the bonus is based on the location of the project. For example, a project in Arizona might get an additional point in water conservation. Up to four extra points can be earned in regional priority. Although the project may be qualified for more than 4 points in Regional Priority credits, the project team can only choose a maximum of 4 credits to apply. Upon project registration on LEED online, LEED Online will automatically determine which credits are available for Regional Priority based on the project’s zip code. Regional 34 USGBC, Guidance on Innovation & Design (ID) Credits, http://www.usgbc.org/Docs/LEEDdocs/IDcredit_guidance_final.pdf website last access:3/2/2011 124 Priority Credits are available for download from the USGBC website: http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1971 7.2 BIM Used for Evaluating Existing Innovation Design Methods 7.2.1 Exemplary Performance Exceptional performance is awarded for exceeding the regular credit requirements and achieving the next percentage threshold. Therefore the method of using BIM for evaluating exemplary performance is same as for method 1, parameters and schedules. Track the percentage changes in schedules to see what qualifies for exemplary performance. Figure 7.1 shows the schedule for Material Resources credit 4, recycled content. If the total recycled percentage reaches 40%, then it will receive 1 more point in this credit. Figure 7.1: Schedule for Material Resources credit 4 Some of the credits are appropriate for using method 2, third party software. For example, for the Water Efficiency credit 3, the project can earn one more point for exemplary performance if it demonstrates a 45% reduction in projected potable water 125 use compared to the design baseline. So the work process for those credits is the same as has been discussed in chapter 5. 7.2.2 Existing Methods for Achieving Innovation Credits There are no detailed requirements for this part; any comprehensive strategies that can demonstrate quantifiable environmental benefits and are not addressed by LEED Rating Systems are qualified for points. USGBC published some existing ways for applying innovation credits which have been accomplished by some projects. The catalog of innovation strategies is shown in figure 7.2. Figure 7.2: Partial of Innovation in Design Credit Catalog USGBC, 2011, http://www.usgbc.org/ShowFile.aspx?DocumentID=3569, (website last access: 3/2/2011) 126 The following chart will suggest which BIM method can be used for some of these strategies and others that that haven’t been approved by USGBC, but do qualify for innovation credits. All the credits and their descriptions below (except Design for Health) are from USGBC’s catalog of Innovation in Design, they can be viewed in http://www.usgbc.org/ShowFile.aspx?DocumentID=3569 Cate gory Credit Title Credit Description BIM Evaluation Methods Description MR Low‐VO C Materia ls ‐ Mainte nance Coating s Intent Reduce installer and occupant exposure to odorous. Method 1 Parameter and Schedules Put the parameter of VOC value into materials. Create schedules for interior and exterior coatings, calculating percentage of qualified coatings to the total. Requir ement s Use low VOC industrial maintenance coatings that meet or exceed the South Coast Air Management District Rule 113. Submit tals List of all exterior coatings showing their VOC performance and the relative % of surfaces covered by these low VOC products Table 7.1 Existing innovation credits for MR parts 127 Cate gory Credit Title Credit Description BIM Evaluation Methods Description SS Bicycle Networ k, Storage, and Changin g Rooms Intent To reduce pollution and land development impacts from automobile use by encouraging bicycle use. Method 3 Directly Draw 3 mile line from the project boundary in the site map. Architects locate 10 bicycle routes within the three mile line. Requir ement s Provide an existing bicycle network that connects to at least 10 diverse uses within 3 miles’ bicycling distance from the project boundary. Submit tals A map with project boundary, bicycle route from the boundary to existing bicycle network. SS Design for Health Intent promotes increased physical activity through building design Method 3 Directly Using BIM to provide plans that can show the easily accessible stairs, and open spaces. Create exercise facility families; locate them to show in plan. Requir ement s Design buildings so that stairs are easily accessible, visible, safe, and attractive to users. Design buildings to improve access to open space and/or exercise facilities for both adults and children. Submit tals Plans that can show how to increase physical activity. SS Vertical Landsca ping Intent Method 1Parameter and Schedules Design green floors; create floors which have landscape separately with