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Interoperability between building information models (BIM) and energy analysis programs
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Interoperability between building information models (BIM) and energy analysis programs
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INTEROPERABILITY BETWEEN BUILDING INFORMATION MODELS (BIM) AND ENERGY ANALYSIS PROGRAMS by Sumedha Kumar A Thesis Presented to the FACULTY OF THE SCHOOL OF ARCHITECTURE UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree MASTER OF BUILDING SCIENCE May 2008 Copyright 2008 Sumedha Kumar ii Acknowledgments I would like to acknowledge my committee members for their guidance and support. I would like to thank my thesis chair Prof Karen Kensek, who first introduced me to Revit and concepts of BIM, and provided valuable guidance while I traversed the relatively unexplored area of interoperability. Thanks to Prof Marc Schiler, for being an excellent thesis coordinator, and for his technical guidance. I am grateful to Prof Ralph Knowles for his continuous support and encouragement and to Prof Murray Milne for his technical inputs on energy analysis terminology. Thanks, also to Chien Si Harriman and Pete Murray, at IES, for their prompt responses and enthusiastic support. And finally, thanks to Mum and Dad, for being there for me, always. iii Table of Contents Acknowledgements ...................................................................................................... ii List of Tables............................................................................................................... vi List of Figures ........................................................................................................... viii Abstract ....................................................................................................................... xi SECTION I ................................................................................................................. 1 Chapter 1: Interoperability ........................................................................................... 1 1.1 Introduction .................................................................................................... 1 1.2 Background: software interoperability .......................................................... 2 1.2.1 Definition ....................................................................................... 2 1.2.2 The present scenario ....................................................................... 2 1.3 Advantages of interoperable software .......................................................... 3 1.4 Objectives of this study .................................................................................. 4 1.5 Methodology for the study and organization of chapters ............................... 4 1.6 Conclusions ................................................................................................... 8 Chapter 2: Building information models ..................................................................... 9 2.1 Introduction to BIM ......................................................................................... 9 2.2 Entity based modeling vs object based modeling .......................................... 11 2.3 Information transfer in BIM .......................................................................... 13 2.4 Organization of information in a Revit Model ............................................... 14 2.4.1 Families ............................................................................................ 14 2.4.2 Type and instance parameters ......................................................... 15 2.4. 3 The ODBC database ........................................................................ 16 Chapter 3: Energy analysis programs ....................................................................... 18 3.1 Introduction to the chapter ............................................................................. 18 3.2 Ecotect ............................................................................................................ 19 3.2.1 Introduction to the tool .................................................................... 19 3.2.2 Energy loads and data analysis ........................................................ 19 3.2.3 Import and export capabilities .......................................................... 22 3.3 IES<VE .......................................................................................................... 22 3.3.1 Introduction to the tool .................................................................... 22 3.3.2 Energy loads and data analysis ........................................................ 25 3.3.3 Import and export capabilities .......................................................... 27 3.4 Summary ........................................................................................................ 27 iv Chapter 4: Interoperability and file formats ............................................................. 29 4.1 Introduction to the chapter ............................................................................. 29 4.2 DXF (Drawing Exchange format) and DWG ................................................ 29 4.3 Gbxml:(Green Building Extensible Markup Language) ............................... 30 4.3.1 Introduction ...................................................................................... 30 4.3.2 Organization of information within the gbXML schema ............... 30 4.4 IFC file formats (Industry Foundation Classes) ............................................. 32 4.4.1 Introduction ...................................................................................... 32 4.4.2 Development of the IFC file format ................................................. 32 4.4.3 IFC compliance ................................................................................ 33 4.4.4 IFC model architecture ..................................................................... 33 4.4.5 Relationship of entities in the IFC model ........................................ 35 4.5 A comparison of the three file formats ......................................................... 37 SECTION II .............................................................................................................. 39 Chapter 5: Test Cases: Comparing the three programs: Revit MEP, IES<VE> and Ecotect ....................................................................................................................... 40 5.1 Introduction to the chapter ............................................................................. 40 5.2 Input values .................................................................................................... 41 5.3 Results ........................................................................................................... 44 5.3.1 Revit MEP ....................................................................................... 45 5.3.1.1 About the MEP-IES<VE> interface .................................. 45 5.3.1.2 Case 1: Within the Revit Engine ........................................ 47 5.3.1.2 Case 2: Revit Model exported to IES<VE> ....................... 47 5.3.2 IES <VE> ......................................................................................... 48 5.3.3 Ecotect ............................................................................................. 49 5.4 Conclusions: Comparing the three programs ................................................. 50 Chapter 6: Test Cases: Comparing the three file formats:DXF, gbXML and IFC .... 52 6.1 Introduction to the chapter ............................................................................. 52 6.2 Interoperable file formats ............................................................................... 53 6.2.1 The IFC file ...................................................................................... 53 6.2.2 The gbXML File .............................................................................. 55 6.2.3 The DXF file .................................................................................... 58 6. 3 Interoperability between Revit MEP and IES<VE> ..................................... 58 6.3.1 Building material .............................................................................. 59 6.3.2 Material thickness ............................................................................ 60 6.3.3 Building location, building services and geometry .......................... 61 6. 4 Conclusions ................................................................................................... 61 v SECTION III ........................................................................................................... 63 Chapter 7: Introduction to the MEP-IES<VE> interface ........................................... 65 7.1 Introduction to the chapter ............................................................................. 65 7.1.1 The MEP-IES Interface: An introduction ........................................ 65 7.1.2 Conversion of a Revit model into an analytical model .................... 66 7.2 Input Values ................................................................................................... 69 7.2.1 Building type .................................................................................... 69 7.2.2 Building services .............................................................................. 71 7.2.3 Place and location ............................................................................ 71 7.2.4 Building construction (default room construction) .......................... 71 7.3 Thermal analysis results ................................................................................. 74 Chapter 8: Improving the Revit MEP-IES<VE> Interface ....................................... 78 8.1 Introduction to the chapter ............................................................................. 78 8.2 Families and their types ................................................................................. 79 8.3 Development of families ................................................................................ 80 8.3.1 Deriving values for parameters in the database ............................... 82 8.3.2 Step 2: Defining the „type parameters‟ in Revit MEP ..................... 83 8.3.3 Step 3: Transferring project standards ............................................. 87 8.4 Standard component families ........................................................................ 88 8.5 Template file: creating a legend .................................................................... 90 8.6 The template file: results ............................................................................... 91 SECTION IV ............................................................................................................ 96 Chapter 9: Conclusions and future work .................................................................... 96 9.1 Conclusions ................................................................................................... 96 9.1.1 Interchangeable file formats ............................................................. 98 9.1.2 The template file ............................................................................ 102 9.2 Areas of future work ................................................................................... 104 Bibliography ............................................................................................................. 108 Appendices ............................................................................................................... 112 Appendix A: Ecotect import and export capabilities ........................................ 112 Appendix B: Load results for Ecotect, MEP and IES<VE> ............................ 115 Appendix C: Categories of building elements carried by the IFC file and its classes.................................................................................................... 126 Appendix D: Construction assignments in the Revit MEP-IES Interface. ....... 128 Appendix E: Values defined for various parameters in the Revit family template…………………………………………………………………….…139 Appendix F: Values defined for various parameters in the Revit family files ................................................................................................................... 148 vi List of Tables Table 2.1 : Importable and exportable file formats accepted by Autodesk Revit. .... 13 Table 2.2: Type and instance parameters. ................................................................. 16 Table 4.1: Hierarchy of information organization in the gbXML schema. .............. 31 Table 4.2: A comparison of DXF, gbXML and IFC formats. ................................... 38 Table 5.1: Method for study. ..................................................................................... 39 Table 5.2: Input variables for the three programs. .................................................... 41 Table 5.3: Load results in Revit MEP ........................................................................ 47 Table 5.4: Load results in the exported Revit MEP model. ...................................... 48 Table 5.5: Load results in IES<VE> .......................................................................... 49 Table 5.6: Load results in Ecotect. ............................................................................ 50 Table 5.7: Comparison of loads in the three programs. ............................................ 50 Table 6.1 Comparison of results: base case file with imported IFC file .................... 53 . Table 6.2 Comparison of results: base case file with imported IFC file .................... 53 Table 6.3: Comparison of information carried by the MEP model and the imported IFC file. ..................................................................................... 54 Table 6.4: Comparison of information carried by the MEP model and the imported IFC file ....................................................................................... 55 Table 6.5 Comparison of results: base case file with imported gbXML file ............. 56 Table 6.6 Comparison of results: base case file with imported IFC file .................... 56 Table 6.7: Comparison of information carried by the MEP model and the imported gbXML file. .............................................................................. 57 vii Table 6.8: Comparison of information carried by the MEP model and the imported gbXML file ................................................................................ 57 Table 6.9: Comparison of loads with different material selections. ......................... 60 Table 6.10: Comparison of loads with different material thicknesses. ..................... 61 Table 6.11: Comparison of the three programs and file formats. ............................. 62 Table 6.12: Comparison of the information carried by the interoperable file formats. .................................................................................................. 62 Table 7.1: Source: Revit MEP user‟s guide: energy analysis building and room type imperial data ...................................................................................... 70 Table 7.2 Default construction assignments for the construction types. ................... 72 Table 8.1: Deriving parameter values from the Apache project constructions .......... 83 Table 8.2: Defining „type parameters‟ ....................................................................... 84 Table 8.3: Defining „type parameters‟ for door and window families. ..................... 89 Table 8.4: Varying load results with different wall thickness ................................... 92 Table 8.5: Construction assignments used for the base case room. .......................... 93 Table 8.6: Results in MEP with and without using the template ............................... 93 Table 8.7: Results in IES with and without using the template. ............................... 93 Table 8.8: Construction assignments selected for the case study building. .............. 94 Table 8.9: Results in MEP with and without using the template. ............................. 95 Table 8.10: Results in MEP with and without using the template ............................. 95 Table 9.1 Comparison of the information carried by interoperable file formats. ... 101 Table 9.2: Comparison of loads in the three programs. .......................................... 102 viii List of Figures Figure 1.1: Methodology for study .............................................................................. 5 Figure 1.2: Chapter organization.................................................................................. 6 Figure 2.1: Interoperability of file formats with BIM and energy analysis tools ...... 14 Figure 2.2: Families of predefined object in the modeling menu. Also, indicated are the instance and type parameters for a wall family type. .................. 15 Figure 2.3:The Access database that contains 144 database tables, representing 72 categories of elements. ........................................................................ 17 Figure 3.1:The Ecotect modeling screen .................................................................... 20 Figure 3.2: The thermal properties can be user defined. ........................................... 21 Figure 3.3: The heating and cooling loads graph ....................................................... 21 Figure 3.4: The „ModelIIT Building Modeler‟ in IES. ............................................. 23 Figure 3.5 The „building template manager‟ in IES<VE>. ........................................ 24 Figure 3.6:‟The Apache construction database .......................................................... 24 Figure 3.7: The „ApacheLocate‟ screen ..................................................................... 24 Figure 3.8: Results from „ApacheLoads‟ in IES showing heating and cooling loads. ...................................................................................................... 26 Figure 3.9: Results from „ApacheLoads‟ in IES showing energy distribution. ........ 26 Figure 4.1: IFC model architecture. .......................................................................... 34 Figure 4.2: Relationships of entities in the IFC model. ............................................ 36 Figure 5.1:The two buttons for a thermal analysis found in the MEP-IES<VE>interface. ........................................................................ 45 Figure 5.2:The exported Revit model in IES<VE>. .................................................. 47 ix Figure 5.3: The IES<VE> building model. ............................................................... 48 Figure 5.4: The Ecotect building model. ................................................................... 49 Figure 7.1: Hierarchy of elements in the Revit analytical model. ............................ 66 Figure 7.2: A model above showing different analytical volumes with the „Compute Room Volume‟ toggle off and on ............................................................ 67 Figure 7.3: Analytical volume ................................................................................... 67 Figure 7.4: Inner volume. .......................................................................................... 67 Figure 7.5: The blue line in IES shows analytical volume ........................................ 68 Figure 7.6: Computing “room volumes” ................................................................... 68 Figure 7.7: Settling the upper limits. ......................................................................... 68 Figure 7.8: Options for building type ......................................................................... 69 Figure 7.9: Building services ..................................................................................... 71 Figure 7.10: Place and locations. .............................................................................. 71 Figure 7.11: The Apache construction database ........................................................ 73 Figure 7.12: Construction assignments for an 8” lightweight concrete block. ......... 73 Figure 7.13: The two buttons for a thermal analysis found in the interface. ............ 74 Figure 7.14: Methods of thermal analysis in the MEP-IES interface. ...................... 75 Figure 7.15: The Apache Simulator generates total annual energy consumption. ... 76 Figure 7.16: System heating loads ............................................................................. 77 Figure 7.17: Room heating plant loads ...................................................................... 77 Figure 7.18: System cooling loads ............................................................................. 77 x Figure 7.19: Room cooling plant loads ...................................................................... 77 Figure 8.1: Development of system family types and standard component families. 81 Figure 8.2: Project constructions for a 4 in face brick wall type. ............................. 82 Figure 8.3 Defining type parameters .......................................................................... 84 Figure 8.4: Defining type parameters ........................................................................ 84 Figure 8.5: Defining the „type properties‟ for the 4” face brick wall ........................ 85 Figure 8.6: Defining the construction layers: plan view ............................................ 85 Figure 8.7: Defining the construction layers: section view. ...................................... 86 Figure 8.8: Assigning values to materials .................................................................. 86 Figure 8.9: Various options for wall types in the template file. ................................ 88 Figure 8.10: Project constructions for low e double glazing windows ...................... 89 Figure 8.11: Defining the „type properties‟ for the low e glazing window. .............. 90 Figure 8.12: Defining the legend for building components ....................................... 90 Figure 8.13: Room modeled with 8 in wall thickness ................................................ 91 Figure 8.14: Room modeled with 16 in wall thickness .............................................. 91 Figure 8.15: Base case room modeled in MEP and IES ............................................ 