other floors. Then create a floor schedule, calculate the percentage of green floors. Details refer to chapter 4. Requir ement s Design and install a vertical landscaping system whose area is at least 50% of the building floor area. Submit tals Narrative describing native landscaping selections and the benefits of the screen for migrating bird species and local insects. Table 7.2 Existing innovation credits for SS parts 128 Cate gory Credit Title Credit Description BIM Evaluation Methods Description WE Process Water Savings Intent Reduce the amount of water sent to the sewer system. Method 1, 3 Parameter and Schedules, Directly Process water includes the water used by clothes washers, dishwashers, ice machines, etc. Families can be created and parameters put in them. Create schedules to calculate the actual water usage. Details refer to chapter 6, WE credit 3 Requir ement s Demonstrate process water savings equal to or greater than 10% of the regulated water use as calculated in WEc3. Submit tals Calculation of process water savings compared to a baseline case WE Reduce Kitchen Water Consum ption Intent Reduce unregulated kitchen water usage and reduce amount of hot water utilized. Method 1,3 Parameter and Schedules, Directly Similar to process water savings put parameters of water use into kitchen fixture schedules; use the schedules to calculate actual water usage. Details refer to chapter 6, WE credit 3 Requir ement s Install pre-rinse spray valves on all spray rinse stations. Demonstrate a process water savings that is equal to or greater than 10% of the regulated water usage as calculated in WEc3. Submit tals Product cut sheet valves and calculations EA Process Energy Savings Intent Method2, Third Party Software Import BIM model to DOE-2 simulation engines, simulate the consumptions of process energy. Details refer to Chapter 5, EA credit 1. Requir ement s Demonstrate savings equal to at least 5% of the regulated building energy budget used in EAc1 with a non regulated load as defined in ASHRAE 90.1∙1999. Submit tals Calculation results Table 7.3 Existing innovation credits for EA and WE parts 129 Cate gory Credit Title Credit Description BIM Evaluation Methods Description EQ Quality Interior Lighting Intent Provide for occupant comfort interior lighting within a space Method 2, 3 Directly, Third Party Software Transfer BIM model to 3d Studio Max to analyze the luminance level of interior space. Using the lighting fixture plans from BIM to describe the lighting controls. Requir ement s The luminance of task- ambient lighting should achieve recommendation of IESNA luminance level. Lighting controls. Submit tals Narrative describing the lighting controls, and drawings showing control locations. Proving the luminance of task-ambient lighting achieved recommendation of IESNA luminance level. EQ Furnitur e ‐ GreenG uard Certifie d Intent Reduce indoor air contaminants that are odorous, potentially irritating and/or harmful to the comfort and wellbeing of installers and occupants. Method 1 Parameter and Schedules Method similar to Furniture ‐ Low Emitting. Put Yes/No parameter into furniture systems, checking if each of them is GreenGuard Certified. Create a furniture schedule. Requir ement s Demonstrate procurement of GreenGuard Indoor Air Quality Certified low emitting systems furniture and seating. Submit tals LEED∙CI EQ Credit 4.5 template ∙ Signed letter declaring that all systems furniture and seating for the project are GreenGuard Certified ∙ Documentation of compliance from product manufacturer for the products utilized Table 7.4 Existing innovation credits for EQ parts 130 7.3 Possibility of Using BIM to Develop New Innovation Design Methods There are 3 baselines for qualifying for an ID credit: quantifiable, positive environmental impact, and replicable result. This section explores how BIM could be used to develop and quantify new innovation design methods that fulfill these 3 requirements, but haven’t been listed on the GBCI website. (This does not imply that GBCI will accept the specific credits described below.) 7.3.1 Minimize Impact on Neighborhood Buildings The use of reflective materials on facades can lead to problems for occupants in other buildings. For example, some residents of a neighboring building may suffer glare problems caused by sunlight that is reflected off these surfaces and concentrated in a manner similar to a parabolic mirror. As the glare problem of the Disney Hall in Los Angeles 35 , this could make the temperature of the rooms of nearby buildings increase and make them unbearably warm. 35 Marc Schiler, Elizabeth Valmont, MICROCLIMATIC IMPACT: GLARE AROUND THE WALT DISNEY CONCERT HALL, Proceedings of the Solar World Congress 2005, 2005 131 Figure 7.3: Glaze analysis in IES-VE IES website http://www.iesve.com/ConsultancyNAmerica/Daylight- Analysis/Glare-Analysis website last access: 3/8/2011 In addition, some buildings will block the view and solar gains of other buildings, which will indirectly affect heating and cooling loads of the neighborhood buildings; while some buildings’ shadows may block the sunlight from public plaza or parks. Therefore it is possible to create an innovation credit that demonstrates that the proposed project will not have these adverse effects on neighboring buildings. Here is an example of an innovation credit designed to do this. Credit Title: Minimize Impact on Neighborhood Buildings Intent: Minimize the project’s negative environmental impacts on neighborhood buildings and public areas. 132 Requirements: Using low-reflective material as building facades; if using highly reflective material, make a computer simulation showing the glare impact on the adjacent sites. Use the computer simulation to show the annual shadow range of building, ensuring all the surrounding buildings and areas at least 70% of a year (between 10 am and 2 pm) have enough day lighting. Submittals: Narrative describing design approach and computer simulation results. Figure 7.4: Shadow range analysis in Ecotect This credit is using the second method, third party software to evaluate. Designers transfer their building information model to Ecotect for annual shadow range analysis (see figure 7.4), and transfer model to IES BIM plug-in tools for glare analysis (see figure 7.3.). 133 7.3.2 Tracking and Reducing Embodied CO2 Credit Title: Tracking and Reducing Embodied CO2 Intent: Tracking the embodied CO2 generated during construction and reducing it versus a baseline case. Requirements: Document the materials type, manufacture information, and transportation methods. Calculate total project’s embodied CO2. Provide a narrative describing how they reduced the embodied CO2. Submittals: Materials documentation, narrative describing how to reduce embodied CO2. According to Frost (2007), embodied CO2 is an energy measurement for construction materials. It measures the energy used in the process of manufacturing raw materials, including the extraction, transportation, and their manufacture into the final. The calculation of the carbon dioxide during the construction is complicated; it is related to each single product’s material, transportation method, transportation distance, etc. In terms of using BIM to measure the embodied CO2 of a building, features that will influence the building’s construction embodied CO2 will be documented as parameters into materials, and put values of the amount of embodied CO2 they will contribute to building. Finally, a material take-off schedule will be created to calculate the total of the embodied CO2. Practically, although this seems quite straight forward, calculating 134 embodied CO2 is a complex process, and it is hoped that further research by others will make this easier to accomplish. 7.3.3 Advanced Acoustic Design Credit Title: Advanced acoustic design Intent: Reduce noise in office, provide friendly acoustic environment for occupants. Requirements: Simulate sound rays in each office, to make sure each office’s acoustical performance won’t influence other offices; reduce the background noise from HVAC systems in office and other core spaces. Submittals: Detail plans show the offices partitions and computer sound rays simulation results. Figure 7.5: Acoustic analysis in Ecotect 135 There is an acoustic credit in LEED for Schools; however, acoustical performance is also importance for office and residential buildings. A better acoustical performance for offices can facilitate better employee-to-employee communications in conference rooms and provide a better working environment. The intent of this proposal is to achieve better shielding of the HVAC equipment. The work flow of evaluating this credit is similar with method 2, third party software: transfer building information from BIM to an acoustic simulation program. 7.3.4 Integrated Process Credit Title: Integrated Process Intent: Engage all project teams for the purpose of cost- efficiency and sustainable integrated decisions throughout the design and construction process. Develop an early understanding of the relationships between different design teams. Requirements: Iterative analysis during the conceptual design phase, perform multiple systems’ analyses that can demonstrate systems’ synergies. The analyses can include energy simulation, day light analysis, water usage predictions, solar gain, etc. Submittals: Basic information of conceptual designs; analyzing results from different design teams; descriptions of how the team worked together to integrate the results. 