93 Figure 8.16: Base case room modeled in MEP and IES. .......................................... 93 Figure 8.17: Case study building modeled in MEP. ................................................. 94 Figure 8.18: Case study building modeled in MEP ................................................... 94 Figure 8.19: Case study building model exported to IES .......................................... 94 xi Abstract: Building information modeling (BIM) is projected as tomorrow‟s technology; however, its interoperability with energy analysis programs is a developing area. The intent of this study was to test whether BIM software, specifically Revit MEP, was robust enough to allow seamless interoperability with analysis programs such as Ecotect and IES<VE>. This study tested interoperability for three file formats: DXFs, gbXMLs and IFCs, and analyzed what information, apart from geometry was transferred during data transfer. The study also tested information transfer between the MEP building model and its analytical model. The last part of the study improved upon the MEP-IES interface by building a Revit template file, designed as a “patch” to address the gap between building and analytical models. This template file defined a set of „families‟ that derived its values from the IES construction database and could be imported into a Revit project, making the BIM model more accurate and informative. 1 Section I Chapter 1: Interoperability. 1.1 Introduction. Building Information Modeling (BIM) technology is getting increasingly valuable in the architecture, engineering and construction (AEC) industry, and is being widely projected to be the technology of tomorrow. By virtue of its definition, it contains/ (should contain) a complete set of information about the life cycle of a building in the form of a digital model. The information set could range from the building‟s geometric data, to spatial relationships, geographic data, building components, manufacturer details, construction schedules, fabrication processes and so on; therefore, as a knowledge resource database, it is an extremely powerful tool. Energy analysis programs, such as Ecotect, IES<VE>, eQuest, Energy Plus, Design Builder, HEED etc have traditionally been used to study the energy performance of buildings in order to design more sustainable and energy efficient buildings. Programs may range from simple, user friendly, free tools to extensive, sophisticated programs that need specialized knowledge and are used by building engineering firms. The range of applications include simulations, load calculations and thermal, solar, lighting, acoustic, ventilation, computational fluid dynamics(CFD) analysis as well as a host of other functions. Most of these programs support 3-D modeling functions, and may allow the engineering/design team to be able to import drawings from CAD or other drawing formats. 2 In order that BIM programs be robust and truly informative, their interoperability with energy modeling programs and/or techniques needs to be established. In an ideal world, design tools and energy simulations should be so well integrated such that a change in building design would be reflected in the building‟s predicted energy performance and be updated automatically. This interoperability would help designers at optimizing energy performance and design more efficient buildings. 1.2 Background: software interoperability. 1.2.1 Definition. Software interoperability could be defined as the ability of two or more systems or elements to exchange information and to use the information that has been exchanged. Software interoperability should ideally be a seamless exchange of data among software tools, eliminate the need for duplicate data generation, and allow for the data to have bidirectional updates, the changes in one program should be able to flow between the programs. 1.2.2 The present scenario. Interoperability between BIM and energy analysis programs is a developing area and the potential of BIM in terms of energy analysis has not been completely realized as yet. This study looks at integration between BIM and energy analysis at two levels: a) Incorporation and integration of energy analysis functions within BIM 3 software and b) Interoperability between the two types, that is, data transfer from BIM to energy models and vice versa. The incorporation of energy analysis functions into BIM programs, is at best, in the nascent stage; one of the first steps in this direction has been the recent Revit MEP-IES<VE> connection that was launched in February 2007.For the first time, a sub set of an energy analysis program (IES<VE>) was incorporated within the BIM (Revit MEP) engine, such that simple energy calculations can be performed. The integration of IES and Revit MEP and their interoperability will be discussed in further detail in Chapter 7. 1.3 Advantages of Interoperable software: Interoperable software offers many advantages, making it possible to streamline transfer of building information to and from engineering and analysis tools. If the data exchange between various applications could be seamless, there would be a huge reduction in the time, costs and effort involved in the design of high performance, resource efficient buildings in the AEC industry. For instance, duplication of data and redundancy in model generation can be eliminated if information transfer between a BIM model and an analytical model is seamless. This back and forth data transfer would lead also lead to better energy conscious decisions early in the design process as well as a better collaboration between the design and engineering teams. 4 1.4 Objectives of this study. This study used three programs in order to compare and test interoperability: the BIM software used was Revit MEP and Energy modeling programs were Ecotect and IES<VE>. The objective of the first part of the study was to test if BIM software was robust enough to allow ease of interoperability with the analysis software. The study looked at building models and analyzed what information associated with the building model was retained and what was lost during the process of data transfer from one format to another. As a result of the first set of experiments, the second part of the study specifically focused on improving the interface between IES and Revit MEP, the objective being to build a “patch” or a „family template‟ which, when added on to a Revit program, would make the BIM model more valuable and informative. Chapter 8 will detail the methodology and conclusions of this study. 1.5 Methodology for the study and organization of chapters. The methodology followed for the study consists of research into BIM, energy analysis programs and interoperable file formats in order to achieve a better understanding of their definitions and capabilities. The research then branches into two parallel “streams”: a) A detailed analysis into interoperable file formats and the building information they carry and b) Integration of analysis programs into BIM, specifically, improving the interface between the two. The research then proceeds 5 towards overall issues concerning interoperability, conclusions and opportunity for future work. Figure 1.1: Methodology for study Section I: This consists of background research into BIM, energy analysis programs and interoperable file formats. The objective of this section is to develop an understanding of definitions, different tools, their import/export capabilities and organizational structure, specifically that of Revit, and interoperable file formats. This is organized into the following four chapters: Chapter 1: Introduction Chapter 2: Building information models: 6 Chapter 3:Energy analysis programs: Ecotect and IES<VE> Chapter 4: Interoperable file formats. Chapters are organized in the four sections as shown in the diagram. Figure 1.2: Chapter organization. 7 Section II: This section consists of test cases for analysis of data transfer: Comparison of three file formats( DXF, gbXML and IFC) through test cases. The objective for the exercise was to compare the results of heating and cooling load analyses of a base case scenario, in order to compare the information that they carry beyond building geometry. Step one involved modeling and simulation of a single room, within Revit MEP, Ecotect and IES <VE> and comparing the results of the three programs. Step two involved conversion of the Revit file into IFC, DWG and gbXML file formats, importing them into MEP, Ecotect and IES <VE> respectively and comparing results with the previous ones. The next phase in this chapter tested the data transfer from building models to analytical models. This information is organized into the following chapters: Chapter 5: Comparing the three programs -Revit MEP, Ecotect and IES <VE>. Chapter 6: Comparing the three file formats- IFC, DWG, gbXML. Section III: This section consists of improving the interface and constructing a family template that can be imported into a Revit model. The objective of the exercise was to develop an understanding of the Revit MEP-IES <VE> interface, understanding families and construction of a template for system families and standard component families. This section is organized in the following chapters: Chapter 7: Introduction to the MEP-IES interface. Chapter 8: Development of the interface. 8 Section IV: This section will comprise the conclusions about BIM in general and also the specific conclusions derived from the chapters. The chapter also contains areas of further study and future work. Chapter 9: Conclusions and future work. 1.6 Conclusions. Software interoperability is defined as the ability of two or more systems to exchange information and should ideally be seamless. The advantages that seamless data transfer offers is that this will remove redundancy and duplicate data generation, in analytical models and ensure the incorporation of sustainable features, at an early design stage. This study looks at the interoperability between building information models (BIM) and energy analysis programs, an emerging area. The BIM software used for this program is Revit MEP and the energy analysis tools used are IES<VE> and Ecotect. This study consists of two parts: the objective of the first part of the study was to test whether BIM software was robust enough to allow ease of interoperability with the analysis tools. This part of the study presents test cases that compare the thermal load results of the three programs as well as assesses the information that is carried by interoperable file formats. The second part of the study looks at the integration of energy analysis features within BIM and in the context of this study, the improvement of the interface between Revit MEP and IES<VE>. 9 Chapter 2: Building information models. Introduction to the Chapter. This chapter is a research on building information models, their development, the export and import capabilities and organizational structure within a BIM model. It includes an introduction to and definitions of BIM. It contains basic concepts pertaining to entity based modeling vs object based modeling and their development. The chapter then goes on to look into the information transfer in BIM and specifically export/import capabilities of Revit MEP. The later section contains research into the organization of information in a Revit model, definitions of families, parameters and their types; and information organization in the ODBC database. 2.1 Introduction to BIM: One of the earliest definitions of BIM was introduced by Prof Charles Eastman at the Georgia Institute of technology whose theory is based on the view that the term „building information model‟ is the same as a „building product model.‟ Building information modeling integrates all of the geometric model information, the functional requirements and capabilities, and piece behavior information into a single interrelated description of a building project over its lifecycle. It also includes process information dealing with construction schedules and fabrication processes. (Eastman 1999) Companies such as Autodesk define BIM as a building design technology that is characterized by the creation and use of coordinated, internally consistent, computable information about a building project in design and construction. 10 (Eastman n.d.) Others such as Bentley describe it as a modeling of both graphical and non graphical aspect of the entire building life cycle in a federated database management system.(Eastman n.d.) A more comprehensive definition of BIM, defined by the US General Services Administration (GSA) is as follows: Building Information Modeling is the development and use of a multi-faceted computer software data model to not only document a building design, but to simulate the construction and operation of a new capital facility or a recapitalized (modernized) facility. The resulting Building Information Model is a data-rich, object-based, intelligent and parametric digital representation of the facility, from which views appropriate to various users‟ needs can be extracted and analyzed to generate feedback and improvement of the facility design.(GSA n.d.) In summary, BIM is a model based technology linked with a database of information. It has a parametric change engine, which automatically coordinates changes made anywhere- in model views or drawing sheets, schedules, sections and plans. BIM increases the ability to control data and information in an interoperable format. It can be used with a variety of programs/functions such as cost estimations, simulations, scheduling, structural design, GIS integration, facilities management and energy analysis. 11 2.2 Entity based modeling vs object based modeling: Building information modeling, also referred to as virtual building modeling, parametric modeling and model based designing, is derived from the object based modeling method. Entity based building models represent raw graphic entities such as lines and arcs and do not provide rich semantic information about the building as opposed to object based models which do. An entity based model is essentially used as a digital drafting tool, rather than a design tool and data remains in the form of 2D geometry data, compiled by software such as AutoCAD and Microstation. On the other hand, object based models comprise parametric objects such as walls, columns and windows constructed within the model and are therefore, generally considered more powerful and sophisticated than entity based models.( Tse Wong Wong 2005) The difference between CAD and BIM, can be based upon this conceptual differences between entity based and object based models. As an example, AutoCAD uses the electronic drafting of lines and circles to represent architectural entities. On the other hand, BIM uses the more interactive concept of parametric modeling of architectural objects such as walls, roofs or floors. These objects are tied to a database, from which plans, sections, elevations and details of the building can be extracted. Walls and doors can be moved together and work together as assemblies. Details can be linked to their position in the design and changes made in a component is updated automatically and reflected in all the drawings. (Seletsky 2004) 12 Development of entity based and object based models: The commercial development of object based and entity based modeling begun at around the same time in the early 1980‟s. 1 While Nemetschek Allplan and Graphisoft ArchiCAD were introduced in 1980 and 1984 resp., the first versions of Autodesk Auto CAD and Bentley Microstation also came around in 1983-84. However, the 90‟s belonged to object based modeling programs such as Autodesk AutoCAD and Microstation. By nature, object based modeling was more sophisticated, required faster calculations and graphic displays and more memory and storage than entity based modeling programs, and given the earlier versions of Intel microprocessors such as 80286,80386 and 80486 the development of object based modeling programs was slow.( Tse Wong Wong 2005) The development of object based modeling continued by companies such as Nemetschek and GraphiSoft, while traditional entity based companies such as Bentley and Autodesk, followed the lead, eventually launching Bentley Microstation Triforma and Autodesk Architectural Desktop in 1996 and 1998. In the year, 2000, Revit Technology Corporation launched a parametric model called Revit that was subsequently acquired by Autodesk, two years later. Other companies quickly followed suit with products such as Bentley Information Modeling with submodules in Architecture, HVAC and Structure while Nementschek introduced AllPlan in 2003 and Graphisoft produced ArchiCAD 1 While commercial development of object based models happened later, early theories of BIM as a building product model and data model were proposed by Prof Charles Eastman in the late 1970‟s. 13 version 9 in 2004. Thus, a more widespread use of building information models came about only in the early 2000‟s. 2.3 Information Transfer in BIM In building information models, the building model is exported as a data file, based on an open standard, which in turn can be imported by various modules. However, the absence of a dynamic data link means that changes in BIM may not be accurately and effectively reflected in the modules. Autodesk Revit is able to import and export the following formats: Imports the following formats: Exports the following formats: Rvt, Rfa files ACAD dwg and dxf files IFC formats Rvt and Rfa files CAD formats such as dwg and dxf files ODBC database Image files such as jpegs gbXML files IFC formats. Table 2.1 : Importable and exportable file formats accepted by Autodesk Revit. 14 rvt rfa dwg dxf gbXML IFC ODBC Interoperable File Formats BUILDING INFORMATION MODEL REVIT ARCHITECTURE ECOTECT REVIT MEP IES <VE> 3 of 21 Figure 2.1: Interoperability of file formats with BIM and energy analysis tools. The table above shows various file formats that can be imported and exported via BIM software such as Revit Architecture as well as energy analysis programs. 2.4 Organization of information in a Revit Model. 2.4.1 Families: All elements in Revit are “family based” and each family element can have multiple types defined with it, each with a different size, shape, material set or parameter variables. Revit Architecture contains three types of families: system families, standard component and in-place families, the detail description of which 15 may be found in Chapter 8. The default Revit menu has 17 families of predefined building objects that are listed in the modeling menu. Figure 2.2: Families of predefined object in the modeling menu. Also, indicated are the instance and type parameters for a wall family type. 2.4.2 Type and instance parameters: Each family of a certain building object, such as a wall, is associated with parameters of two types: type parameters and instance parameters. While type parameter is common information for an element in a family, instance parameters are usually for that specific instance or model and are generally user created. A type parameter affects all instances (individual elements) of that family in the project and any future instances that are placed in the project. The value for instance parameters is generated as the user models the building. It affects only one selected element, or the element that the user is creating. 16 For example, the dimensions of a window are its type parameters, while its elevation from the level is an instance parameter. Similarly, cross-sectional dimensions of a beam are its type properties, while the beam length is an instance parameter. The following table indicates the type and instance parameters associated with a generic wall type family. Type Parameters Instance Parameters Construction Structure -Wrapping at ends -Width -Wall function Graphics -Coarse scale fill pattern Identity Data -Model -Manufacturer -Assembly description -Assembly Code -Fire rating -Type Mark Constraints: -Location line -Base Constraint -Base Offset -Top Constraint -Unconnected height -Room Bounding Structural Dimensions -Length -Area -Volume Identity Data -Phasing --Phase Created --Phase Demolished. Table 2.2: Type and instance parameters. 2.4.3 The ODBC Database In order to reveal export parameters, data contained in a BIM file was exported to an Access database. The following list reveals 144 database tables representing 72 element categories. Each element has a pair of tables for a model instance and a model type.(Example, wall and wall type.) An instances table lists all the model objects and the associated parameters under the same category. 17 Figure 2.3: The Access database that contains 144 database tables, representing 72 categories of elements. 2 2 This database has been derived from a generic Revit MEP file. 18 Chapter 3: Energy analysis programs. 3.1 Introduction to the chapter. Energy simulation and analysis tools have traditionally been used to assist in designing sustainable and energy efficient buildings. Programs such as Ecotect, IES<VE>, eQuest, Energy Plus, DOE-2,Design Builder, HEED etc. include several applications such as thermal, solar, lighting, acoustic, ventilation, computational fluid dynamics(CFD) analysis. These tools are generally used late in the design process for analyzing energy decisions. Typically, it is a costly labor intensive process to recreate the building model to be used for analysis. The obvious advantage that BIM and interoperability have to offer is that data models can be exported to these programs and need not be created from scratch. This thesis utilizes two energy programs in order to test interoperability: namely Ecotect v 5.6 and IES<VE> v 5.8.0.The decision to use these tools depended upon the type of simulation tool it was, a “stand-alone energy tool” or the “embedded energy analysis tool”. Ecotect, a free, easy to use program, is a typical „stand alone energy simulation tool‟ that includes several features discussed in later chapters. „Embedded energy analysis tools‟, such as IES, are programs that are currently being integrated in the BIM environment. These tools eliminate the need to import and export geometry and other information through interchangeable file formats. IES<VE> a powerful energy analysis tool, is one such example.IES does function as a stand-alone tool, but was recently integrated into Revit MEP. 19 The intent of this chapter is to have an understanding of these two tools and their capabilities. This chapter also looks at two important aspects of the tools: the energy loads as well as their import/export capabilities. This is because various tests were conducted, as elaborated in Section II that compared the energy loads for different cases, in order to test data transfer and interoperability. 