136 Figure 7.6: Integrated design process This credit has been rewarded as a pilot credit 36 for designers to test and pursue as an innovation credit. Integrated process before conceptual design phase does not just simply simulate the energy consumption, daylight, water usage, natural ventilation, etc. which are addressed by different credits; rather, it puts different design teams together, to optimize design proposals that can benefit all aspect of sustainable issues. BIM provides an ideal platform for all design teams work together. By sharing the same building database, theoretically they can easily exchange information and ideas. By seeing analysis results from different programs, the design teams can better cooperate with each other and improve the design to the final most optimized one. 36 The LEED Pilot Credit is designed to encourage designers testing of new or innovative green building technologies and concepts. Pilot Credit can be applied as innovation credit. 137 The detailed work flow of using BIM conceptual model to analyze sustainable issues has been discussed in Chapter 5, the Energy & Atmosphere credit 1. The same work flow applies in this case. 7.3.5 Life Cycle Management Credit Title: Building Life Cycle Management Intent: Improve the original building’s space planning, better energy consumption, and asset management after operations. Requirements: Provide detailed building management plans and building performance improvement plans after it has been occupied. Submittals: Provide basic building simulation results and detailed performance improvement plans. Life cycle management of building is a process that considers the building service from its initial design to demolition and the resource impacts of the building. BIM technology supports life cycle management by helping to answer complex questions about project information and buildings operations processes. Building operations management can use BIM to track actual building performance, improve space planning, and manage energy consumption. 138 7.3 BIM Used for Evaluating Regional Priority Credits Figure 7.7: Regional priority credits check list USGBC website, http://www.usgbc.org/DisplayPage.aspx?CMSPageID=1984 website last access: 3/8/2011 As figure 7.7 shows, based on the location’s zip code, each project has a potential of up to 6 credits for regional priority. If the project achieves the requirements of these credits, they will earn one additional point. So the evaluation method for regional priority is the same with the credits discussed in last 3 chapters. Before evaluating regional priority credits, designers have to refer to the regional credit spreadsheet provided by USGBC and then determine which credits they can receive. As discussed in method 1, parameters and schedules, to better use BIM to document LEED information, a simple API inside Revit could be created. As with method 1, it would then be possible for Revit to automatically detect which 6 credits are available for regional priority, and then update the schedules for the 6 credits, adding 1 point when achieving the threshold. 139 7.4 Conclusions This chapter only describes a few examples of possible innovation credits. BIM is ideally suited for storing and delivering the information that can be used to improve building design and its performance because it has the ability to interface with multiple analysis tools and because it can be used for documentation, especially with regards to scheduling. BIM is playing a significant role in delivering innovation to the building industry and can help achieve LEED accreditation with many of the existing credits and for new ideas in the innovation design credits. 140 Chapter 8: Future Work and Conclusion 8.1 What the Thesis Has Done BIM is playing an increasingly significant role in the building industry today; it has developed an efficient workflow between different people in the industry such as architects, engineers, contractors and owners. This thesis focused on developing an efficient workflow to get BIM involved in evaluating the LEED credits, exploring whether BIM can make the compliance path easier, and recording the working process for achieving this. The ideal workflow the thesis developed for using BIM in evaluating LEED credits is seen in figure 8.1. The red part is what this thesis has done; the blue part is future work, which will be discussed in chapter 8.2. Figure 8.1 Ideal work process of Using BIM evaluating LEED credits A final table is produced listing each point, a short description, an evaluation as to whether or not a well constructed BIM could help achieve compliance, and if so, specifically how to achieve this. This final table is attached in Appendix A. In addition, 141 cut sheets for each credit are created; the cut sheets include the credit descriptions, applied method, schedule template, etc. All the cut sheets are attached in Appendix B. 8.2 Future Work There is much future work that could be done to make the evaluation process more convenient for designers. A few are discussed below: more extensive and applicable component libraries, customization of the software to achieve better interoperability, and a commitment by the GBCI towards BIM integration with LEED certification. 