3.2 Ecotect. 3.2.1 Introduction to the tool. Ecotect is a building design and environmental analysis tool that covers a broad range of simulation and analysis functions required to understand how a building design will operate and perform. It allows designers to work easily in 3D and apply tools necessary for an energy efficient and sustainable future. (Ecotect) Some of its features include a shading design and solar analysis, lighting analysis, acoustic analysis, thermal analysis, ventilation and air flow analysis, building regulations and resource management. 3.2.2 Energy loads and data analysis. In this thesis study, a thermal analysis of a base case study room was conducted using Ecotect ver 5.5.For this, a thermal zone had to be defined, the basic unit in thermal calculations for which internal temperatures and heat loads are calculated. A thermal zone is defined by a completely enclosed space, bound by its 20 floors, walls and ceiling/roof. Once the zone is made, Ecotect assigns default values to materials for these components that can be edited by the user. Figure 3.1: The Ecotect modeling screen The Simulation Engine: Ecotect v 5.5 uses the Chartered Institute of Building Services Engineers (CIBSE) “admittance method” used to determine internal temperatures and heat loads. This thermal algorithm is very flexible, quick to calculate and can be used to display a wide range of very useful design information. In the admittance method, the temperatures and load calculations are two separate processes. Once detailed hourly internal temperatures are known, a second calculation is performed to determine the absolute heating and cooling loads. Ecotect calculates heating and cooling loads, which are essentially room loads (and not plant loads) for a space. Plant loads depend upon the efficiency of the system; for the same space load requirements, an inefficient system may require far greater loads than an efficient system. (Ecotect n.d.) 21 Figure 3.2: The thermal properties can be user defined. Figure 3.3: The heating and cooling loads graph The user can set a host of thermal properties in Ecotect ranging from type of HVAC system and its efficiency, the thermostat range, occupancy, internal gains and infiltration rates. Heating loads are displayed in red and project above the center line 22 of the graph whereas cooling loads are blue and project below, as indicated in Figure 3.3. 3.2.3 Import and export capabilities. The Ecotect v 5.5 model has a range of import and export capabilities. The Ecotect model can be exported to a host of programs including lighting simulation software like Radiance(*.RAD, *.OCT), ray-tracing program like POV Ray(*.POV), VRML models(*.WRL) and even thermal simulation and analysis softwares like EnergyPlus(*.IDF) and HTB2(*.TOP). It can export AutoCAD (*.DXF)files and DOE-2 Input files(*.INP) as well a range of others. Ecotect can import files that carry geometric information as well as general data files. Some of the files carrying geometric information that it is able to import include AutoCAD drawing files, (*.DXF), Lightscape(*.LP)Lightwave (*.LWO) VRML (*.WRL). Some of the general data files that it imports include Green Building XML(*.XML), ASCII model files(*.MOD), Energy Plus Input Data files(*.IDF), Weather data files(*.WEA) and Radiance Scene files(*.RAD). Ecotect is not yet IFC compliant, although version 5.6, promises it to be so. A more comprehensive list of the import and export capabilities of Ecotect is listed in Appendix A. 3 3.3 IES<VE. 3.3.1 Introduction to the tool. IES <VE> Integrated Environment Solutions is a software system for integrated building performance analysis, providing tools for thermal analysis, value 3 The importable and exportable files have been derived from a generic Ecotect file. 23 engineering, cost planning, lifecycle analysis, airflow analysis, lighting, and occupant safety, in one unified system.(Khemlani 2006) IES <VE> contains the Integrated Data Model or IDM, which captures all the information about the building, including the geometric data that is needed to carry out a range of analyses. The model is created inside the “Model IIT Building modeler” that contains a number of 3D shape options that can be used to create rooms. 3D geometry can also be imported straight from CAD or Revit packages using gbXML.(IESVE) Figure 3.4: The „ModelIIT Building Modeler‟ in IES. Materials and constructions can be selected from a built in database called the Apache construction database. The program also contains a building template that automatically assigns information to the model, and may include occupancy profiles, constructions, surface colors and building control information. These values can be edited in the building template manager. The site location and weather data can be 24 selected from a database in the „ApacheLocate‟ engine while the „Apache Systems‟ feature simulates HVAC systems. 4 Figure 3.5 The „building template manager‟ in IES<VE>. Figure 3.6:‟The Apache construction database Figure 3.7: The „ApacheLocate‟ screen. 4 This information is derived from a generic IES<VE> file. 25 3.3.2 Energy loads and data analysis. The Simulation engine: The IES<VE> engine called „ApacheLoads‟ uses the procedures laid down by the American Society of Heating Refrigeration and Air- Conditioning Engineers (ASHRAE) “Heat Balance Method” to calculate the design heating and cooling loads. These calculations use the IDM to undertake two principal calculations: steady state heat loss calculations to predict the heating requirements for the building and a heating loads calculation, to predict the building cooling requirements. The heat gain calculations and cooling load calculations can be performed for a selected design day of the week, and for a range of design months. (IESVE) Load results are available in both graphical and tabular forms. Unlike Ecotect that gives primarily annual and peak loads, the results for calculations are quite comprehensive in IES<VE>. A more detailed analysis of the heating and cooling results calculated in IES can be found in Chapter 7. 26 Figure 3.8: Results from „ApacheLoads‟ in IES showing heating and cooling loads. Figure 3.9: Results from „ApacheLoads‟ in IES showing energy distribution. 27 3.3.3 Import and export capabilities. IES<VE>, unlike Ecotect, is unable to import a large number of file formats and the primary import format it uses is gbXML. The IES file is saved in a number of folders apart from the main *.ve file, such as, apache, lights, cfd, macroflo, Radiance and suncast corresponding to the various IES applications. Interoperability takes place in the form of data exchange between several applications existing inside the program. For instance, the integrated data model(IDM), can be used for thermal simulation in „ApacheSim‟ application and for more detail HVAC analysis in „ApacheHVAC‟. „ApacheLoads‟ can also predict air supply rates that are used by the „IndusPro‟ duct sizing module application. The effects of thermal shading can be imported from the SunCast application to enhance heating load calculations. 3.4 Summary In conclusion, Ecotect and IES<VE>, the two programs that have been used for this study, are popular energy analysis tools. While Ecotect is a typical stand alone energy tool, IES, has the added advantage that its thermal analysis application has been incorporated with Revit MEP and therefore, its results can easily be compared with those of MEP. The simulation engine and load calculation methods are different in the two programs. While Ecotect uses the CIBSE „admittance method‟ for calculating thermal loads, the „ApacheLoads‟ application in IES uses the ASHRAE „heat 28 balance‟ method. Results for heating and cooling loads in the two programs are different; while Ecotect shows annual and peak room loads, IES displays more extensive results such as plant loads, room loads and latent and sensible load components. Ecotect v 5.5 is interoperable with a large number of programs, and in the context of this study, can import DXF‟s and gbXML‟s. IES<VE>5.8.0 can import the gbXML file format. At present, neither of the two programs are IFC compliant. 29 Chapter 4: Interoperability and file formats. 4.1 Introduction to the chapter. This chapter is a research on some of the common interoperable formats that can be imported and exported by both drafting and modeling programs, such as Autodesk AutoCAD, Autodesk Revit as well as energy analysis programs. There are three commonly used file formats that are explored in this chapter, namely DXF, the gbXML schema and the IFC format. The intent of the chapter is to have a theoretical framework, and an understanding of the file formats before testing them for the information that they carry. It includes a brief introduction to DXF and DWG, a common file formats associated with AutoCAD, representing 2 D and 3D data. Another section contains an introduction and description of gbXML, a commonly used building schema, capable of carrying huge amounts of building information. The section also carries a brief description of the organization of information in a gbXML building information model. The next section contains an introduction and description of the commonly used IFC file format. It includes a description of the architecture and organization within an IFC file, as well as relationships between entities in this format. The last section is an attempt to compare the three file formats by analyzing the information that each file carries. 4.2 DXF (Drawing Exchange format) and DWG: AutoCAD DXF (Drawing Interchange Format, or Drawing exchange format) is a CAD data file format and was developed by Autodesk, for data interoperability 30 between CAD and other programs. When introduced, it was supposed to be a representation of DWG, which was the native file format of AutoCAD. DWG, however, is the more common and widely used format for data interoperability, since certain object types such as solids, regions and blocks are not documented or partially documented in DXF‟s for commercial developers.( DXF n.d.,) 4.3 Gbxml:(Green Building Extensible Markup Language) 4.3.1 Introduction: The green Building XML schema, commonly referred to as “gbXML” was developed to facilitate the transfer of building information stored in CAD building information models, enabling integrated interoperability between building design models and a wide variety of engineering analysis tools and models available today. (About gbXML n.d.)It facilitates transfer of building information including product characteristics and equipment performance data between manufacturer‟s databases, CAD applications, and energy simulation engines. It carries a detailed description of a single building or a set of buildings for energy analysis and simulation. This file format is widely used by manufacturers such as Autodesk, Graphisoft and Bentley for data exchange. 4.3.2 Organization of information within the gbXML schema. The gbXML file organizes information according to the following hierarchy: 31 Component Characteristics Information that it carries Campus A group of buildings that are geographically similar Id, name, description, location Building One building. Id, name, description, street address, square area, its spaces Zone A group of rooms located in a building that are served by the same HVAC plant or VAV box. Each zone may contains a group of spaces (or rooms) that have their own unique set of characteristics such as similar orientation or temperature setpoint. Id, name, description, flow, airflow changes per hour, flow per area, flow per person, outside air flow. Space A room defined by its own set of walls, ceiling, and/or roof. A space may be an office, conference room, warehouse, or any other entity Id, name, description, infiltration flow, number of people, people heat gain, lighting power per area Surface A wall, floor, ceiling, or roof. Each space (or room) will have its own set of surfaces Id, name, description, construction type, geometry, and any openings Opening Opening in a space, such as a door or window Id, name, description, u-value, shading coefficient, transmittance, reflectance. Construction Type A type of composite construction that makes up a wall, roof, ceiling, or floor Id, name, description, u-value, absorptance, roughness, reflectance Table 4.1: Hierarchy of information organization in the gbXML schema Source:< http://www.carmelsoft.com/html/Software/Software_LS_ABS_Integrate.htm> 32 4.4 IFC file formats (Industry Foundation Classes) 4.4.1 Introduction: The IFC file format is developed by the IAI (International Alliance for Interoperability)to facilitate interoperability and is an open data exchange format that is used by model based applications to exchange data.(Khemlani 2004) IFC is an international standard that stores building data in a database, permitting information to be shared and maintained throughout the life cycle of the construction project, that is, design, analysis, specification, fabrication, construction and occupancy.(Khemlani 2004) The IFC model consists of tangible components such as walls, doors, beams, furniture etc, as well as the more abstract concepts of space, geometry, materials, finishes, activities etc. 4.4.2 Development of the IFC file format: The IFC file format is a derivative of one of the earlier efforts by the International Standards Organization, in 1984 called STEP (STandard for the Exchange of Product Model Data). The IFC model uses several resource definitions similar to that of STEP, and the same modeling language, EXPRESS. Many application developers that were involved in STEP, were responsible for creation of the IFC format. There have been several releases since IFC was first launched in 1997, starting from IFC version 1.0 to the IFC 2x2, the seventh version. 33 4.4.3 IFC Compliance: In order that a program is IFC compliant, that is, it is able to import and export IFC file, it needs to be “IFC certified”. The IFC model is posted online and provides a framework for software developers to incorporate the IFC import and export capabilities within their program. The IFC is organized into sections that address different core areas and domain areas. 4.4.4 IFC Model Architecture The IFC Model architecture for 2x2 consists of the following 4 layers: Resource Layer Core Layer - Kernel - Extensions Interoperability Layer Domain Layer Resource Layer: The Resource layer forms the lowest layer in IFC architecture as illustrated in Figure 4.1.This layer provides common resources that are used by classes in the upper layers. For example, all information concerning basic concepts of costs is collected in the cost schema, IfcCostResource in the resource layer. Any classes in the core, interoperability or domain layers that need to use cost will reference this source. (Eastman 1999, p 288-289) 34 Core Layer: The core layer forms the next layer in IFC model architecture. Classes that are defined in this layer can be referenced by the classes in the upper layers that is, interoperability and domain layers. This layer includes two levels of generalization: The Kernel and 2. The Core Extension. (Eastman 1999, p 288-289) The Kernel schema defines the most abstract part of IFC architecture and defines objects and their relationships. Core extensions include generic concepts; for example, the “product extensions” contains the classes of objects that make up the physical description of a building, such as generalizations for walls, space and roofs. Figure 4.1; IFC model architecture (Source: IFC Technical Guide: Online Documentation.) Interoperability layer: This layer defines concepts or classes common to two or more domain models and enables interoperability between them. For example, these include building elements and building services. (Eastman 1999, p 288-289) Domain Layer Interoperability Layer Core Layer Resource Layer 35 Domain Layer: This layer is the domain specific application layer, and supports applications used by architects, engineers and contractors. 4.4.5 Relationship of entities in the IFC model: The following is an example of how entities are related to each other according to the hierarchy shown in Figure 4.2.This takes up the example of a wall and space entity and how they are related at an upper level entity. The Wall entity (IFC Wall) as seen in Figure 4.2, is defined as a subtype of the Building Element entity (IFCBuildingElement) which is a subtype of the Element entity (IFCElement) and so on, all the way up to the Root entity IFCRoot). (Khemlani 2004) The Wall entity inherits the attributes of its parent entities, known as supertypes. All the upper levels entities are abstract, that is, one cannot create an actual instance of the entity type. The Wall entity, itself is not abstract, and therefore can be instantiated, to create actual wall objects that exist in the building model. Most of the attributes of the wall, such as type, shape, location, quantity, connections, openings etc are defined by the supertype, IFCElement, since these properties are common to all elements. (Khemlani 2004) 36 Figure4.2: Relationships of entities in the IFC model. (Source: IFC Technical Guide: Online Documentation) 37 Similarly, a parallel entity such as the space entity (IFCSpace) is defined as a subtype of spatial structure element entity (IFCSpatialStrcutureelement) which is a subtype of product entity(IFCproduct) and so on. To associate a wall with a space, a „containment relationship‟ IFCRelContainedInSpatialStructure is used. This operates at the level of IFCElement and IFCSpatialStrcutureElement, and basically implies that any element, (such as a wall, beam or column) can be associated with any spatial structure. (such as a site, building, storey or space) (Khemlani 2004) All the objects that can be instantiated or user defined are indicated in green, while all others that are abstract, are indicated in yellow. 4.5 A comparison of the three file formats. In the following table, an attempt has been made in order to understand the information that is carried by these three file formats. A simple single storey unit, 18‟ x 12‟ was modeled in Autodesk Revit MEP, and the file stored in the formats DXF, gbXML and IFC 2x2.The information shown in the following table is representative of the type of information that is being carried by the respective files. 38 DXF File gbXML IFC File Version Units Origin Size Pen number Pen weight Linetype File Version Units Campus ID Location( Zip Code, latitude, longitude) Area, Volume Building Id Description Shell Geometry Id Cartesian Points, Co- ordinates. Shell Surface(Types such as Walls) Shell Openings (Types such as windows) Space ID Surface ID Program Information Product name, version Platform File Description, File name and file schema Units (Length, Area, Volume) Organization, Person, owner history. Cartesian points, direction, dimensional exponents, shape representation Product definition and shape. Property value (Offsets, extensions, room bounding, wrapping, assembly description, wall/window functions, thickness.) Predefined parameters associated with elements, for example, roof: rafter cut, fascia depth, truss, thickness, base offset etc. Material, layer set, Color. Table 4.2: A comparison of DXF, gbXML and IFC formats. As indicated above, information that is carried by a DXF file is rudimentary, and primarily consists of geometric information represented by the drawing. GbXML files carry more information more than mere geometry (area, volume, cartesian points, co-ordinates) and include definitive information pertaining to hierarchy of components such as Campus, Building, Zone, Space, Surface, Openings and Construction types. The information carried by the IFC file, is also, comprehensive, 39 carrying geometric information as well as information that is encompassed by type and instance parameters defined by the user in the building model. Introduction to Section II: The following section contains test cases to check data transfer between building information models and energy analysis programs. The exercise involved comparing the results of the heating and cooling load analysis of a base case scenario, and evaluating the information that they transfer. This was done in two steps as represented in Chapters 5 and 6 respectively. Step one involved modeling and analysis of a single room, within Revit MEP, IES <VE> and Ecotect and comparing the results of the three programs with each other(X1, Y1 and Z1). Step two involved conversion of the Revit building model into IFC, gbXML and DXF file formats, importing them into MEP, IES <VE> and Ecotect respectively and comparing results with the previous ones.(X2 with X1, Y2 with Y1 and Z2 with Z1). Table 5.1: Method for study. REVIT MEP IES <VE> ECOTECT Step 1: Comparison of base case X1 Y1 Z1 Step 2: Comparison of results from exported data. X2 (IFC) Y2(gbXML) Z2 (DXF) 40 Chapter 5: Test Cases: Comparing the three programs: Revit MEP, IES<VE> and Ecotect. 5.1 Chapter Introduction: The objective for the exercise was to compare the results of heating and cooling load analyses of a base case scenario, in order to compare the information that interoperable file formats carry. All the formats tested were able to carry over the geometry and were subsequently tested for building material, location and other parameters. The initial step in the exercise was to model a room in the three programs, namely, Revit MEP, IES<VE> and ECOTECT. A single room, 18‟ x 12‟x10‟ with windows 6‟ x 4‟ set in the south wall, was modeled as the base case scenario, in all the three programs. The objective was to model the room, in a way, that the input values in the three programs could be kept as close as possible. The idea was that if the base case results in the three programs came out as the same, one had a better chance at comparison with different file formats. The initial section in this chapter contains a table that lists and compares the input variables for the three programs. The intent was to compare the input values with each other, and select similar options. The next section contains the results of heating and cooling loads for all the three programs. An explanation of the two types of calculations possible in Revit MEP is provided. The intent of the section was to enlist the kinds of information (such as peak loads, total loads, plant loads etc) that is 41 calculated by each program. The chapter concludes with a set of conclusions and comparisons between the three programs. 5.2 Input values: The following table indicates the input values required for the three programs. Table 5.2: Input variables for the three programs. Revit MEP ECOTECT IES <VE> Building Type Office-enclosed Office/shop/assembl y Office Location Source of weather design Los Angels, CA Los Angeles, CA Aplocate: Los Angeles, CA Units Feet and inches US Standard: (Feet and inches) US IP: (Feet and inches) Modeling Room and area ( defines a room) Defines a zone Defines a zone Room Size 18‟x12‟ 18‟ x 12‟ 18‟ x 12‟ Height 10‟(program uses 8‟) 8‟ 8‟ Window opening 6‟ x4‟, sill height 2‟8” 6‟ x 4‟, sill height 2‟8” 6‟ x 4‟, sill height 2‟8” Wall Specs Standard Wall Cons. (2002 regs) Brick Cavity Conc Block plaster Standard Wall Construction( 2002 regs) U Value (Btu/F hr ft 2) 0.0616 0.0616 0.0616 Admittance(Btu/F hr ft 2) 0.74322 Solar Absorbtion 0.7 Transparency 0 Thermal decrement 0.41 42 Table 5.2: Continued. Thermal lag (hrs) 7.8 Resistance 0.341,0.665 Emissivity 0.900,0.900 Solar Absorbtance 0.700,0.550 Thermal bridging coeffi(Btu/h.ft 2 .de g.F) 0.0062 Thickness (in) 10 10 Brickwork+Insln + conc block+ plaster Brick masonry + insulation+ conc. cinder+ plaster Brickwork+Ins ln+conc block+ plaster Window Glazing Specs Low e Double glazed(6mm+6m m)2002 regs Double Glazed LowE Alum Frame Low e Double glazed(6mm+ 6mm)2002 regs. U Value(Btu/F hr ft 2) 0.3482 0.3482 0.3482 Admittance (Btu/F hr ft 2) 0.41916 Solar heat gain coefficient 0.75 Transparency 0.92 Refractive index of glass 1.74 Alt Solar gain (heavy wt) 0.21 Alt Solar Gain(light wt) 0.29 Emissivity 0.1,0.1 0.900, 0.900 Resistance 0.341,0.665 Thermal bridging coefficient 0.0062 Thickness 6+12+6=24 mm ¼”+1/2”+1/4” 6+12+6=24 mm 43 Table 5.2: Continued. Glass +air gap + glass Glass+ air gap + glass Glass +air gap + glass Floor Specs Standard Floor Construction (2002 regs) ConcSlab_ Carpeted_OnGrou nd Standard Floor Construction( 2002 regs) U Value (Btu/F hr ft 2) 0.0440 0.0440 0.0440 Admittance(Btu/F hr ft 2) 1.05671 Solar Absorbtion 0.324 Transparency 0 Thermal decrement 0.31 Thermal lag (hrs) 4.2 Resistance 0.227,0.665 Emissivity 0,0 0.900,0.900 Solar Absorbtance 0.700,0.550 Thermal bridging coeffi. (Btu/h.ft 2 .deg.F) 0.0062 Thickness (ft) 4 4 Clay +brickwork +cast conc+ slab insuln +chipboard+ carpet. Soil+ concrete+ carpet underlay+ carpet. Clay +brickwork +cast conc+ slab insuln +chipboard+ carpet. Roof Specs Flat Roof (2002 regs) Suspended Concrete Ceiling Flat Roof (2002 regs) U Value (Btu/F hr ft 2) 0.0440 0.0440 0.0440 Admittance(Btu/F hr ft 2) 0.7397 Solar Absorbtion 0.1317 Transparency 0 44 Table 5.2: Continued. Thermal decrement 0.7 Thermal lag 4 hrs Resistance 0.227,0.665 Emissivity 0.9,0.9 0.900,0.900 Solar Absorbtance 0.500,0.550 Thermal bridging coeff.(Btu/h.ft 2 .de g.F) 0.0062 Thickness (ft) 1‟4” 1‟ 4” 1‟ 4” Bitumen layer+ Cast concrete +glass fiber quilt +cavity+ ceiling tiles. Ceramic tile+ screed+ conc floor+ air gap+ gypsum. Bitumen layer +Cast concrete +glass fiber quilt +cavity +ceiling tiles. Table 5.2: Input variables for the three programs. As indicated in the table above, a minimal amount of information is required from the user in the case of Revit MEP while more comprehensive data can be input or edited in MEP and IES<VE>.MEP allows the user to select from a set of values for building type, building services, construction material and location. However, all of the information associated with each choice is derived from IES<VE>. In order that input values were as close as possible, the U-values, thicknesses and construction materials were modified from their default values in ECOTECT in order to match those of the other programs. 5.3 Results: Since the building modeled was the simplest base case scenario, the results were not as close as expected. Table 5.7 lists a comparison between the results of the 45 three programs. This section gives a description of the results in each of the three programs. 5.3.1 Revit MEP: 5.3.1.1 About the MEP-IES<VE> interface: The IES interface in MEP allows the user to select and define values for building type, building services, building construction assignments, place and location. The interface and its options are more elaborately explained in Chapter 7. This is an attempt to explain the two sets of energy analysis that can be done through this interface. Figure 5.1: The two buttons for a thermal analysis found in the MEP-IES<VE>interface. 1) Energy analysis within the Revit engine: These calculations take place inside the Revit engine, and are done by the IES component that is installed within 2 1 46 Revit MEP. On using the “Calculate” button, the engine computes the heating and cooling loads, and gives additional information about the sensible and latent loads, analytical areas and volumes. For a more comprehensive analysis, the user can click the “Virtual Environment” button, in which case, the model gets exported to the IES <VE> and opens it there. 2) Energy analysis using the Apache simulator outside Revit MEP: Virtual Environment, provides two sets of calculations for energy analysis: The Apache Sim calculator and the ASHRAE Loads method. Apache Sim runs the simulation for the entire year and calculates the annual total energy consumption in MMBtu. It also breaks up total energy consumption into heating, cooling, fans, pumps and controls, lights and equipment for each month. The ASHRAE loads method utilizes the worst month scenario for heating load calculations (in this case, January for Los Angeles) and a period of May to September for its cooling load calculations. It calculates the system heating and cooling loads as well as the room heating and cooling plant loads. Greater details of loads calculated in IES can be found in Chapter 8. 47 5.3.1.2 Case 1: Within the Revit Engine: Analytical Area 216 sq ft Total Cooling Load 5551.8 Btu/hr Analytical Volume 1728 cu ft Total Heating Load 2268.9 Btu/hr Sensible Load Latent Load Total Cooling Load (Btu/h) 5252.9 298.9 5551.8 Heating Load (Btu/h) 2268.9 0 2268.9 Table 5.3: Load results in Revit MEP 5.3.1.2 Case 2: Revit Model exported to IES<VE> Figure 5.2: The exported Revit model in IES<VE>. 48 Total Annual Energy Consumption 10.764 MMBtu Heating(Boilers) MMBtu Cooling(Chillers) Fans, Pumps, Controls Lights Equip. 0.508 1.156 3.45 2.959 2.690 System Heating Load 2.776 MBH Room heating Plant Load(Sensible) 3237.0 Btu/h Room Cooling Plant Load 5882.0 Btu/h Table 5.4: Load results in the exported Revit MEP model. 5.3.2 IES <VE> Figure 5.3: The IES<VE> building model. 49 Total Annual Energy Consumption 10. 495 MMBtu Heating(Boilers) MMBtu Cooling(Chillers) Fans, Pumps, Controls Lights Equip. 0.129 1.730 2.987 2.959 2.69 System Heating Load 2.776 MBH Room heating Plant Load(Sensible) 2496 Btu/h Room Cooling Plant Load 5181 Btu/h Table 5.5: Load results in IES<VE> 5.3.3 Ecotect Figure 5.4: The Ecotect building model. 50 Maximum Heating 2759.7 Btu/hr at 05:00 on 1st January Maximum Cooling 4964.9 Btu/hr at 15:00 on 24th September Annual Heating Loads 613089 Btu Annual Cooling Loads 8215399Btu Total Annual Load 8828488 Btu Table 5.6: Load results in Ecotect. 5.4 Conclusions: Comparing the three programs. The input values required from the user for the three programs are different, in terms of the amount of information required. There are very few user inputs that can be selected or edited in MEP, while IES has a more comprehensive selection. The units of the output results vary substantially and are in different units. Ecotect gives annual BTU consumption and peak loads at worst case times. The Revit MEP engine gives peak loads, while the IES Apache Simulator gives comprehensive data in total annual energy consumption in MMBtu, plant loads and room loads in MBH and Btu/h. Cooling Loads Heating Loads Annual Totals ECOTECT 4964.9 Btu/hr 2759.7 Btu/hr 8828488 Btu Revit MEP Within the Revit engine 5551.8 Btu/h 2268.9 Btu/h - IES Apache engine 5882 Btu/h 3237 Btu/h 10.764 MMBtu IES<VE> 5181 Btu/h 2496 Btu/h 10.495 MMBtu Table 5.7: Comparison of loads in the three programs. 51 The comparison of loads between the exported MEP model and IES<VE>is easier and more valid because the calculation engines and therefore, the units, are the same. Table 5.7 shows the results of the three programs. The annual energy consumption in IES and the exported Revit model are comparable. The heating and cooling loads calculated in the Revit engine are also comparable with the peak room loads in IES. The variation in Ecotect in terms of the heating and cooling loads may be due to the calculation methodology used by the program. Ecotect uses the worst case annual design load while the ASHRAE load calculator uses a worst month scenario (January) for heating loads and 5 months (May-September) for cooling loads. The load results for MEP, Ecotect and IES<VE> as indicated in Table 5.7 are listed in Appendix B. 52 Chapter 6: Test Cases: Comparing the three file formats: DXF, gbXML and IFC. 6.1 Introduction to the chapter. In this chapter, testing was done to check interoperability and evaluate information transfer. This is done in two parts: the first part specifically deals with interoperable file formats, and what data is transferred in the file. The second part of the chapter looks at the interface between Revit MEP and IES and evaluates the data transfer between the building model and the interface. The intent of the initial section was to see what information was carried over by each of the interoperable file formats: IFC, gbXML and DXF. The base case room modeled in MEP was exported as a 2x2 IFC file, gbXML and Autocad 2004 DXF file. These files were subsequently imported into, Revit MEP, IES<VE> and ECOTECT respectively and the results compared with the data in the previous chapter. In the next section, in order to test what data was included in each of the file formats, the building model was tested for building material, thickness, geometry, (area and volume) building services, location and building types. All input variables were kept constant in the base case, and testing was done with one alteration at a time. The last section contains conclusions and results, a comparative analysis of the three file types, as well as the information that they carry. 53 6.2 Interoperable file formats: 6.2.1 The IFC file. In order to test information carried by IFC files, the base case building model was exported as an IFC file and then imported back into MEP. Heating and cooling load runs were done, with the results as indicated. The following chart gives a comparison of the new results with the base case. Cooling Load Heating Load Base Case X1 5551.8 Btu/h 2268.9 Btu/h Imported IFC X2 6996.3 Btu/h 8929.3 Btu/h Table 6.1 Comparison of results: base case file with imported IFC file. The IFC file, was able to carry geometric information such as shape, areas and volumes, but not other critical information such as location, construction assignments and units. The following chart gives a more detailed comparison of the results. X1 X2 Sensible Cooling Load Latent Cooling Load Sensible Heating Load Latent Cooling Load 5252.9 Btu/h 298.9 Btu/h 2268.9 Btu/h 0 6114.8 Btu/h 881.4 Btu/hr 8929.3 Btu/h 0 Analytical Floor area Analytical Volume 216 sq ft 1728 cu ft 216 sq ft 1728 cu ft Lighting Load Equipment load People Load 1.1 W/sq ft 0 1.73 1.0 W/sq ft 0 1.44 Airflow flow rate Flow density Air changes 243 cfm 1.13 8.45 283 cfm 1.31 9.84 Table 6.2 Comparison of results: base case file with imported IFC file 54 As indicated in the comparison table above, the IFC file carries geometric data such as area and volume. However, since it is not carrying all the information, its assumptions for lighting, equipment and people loads as well as air flow data is different. The Table below shows the information that the imported IFC file carries. MEP Model Imported IFC File Units Feet and inches Meters Area 216 sq ft 20.067 m 2 (equals 216 sq ft) Volume 1728 cu ft 48.932 m 3 (equals 1728 cu ft) Building Constructions Standard Wall construction(2002 regs) 8” Lightweight concrete block Un Insulated solid ground floor Un insulated ground floor Flat Roof(2002 UK regs) 4” Light weight concrete Low e Double Glazing (2002 regs) Large Double Glazed windows(Reflective Coating Building Services VAV Single duct VAV Single duct Building Type Office Office Place and Location Los Angeles, CA Boston, MA Table 6.3: Comparison of information carried by the MEP model and the imported IFC file. From the table above, it seemed that the IFC file was able to carry information such as building type (enclosed office building) and building services (VAV single duct). However, these are the default values accepted in MEP and therefore, new values for building type (exercise center) and building services (forced convection heater-Flue) were selected, to confirm whether these were carried over. In the following chart, X3 55 and X4 are the results for the new values for building type and building services. The results were as follows: Cooling Load Heating Load Base Case X1 5551.8 Btu/h 2268.9 Btu/h Imported IFC X2 6996.3 Btu/h 8929.3 Btu/h Base Case X3 858.3 Btu/h 2268.9 Btu/h Imported IFC X4 6996.3 Btu/h 8929.3 Btu/h Table 6.4: Comparison of information carried by the MEP model and the imported IFC file. The table above shows that X4 is the same as X2, hence the IFC file was unable to carry data containing information about building type and services. In order to validate what was not being carried over, the IFC file was modified to match the building type, construction assignments, building services and location with the base case. It was found that the results matched the base case scenario. Appendix C lists all of the components of the building in the Revit file that were carried over to the IFC file, and its IFC category. 6.2.2 The gbXML File: The Base case room was exported as a gbXML file format and then imported into IES <VE>. The following chart gives a comparison of the new results with the base case. 56 Annual energy consumption Room Cooling Plant Load Room Heating Plant Load Base Case Y1 10.495 MMBtu 5181 Btu/h 2496 Btu/h Imported gbXML Y2 21.610 MMBtu 7369 Btu/h 10555 Btu/h Table 6.5 Comparison of results: base case file with imported gbXML file The gbXML file, like the IFC and DXF was able to carry geometric information such as shape, areas and volumes. However, it was unable to carry information about location (for example, Los Angeles), and construction assignments. The following chart gives a more detailed comparison of the results. Y1 Y2 Annual total energy consumption Heating Cooling Fans, pumps and Controls Lights Equipment 10.495 MMBtu 0.129 MMBtu 1.730 MMBtu 2.987 MMBtu 2.959 MMBtu 2.690 MMBtu 21.610 MMBtu 12.880 MMBtu 0.725 MMBtu 2.625 MMBtu 2.690 MMBtu 2.690 MMBtu Analytical Floor area Analytical Volume 216 sq ft 1728 cft 216 sq ft 1728 cu ft Carbon dioxide emissions 2842.5 lb 3994.8 lb Room heating plant load System heating load: Plant load 2496 Btu/h 2.776 MBH 10555 Btu/h 12.372 MBH System Cooling Load: Peak plant load Peak Month/time Room Cooling Plant Load: Peak No. of people 5.731 MBH Sep, 13:30 5181 Btu/h 1.73 7.533 MBH Aug 15:30 7369 Btu/h 1.44 Table 6.6 Comparison of results: base case file with imported IFC file The following table shows the information that the imported gbXML file carries. 57 MEP Model Imported gbXML File Units Feet and inches Metres Area 216 sq ft 216 sq ft Volume 1728 cu ft 1728 cu ft Building Constructions Standard Wall construction(2002 regs) 8” Lightweight concrete block Un Insulated solid ground floor Un insulated ground floor Flat Roof(2002 UK regs) 4” Light weight concrete Low e Double Glazing (2002 regs) Large Double Glazed windows(Reflective Coating) Building Services VAV Single duct VAV Single duct Building Type Office Office Place and Location Los Angeles, CA Long Beach, CA Table 6.7: Comparison of information carried by the MEP model and the imported gbXML file. From the table above, it seemed that the gbXML file was able to carry other information such as building type, that is, enclosed office building and building services that is VAV single duct. Since these are the default values accepted in MEP and therefore, new values for building type (exercise center) and building services (forced convection heater-Flue) were selected, to confirm whether these were carried over. The results were as follows: Annual energy consumption Room Cooling Plant Load Room Heating Plant Load Base Case Y1 10.495 MMBtu 5181 Btu/h 2496 Btu/h Imported gbXML Y2 21.610 MMBtu 7369 Btu/h 10555 Btu/h Base Case Y3 6.626 MMBtu 559 Btu/h 3237Btu/h Imported gbXML Y4 23.415 MMBtu 12005Btu/h 4444 Btu/h Table 6.8: Comparison of information carried by the MEP model and the imported gbXML file. 58 The gbXML file was not able to carry information on building services but could pertaining to building type. This is reflected in the result above, as Y4 does not equal Y2. In order to validate what was not being carried over, the gbXML file was modified to match the location, building services and construction assignments with the base case. It was found that the results matched the base case scenario. 6.2.3 The DXF File In order to test information carried by DXF files, the base case building model was exported as an Autocad 2004 DXF file and then imported back into Ecotect. It was found however, that while geometry (areas and volumes) were transmitted through DXF. However, the building as a „zone‟ was not carried through, and that, the building could not undergo a load analysis because of the lack of a thermal zone. As already explained in Chapter 3, a building/room has to be transformed into a thermal zone in Ecotect, in order to undergo a thermal analysis. It was found that a gbXML model could be imported into Ecotect, and manually converted into a zone, whereas the DXF file could not be done so. 6.3 Interoperability between Revit MEP and IES<VE> Revit MEP is essentially a modeling tool, where it is possible to model a building, define building materials, thickness and construction layers for the walls, 59 roofs and ceilings. The user can also define a host of other parameters such as units, location and services in the modeling menu. The MEP-IES energy analysis interface allows the user to input values for building type, construction assignments, building services and location, independent of the options in the modeling screen. This section is an attempt to test what information gets transferred from the model to the interface. The building model was tested for building material, thickness, geometry (area and volume) building services, location and building types. All input variables were kept constant in the base case, and testing was done with one alteration at a time. 6.3.1 Building Material: The base case was modeled in MEP, using the wall default material assignment as 8” generic wall. The wall material was changed to 8” heavy weight concrete block using the construction assignments defined in IES for this material. The block basically comprises stucco, HW concrete block, and gypsum/plasterboard. The same option was selected in the MEP-IES interface for building construction assignments (exterior wall).Heating and cooling loads runs were done in MEP and IES, with the results as shown in table. In order to test whether information regarding the material choice in the model was carried over for analysis, a new material was assigned to the model. The wall material was changed to timber frame wall, comprised as brickwork(outer leaf), cavity, plywood(lightweight), mineral fiber slab, cavity and gypsum plasterboard. 60 However, the option selected in the MEP IES interface for the construction assignments (exterior wall) was kept as the original. A quick run in the MEP and IES results show that the result is exactly the same. This seems to indicate that the assigned material in the model does not, in fact, have a bearing on the results. . This is very important to realize. Table 6.9 shows that even though a wall was modeled in Revit with two materials (8” heavy weight concrete block, U=0.3671 and timber frame wall, U=0.1018) the IES loads were the same. Modeling MEP Selection MEP Loads IES Loads 8” Heavy weight Concrete Block 8” Heavy weight Concrete Block(U=0.3671) 7082.0 Btu/h 5757.7 Btu/h 17.311 MMBtu Timber Frame Wall 8” Heavy weight Concrete Block(U=0.3671) 7082.0 Btu/h 5757.7 Btu/h 17.311 MMBtu Timber Frame Wall Timber Frame Wall (U=0.1018) 5579.8 Btu/h 2491.7 Btu/h 15.148 MMBtu Table 6.9: Comparison of loads with different material selections. In the third case, the timber frame wall was modeled as the wall material, and the same option was selected in the MEP IES interface, that is, timber frame wall(U=0.1018).The difference in the results indicates that the selection in the MEP- IES interface overrides any selection made during modeling of the building. This is important because this indicates a gap in the information transfer in the building model and analytical model. 6.3.2 Material Thickness The base case was modeled in Revit MEP, with the wall type as selected in 61 the previous example: 8” heavy weight concrete block. In order to test whether the program was carrying the thickness of materials to the model, the wall thickness was changed from 8” to 16”.This was done such that internal volume of the space remained the same, that is 1728 cu ft. A quick run in the MEP and IES results show that the result differs slightly from the original case. This seemed to indicate that the wall thickness modeled in the program, was being carried over for the analysis, but could not be proved so conclusively. Table 6.10: Comparison of loads with different material thicknesses. 6.3.3 Building location, building services and geometry. Apart from material thickness, the geometry, building services, location and building types that were defined in the model were getting transferred to the interface. In other words, a specific location defined in the model was automatically carried over to the interface assignments. However, this was not necessarily the case with building material. 6.4 Conclusions: The following chart is a comparison of the heating/cooling loads carried by the three files. Modeling menu MEP Selection MEP Loads IES Loads 8” Heavy weight Concrete Block 8” Heavy weight Concrete Block(U=0.3671) 7082.0 Btu/h (CL) 5757.7 Btu/h (HL) 17.311 MMBtu 16” Heavy weight Concrete Block 8” Heavy weight Concrete Block(U=0.3671 7179.1 Btu/h(CL) 5907.5 Btu/h(HL) 17.534MMBtu 62 X1 Y1 Z1 Cooling Load Heating Load 5551.8 Btu/h 2268.9 Btu/h 5181 Btu/h 2496 Btu/h 4964.9 Btu/hr 2759.7 Btu/hr X2 Y2 Z2 Cooling Load Heating Load 996.3 Btu/h 8929.3 Btu/h 7369 Btu/h 10555 Btu/h - Table 6.11: Comparison of the three programs and file formats. The table above indicates that there is some amount of information that is not carried by interoperable files. The table below is an attempt to compare the file type and the information they are capable of carrying. DXF IFC gbXML Drawing units yes no yes “Zone” definition no yes yes Geometry Shape yes yes yes Area yes yes yes Volume yes yes yes Building type no no yes Location no no yes Building Services no no no Building Materials no no no Material Thicknesses yes yes yes Table 6.12: Comparison of the information carried by the interoperable file formats. 