8.2.1 Family and Material Libraries The modeling process in BIM is based on component libraries with corresponding parameters and ability to add information. These libraries contain arrays of material and family types broken up by categories. Among the 3 methods discussed in this thesis 2 methods directly relate to the family and material libraries: method 1, parameters and schedules; and method 3, directly editing families. Designers can put all the LEED parameters into each material type and add their own component families in libraries. They can even create their own libraries, which include their most frequently used design features. In that case, the libraries currently in Revit can be expanded to consist of specific popular brands or LEED certificated materials. Furthermore, new sustainable finishes that are discussed in the LEED reference guide and the important parameters can be added in. So when building a model, designers can directly select materials and components from the libraries; they don’t need to add LEED parameters one by one. 142 That work could be accomplished as a further addition to this study. However, a better solution might be to encourage manufacturers and suppliers to provide content rich models directly. It is a lot of work to create and maintain these libraries including updating them with LEED requirements. But if they existed, designers could directly use those components for their designs, be able to analyze more quickly and perhaps save some effort in the process. 8.2.2 API of BIM As discussed in method 2, third party software, the analysis tools, at their most fundamental, basic level, only receive geometric data from the BIM model. However, in the ideal situation, all information needed by the simulation software would be exported from the BIM. To make matters worse, interoperability between BIM and third party software is not as developed as it could be with software glitches, missing information, and poor user interfaces all too common. In addition, in the case of schedules in method 1, some can be difficult to create or rely upon calculations that are hard to extract from the BIM data. For that reason advanced programming with the application programming interface (API) is necessary to provide a more seamless workflow for BIM. For method 1, the API inside the BIM should make BIM more intelligent to extract building data and create schedules. For method 2, an API between analysis results and BIM can be created, finding ways to make BIM more intelligent in transferring information to third party software, reporting 143 analyzing results and credits, and maximizing parameters existing in BIM. This could also be achieved not just directly through the software’s API, but also with a series of custom plug-ins that are developed for information interchange. 8.2.3 GBCI acceptance Chapters 4 to Chapter 7 discussed the possibility of using BIM to evaluate LEED credits and generate documents that could be submitted online. However, at this point of time the GBCI will not accept all the documents (for example, the schedules) generated by BIM, but specific on-line LEED compliance templates must be filled out. As Jim Brain (2010) said, currently their construction team in Pankow exports their schedules in Revit to the Excel format, and then they modify the Excel file to make it qualify for final submission. This takes time. However, perhaps the managers of LEED have seen the power of using BIM in evaluating LEED credits: as the vice president of LEED technical development, Mike Opitz (2010) said, they would like for future versions of LEED online to allow project teams to have their BIM software automatically send in their data, rather than laboriously upload it into the system. 