63 Section III: Improving the MEP-IES<VE> interface. Introduction to the Section: In this section, the study focuses on the MEP-IES interface and looks at ways to improve the interface between Revit MEP and IES. The initial hypothesis, testing whether Revit was a robust BIM system, led to the development of a Revit template file that when imported into a project could provide more information about the materials being used in the project. This file contained information about building components that is walls, roofs, floors, windows, doors, and skylights. Eventually, the information associated with this file could be imported into the user‟s Revit project and the user could model the exact material that one was doing an analysis for. The purpose of this template was is fold: First, it performed an informative role and provided the user with information such as composition, thickness, specific heat, U-values, thermal bridging coefficient, emissivity, resistance and solar absorbtance of each material. This was critical to a BIM model; after all, a truly robust building model is informative by its very nature. The second is that the template allowed for modeling a more accurate building model and thereby it followed that it was a more accurate result even though the difference in analysis results was not very large. This section specifically explains the development of the template file and is organized in two chapters. The first chapter in this section explains the theoretical framework, background information about the interface, input values required and how a model is set up for an analysis. 64 The second chapter explains how the two types of families, system family types and the standard component template were developed. It explains the sequential series of steps that were followed for both the family types. It contains results and comparisons between the analysis results of two case studies. 65 Chapter 7: Introduction to the MEP-IES<VE> interface. 7.1 Introduction to the Chapter: The objective of this chapter is to give an overview of the Revit MEP-IES <VE> interface and the method employed as well as the inputs required for a building performance analysis. It contains an introduction to the MEP-IES interface, some of the concepts, including the hierarchy of building elements in an analytical model and steps for converting a Revit model into an analytical model. A section is devoted to the input selections required for the energy analysis and the last section explains the two sets of calculations possible through the interface. While the first set is calculated within the Revit engine, the second set is done outside, when the MEP model gets exported to IES. 7.1.1 The MEP-IES Interface: An introduction. The IES interface in MEP allows the user to select and define values for building type, building services, building construction assignments, place and location. These values exist as a drop down menu in the interface and are independent of the options available to the user in the modeling screen. There are two types of building performance analysis that are possible: One is done within the Revit engine and gives heating/cooling loads, while the other takes the user outside the engine, and is able to give a more comprehensive analysis. Chapter 5 discussed these two methods in relation to how much data about the original Revit model is used. 66 7.1.2 Conversion of a Revit model into an analytical model. For an accurate building performance analysis and an efficient workflow between the two platforms, first the Revit physical model is converted into an analytical model. First, there is a conversion of spaces into rooms. In Revit, rooms are the equivalent of zones and need to be defined as such. As described in chapter 3, a thermal zone is a completely enclosed space, bound by its floors, walls and ceiling/roof and is the basic unit for which heat loads are calculated. The extent of a “room” is defined by its bounding elements such as walls, floors and roofs. Once, a “room” is defined for a building performance analysis, these bounding elements are converted to 2 D surfaces that represent their geometry. Openings such as windows, doors, openings and skylights act as “children” elements of the bounding elements. Also, overhangs and balconies that do not have a room as a “parent” are considered as shading surfaces. In order to determine whether a room is interior or exterior, adjacencies of a room are determined in the analytical model. The hierarchy of the elements contained in the Revit Analytical model is shown in Figure 7.1. Figure 7.1: Hierarchy of elements in the Revit analytical model. 67 Computing room volumes: For a more accurate analysis, the „Compute Room Volume‟ toggle, found in the Room and Area Settings dialogue, is turned on. This is able to detect the bounding elements in all directions and turns on the calculation to handle rooms as 3 D elements. Figure 7.2: A model above showing different analytical volumes with the „Compute Room Volume‟ toggle off and on. Revit MEP calculates two volumes for computations: analytical and inner room Volume. The analytical room volume is used for thermal and energy calculations and is bounded by the center plane of walls and top plane of roofs and floors. Figure 7.3 Analytical volume Figure 7.4 Inner volume. 68 Fig 7.5 The blue line in IES shows analytical volume Fig 7.6: Computing “room volumes” The inner room volume, is bounded by interior volumes, and is used for air computations and lighting calculations. When a building is transferred to IES<VE>, the analytical room volume is shown by the outer blue line, while the inner room volume is indicated in grey. Setting the “Upper limits”: The upper limit of the model is set to the next level in Revit, and the limit offset set to zero. By default, the rooms is created with an 8‟ limit offset with the upper limit set to current level in MEP. Bounding element status: To ensure that bounding elements are used as such, the user can do so by toggling the “Room Bounding” parameter that is available in the Element Properties dialog. Figure 7.7: Settling the “Upper Limits”. 69 7.2 Input Values required for a building performance analysis in Revit MEP. The Revit MEP Interface has four sets of input values required from the user Building type Building construction (default room construction) Building services Place and location. 7.2.1 Building Type: As indicated in Figure 7.7, the option for Building type are available in the form of a drop down menu and contain some 32 choices including office, hospital, multifamily etc. Predefined parameters that define each building type already exist in MEP. Building type data associated with an office building is listed in as follows: Fig 7.8: Options for Building Type 70 Room Type: Office - Enclosed HVAC System: Temperature Control: Heating Set Point - degrees F: 70 Heating Schedule: On continuously Cooling Set Point - degrees F: 75 Cooling Schedule ASHRAE 8-6 System fresh air supply rate - cfm/ft 2 : 0.1423 Humidity Control: Min. percentage saturation (%): 0 Max. percentage saturation (%): 70 Internal Gains: Lighting Gain - W/ft 2 : 1.1 Lighting Schedule: ASHRAE 8-6 Equipment (Miscellaneous) gain - W/ft 2 : 1 Equipment (Miscellaneous) Schedule: ASHRAE 8-6 Occupancy density - ft 2 /person: 125 Occupancy sensible gain - Btu/h/person: 250 Occupancy latent gain - Btu/h/person: 200 Occupancy Schedule: ASHRAE 8-6 Air exchanges (ach): 0.167 Table 7.1: Source: Revit MEP User‟s Guide: energy analysis building and room type imperial data Some of this data also appears in the analysis and output results, for example, electrical data (lighting loads, equipment loads and misc. loads) and people loads(people, area/person, sensible/person, latent/person) 71 7.2.2 Building services: As indicated in Figure 7.8, the options for building services are available in the form of a drop down menu and contain some 27 choices such as VAV single duct, split systems with natural ventilation, radiant heating and so on. A complete list of Building services that are available as selections in MEP is found in Appendix B. Figure 7.9: Building Services Figure 7.10 : Place and Locations. 7.2.3 Place and location: Place: This option consists of a drop down menu containing a list of cities around the world, along with their latitudes and longitudes. Locations: This option is used for orientation and position of the project on the site and in relation to other buildings. There may be many shared locations defined in one project. The user can also define the angle from project north to true north. 7.2.4 Building Construction (default room construction) The following options are available to the user for construction assignments: 72 exterior walls, interior walls, slabs, roofs, floors, doors, exterior windows, interior windows and skylights. Table 7.3 shows the default construction assignments available to the user. Construction assignments for all construction types are listed in Appendix D. Construction type Construction Assignment Exterior Walls 8 in Light Weight Concrete Block (U=0.1428) Interior Walls Frame Partition with 0.75 in Gypsum Board(U=0.2595) Slabs Un-Insulated Solid-Ground Floor (U=0.1243) Roofs 4 In Light Weight Concrete(U=0.2245) Floors 8 In Light Weight Concrete Floor Deck (U=0.2397) Doors Metal Door(U=0.652) Exterior Windows Large Double-Glazed Windows(Reflective Coating)- Industry (U=0.5141) Interior Windows Large Single-Glazed (U=0.6498) Skylights Large Double Glazed Windows(Reflective Coating)- Industry(U=0.5628) Table 7.2 Default construction assignments for the construction types. The values for the construction assignments are derived from the construction database in IES<VE>, called the Apache Construction database. For example, the 8 in Light Weight Concrete Block exists with the ID ASHWL 66 in the “Project Constructions” Apache database, as indicated in Figure 7.4. This particular construction type has several parameters associated with it that are defined in this database. 73 Figure 7.11 : The Apache construction database Figure 7.12: Construction assignments for an 8” lightweight concrete block. Figure 7.11 shows the construction assignment 8 in Light Weight Concrete and the various parameters associated with it. Some of these are emissivity, 74 resistance, solar absorbtance, construction layers (thickness, conductivity, density and specific heat capacity of the materials) , construction thickness and the CIBSE as well as the EN-ISO U-values. Further details of construction parameters in IES<VE> are provided in Chapter 8. 7.3 Thermal analysis results. Figure 7.13: The two buttons for a thermal analysis found in the interface. As explained earlier, there are two types of analysis possible in the Revit MEP-IES interface. There are two separate buttons that take the user inside and outside the Revit engine. 2 1 75 Figure 7.14: Methods of thermal analysis in the MEP-IES interface. 1) Energy analysis within the Revit engine: On pressing the “Calculate” button, the sub component of IES inside Revit computes the heating and cooling loads. This also gives additional information about the sensible and latent loads, analytical areas and volumes. It displays assumptions for air flows, electrical loads and people loads. It is useful for users who might want a quick calculation, but gives very little information. For a more comprehensive analysis, the user can click the “Virtual Environment” button, in which case, the model gets exported to the IES <VE> and opens it there. 2) Energy analysis using the Apache simulator outside Revit MEP. Virtual Environment, provides two sets of calculations for energy analysis: 76 The Apache Sim calculator The Ashrae Loads method Apache Sim runs the simulation for the entire year and calculates the annual total energy consumption in MMBtu. It also breaks up total energy consumption into heating, cooling, fans, pumps and controls, lights and equipment for each month. It gives the total carbon dioxide emissions in pounds, as well as information such as peak hourly room loads, and room environmental conditions such as temperature, relative humidity for each room. Figure 7.15: The Apache Simulator generates total annual energy consumption. The ASHRAE loads method: This method utilizes the worst month scenario for heating load calculations (in this case, January for Los Angeles) and a period of May to September for its cooling load calculations. It calculates the system heating and cooling loads as well as the room heating and cooling plant loads. 77 Figure 7.16: System heating loads Figure 7.17: Room heating plant loads System Heating loads includes room heating loads (sensible and humidification loads in MBH), domestic hot water and plant loads(MBH), while room heating plant loads include air temperature, conduction gains(Btu/h), ventilation gains(Btu/h) and sensible loads(Btu/h).System cooling loads include the month and time for the worst day design scenario, room cooling loads(sensible and dehumidification in MBH) outdoor air primary loads(MBH) and peak plant load(MBH). Refer to Appendix B for results in system and plant loads. Figure 7.18: System cooling loads Figure 7.19: Room cooling plant loads 78 Chapter 8: Improving the Revit MEP-IES<VE> Interface. 8.1 Introduction to the chapter. In a typical Revit model, at the modeling stage, the user has the option of selecting certain wall types that exist as default values, for instance 6”, 8” or 12” generic walls. However, when running a thermal analysis the user may opt for a completely different wall selection according to the choices existing in the interface, as explained in the previous chapter. This choice could be a wall selection such as 8” heavy weight concrete wall with 1” insulation because this is what comes closest to what he plans for the building. The objective of the exercise was to develop a template file that contained this information about building components that is, walls, roofs, floors, slabs, doors and windows. Parameters associated with these components were derived from their counterparts in IES<VE>.The user, then, could import this file into the Revit project, and model the exact material that one was doing an analysis for. Parametric components in Revit such as walls, roofs or even furniture are referred to as „families‟. Revit families are essentially driven by Revit's parametric change engine, which ensures that a change made to a family is propagated throughout the entire project. Once created, a family's parameters can be edited directly within a Revit project. There were two types of templates that were made, depending on their family type. Walls, floors and roofs belong to the system family type and were made into a 79 system family template. Windows, roof lights and doors are types of standard component families and were defined as such. This chapter contains an introduction to various family types, specifically system families and standard component families. It explains a step by step procedure of how the system family template was developed, and illustrates it with an example of a wall type. It also explains how values were derived from various construction parameters, how type parameters were defined in Revit and subsequently, how the project standards were transferred to a Revit project. Another section includes the development of standard component families, following a similar procedure to the system family template. This chapter also includes an introduction to the building component legend and its significance. The last section highlights the advantages and results of a basic thermal analysis after using the template. 8.2 Families and their types: Revit Architecture contains three types of families: system families, standard component and in place families. System families: These families are predefined within Revit Architecture and consist of primary building components of a building such as walls, roofs and floors. These can be duplicated or modified in a project but cannot be created in a project. For example, a wall family may be basic wall, curtain wall or stacked wall and each may have several types, such as exterior generic, interior, foundation, retaining and 80 soffit. Since system families themselves cannot be created in a project, all the wall, floor, slab and roof categories were created as types and stored as a Revit template file, with extension rte. Standard component families: Standard component families are loaded into the project templates and are stored by default in component libraries. These families can be either host based or stand alone. Host based families such as doors, windows or lighting fixtures require hosts such as walls or ceilings. Examples of stand-alone families can include trees, furniture, columns etc and by definition, do not require a host family. Standard component families exist outside the project and can be loaded onto projects, as well as transferred. These have an extension .rfa. Windows, roof lights and doors were modeled as families and store as separate rfa files. In place families: In place families are either model or annotation components and are particular to a project. In place families are created within a project so they are unique only to that project, for instance custom wall treatments or a roof. 8.3 Development of families For the improvement of the MEP-IES interface, two kinds of families were created: system family template and standard component families. 81 8.3 The System family Template As indicated in figure 8.1 above, the system families for the project include external walls, internal walls, roofs, slabs and floors. The parameters defined for the family template are: 1. Construction material(layers and their respective thicknesses, conductivity, density and specific heat capacity) 2. U-value 3. Thermal bridging coefficient 4. Emissivity (outside and inside surface) 5. Resistance(outside and inside surface) 6. Absorbtance(outside and inside surface) System Family Types Standard Component families External Walls Internal Walls Roofs Floors Slabs External Windows Internal Windows Roof Lights Doors Energyanlasistemplate.rte Exwin.rfa Inwin.rfa roof.rfa door.rfa Transfer Project Standards Imported Into project Figure 8.1: Development of the system family types and standard component families. 82 As explained, the values for these parameters were derived from IES<VE> Apache construction database. The following is an example of a certain wall type, and comprises the various steps taken to include it in the template file. 8.3.1 Deriving values for parameters in the database. The project constructions for a 4” face brick (ID ASHWL-59) are defined in the Apache construction database in IES<VE>. It has the following values associated with it: Figure 8.2: Project Constructions for a 4 in face Brick wall type. 83 Description 4” Brick face Outside surface Inside surface Emissivity 0.900 0.900 Resistance 0.341 0.665 Solar Absorbtance 0.700 0.550 Thermal bridging coefficient 0.0062 Btu/h ft 2 deg F Construction thickness 10 ¾” EN ISO U Value 0.1097 Material Thickness Conductivit y Btu in/h ft 2 Density Lb/ft 3 Specific heat capacity Btu/lb deg F Face brick Insulation Board HW concrete undried aggregate Gypsum plasterboard 4” 2” 4” ¾” 9.228 0.298 11.995 1.109 130.037 1.998 140.026 50.005 0.2200 0.1999 0.1999 0.1999 Table 8.1: Deriving parameter values from the Apache project constructions 8.3.2 Step 2: Defining the „type parameters‟ in Revit MEP. In the Revit template file, the type parameters for a wall such as U-values, surface resistance (inside and outside), emissivity (inside and outside), solar absorbance (inside and outside) and thermal bridging coefficient were defined. These new type parameters were defined using the “Project Parameters” dialogue box. 84 Figure 8.3 and Figure 8.4: Defining type parameters. The following table shows the values assigned to the different parameters, and their categories in the „Parameter properties‟ dialogue box above. Parameter Name Discipline Type of Parameter Group Parameter under U Value Common Number Construction Conductivity Common Number Construction Density Common Number Construction Inside Surface Emissivity Common Number Construction outside Surface Emissivity Common Number Construction Inside Surface Resistance Common Number Construction Outside Surface Resistance Common Number Construction Inside Surface Solar Absorbtance Common Number Construction Outside Surface Solar Absorbtance Common Number Construction Thermal Bridging Coefficient Common Number Other Table 8.2: Defining „type parameters‟ 85 Figure 8.5: Defining the „Type properties‟ for the 4” Face Brick wall. Construction layers, (that is face brick, insulation board, HW concrete, gypsum plasterboard) and their respective thicknesses were also defined. Figure 8.5 above shows the type properties that are defined for each type while the figure below shows the construction layers. Figure 8.6: Defining the construction layers: Plan view 86 Figure 8.7: Defining the construction layers: Section view. Figure 8.8: Assigning values to materials. 87 The building material in the construction layers were assigned values based on existing materials. Figure 8.6 indicates the physical parameters associated with a heavy weight concrete block. 8.3.3 Step 3: Transferring Project Standards: Once all the types were defined for walls, roofs, slabs and floors as type parameters, the file was saved as a Revit template file. At any stage during the project, the user can import this project template file, using the option “Transfer project standards.” Project standards (information related to family types in a file) can be transferred from one project to the other, using this option. The file to be transferred has to be opened first and categories selected from the “select items to copy” dialogue box. The destination project is opened next and process is repeated. Once the template is imported into the user‟s project, all the family types get loaded and can be used as indicated in the figure below. 88 Figure 8.9: Various options for wall types in the template file. Examples of a roof and floor type families can be found in Appendix D. 8.4 Standard Component Families: As indicated in figure 8.1, external and internal windows, roof lights and doors were included as standard component families. Since these were regular family files, these were made by modifying existing window and door based families. Like the system family types, the values for the parameters were derived from IES<VE> Apache construction database. The following figure illustrates the various parameters associated with a low e double glazing window type, found in the Apache database. 89 Figure 8.10: Project constructions for Low e double glazing windows. In the window/door family file, various family types were defined. The following table indicates the parameters that were defined and put in the categories “Construction” and “Materials and Finishes”. Parameter Name Discipline Type of Parameter Group Parameter under U Value Common Number Construction Inside Surface Emissivity Common Number Construction outside Surface Emissivity Common Number Construction Inside Surface Resistance Common Number Construction Outside Surface Resistance Common Number Construction Frame Material Common Text Materials and Finishes Frame Resistance Common Number Materials and Finishes Frame Absorbtance Common Number Materials and Finishes Table 8.3: Defining „type parameters‟ for door and window families. Figure 8.9 shows the screenshot of the window family file and also the family types, associated with it. This family can then be imported into a Revit project file. 90 Figure 8.11: Defining the „Type properties‟ for the low e glazing window. 8.5 Template File: Creating a legend: Figure 8.12: Defining the legend for building components. The purpose of creating a legend in the template file is an informative one. This legend provides information to the user regarding wall, floor, slab and roof types. As indicated in Figure 8.10, the legend contains a plan, section, and provides 91 information to the user about the construction layers, U values, emissivity, resistance and solar absorbtance. More information about the parameters that were defined for the analysis template and family files can be found in family template file „energyanalysistemplate.rte‟(for walls, roofs, floors, slabs) and „exwin.rfa‟, „inwin.rfa‟, „roof.rfa‟ and „door.rfa‟(for windows, , rooflights, doors)Samples of these can be found in Appendix E and Appendix F. 8.6 The template file: results. In the previous section, results were given on the tests conducted to see whether the building model was able to transfer information about the geometry, thickness and material to the interface. It was found that while geometry was being carried over, the building material was not. Ideally, checks for material related parameters such as conductivity, U-value, density and specific heat ought to have been conducted, but this was not a possibility in MEP, since these options are not available to the user. Also, it seemed that the material thickness was getting carried over, since the result was coming out different. Fig 8.13: Room modeled with 8 in wall thickness Fig 8.14: Room modeled with 16 in wall thickness 92 The figures above show a room with different material thicknesses, while the inner room volume is constant. The results, in Table 8.6 below indicate that the model is able to carry over material thickness since the results are different. IES (Within Revit) 8” Wall thickness 16” Wall thickness Cooling loads 2043.6 Btu/hr 2104.2 Btu/hr Heating Loads 2080.9 Btu/hr 2190.4 Btu/hr Table 8.4: Varying load results with different wall thickness. However, on communicating with the IES Technical Support, it was found that the building model is able to transfer only geometry to the analysis interface. The discrepancy in the results arises due to an increased external surface area and therefore an increased heat transfer. This led to the question, about whether using the template file would lead to a more accurate result or not. To begin with, one had assumed that it would be more accurate since one was modeling exactly what one selected for the analysis. There was no way to test this information, and was eventually confirmed by IES Technical Support that using the template would improve upon the accuracy in result. The following example uses the base case room, with material selections as listed in Table 8.7.The Tables 8.8 and 8.9 indicate results for the analysis within MEP and outside of it, for a building model with generic materials, without using the template and then using it. There is a difference in the result, albeit a small one. As indicated in the table, cooling and heating loads increase by 2.02% and 2.62% respectively. 93 Fig 8.15 and fig 8.16: base case room modeled in MEP and IES. Exterior Wall Standard Wall Construction (2002 UK regulations) (U=0.0527) Roof 4” Light weight Concrete (U=0.225) Floor 8” Lightweight Concrete floor deck (U=0.2397) Exterior Window Large Double Glazed Windows(U=0.5141) Table 8.5: Construction assignments used for the base case room. Results: IES (Within Revit) Without using template Using Template Cooling loads 3334.8 Btu/hr 3247.6 Btu/hr Heating Loads 3821.5 Btu/hr 3761.5 Btu/hr Table 8.6: Results in MEP with and without using the template. IES <VE> Without using template Using Template Cooling loads 5.249 MBH 5.143 MBH Heating Loads 3.440 MBH 3.350 MBH Table 8.7: Results in IES with and without using the template. 94 The following example uses a more elaborate building, with material selections as listed in Table 8.10.As with the previous example, Tables 8.11 and 8.12 indicate results for the analysis within MEP and outside of it, for the case study building model. Fig 8.17 and Fig 8.18: Case study building modeled in MEP. Fig 8.19: Case study building model exported to IES. Exterior Wall 4” face brick 2” Insulation and 4” Heavy wt concrete(U=0.1097) Roof 4” Common brick with .75” plaster (U=0.2758) Floor 6” Heavy weight concrete with 2” Insulation(U=0.1201) Exterior Window 8” Heavy weight concrete deck with false ceiling(U=0.2173) Table 8.8: Construction assignments selected for the case study building. 95 Results: IES (Within Revit) Without using template Using Template Cooling loads 42156.9 Btu/hr 43250.2 Btu/hr Heating Loads 93807.5 Btu/hr 94810.8 Btu/hr Table 8.9: Results in MEP with and without using the template. IES <VE> Without using template Using Template Cooling loads 40.663 MBH 40.917 MBH Heating Loads 124.105 MBH 125.182 MBH Table 8.10: Results in MEP with and without using the template As indicated in the results above, the difference in results is quite small(less than 1%) and much less than the previous example. There is an increase in cooling loads by 0.624% while heating loads increase by 0.87%. Thus, the difference in results becomes less substantial as the building area increases. In effect, using the template file will not cause the material, its U-value or even its thickness to get carried over. However, using the template will result in an increase or decrease in the surface area of the building model, which gets carried over to the analytical model and result in an increased/decreased heat transfer. Since the building model is more accurately modeled (or at least, modeled exactly for what it is analyzed for) with the template, one can conclude that the results will get more accurate. 96 Section IV Chapter 9: Conclusions and future work 9.1 Conclusions: Building information models have an increasingly significant role to play, in the construction industry today, to have a more efficient workflow between different players in the industry such as architects, engineers, contractors and owners. Its strength lies in being a multifaceted, data rich model that provides the user with a database of building information. In this respect, Revit performs well as a BIM prototype, in that it is able to support a host of functions, from building models to schedules, assemblies and sequences. Once a Revit model has been made, it can be analyzed for various purposes such as structural member determination or for electrical and mechanical loads through Revit Structure and Revit MEP respectively. In addition, Revit is interoperable with a wide range of scheduling and project management programs that strengthens its role as a BIM program. Autodesk Revit is not the only BIM program available-it was chosen because of its direct link to IES<VE>. Interoperability of building information models with energy analysis programs is an emerging area, and is gaining increasing attention in the building industry. Almost 3% of the projects costs are related to the lack of software interoperability (Interoperability in the Construction industry, 2007). Software incompatibility often leads to redundant work and a need to spend more time and money in non standard solutions that drive the project costs up. The benefits of 97 interoperability and data sharing include increased speed of project delivery, greater reliability of information through the project life cycle. Using a building information model also helps in early decision making that often helps control costs. (Interoperability in the Construction industry, 2007) This thesis had started out with the larger question related to a building information model, specifically in relation to energy analysis tools, whether the building information model is truly robust or not? Whether it was able to carry information across software programs, and if, so was the information transfer seamless? What data was being retained or destroyed as the program‟s information went between file formats and into other programs? Given that BIM is very powerful tool, its key strength lies in its interoperability with other programs. However, at the moment, there is a large gap in the promise made by BIM proponents and what it actually delivers. Presently, interoperability with energy analysis programs is limited, even though new solutions such as interoperable file formats are being developed. Industry groups and technology providers are experimenting with standards in order to establish universally accepted ways of transferring data across different software packages and seamlessly exchange information. Efforts such as the Industry foundation classes(IFC) and extensible markup language(XML) are currently being promoted by various industry groups. The other part of the study, that is, integration of energy analysis functions, within BIM software, is also at a nascent stage. The integration of IES into Revit is a 98 step in this direction and the analysis provided by this tool is extremely limited and is intended as a quick analysis tool for users. However, this is a step in the right direction and may be indicator of future trends. Comprehensive energy analysis functions incorporated into building information models would be extremely valuable step in making it a more powerful tool. There is serious disagreement in the field as to those who favor an open standard and those who prefer integration within a single software package or bundle. Both approaches were touched upon in this study. 9.1.1 Interchangeable file formats: Interchangeable file formats such as IFCs and gbXML are being developed and promoted as international standards, such that building models can be carried across different platforms through these. Also, a parallel development is, for application and program developers to ensure that their programs are IFC or gbXML compliant. At present, while programs such as Revit are IFC 2x2 compliant, the developers of Ecotect are promising it to be so, soon. To a large extent, these file formats have been very successful in carrying building models. However, in an ideal world, information transfer would be seamless and data transfer should happen back and forth without loss of information. Also, a change in the building model should be reflected in the analytical model as well. Neither program tested was able to do this. While newer versions of the IFC format is getting progressively better in its ability to carry information, however a seamless data exchange is still a long way off. 99 Some of the earlier formats such as DXF‟s were files designed to carry geometric information and were designed in particular, for use with AutoCAD files, and so, most of its data is stored as layers. At the beginning of the study, one assumed that the geometric information carried by the DXF would be good enough for a daylighting analysis(primarily involving the geometry of the building), but did not prove to be so. Even though DXF carried over the geometry, there was no meaning attached to the lines. For instance, when a DXF model was imported into Ecotect, it did not automatically convert rooms into zones, and ended up converting certain layer types into zones. In effect, the user has to end up redrawing the building and the use of DXF is largely limited to importing 2 D plans that become a sort of foot print, from which the building has to be generated again. However, with the advent of gbXML file schema and the IFC formats, it was possible for more comprehensive building information, apart from geometry, to be carried by these files. As explained in Chapter, Table 4.1, the gbXML schema was quite effective in organizing file information. Building data is sorted into levels (ranging from campus, buildings, zone, space, surface, opening and construction type)each of which is able to carry information about material related parameters such as U values, absorbance, reflectance, roughness, construction type and so on. Similarly, the IFC model consists of tangible components such as walls, doors, etc, as well as the more abstract concepts of space, geometry, activities etc. Building model data is stored in layers and in a hierarchical fashion, with lower level entities inheriting its attributes from higher level entities. 100 During the testing stages, DXFs, gbXMLs and IFCs were tested for their carrying capacity by comparing the results of these files with the original base case. One had started out with assuming that DXFs would give a major discrepancy, since it was carrying only geometry. However, one found that this was not necessarily so and that both the IFC;s and gbXML‟s were giving large discrepancies too. This was important because one found that even if the files were not carrying single critical information, it would affect the result. For instance, the IFC was not able to carry the location information as defined in the Revit file, and when imported into IES, the model would assume default values for location, that is Boston (and not Los Angeles, the location given when creating the digital model.) As indicated in table 9.1 below, all the three file formats are able to carry over geometric information and material thicknesses. DXF was unable to carry the building “zone” definition and the gbXML file scored better in comparison with the IFC in that it was able to carry building type and location. 101 DXF IFC GbXML Drawing units yes no yes “Zone” definition no yes yes Geometry Shape yes yes yes Area yes yes yes Volume yes yes yes Building type no no yes Location no no yes Building Services no no no Building Materials no no no Material Thicknesses yes yes yes Table 9.1 Comparison of the information carried by the interoperable file formats. One of the key reasons for selecting Revit MEP and IES<VE> for the study was that they have the same calculation engine, and hence, one expected them to have comparable results. The discrepancy in results between Revit/IES and Ecotect had been expected, because of different load calculation techniques, calculation engines and discrepancy in materials and their associated values found in the programs. One found that the results between Revit MEP and IES were comparable, but not as close as might have been expected. The same Revit model gave different results when calculations were run in MEP and in IES. (Row B and C)Also, results 102 for the exported model should have been comparable to the new building modeled in IES. (Row C and D) Cooling Loads Heating Loads Annual Totals ECOTECT A 4964.9 Btu/hr 2759.7 Btu/hr 8828488 Btu Revit MEP Within the Revit engine B 5551.8 Btu/h 2268.9 Btu/h IES Apache engine C 5882 Btu/h 3237 Btu/h 10.764 MMBtu IES<VE> D 5181 Btu/h 2496 Btu/h 10.495 MMBtu Table 9.2: Comparison of loads in the three programs. At present, Revit MEP transfers only the model geometry to IES<VE> for analysis. No information about building materials or associated parameters that are defined in the model is transferred over. In effect, apart from geometry, what is modeled in the program has no bearing upon the analysis. Obviously, better integration of the building model and the analytical model is required. In an ideal BIM system, information required for an analysis should defined in the model itself and then eventually be transferred to the analytical model. 9.1.2 The Template file: The system family template and standard component families were an attempt to address this gap and create a “patch” between the building model and the analytical model. The user is able to model a building with the same material that one was doing an analysis for. Chapter 8 contains a detail description of this. 103 The major role of the template file and families is an informative one; even though values for materials are defined in the type parameters for the building components, they are, in effect a description only and are not carried over, for analysis. However, the BIM model gets richer because data that is inherently used for analysis is now being displayed for evaluation in the building model. Also, it was established in the last section that using the template improves upon the accuracy of the model, even if only slightly so. The building material being modeled is more consistent, and closer to the real life building. However, there is not a large difference in results, after using the template, particularly in large buildings, primarily because the difference in results is due to increased surface area. A disadvantage that one faced whilst making the files was that the program, Revit does not allow building components such as walls, roofs and floors to be created in a project, as standard component families. For this reason, these components had to be defined as family types. The advantage was that they could be put together in a single file, thereby establishing their ease of transfer into a project. Host based components such as doors, windows and rooflights, had to be defined as separate families that could eventually be imported into a project. Apart from this, these family files (doors, windows, rooflights) have specific sizes designated to them. This means that if the user wants a separate size for a certain family, one has to manually alter the sizes in the type properties of that component. 104 9.2 Areas of future work: Interoperability between building information models and energy analysis programs is a vast area of study and future work can take several directions. These can include areas in BIM interoperability, interoperable file formats, testing procedures and the interoperable interface. BIM interoperability: The thesis started off with an overview of BIM, and narrowed its focus to interoperability with energy analysis programs. The BIM software selected for this particular study was Revit and energy analysis tools were IES and Ecotect. A future study in BIM could take a different program such as Graphisoft ArchiCAD and compare it with Revit in terms of performance and interoperability. Similarly, other programs could be used for energy analysis programs, such as Energy Plus, that is both IFC and gbXML compliant and would make for a useful study. BIM development. The background research in the thesis touched upon development of entity based and object based models. A further study in this direction could be one that provides a comparative analysis, the historical development as well as a theoretical framework for BIM, its definitions, capabilities and potentials. Embedded energy analysis tools. This study specifically looked at the incorporation of IES into Revit MEP.A further study could look at such embedded energy programs that are incorporated within other BIM software. 105 Interoperable file formats: This study looked at Interoperable file formats such as DXF, IFC and gbXML. At present, IFCs and gbXMLs are looked upon and promoted as international standards that facilitate data interoperability. In the area of interoperability, these are the critical components that ensure seamless interoperability. Future work in this direction can include an in depth study of data organization within the IFC files and gbXML files and their file structure. A comparative analysis of IFC‟s and gbXML‟s using a case study, would prove to be a useful study. A study that shows what information is carried by IFC‟s and its subsequent versions, starting from IFC 1.1 (released in 1997)to IFC 2x2, the seventh version, has potential to show the direction in which interoperable file formats are being developed. Test studies for the file formats: The test case used for this study was a simple room model, with minimal values assigned to it. The reason was that one wanted the simplest case scenario, where one could test interoperability. Further studies could use larger and more complex building models and analysis of data transfer in them. This could also lead to a comparison with smaller building models, such as the base case room, and an analysis of data loss that occurs in more complex models. Testing building components for information transfer. A Revit BIM model is composed up of building elements such as roofs, walls, floors, ceilings, curtain panels, lighting fixtures and so on. Each building element is made up of several components, as listed out in Appendix D. For example, a ceiling may contain 106 its common edges, cut pattern, finish, hidden lines, membrane layers, structure, substrate, surface pattern and thermal/air layer. When this information is carried across, in an IFC file, it gets stored in a specific IFC class. For example, a ceiling and its components may get stored in IfcCeiling, or a certain mass form may get stored as IfcBuildingElementproxy. During data transfer, some building elements, their components or even an IFC class may not get transferred. Further research could look into this direction and test building models in varying scales to check data loss. Testing the template for accuracy. The building template in this thesis developed from the idea of creating a “patch” between the building model and analytical model. One of the underlying assumptions was that with the template, the user models exactly what one is doing an analysis for, and therefore, improves upon the accuracy of the result. This thesis has not tested whether the template is indeed more accurate. Various case study models of varying sizes could be tested in both MEP and IES to verify if the template model was getting more accurate. Testing the usefulness of the template. Another assumption underlying the building template was that it would be more useful, not only because it would be more accurate but also because it would be informative. Strategies to test this would make a better case for the template. Exploring parameters in BIM . 