8.3 Conclusions This thesis has examined whether BIM can be a useful tool in evaluating LEED credits, and how to use it when a design team has a BIM model. As a documentation tool, designers can add all the LEED information into BIM model, and create schedules to determine the threshold. As an information source, BIM can provide the most basic 144 building data, such as building geometry, to third party analyzing tools. As a modeling tool, with slightly changes in families or plans, BIM can directly contribute to the LEED submission documents. By using BIM, although not all the credits discussed in the thesis are more convenient compared to the traditional ways, BIM does provide a platform for all designers working together, making the design information exchange faster, optimizing design proposal that can benefit all aspect of sustainable issues. In conclusion, sharing information using the BIM model provides a work platform used by different design teams, and using BIM as a source of all project information could allow designers to study green alternatives more quickly, make timely decisions, and communicate effectively both during design and construction. If BIM can be engaged in LEED credit evaluation, it would assist project stakeholders in making decisions for new and existing buildings considering the best value with regard to the applicable green building rating system score. The increasing number of users of building information modeling encourages the improvement of BIM and related BIM tools. Developers are updating their software to make them easier to user, better suited to the management needs, and sometimes even better at interoperability. As experience grows, it will drive the industry to adopt using BIM models for green design and also help designers comply with LEED more easily and faster, while letting them make more informed decisions about the LEED rating, cost of decisions, and their design. 145 Bibliography Autodesk, 2011. Building Information Modeling, Autodesk, Inc, accessed 27 March 2011, <http://usa.autodesk.com/building-information-modeling/> Barnes, Shannon and Castro-Lacouture, 2009. BIM-enabled Integrated Optimization Tool for LEED Decisions, Georgia Institute of Technology, Atlanta. Brain, Jim, 2010. Leveraging BIM to Achieve LEED Credits and/or CALGreen Requirements, BuildingSuccess discussion event, Long Beach. Bright Power, 2010. LEED Innovation Credit: Design for Health, Bright Power, last accessed 4 March 2011, <http://www.brightpower.biz/greenbuilding/ID- designforhealth> Dowhower, Justin Firuz, 2010. Adapting Building Information Modeling (BIM) for Affordable & Sustainable Housing, University of Texas at Austin, Austin, TX. Environmental Information Administration, 2008. EIA Annual Energy Outlook, US Department of Energy, Washington DC Energy Information Administration, 2008. Assumptions to the Annual Energy Outlook, US Department of Energy, Washington DC Haynes, David, 2008. LEEDing The Way, Ideate, Inc. Seattle, WA James J. Hirsch & Associates, DOE-2 Building Energy Use and Cost Analysis Tool, last accessed 27 March 2011, <http://doe2.com/DOE2/> Jia, Sen, 2010. Personal Interview, 17 September 2010, China Construction, Beijing, China. Kensek, Karen, 2009. Sustainable Parametric Objects a Professor’s Challenge, AUGI AEC EDGE, 2009Fall Krygiel, Eddy, and Nies, 2008. Green BIM: Successful Sustainable Design with Building Information Modeling. San Francisco: Sybex. 146 Kumar, Sumedha, 2008. Interoperability between Building Information Models (BIM) and Energy Analysis Programs, University of Southern California, Los Angles. Lenssen and Roodman, 1995. Worldwatch Paper 124: A Building Revolution: How Ecology and Health Concerns are Transforming Construction, World Institute, Washington DC. McGraw-Hill Construction, 2010, BIM and LEED Credit Calculations, Green BIM Smart Market Report, pp. 43 NBIMS, 2007. National Building Information Modeling Standard V1, Part 1, Chapter 1.1, pp. 6, National Institute of Building Sciences, Washington DC. Mills, Jon, 2010. Personal Interview, 1 October 2010, LPA, Inc, Irvine. ROPATEC, 2010. The formulas for the wind turbine are for specific models made by ROPATEC. The information is from http://www.ropatec.com, click on “Wind calc,” and open the file EN-IT_AEP_WindCalc_2011.xls. (website last accesses 14 March 2011). Roth, Stephen, 2011. About gbXML, gbXML.org, last accessed 27 March 2011, http://www.gbxml.org/aboutgbxml.php Schiler, Marc and Valmont, Elizabeth 2005. MICROCLIMATIC IMPACT: GLARE AROUND THE WALT DISNEY CONCERT HALL, Proceedings of the Solar World Congress 2005 Schwaller, NoéMie, 2009. Conrad by MAD, Daily Tonic, last accessed 11 Feburary 2011, <http://www.dailytonic.com/conrad-hotel-by-mad/> SCIA, 2010. Interaction of BIM with multiple design objectives, accessed 24 November 2010, <http://www.scia-online.com/eNews/en/eNewsDec06_EN.html> Sims, Larry C., 2009. LEED Green Associate Study Guide, Studio4, LLC Smallwood, Timothy, 2010. Personal Interview, 14 October 2010,LPA, Inc, Irvine. U.S. Environmental Protection Agency, 1997. U.S. EPA Characterization of Building- Related Construction and Demolition Debris in the United States, Franklin Associates, Prairie Village, KS U.S. Geological Survey, 2000. 