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Appendix A: Ecotect import and export capabilities: Imports: General Data Files: Imports Geometry: DXF *.DXF DXF Point Cloud *.DXF IFF to 3D *.IFF IFF to DEM *.IFF Imagine *.IOB Lightscape *.LP Lightwave *.LWO Maya RTG *.RTG MaxNC Digital probe *.TXT MicroDEM *.DEM Open Inventor *.IV RealiMation *.RBS Renderware *.RWX Scenery animator *.LAND ASCII Model Files *.MOD Analysis grid Data Files *.GRD Ray/Particle Data Files *.RAY Weather data files *.WEA Radiance Point Value data *.DAT Radiance Scene Files *.RAD EnergyPlus Input data File *.IDF Energy Plus Model summary *.EIO AutoCAD DXF Files *.DXF Green Building XML *.XML Stereo lithography file *.STL HPGL Plot Files *.PLT, *.HGL Material Library Files *.LIB CFD Output Data File Windows Bitmap *.BMP 113 Appendix A, continued. Sculpt *.SCENE Shopbot Digital Probe *.SBP SoftimageXSI *.XSI StereoLithography *.STL trueSpace *.COB, *.COA USGS GTOPO30/SRTM30 *.DEM USGS 1 degree DEM *.DEM USGS SDTS *.DDF USGS SRTM-1/SRTM-3 *.HGT Videoscape *.GEO VistaPro *.DEM VRML *.WRL Wavefront *.OBJ X3D *.X3D XGL, ZGL *.XGL,*.ZGL XYZ *.XYZ Exports: ASCII Model Files *.MOD Radiance scene Files *.RAD Radiance Octree Files *.OCT POV Ray Scene files *.POV VRML Scene files *.WRL Radiance Scene Files *.RAD AutoCAD DXF Files *.DXF EnergyPlus Input data File *.IDF DOE-2 Input Files *.INP SBEM Input Files *.INP AIOLOS Input Files *.PPA HTB2 Files *.TOP Accurate Scratch file *.LIB ESP-r input File *.CFG Ray/Particle data files *.RAY Analysis grid data files *.GRD 114 Appendix A, continued. WinAir4 CFD Geometry File *.GEO NIST FDS Input data File *.data Windows metafile *.WMF Windows bitmap *.BMP 115 Appendix B: Load Results for Ecotect, MEP and IES<VE> Load reports for MEP model within the MEP engine. Loads Report Summary Powered by Project Information Project: Los Angeles Room Run Time: 2/26/2008 11:11 AM Address: Latitude: 34° 01' 48" Longitude: 118° 08' 35" Building Analytical Area: 216 SF Building Analytical Volume: 1728.00 CF Room Summary Name Area Airflow Cooling Load (Total) Heating Load (Total) 3 Room 216 SF 243 CFM 5551.8 Btu/h 2268.9 Btu/h Totals 216 SF 243 CFM 5551.8 Btu/h 2268.9 Btu/h 116 Appendix B, continued. Loads Report: 3 Room Powered by Project Information Project: Los Angeles Room Run Time: 2/26/2008 11:11 AM Input Data Room Data Electrical Data Analytical Floor Area: 216 SF Lighting Load: 1.10 W/ft² Analytical Roof Area: 216 SF Equipment Load: 0.00 W/ft² Analytical Wall Area: 456 SF Misc. Load: 1.00 W/ft² Analytical Window Area: 24 SF People Loads Analytical Volume: 1728.00 CF People: 1.73 Area / Person 125 SF Sensible / Person: 250.0 Btu/h Latent / Person: 200.0 Btu/h Load Data Cooling Loads Heating Loads Sensible Cooling Load: 5252.9 Btu/h Sensible Heating Load: 2268.9 Btu/h Latent Cooling Load: 298.9 Btu/h Latent Heating Load: 0.0 Btu/h Total Cooling Load: 5551.8 Btu/h Total Heating Load: 2268.9 Btu/h Airflows Flow Rate: 243 CFM Flow Density: 1.13 Air Changes: 8.45 117 Appendix B, continued. Load reports for MEP model in the IES Engine. <ApacheSim calculations.> 1. Simulation: "SAMPLE~1.aps" 1.1 Building systems energy summary 1.2 Building systems carbon dioxide summary 1.3 Peak hourly room loads 1.4 Room environmental conditions (while occupied) 1.5 Room environmental conditions (whole day) 1. Simulation: "SAMPLE~1.aps" Model Data Simulation File Data Project file: "SampleModel.mit" Climate file name = 'LosAngelesTMY2..fwt' Total conditioned floor area = 216.0 ft² Simulation results file: "c:\..\Vista\SAMPLE~1.aps" Total conditioned volume = 1728.0 ft³ Calculated at 18:35 on 30/Mar/08 Number of rooms = 1 Calc. Period: 01/Jan - 31/Dec 1.1 Building systems energy summary Energy totals in MMBtu Month Heating (boilers etc.) Cooling (chillers etc.) Fans, pumps and controls Lights Equip. Jan 0.164 0.038 0.378 0.251 0.228 Feb 0.118 0.038 0.332 0.227 0.206 Mar 0.091 0.036 0.340 0.251 0.228 Apr 0.032 0.052 0.272 0.243 0.221 May 0.008 0.061 0.244 0.251 0.228 Jun 0.000 0.081 0.225 0.243 0.221 Jul 0.000 0.151 0.260 0.251 0.228 Aug 0.000 0.196 0.279 0.251 0.228 Sep 0.000 0.184 0.267 0.243 0.221 118 Appendix B, continued. Oct 0.000 0.154 0.261 0.251 0.228 Nov 0.005 0.100 0.252 0.243 0.221 Dec 0.089 0.064 0.341 0.251 0.228 Total 0.508 1.156 3.450 2.959 2.690 Total energy consumption = 10.764 MMBtu 1.2 Building systems carbon dioxide summary Carbon dioxide totals in lbCO 2 Month System (boilers, chillers, fans, pumps etc.) Lights Equip. Jan 134.2 68.5 62.3 Feb 115.6 61.9 56.3 Mar 114.0 68.5 62.3 Apr 92.4 66.3 60.3 May 84.1 68.5 62.3 Jun 83.5 66.3 60.3 Jul 112.2 68.5 62.3 Aug 129.5 68.5 62.3 Sep 123.0 66.3 60.3 Oct 113.0 68.5 62.3 Nov 96.5 66.3 60.3 Dec 121.7 68.5 62.3 Total 1319.7 806.8 733.5 Total carbon dioxide emissions = 2860.0 lbCO 2 119 Appendix B, continued. 1.3 Peak hourly room loads Room Name Peak Room Conditioning Loads (Btu/h) Internal Gains (Btu/h) * Cooling Checks Sensible Heating Sensible Cooling Humidi- fication Dehumidi- fication (Btu/h·ft²) (cfm/ft²) 3 Room 1126 3335 4 730 1980 15.44 0.99 * Peak sensible cooling load and corresponding supply air flow requirement, assuming 14.4F delta-T and 0.0749lb/ft 3 air density. 1.4 Room environmental conditions (while occupied) Room Name Temperature (°F) Relative Humidity (%) PPD (%) Max Min Max Min Max Min 3 Room 75.0 70.2 70.6 16.2 20.1 5.0 1.5 Room environmental conditions (whole day) Room Name Temperature (°F) Relative Humidity (%) PPD (%) Max Min Max Min Max Min 3 Room 76.8 70.0 74.9 12.8 20.8 5.0 120 Appendix, continued. Load reports for MEP model in the IES Engine. <ASHRAE loads results.> 1. General Summary 2. System: VAVSingleDuct 2.1 Heating Loads 2.2 Cooling Loads and Airflow Rates 1. General Summary Model Data Heating Calculation Data Cooling Calculation Data Project file: "SampleModel.mit" Heating results file: "SAMPLE~1.htg" Cooling results file: "SAMPLE~1.clg" Total conditioned floor area = 216.0 ft² Calculated at 18:37 on 30/Mar/08 Calculated at 18:37 on 30/Mar/08 Total conditioned volume = 1728.0 ft³ Profile Evaluation Month: January Calc. Period: May - Sep Number of rooms = 1 2. System: VAVSingleDuct 2.1 Heating Loads System Heating Loads Room heating load (MBH) Outdoor air primary load (MBH) DHW (MBH) Plant load * Sensible Humidification Mech vent Aux vent Heating demand Plant load * (MBH) (Btu/h·ft²) 3.237 0.000 0.000 0.000 0.000 0.000 3.794 17.56 * includes pipe & duct heat losses Room Heating Plant Loads Room Name Air temp. (°F) Conduction gain (Btu/h) Ventilation sensible gain (Btu/h) Sens. load (Btu/h) DHW heating demand (Btu/h) External Internal Mech vent (outdoor air) Aux vent Infiltration Natural vent 3 Room 70.00 -2117 0 -968 0 -151 0 3237 0 121 Appendix B, continued. 2.2 Cooling Loads and Airflow Rates System Cooling Loads Peak Room cooling load (MBH) Outdoor air primary load (MBH) Peak plant load * (MBH) Engineering Checks Month Time Sensible Dehum. Mech vent sens. Mech vent lat. Aux vent sens. Aux vent lat. (Btu/h·ft²) (cfm/ft²) No. People Sep 13:30 5.882 0.000 0.000 0.000 0.000 0.000 6.013 27.84 1.29 1.73 * includes duct heat gains Room Cooling Plant Loads Room Name Peak Air temp. (°F) Plant load (Btu/h) Month Time Sensible Dehumidification Peak total 3 Room Sep 13:30 75.00 5882 0 5882 Room Sensible Cooling and Airflow Rates Room Name Peak Air Temp. (°F) Peak Space sensible (Btu/h) Airflow (cfm) Engineering Checks Month Time SADB Return (Btu/h·ft²) (cfm/ft²) No. People 3 Room Sep 13:30 55.00 75.00 5253 243 24.32 1.13 1.73 122 Appendix B, continued. Load reports in the IES Engine. <ApacheSim Calculations> 1. General Summary 2. System: VAVSingleDuct 2.1 Heating Loads 2.2 Cooling Loads and Airflow Rates 1. General Summary Model Data Heating Calculation Data Cooling Calculation Data Project file: "SampleModel.mit" Heating results file: "SAMPLE~1.htg" Cooling results file: "SAMPLE~1.clg" Total conditioned floor area = 216.0 ft² Calculated at 18:37 on 30/Mar/08 Calculated at 18:37 on 30/Mar/08 Total conditioned volume = 1728.0 ft³ Profile Evaluation Month: January Calc. Period: May - Sep Number of rooms = 1 2. System: VAVSingleDuct 2.1 Heating Loads System Heating Loads Room heating load (MBH) Outdoor air primary load (MBH) DHW (MBH) Plant load * Sensible Humidification Mech vent Aux vent Heating demand Plant load * (MBH) (Btu/h·ft²) 3.237 0.000 0.000 0.000 0.000 0.000 3.794 17.56 * includes pipe & duct heat losses 123 Appendix B, continued. Room Heating Plant Loads Room Name Air temp. (°F) Conduction gain (Btu/h) Ventilation sensible gain (Btu/h) Sens. load (Btu/h) DHW heating demand (Btu/h) External Internal Mech vent (outdoor air) Aux vent Infiltration Natural vent 3 Room 70.00 -2117 0 -968 0 -151 0 3237 0 2.2 Cooling Loads and Airflow Rates System Cooling Loads Peak Room cooling load (MBH) Outdoor air primary load (MBH) Peak plant load * (MBH) Engineering Checks Month Time Sensible Dehum. Mech vent sens. Mech vent lat. Aux vent sens. Aux vent lat. (Btu/h·ft²) (cfm/ft²) No. People Sep 13:30 5.882 0.000 0.000 0.000 0.000 0.000 6.013 27.84 1.29 1.73 * includes duct heat gains Room Cooling Plant Loads Room Name Peak Air temp. (°F) Plant load (Btu/h) Month Time Sensible Dehumidification Peak total 3 Room Sep 13:30 75.00 5882 0 5882 Room Sensible Cooling and Airflow Rates Room Name Peak Air Temp. (°F) Peak Space sensible (Btu/h) Airflow (cfm) Engineering Checks Month Time SADB Return (Btu/h·ft²) (cfm/ft²) No. People 3 Room Sep 13:30 55.00 75.00 5253 243 24.32 1.13 1.73 124 Appendix B, continued. Load reports in the IES Engine. <ASHRAE Loads Results> 1. General Summary 2. System: VAVSingleDuct 2.1 Heating Loads 2.2 Cooling Loads and Airflow Rates 1. General Summary Model Data Heating Calculation Data Cooling Calculation Data Project file: "SampleModel.mit" Heating results file: "SAMPLE~1.htg" Cooling results file: "SAMPLE~1.clg" Total conditioned floor area = 216.0 ft² Calculated at 18:37 on 30/Mar/08 Calculated at 18:37 on 30/Mar/08 Total conditioned volume = 1728.0 ft³ Profile Evaluation Month: January Calc. Period: May - Sep Number of rooms = 1 2. System: VAVSingleDuct 2.1 Heating Loads System Heating Loads Room heating load (MBH) Outdoor air primary load (MBH) DHW (MBH) Plant load * Sensible Humidification Mech vent Aux vent Heating demand Plant load * (MBH) (Btu/h·ft²) 3.237 0.000 0.000 0.000 0.000 0.000 3.794 17.56 * includes pipe & duct heat losses Room Heating Plant Loads Room Name Air temp. (°F) Conduction gain (Btu/h) Ventilation sensible gain (Btu/h) Sens. load (Btu/h) DHW heating demand (Btu/h) External Internal Mech vent (outdoor air) Aux vent Infiltration Natural vent 3 Room 70.00 -2117 0 -968 0 -151 0 3237 0 Appendix B Continued. 125 Appendix B, continued. 2.2 Cooling Loads and Airflow Rates System Cooling Loads Peak Room cooling load (MBH) Outdoor air primary load (MBH) Peak plant load * (MBH) Engineering Checks Month Time Sensible Dehum. Mech vent sens. Mech vent lat. Aux vent sens. Aux vent lat. (Btu/h·ft²) (cfm/ft²) No. People Sep 13:30 5.882 0.000 0.000 0.000 0.000 0.000 6.013 27.84 1.29 1.73 * includes duct heat gains Room Cooling Plant Loads Room Name Peak Air temp. (°F) Plant load (Btu/h) Month Time Sensible Dehumidification Peak total 3 Room Sep 13:30 75.00 5882 0 5882 Room Sensible Cooling and Airflow Rates Room Name Peak Air Temp. (°F) Peak Space sensible (Btu/h) Airflow (cfm) Engineering Checks Month Time SADB Return (Btu/h·ft²) (cfm/ft²) No. People 3 Room Sep 13:30 55.00 75.00 5253 243 24.32 1.13 1.73 126 Appendix C: Categories of building elements carried by the IFC file and its classes. Category Includes IFC Class name Ceiling Common edges, cut pattern, finish, hidden lines, membrane layers, structure, substrate, surface pattern, thermal/air Layer IfcCovering Columns IfcColumn Curtain Panels Glass, hidden lines, curtain wall mullions IfcCurtainWall Doors Frame/Mullion, Elevation swing, Glass, hidden lines, opening, panel, plan swing IfcDoor Electrical equipment and fixtures IfcBuildingElementProxy Entourage IfcBuildingElemenproxy Floors Analytical model, common edges, cut pattern, finish, hidden lines, interior edges, membrane layer, slab edges, structure, substrate, surface pattern, thermal/air layer IfcFloor Lighting fixtures IfcBuildingElementProxy Massing IfcBuildingElementProxy Mechanical equipment IfcBuildingElementProxy Roofs Common edges, curtain roof grids, cut pattern, fascias, finish, gutters, hidden lines, interior edges, membrane layer, roof soffit, structure, substrate, surface pattern, thermal/air layer. IfcRoof 127 Appendix C, continued. Site Hidden lines, landscape, pads, property, property lines, stripe, utilities Speciality Equipment IfcBuildingElementProxy Stairs Down arrow, down text, hidden lines, incomplete stairs, stairs beyond cut line, stringers, stringers beyond cut line, up arrow, up text. IfcStair. Structural Columns Analytical model, hidden line, hidden faces, rigid links, stick symbols. Structural Foundations Analytical model, hidden lines. IfcBuildingElementproxy Structural Framing Analytical model, chord, girder, hidden faces, hidden lines, horizontal bracing, joist, kicker bracing, other, purlin, rigid links, stick symbols, vertical bracing, web. IfcBuildingElementproxy Topography Boundary point, hidden lines, interior point, primary contours, secondary contours, triangulation edges. IfcBuildingElementProxy Walls Analytical model, common edges, curtain wall grids, cut pattern, finishes, hidden lines, membrane layer, structure, substrate, surface pattern, thermal/air layer, wall sweeps. IfcWall. Windows Elevation swing, frame/mullion, glass, hidden lines, opening, plan swing, sill/head, trim, trim projection. IfcWindow. 128 Appendix D: Construction assignments in the Revit MEP-IES Interface. (Family files defined in the template file) Exterior Walls: Standard Wall Construction (2002 UK regulations) (U=0.0616) Standard Wall Construction (2002 UK Regulations Scotland) (U=0.527) Standard Wall Construction (Insulated to 1995 UK Regulations) (U=0.0699) Brick/Block Wall (U=0.0774) Timber Frame Wall (U=0.0791) Lightweight Curtain Wall (Insulated to 1995 UK Regulations) (U=0.0796) Metal Clad Wall (Insulated to 1995 UK Regulations) (U=0.0801) Brick/Block Wall (Insulated to 1985 UK Regulations) (U=0.0903) Lightweight Concrete Clad Wall (Insulated to 1985 UK Regulations) (U=0.0959) Brickwork Single Leaf Construction Dense Plaster (U=0.3846) Brickwork Single Leaf Construction Light Plaster (U=0.3432) Brickwork Single Leaf Construction with Insulation and Plaster (U=0.1184) Brickwork Single Leaf Construction Fiber Insulation and render (U=0.1297) Brickwork Single Leaf Construction EPS Insulation and render (U=0.0986) Lightweight Concrete Block Air Gap and Plasterboard (U=0.1202) Lightweight Concrete Block GRP Insulation and Plasterboard (U=0.0987) Lightweight Concrete Block Ploy-Insulation and Plasterboard (U=0.0771) Brick Cavity with Dense Plaster (U=0.2627) Brick Cavity with Mineral Insulation and Lightweight Plaster (U=0.1223) Brick Cavity Full Mineral Insulation and Lightweight Plaster (U=0.0892) Brick Cavity with UF Foam Insulation and Lightweight Plaster (U=0.1505) Brick Air H/W Concrete Block and Phenolic Foam and L/W Plaster (U=0.1417) Brick Air H/W Concrete Block and Full Mineral Insulation & L/W Plaster (U=0.0944) Brick Air M/W Concrete Block and UF Foam Insulation & L/W Plaster (U=0.0966) Brick-Air Thermolite Block and UF Insulation and L/W Plaster (U=0.0818) Brick-Air L/W Concrete Block and L/W Plaster (U=0.1627) Brick-Air UF Insulation L/W Concrete Block and L/W Plaster (U=0.1031) Brick Mineral Insulation Thermolite Block and L/W Plaster (U=0.0679) Un-Insulated Brick/Block Wall (U=0.2513) Super-insulated External Wall (U=0.0388) Sheet Steel (U=1.0358) Sheet Aluminum (U=1.0359) 4 In Face Brick, 2 In Insulation, and 4 In light Wt Concrete Block (U=0.0971) 4 In Light Weight Concrete (U=0.2009) 4 In Face Brick, Air Space and 8 In Common Brick (U=0.2131) 4 In Face Brick, Air Space and 8 In Heavy Wt Concrete Block (U=0.2509) 4 In Face Brick, Air Space and 8 In Light Wt Concrete Block (U=0.2036) 129 Appendix D, continued. 4 In Face Brick, Air Space and 8 In Clay Tile (U=0.1951) 4 In Face Brick, Air Space and 2 In Heavy Wt Concrete Block (U=0.3056) 4 In Face Brick, Air Space and 4 In Common Brick (U=0.2565) 4 In Face Brick, Air Space and 4 In Heavy Wt Concrete Block (U=0.282) 4 In Face Brick, Air Space and 8 In Light Wt Concrete Block (U=0.2163) 12 In Heavy Weight Concrete Block (U=0.3517) 8 In Heavy Weight Concrete with 2 In Insulation (U=0.1085) 8 In Heavy Weight Concrete with 1 In Insulation (U=0.1705) 8 In Heavy Weight Concrete with Air Space (U=0.2831) 8 In Heavy Weight Concrete (U=0.3984) 4 In Face Brick, 8 In Common Brick with 1 In Insulation (U=0.1425) 4 In Face Brick, 8 In Common Brick with Air Space (U=0.2134) 4 In Face Brick, Air Space and 4 In Lightweight Block (U=0.1738) Wall with 3 In Fiberglass Insulation and Stucco Outside Finish (U=0.0879) Two-Sided Brick Wall with Air Space (U=0.3504) Brick Wall, 8 In Concrete Block and no Air Space (U=0.217) Brick Wall with 4 In Concrete Block (U=0.3295) Brick Wall with 8 In Concrete Block (U=0.2877) Brick Wall with 6 In Concrete (U=0.2053) Frame Wall with 2 In Insulation and 4 In Brick Veneer (U=0.1208) Frame Wall with 2 In Insulation (U=0.1247) Metal Curtain Wall with 3 In Insulation (U=0.0904) Metal Curtain Wall with 2 In Insulation (U=0.1297) Metal Curtain Wall with 1 In Insulation (U=0.2295) Wall 12 In Concrete with 2 In Insulation On the outside (U=0.1128) Wall 8 In Concrete with 2 In Insulation On the outside (U=0.1172) Wall 12 In Concrete with 2 In Insulation On the outside (U=0.1128) Wall 4 In Concrete with 2 In Insulation On the outside (U=0.1220) Wall 12 In Concrete with 2 In Insulation On the inside (U=0.113) Wall 8 In Concrete with 2 In Insulation On the inside (U=0.1174) Wall 4 In Concrete with 2 In Insulation On the inside (U=0.1222) Frame Wall with 3 In Insulation (U=0.0773) Frame Wall with 2 In Insulation (U=0.1045) Frame Wall with 1 In Insulation (U=0.1608) Frame Wall without Insulation (U=0.349) 2 In Insulation with 12 In Heavy Weight Concrete (U=0.1047) 2 In Insulation with 8 In Heavy Weight Concrete (U=0.1085) 2 In Insulation with 8 In Common Brick (U=0.0986) 2 In Insulation with 8 In Heavy Weight Concrete (U=0.106) 2 In Insulation with 8 In Light Weight Concrete (U=0.0863) 2 In Insulation with 8 In Clay Tile (U=0.0946) 130 Appendix D, continued. 2 In Insulation with 4 In Heavy Weight Concrete (U=0.1126) 2 In Insulation with 4 In Common Brick (U=0.107) 2 In Insulation with 4 In Light Weight Concrete Block (U=0.1112) 2 In Insulation with 4 In Light Weight Concrete Block (U=0.0993) 2 In Insulation with 4 Clay Tile (U=0.1046) 4 In Face Brick, 2 In Insulation and 12 In Heavy Weight Concrete (U=0.1022) 4 In Face Brick, 2 In Insulation and 8 In Heavy Weight Concrete (U=0.1058) 4 In Face Brick, 2 In Insulation and 8 In Common Brick (U=0.0964) 4 In Face Brick, Air Space and 12 In Heavy Weight Concrete (U=0.2439) 4 In Face Brick, Air Space and 8 In Heavy Weight Concrete (U=0.2656) 4 In Face Brick, 2 In Insulation and 8 In Heavy Weight Concrete Block (U=0.1035) 4 In Face Brick, 2 In Insulation and 8 In Light Weight Concrete Block (U=0.0944) 2 In Face Brick, 2 In Insulation and 8 In Clay Tile (U=0.0925) 4 In Face Brick, 2 In Insulation and 4 In Heavy Weight Concrete Block (U=0.1097) 4 In Face Brick, 2 In Insulation and 4 In Common Brick (U=0.1044) 4 In Face Brick, 2 In Insulation and 4 In Heavy Weight Concrete Block (U=0.1084) 4 In Face Brick, with 8 In Common Brick (U=0.273) 8 In Heavy Weight Concrete Block with 1 In Insulation (U=0.1645) 8 In Heavy Weight Concrete Block (U=0.3671) 8 In Light Weight Concrete Block with Insulation (U=0.2741) 8 In Light Weight Concrete Block (U=0.1428) 4 In Face Brick, 8 In Clay Tile and 1 In Insulation (U=0.0925) 4 In Face Brick, 8 In Clay Tile and Air Space (U=0.1953) 4 In Face Brick with 8 In Clay Tile (U=0.2441) 8 In Clay Tile with 1 In Insulation (U=0.1385) 8 In Clay Tile with Air Space (U=0.2047) 8 In Clay Tile (U=0.2588) 4 In Heavy Weight Concrete with 2 In Insulation (U=0.1126) 4 In Heavy Weight Concrete with 1 In Insulation (U=0.1808) 4 In Heavy Weight Concrete with Air Space (U=0.3126) 4 In Heavy Weight Concrete (U=0.4594) 4 In Face Brick, 4 In Common Brick and 1 In Insulation (U=0.1607) 4 In Face Brick, 4 In Common Brick and Air Space (U=0.2569) 4 In Face Brick with 4 In Common Brick (U=0.3484) 4 In Common Brick (U=0.3793) 4 In Heavy Weight Concrete Block (U=0.4379) 4 In Face Brick, 4 In Light Wt Concrete Block and 1 In Insulation (U=0.1439) 4 In Face Brick, 4 In Light Wt Concrete Block and Air Space (U=0.2166) 4 In Face Brick with 4 In Light Weight Concrete Block (U=0.2782) 4 In Light Weight Concrete Block and 1 In Insulation (U=0.1489) 4 In Light Weight Concrete Block and Air Space (U=0.2281) 131 Appendix D, continued. 4 In Light Weight Concrete Block (U=0.2975) 4 In Face Brick, 4 In Clay Tile and 1 In Insulation (U=0.1553) 4 In Face Brick, 4 In Clay Tile and Air Space (U=0.2434) 4 In Face Brick and 4 In Clay Tile (U=0.3239) 4 In Clay Tile and 1 In Insulation (U=0.1611) 4 In Clay Tile and Air Space (U=0.2580) 4 In Clay Tile (U=0.3504) Sheet Metal with 1 In Insulation (U=0.1872) Sheet Metal with 2 In Insulation (U=0.115) Sheet Metal with 3 In Insulation (U=0.083) Interior Walls: 13 mm Lightweight Plaster 105 mm Brick 13 mm Lightweight Plaster (U=0.2976) 13 mm Lightweight Plaster 105 mm Brick 25 mm Air 105 mm Brick 13 mm Lightweight Plaster (U=0.1871) 13 mm Lightweight Plaster 100 mm Heavy Weight Concrete Block 13 mm Lightweight Plaster (U=0.364) 13 mm Lightweight Plaster 100 mm Medium Weight Concrete Block 13 mm Lightweight Plaster (U=0.2847) 13 mm Lightweight Plaster 100 mm Light Weight Concrete Block 13 mm Lightweight Plaster (U=0.1856) 25 mm Gyp. 100 mm Air Gyp. (U=0.234) 12mm Fiberboard 100 mm Air 12mm Fiberboard(U=0.2097) 115 mm Single-Leaf Brick (Plastered Both Sides) (U=0.3471) 230 mm Single-Leaf Brick (Plastered Both Sides) (U=0.2542) 360 mm Single-Leaf Brick (Plastered Both Sides) (U=0.1951) Solid Breeze Blocks (Plastered both sides) (U=0.2076) 115 mm Single-Leaf Brick (U=0.3953) 125 mm Single-Leaf Brickwork (Plastered on one side) (U=0.3575) Aerated Concrete Blocks (U=0.2603) Hollow Concrete Blocks (U=0.224) Thermalite (U=0.1506) Glass Blocks (U=0.4372) 100 mm Reinforced Concrete (U=0.5314) 220 mm Medium Weight Concrete Block (U=0.2547) 500 mm Dense Concrete (U=0.2854) 25 mm Polysterene Faced with 3 mm Hardboard on 9 mm Plasterboard (U=0.1407) 13 mm Expanded-Wood Chipboard (U=0.508) 200 mm Block-Cavity Wall with 50mm Air Gap (Plastered) (U=0.2357) 132 Appendix D, continued. 