200 data. USGS, Rolla, Missouri 147 U.S. Green Building Council, 2009. Green Building Design and Construction Reference Guide, description of all the LEED credits and submittal documents are from this book. The U.S. Green Building Council, Inc. Washington DC US Green Building Council, 2010. LEED templates, last accessed 11 November 2010, <http://www.usgbc.org/DisplayPage.aspx?CMSPageID=222> U.S. Green Building Council, Guidance on Innovation & Design (ID) Credits, the description of existing Innovation Design credits are from http://www.usgbc.org/Docs/LEEDdocs/IDcredit_guidance_final.pdf (website last access:3/2/2011) Wikipedia, 2011. Industry Foundation Classes, last accessed 27 March 2011, <http://en.wikipedia.org/wiki/Industry_Foundation_Classes> Wikipedia, 2011. AutoCAD DXF, last accessed 27 March 2011, <http://en.wikipedia.org/wiki/AutoCAD_DXF> Xing, Tommy, 2010. BIM Integrated Energy Modeling, BuildingSuccess discussion event, Long Beach. Zhao, Xin, 2010. Homework from Revit class ARCH-507, University of Southern California, Los Angeles. 148 Appendix Appendix A: Evaluation Table for LEED credits All the LEED credits and submission documents descriptions are from the Green Building Design and Construction Reference Guide which is published by USGBC in 2009. The copy can be purchased in USGBC’s website: http://www.usgbc.org/Store/PublicationsList_new.aspx?CMSPageID=1518 Website last access: 3/23/2011 149 Figure A.1 Evaluating chart for Sustainable Site 150 Figure A.2 Evaluating chart for Sustainable Site 151 Figure A.3 Evaluating chart for Water Efficiency 152 Figure A.4 Evaluating chart for Energy & Atmosphere 153 Figure A.5 Evaluating chart for Energy & Atmosphere 154 Figure A.6 Evaluating chart for Material Resources 155 Figure A.7 Evaluating chart for Material Resources 156 Figure A.8 Evaluating chart for Environmental Quality 157 Figure A.9 Evaluating chart for Environmental Quality 158 Appendix B: Cut Sheets All the LEED credits and implementation option descriptions are from the Green Building Design and Construction Reference Guide which is published by USGBC in 2009. The copy can be purchased in USGBC’s website: http://www.usgbc.org/Store/PublicationsList_new.aspx?CMSPageID=1518 Website last access: 3/23/2011 159 Figure B.1 Cut sheet for SS Credit 1 160 Figure B.2 Cut sheet for SS Credit 2 161 Figure B.3 Cut sheet for SS Credit 4.1 162 Figure B.4 Cut sheet for SS Credit 4.2 163 Figure B.5 Cut sheet for SS Credit 4.3 164 Figure B.6 Cut sheet for SS Credit 4.4 165 Figure B.7 Cut sheet for SS Credit 5.1 166 Figure B.8 Cut sheet for SS Credit 7.1 167 Figure B.9 Cut sheet for SS Credit 7.2 168 Figure B.10 Cut sheet for WE Prerequisite 1 169 Figure B.11 Cut sheet for WE Credit 1 170 Figure B.12 Cut sheet for WE Credit 2 171 Figure B.13 Cut sheet for WE Credit 3 172 Figure B.14 Cut sheet for EA Prerequisite 2 173 Figure B.15 Cut sheet for EA Credit 1 174 Figure B.16 Cut sheet for EA Credit 2 175 Figure B.17 Cut sheet for EA Credit 4 176 Figure B.18 Cut sheet for MR Credit 1.1 177 Figure B.19 Cut sheet for MR Credit 1.2 178 Figure B.20 Cut sheet for MR Credit 2 179 Figure B.21 Cut sheet for MR Credit 3 180 Figure B.22 Cut sheet for MR Credit 4 181 Figure B.23 Cut sheet for MR Credit 5 182 Figure B.24 Cut sheet for EQ Prerequisite 2 183 Figure B.25 Cut sheet for EQ Credit 6.1 184 Figure B.26 Cut sheet for EQ Credit 8.1 185 Appendix C: Calculation Statement for Turbine Efficiency This statement provides the calculation from wind speed 1 to 7, and turbine model 1 to 7. (if ( and (Wind Speed = 4 , Turbine Model = 7), 713.44 , if ( and (Wind Speed = 4 , Turbine Model = 6), 241 , if ( and (Wind Speed = 4 , Turbine Model = 5), 157 , if ( and (Wind Speed = 4 , Turbine Model = 4), 112 , if ( and (Wind Speed = 4 , Turbine Model = 3), 96 , if ( and (Wind Speed = 4 , Turbine Model = 2), 64 , if ( and (Wind Speed = 4 , Turbine Model = 1), 17 , if ( and (Wind Speed = 5 , Turbine Model = 7), 1542.734 , if ( and (Wind Speed = 5 , Turbine Model = 6), 500 , if ( and (Wind Speed = 5 , Turbine Model = 5), 314 , if ( and (Wind Speed = 5 , Turbine Model = 4), 224 , if ( and (Wind Speed = 5 , Turbine Model = 3), 191 , if ( and (Wind Speed = 5 , Turbine Model = 2), 127 , if ( and (Wind Speed = 5 , Turbine Model = 1), 33 , if ( and (Wind Speed = 6 , Turbine Model = 7), 2838 , if ( and (Wind Speed = 6 , Turbine Model = 6), 1005, if ( and (Wind Speed = 6 , Turbine Model = 5), 552, if ( and (Wind Speed = 6 , Turbine Model = 4), 394, if ( and (Wind Speed = 6 , Turbine Model = 3), 336, if ( and (Wind Speed = 6 , Turbine Model = 2), 224, if ( and (Wind Speed = 6 , Turbine Model = 1), 57, if ( and (Wind Speed = 7 , Turbine Model = 7), 4779, if ( and (Wind Speed = 7 , Turbine Model = 6), 1734, if ( and (Wind Speed = 7 , Turbine Model = 5), 893, if ( and (Wind Speed = 7 , Turbine Model = 4), 638, if ( and (Wind Speed = 7 , Turbine Model = 3), 543, if ( and (Wind Speed = 7 , Turbine Model = 2), 362, if ( and (Wind Speed = 7 , Turbine Model = 1), 90, 0))))))))))))))))))))))))))))/Surface)/ (Wind Speed ^3*1.225*0.5)

Abstract (if available)

Abstract Proponents of building information modeling (BIM) enthusiastically tout as one of its advantages its ability to work in conjunction with other software programs to predict the performance of buildings. Theoretically this would help in the design of sustainable buildings. The U.S. Green Building Council (USGBC) through its Leadership in Energy & Environmental Design (LEED) building certification system “encourages and accelerates global adoption of sustainable green building and development practices through a suite of rating systems that recognize projects that implement strategies for better environmental and health performance.” (USGBC website 2010) Although LEED is a rating system and BIM is an information technology, there is an opportunity for them to work together with BIM serving as a depository of project information for the design team, consultants, contractor, and potentially operations and maintenance. Using BIM in this approach could allow designers to study green alternatives more quickly, make timely decisions, and communicate effectively both during design and construction. BIM could also assist in fulfilling requirements for LEED points and submitting documentation for the LEED worksheets. It could assist project stakeholders in making decisions for new and existing buildings considering the best value with regard to the applicable green building rating system score.

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Asset Metadata

Creator Zhao, Xin (author)

Core Title An investigation on using BIM for sustainability analysis using the LEED rating system

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Degree Conferral Date 2011-05

Publication Date 05/03/2011

Defense Date 03/29/2011

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag BIM,LEED,OAI-PMH Harvest,sustainability

Place Name USA (countries)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Kensek, Karen (committee chair), Lin, Shih-Hsin (committee member), Woll, Edwin (committee member)

Creator Email rgzhaoxin@gmail.com,xinzhao@usc.edu

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m3811

Unique identifier UC1486679

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Document Type Thesis

Rights Zhao, Xin

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

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Repository Location Los Angeles, California

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