200 mm Cast Concrete Cavity Wall with 50 mm Air Gap (Plastered) (U=0.2058) 115 mm Brick Cavity Wall With 50 mm Air Gap (U=0.2172) 115 mm Brick Cavity Wall with 12 mm Plaster Both sides (U=0.2029) 2x12 Plasterboard Leaves with 25 mm Glass wool in Cavity (U=0.1702) 9mm Plasterboard on 50x100 Studs at 400 Centers (U=0.3188) 13 mm Plasterboard on 50x100 Studs at 400 Centers (U=0.2923) 13 mm Plasterboard on Studs @400 with Mineral Fib Slab (U=0.1337) 6 mm Plywood on 50x50 Studs at 600 Centers (U=0.3387) 9 mm Plywood on 50x50 and 25x50 Studs @1200 Centers 50 Apart (U=0.3145) Asbestos Wallboard on 30 mm Timber Frame 200 mm Apart (U=0.3721) Solid Party Wall-Domestic (U=0.2566) Lightweight Party Wall-Domestic (U=0.2097) Lightweight Plasterboard Partition (U=0.2806) Solid partition (U=0.2053) 4 In Clay Tile with 0.75 In plaster (U=0.2603) 4 In Lightweight Concrete Block with 0.75 In plaster (U=0.2299) 4 In Heavy weight Concrete Block with 0.75 In plaster (U=0.3056) 4 In Common Brick with 0.75 In plaster (U=0.2758) 4 In Common Heavy weight Concrete with 0.75 In plaster (U=0.3159) 5 In Clay Tile with 0.75 in plaster (U=0.2442) 8 In Light weight Concrete block, Plastered both sides (U=0.1704) 8 In Heavy weight Concrete block, Plastered both sides (U=0.2693) 8 In Common brick, Plastered both sides (U=0.2263) 8 In Heavy concrete, Plastered both sides (U=0.2858) 12 In Heavy Concrete, plastered both sides (U=0.2609) 4 In Clay Tile (U=0.4021) 4 In Light weight Concrete Block (U=0.3339) 4 In Heavy weight Concrete Block (U=0.5217) 4 In Common brick (U=0.4405) 4 In Heavy Weight Concrete (U=0.5525) 8 In Clay Tile (U=0.286) 8 In Light weight concrete block (U=0.2216) 8 In Heavy weight concrete block (U=0.4242) 8 In Common brick (U=0.3264) 8 In Heavy Weight Concrete (U=0.4666) 12 In Heavy Weight Concrete (U=0.4038) Frame partition with 0.75 in gypsum board (U=0.2595) 1 In Wood (u=0.3748) 2 In Wood (u=0.259) 3 In Wood (u=0.1979) 4 In Wood (u=0.1602) 133 Appendix D, continued. Frame partition with 1 In Wood (U=0.2048) 2 In Furniture (U=0.1376) 3 In Furniture (U=0.1036) 2 In Heavy Weight Concrete (U=0.6086) Slabs: Standard Floor construction (2002 UK regulations) (U=0.044) Standard Floor construction (Insulated to 1995 UK regulations) (U=0.0716) Solid Ground Floor (Insulated to 1995 UK regulations) (U=0.0716) Suspended Timber Floor (Insulated to 1995 UK regulations) (U=0.0679) Solid Ground Floor-Industry (Insulated to 1995 UK regulations) (U=0.0719) Un-Insulated Solid Ground Floor (U=0.1243) Un-Insulated suspended Timber Floor (U=0.1106) Super-Insulated Floor (U=0.0485) Roofs: Flat roof (2002 UK Regulations) (U=0.044) Flat roof (Insulated to 1995 UK Regulations) (U=0.0401) Sloping Roof Including Loft (2002 UK regulations) (U=0.028) Sloping Roof Including Loft (Insulated to 1995 UK regulations) (U=0.041) Lightweight Curtain Roof (2002 UK regulations) (U=0.0438) Lightweight Curtain roof (Insulated to 1995 UK regulations) (U=0.0421) Flat Roof (Insulated to 1985 UK Regulations) (U=0.0561) Sloping roof-domestic (U=0.5948) Un insulated Flat Roof (U=0.2744) 19mm Asphalt 75mm Screed 150mm cast Concrete (Dense) 13mm Plaster (Dense) (U=0.3564) 19mm Asphalt 150 mm Aerated concrete Slab 13mm Plaster (Dense) (U=0.1543) 25mm Stone Chipping 19mm Asphalt 40mm Screed 150mm Concrete Block(heavy) (U=0.4474) 25mm Stone Chipping 19mm Asphalt 40mm Screed 150mm Concrete Block(light) (U=0.1614) 19mm Asphalt 13mm Fiberboard 10mm Aced (U=0.2794) 19mm Asphalt 13mm Fiberboard 25mm Air 10mm Gyp (U=0.2326) 19mm Asphalt 13mm Fiberboard 25mm Air 25mm Batt 10mm gyp. (U=0.1395) 19mm Asphalt 13mm Fiberboard 25mm Air 50mm Batt 10mm gyp. (U=0.0933) 19mm Asphalt 13mm Fiberboard 25mm Air 75mm Batt 10mm gyp. (U=0.0701) 134 Appendix D, continued. 19mm Asphalt 13mm Fiberboard 25mm EPS Slab 25mm Air 10mm gyp. (U=0.1303) 19mm Asphalt 13mm Fiberboard 50mm EPS Slab 25mm Air 10mm gyp. (U=0.0853) 19mm Asphalt 13mm Screed 50mm wood wool Slab 25mm Air 10mm gyp. (U=0.185) 19mm felt/bitumen 25mm EPS slab 3mm metal deck (U=0.1973) Super insulated Flat Roof (U=0.0312) Roof Terrace System (U=0.0827) 4 In wood with 2 In insulation (U=0.0649) 2.5 In Wood with 2 In Insulation (U=0.1188) 4 In Wood with 2 In Insulation (U=0.1509) 4 In Wood with 1 In Insulation (U=0.0831) 2.5 In Wood with 1 In Insulation (U=0.0975) 1 In Wood with 1 In Insulation (U=0.1181) 8 In Light weight Concrete (U=0.0944) 6 In Light weight Concrete (U=0.1121) 4 In Light weight Concrete (U=0.1379) 6 In Heavy weight Concrete with 2 In Insulation (U=0.0899) 4 In Heavy weight Concrete with 2 In Insulation (U=0.0912) 2 In Heavy weight Concrete with 2 In Insulation (U=0.0927) 6 In Heavy weight Concrete with 1 In Insulation (U=0.1286) 4 In Heavy weight Concrete with 1 In Insulation (U=0.1315) 2 In Heavy weight Concrete with 1 In Insulation (U=0.1344) Steel Sheet with 2 In Insulation (U=0.0941) Steel Sheet with 1 In Insulation (U=0.0941) Roof terrace system (U=0.2435) 4 In Wood with 2 In Insulation (U=0.0794) 2.5 In Wood with 2 In Insulation (U=0.0925) 1 In Wood with 2 In Insulation (U=0.1109) 4 In Wood with 1 In Insulation (U=0.1082) 2.5 In Wood with 1 In Insulation (U=0.1342) 1 In Wood with 1 In Insulation (U=0.1765) 8 In Light Weight Concrete (U=0.1284) 6 In Light Weight Concrete (U=0.1634) 4 In Light Weight Concrete (U=0.2245) 6 In Heavy weight Concrete with 2 In Insulation (U=0.1201) 4 In Heavy weight Concrete with 2 In Insulation (U=0.1225) 2 In Heavy weight Concrete with 2 In Insulation (U=0.1251) 6 In Heavy weight Concrete with 1 In Insulation (U=0.2011) 4 In Heavy weight Concrete with 1 In Insulation (U=0.2081) 135 Appendix D, continued. 2 In Heavy weight Concrete with 1 In Insulation (U=0.2155) Steel Sheet with 2 In Insulation (U=0.1278) Steel Sheet with 1 In Insulation (U=0.2236) Floors: Carpeted 100mm reinforced concrete ceiling(U=0.402) 200mm reinforced concrete ceiling (U=0.5137) 126mm reinforced concrete ceiling (Upper floor screeded)(U=0.4275) 130 mm concrete ceiling (U=0.6013) 130 mm concrete ceiling (50mm floating screed on upper floor) (U=0.4246) 12mm plaster ceiling with TG boards on 400 joist centers (U=0.2981) 12mm plaster ceiling with TG boards with 25mm glass wool on joists (U=0.1449) 300mm reinforced concrete ceiling (U=0.4251) Ceiling 50mm screed 150mm cast concrete (U=0.3873) Ceiling 25mm wood blocks 50 screed 150mm cast concrete (U=0.2781) Ceiling 12mm Wilton carpet 12mm cellular rubber underlay 50mm screed 150mm cast concrete (U=0.2273) Ceiling 25mm wood blocks 65mm cast concrete 25mm air 25mm batt 16mm gyp (U=0.1313) Ceiling 25mm wood blocks 65mm cast concrete 25mm air 25mm batt 2mm metal deck tray (U=0.1419) Ceiling 10mm timber flooring 200mm air 16mm gyp (U=0.3194) Ceiling 10mm timber flooring 200mm air 25mm batt 16mm gyp (U=0.1497) Ceiling 10mm timber flooring 25mm air 25mm batt 2mm metal deck tray (U=0.1636) Loft floor to 85 regulations- domestic (U=0.0633) Loft floor to 90 regulations- domestic (U=0.0437) Concrete slab internal ceiling (U=0.1882) Timber joist internal ceiling (U=0.2216) Timber joist internal ceiling-Industry (U=0.2805) 2 in heavy weight concrete floor deck (U=0.7678) 4 in heavy weight concrete floor deck (U=0.6807) 2 in light weight concrete floor deck (U=0.66) 8 in heavy weight concrete floor deck (U=0.5547) 8 in light weight concrete floor deck (U=0.2397) 2 in wood deck (U=0.2841) 3 in wood deck (U=0.2122) 2 in heavy weight concrete deck with false ceiling (U=0.2488) 4 in heavy weight concrete deck with false ceiling (U=0.2342) 4 in light weight concrete deck with false ceiling (U=0.1833) 136 Appendix D, continued. 8 in heavy weight concrete deck with false ceiling (U=0.2173) 8 in light weight concrete deck with false ceiling (U=0.1434) 2 in wood deck with false ceiling (U=0.1582) 3 in wood deck with false ceiling (U=0.1331) 12 in heavy weight concrete deck with false ceiling (U=0.2026) 4 in wood deck with false ceiling (U=0.1149) Steel deck with false ceiling (U=0.2541) Doors: Wooden Door(U=0.3865) Metal door(U=0.652) Timber flush panel hollow core door (normally hung) (U=0.4096) Solid hardwood door (normally hung) (U=0.4503) Exterior Windows: Low e double glazing (6mm+6mm) (2002 regulations) (U=0.3842) 4mm Pilkington single glazing (U=0.9747) 6mm Pilkington single glazing (U=0.9795) 10mm Pilkington single glazing (U=0.9733) 12mm Pilkington single glazing (U=0.9222) 4mm single panes with 7mm cavity (U=0.5656) 10mm single pane with 5mm cavity (U=0.4665) 6mm single panes with 10mm cavity(U=0.4646) Pilkington Rw33 double glazing (6mm+6mm) (U=0.5031) Pilkington Rw36 double glazing (10mm+4mm) (U=0.5031) Pilkington Rw38 double glazing (10mm+6mm) (U=0.5031) 4mm single glass pane in unsealed openable frames (U=0.8507) 6mm single glass pane in heavy frame (U=0.8212) 10mm single glass pane in heavy frame (U=0.8207) Double glazing-domestic (U=0.5031) Low e double glazing –Domestic (U=0.3648) Small single-glazed windows (U=0.921) Small double glazed windows (U=0.5583) Small double glazed windows- low e coating(U=0.4127) Large single-glazed windows (U=0.9795) Large double glazed windows- absorbing coating (U=0.5141) Large double glazed windows- reflective coating (U=0.5141) Large double glazed windows- (reflective coating)-industry (U=0.5141) Single glazed windows-domestic(U=0.8505) Clear element(all solar gain transmitted) (U=1.0026) 137 Appendix D, continued. Interior Windows: Low e double glazing (6mm+6mm) (2002 regulations) (U=0.2949) 4mm Pilkington single glazing (U=0.6496) 6mm Pilkington single glazing (U=0.6498) 10mm Pilkington single glazing (U=0.65) 12mm Pilkington single glazing (U=0.6501) 4mm single panes with 7mm cavity (U=0.4383) 10mm single pane with 5mm cavity (U=0.3761) 6mm single panes with 10mm cavity(U=0.3761) Pilkington Rw33 double glazing (6mm+6mm) (U=0.3996) Pilkington Rw36 double glazing (10mm+4mm) (U=0.3996) Pilkington Rw38 double glazing (10mm+6mm) (U=0.3996) 4mm single glass pane in unsealed openable frames (U=0.5806) 6mm single glass pane in heavy frame (U=0.5621) 10mm single glass pane in heavy frame (U=0.5627) Double glazing-domestic (U=0.3995) Low e double glazing –Domestic (U=0.3057) Small single-glazed windows (U=0.6219) Small double glazed windows (U=0.4335) Small double glazed windows- low e coating(U=0.3333) Large single-glazed windows (U=0.6498) Large double glazed windows- absorbing coating (U=0.4073) Large double glazed windows- reflective coating (U=0.4073) Large double glazed windows- (reflective coating)-industry (U=0.4073) Single glazed windows-domestic(U=0.5809) Air partition (U=0.6629) Skylights: Low e double glazing (6mm+6mm) (2002 regulations) (U=0.3704) Polycarbonate double glazed roof lights (U=0.6569) 4mm Pilkington single glazing (U=1.1811) 6mm Pilkington single glazing (U=1.1803) 10mm Pilkington single glazing (U=1.1796) 12mm Pilkington single glazing (U=1.0994) 4mm single panes with 7mm cavity (U=0.6259) 10mm single pane with 5mm cavity (U=0.5063) 6mm single panes with 10mm cavity(U=0.5043) Pilkington Rw33 double glazing (6mm+6mm) (U=0.551) Pilkington Rw36 double glazing (10mm+4mm) (U=0.551) Pilkington Rw38 double glazing (10mm+6mm) (U=0.551) 138 Appendix D, continued. 4mm single glass pane in unsealed openable frames (U=1.10113) 6mm single glass pane in heavy frame (U=0.975) 10mm single glass pane in heavy frame (U=0.9727) Double glazing-domestic (U=0.5511) Low e double glazing –Domestic (U=0.39) Small single-glazed windows (U=1.0996) Small double glazed windows (U=0.6184) Small double glazed windows- low e coating(U=0.4498) Large single-glazed windows (U=1.1803) Large double glazed windows- absorbing coating (U=0.5628) Large double glazed windows- reflective coating (U=0.5628) Large double glazed windows- (reflective coating)-industry (U=0.5628) Single glazed windows-domestic(U=1.1012) 139 Appendix E: Values defined for various parameters in the Revit family template The following are samples of exterior walls, floors and roofs. Refer to the family template file „energyanalysistemplate.rte‟ for the complete list. Exterior Walls: Exterior Walls: Plan Section Emissivity (Outer& Inner) Resistanc e (Outer &Inner) Absorbt ance (Outer &Inner) Thermal bridging coeff. Standard Wall Construction (2002 UK regulations) (U=0.0616) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Standard Wall Construction (2002 UK Regulations Scotland) (U=0.0527) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Standard Wall Construction (Insulated to 1995 UK Regulations) (U=0.0699) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Brick/Block Wall (U=0.0774) 0.900 0.900 0.341 0.665 0.600 0.55 0.0062 Timber Frame Wall (U=0.0791) 0.900 0.900 0.341 0.665 0.600 0.55 0.0062 Lightweight Curtain Wall (Insulated to 1995 UK Regulations) (U=0.0796) 0.900 0.900 0.341 0.665 0.600 0.55 0.0062 140 Appendix E, continued. Metal Clad Wall (Insulated to 1995 UK Regulations) (U=0.0801) 0.900 0.900 0.341 0.665 0.600 0.55 0.0062 Brick/Block Wall (Insulated to 1985 UK Regulations) (U=0.0903) 0.900 0.900 0.341 0.665 0.600 0.55 0.0062 Lightweight Concrete Clad Wall (Insulated to 1985 UK Regulations) (U=0.0959) 0.900 0.900 0.341 0.665 0.500 0.550 0.0062 Brickwork Single Leaf Construction Dense Plaster (U=0.3846) 0.900 0.900 0.341 0.665 0.500 0.550 0.0062 Brickwork Single Leaf Construction Light Plaster (U=0.3432) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brickwork Single Leaf Construction with Insulation and Plaster (U=0.1184) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brickwork Single Leaf Construction Fiber Insulation and render (U=0.1297) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brickwork Single Leaf Construction EPS Insulation and render (U=0.0986) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 141 Appendix E, continued. Lightweight Concrete Block Air Gap and Plasterboard (U=0.1202) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Lightweight Concrete Block GRP Insulation and Plasterboard (U=0.0987) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Lightweight Concrete Block Ploy-Insulation and Plasterboard (U=0.0771) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick Cavity with Dense Plaster (U=0.2627) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick Cavity with Mineral Insulation and Lightweight Plaster (U=0.1223) 0.900 0.900 0.341 0.665 0.700 0.550 Brick Cavity Full Mineral Insulation and Lightweight Plaster (U=0.0892) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick Cavity with UF Foam Insulation and Lightweight Plaster (U=0.1505) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick Air H/W Concrete Block and Full Mineral Insulation & L/W Plaster (U=0.0944) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 142 Appendix E, continued. Brick-Air Thermolite Block and UF Insulation and L/W Plaster (U=0.0818) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick-Air L/W Concrete Block and L/W Plaster (U=0.1627) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Brick-Air UF Insulation L/W Concrete Block and L/W Plaster (U=0.1031) 0.900 0.900 0.341 0.665 0.700 0.550 0.0062 Floors: Floors Section Emissivity (Outer& Inner) Resistance (Outer &Inner) Absorbtance (Outer &Inner) Carpeted 100mm reinforced concrete ceiling(U=0.402) 0.900 0.900 0.665 0.665 0.550 0.550 200mm reinforced concrete ceiling (U=0.5137) 0.900 0.900 0.665 0.665 0.550 0.550 126mm reinforced concrete ceiling (Upper floor screeded)(U=0.4275 ) 0.900 0.900 0.665 0.665 0.550 0.550 130 mm concrete ceiling (U=0.6013) 0.900 0.900 0.665 0.665 0.550 0.550 143 Appendix E, continued. 130 mm concrete ceiling (50mm floating screed on upper floor) (U=0.4246) 0.900 0.900 0.665 0.665 0.550 0.550 12mm plaster ceiling with TG boards on 400 joist centers (U=0.2981) 0.900 0.900 0.665 0.665 0.550 0.550 12mm plaster ceiling with TG boards with 25mm glass wool on joists (U=0.1449) 0.900 0.900 0.665 0.665 0.550 0.550 300mm reinforced concrete ceiling (U=0.4251) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 50mm screed 150mm cast concrete (U=0.3873) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 25mm wood blocks 50 screed 150mm cast concrete (U=0.2781) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 12mm Wilton carpet 12mm cellular rubber underlay 50mm screed 150mm cast concrete (U=0.2273) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 25mm wood blocks 65mm cast concrete 25mm air 25mm batt 16mm gyp (U=0.1313) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 25mm wood blocks 65mm cast concrete 25mm air 25mm batt 2mm metal deck tray (U=0.1419) 0.900 0.900 0.665 0.665 0.550 0.550 144 Appendix E, continued. Ceiling 10mm timber flooring 200mm air 16mm gyp (U=0.3194) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 10mm timber flooring 200mm air 25mm batt 16mm gyp (U=0.1497) 0.900 0.900 0.665 0.665 0.550 0.550 Ceiling 10mm timber flooring 25mm air 25mm batt 2mm metal deck tray (U=0.1636) 0.900 0.900 0.665 0.665 0.550 0.550 Loft floor to 85 regulations- domestic (U=0.0633) 0.900 0.900 0.665 0.665 0.550 0.550 Loft floor to 90 regulations- domestic (U=0.0437) 0.900 0.900 0.665 0.665 0.550 0.550 Concrete slab internal ceiling (U=0.1882) 0.900 0.900 0.665 0.665 0.550 0.550 Timber joist internal ceiling (U=0.2216) 0.900 0.900 0.665 0.665 0.550 0.550 Timber joist internal ceiling-Industry (U=0.2805) 0.900 0.900 0.665 0.665 0.550 0.550 2 in heavy weight concrete floor deck (U=0.7678) 0.900 0.900 0.665 0.665 0.550 0.550 145 Appendix E, continued. 4 in heavy weight concrete floor deck (U=0.6807) 0.900 0.900 0.665 0.665 0.550 0.550 2 in light weight concrete floor deck (U=0.66) 0.900 0.900 0.665 0.665 0.550 0.550 8 in heavy weight concrete floor deck (U=0.5547) 0.900 0.900 0.665 0.665 0.550 0.550 8 in light weight concrete floor deck (U=0.2397) 0.900 0.900 0.665 0.665 0.550 0.550 2 in wood deck (U=0.2841) 0.900 0.900 0.665 0.665 0.550 0.550 3 in wood deck (U=0.2122) 0.900 0.900 0.665 0.665 0.550 0.550 2 in heavy weight concrete deck with false ceiling (U=0.2488) 0.900 0.900 0.665 0.665 0.550 0.550 Roofs: Roofs Section Emissivity (Outer& Inner) Resistance (Outer &Inner) Absorbtan ce (Outer &Inner) Thermal bridging coef. Flat roof (2002 UK Regulations) (U=0.044) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 Flat roof (Insulated to 1995 UK Regulations) (U=0.0401) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 146 Appendix E, continued. Sloping Roof Including Loft (2002 UK regulations) (U=0.028) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 Sloping Roof Including Loft (Insulated to 1995 UK regulations) (U=0.041) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 Lightweight Curtain Roof (2002 UK regulations) (U=0.0438) 0.900 0.900 0.227 0.665 0.200 0.550 0.0062 Lightweight Curtain roof (Insulated to 1995 UK regulations) (U=0.0421) 0.900 0.900 0.227 0.665 0.200 0.550 0.0062 Flat Roof (Insulated to 1985 UK Regulations) (U=0.0561) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 Sloping roof- domestic (U=0.5948) 0.900 0.900 0.227 0.665 0.600 0.550 0.0062 Un insulated Flat Roof (U=0.2744) 0.900 0.900 0.227 0.665 0.500 0.550 0.0062 19mm Asphalt 75mm Screed 150mm cast Concrete (Dense) 13mm Plaster (Dense) (U=0.3564) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 150 mm Aerated concrete Slab 13mm Plaster (Dense) (U=0.1543) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 25mm Stone Chipping 19mm Asphalt 40mm Screed 150mm Concrete Block(heavy) (U=0.4474) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 147 Appendix E, continued. 25mm Stone Chipping 19mm Asphalt 40mm Screed 150mm Concrete Block(light) (U=0.1614) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 10mm Aced (U=0.2794) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 25mm Air 10mm Gyp (U=0.2326) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 25mm Air 50mm Batt 10mm gyp. (U=0.0933) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 25mm Air 75mm Batt 10mm gyp. (U=0.0701) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 25mm EPS Slab 25mm Air 10mm gyp. (U=0.1303) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Fiberboard 50mm EPS Slab 25mm Air 10mm gyp. (U=0.0853) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm Asphalt 13mm Screed 50mm wood wool Slab 25mm Air 10mm gyp. (U=0.185) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 19mm felt/bitumen 25mm EPS slab 3mm metal deck (U=0.1973) 0.900 0.900 0.227 0.665 0.700 0.550 0.0062 148 Appendix F: Values defined for various parameters in the Revit family files. The following are samples of exterior windows and doors. Refer to the family files „exwin.rfa‟, „inwin.rfa‟, „roof.rfa‟ and „door.rfa‟ for the complete list. Exterior Windows: Exterior Windows Exterior Windows Emissivity (Outer& Inner) Resistance (Outer &Inner) Frame Absorbtan ce Frame Resistance Thermal bridging coeff. Low e double glazing (6mm+6mm) (2002 regulations) (U=0.3842) 0.900 0.900 0.341 0.665 0.700 1.892 0.0062 4mm Pilkington single glazing (U=0.9747) 0.900 0.900 0.341 0.665 0.700 0.514 0.0062 6mm Pilkington single glazing (U=0.9795) 0.900 0.900 0.341 0.665 0.700 0.33 0.0062 10mm Pilkington single glazing (U=0.9733) 0.900 0.900 0.341 0.665 0.700 0.077 0.0062 12mm Pilkington single glazing (U=0.9222) 0.900 0.900 0.341 0.665 0.700 1.117 0.0062 4mm single panes with 7mm cavity (U=0.5656) 0.900 0.900 0.341 0.665 0.700 1.138 0.0062 10mm single pane with 5mm cavity (U=0.4665) 0.900 0.900 0.341 0.665 0.700 1.108 0.0062 6mm single panes with 10mm cavity(U=0.4646) 0.900 0.900 0.341 0.665 0.700 1.09 0.0062 Pilkington Rw33 double glazing (6mm+6mm) (U=0.5031) 0.900 0.900 0.341 0.665 0.700 1.02 0.0062 149 Appendix F, continued. Pilkington Rw36 double glazing (10mm+4mm) (U=0.5031) 0.900 0.900 0.341 0.665 0.700 1.02 0.0062 Pilkington Rw38 double glazing (10mm+6mm) (U=0.5031) 0.900 0.900 0.341 0.665 0.700 1.02 0.0062 4mm single glass pane in unsealed openable frames (U=0.8507) 0.900 0.900 0.341 0.665 0.700 0.956 0.0062 6mm single glass pane in heavy frame (U=0.8212) 0.900 0.900 0.341 0.665 0.700 1.242 0.0062 Doors: Doors Exterior Windows Emissivity (Outer& Inner) Resistance (Outer &Inner) Absorbtance( Outer &Inner) Thermal bridging coeff. Wooden Door(U=0.3865) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Metal door(U=0.652) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Timber flush panel hollow core door (normally hung) (U=0.4096) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062 Solid hardwood door (normally hung) (U=0.4503) 0.900 0.900 0.341 0.665 0.700 0.55 0.0062
Abstract (if available)
Abstract
Building information modeling (BIM) is projected as tomorrow 's technology
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University of Southern California Dissertations and Theses
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Asset Metadata
Creator
Kumar, Sumedha
(author)
Core Title
Interoperability between building information models (BIM) and energy analysis programs
School
School of Architecture
Degree
Master of Building Science
Degree Program
Building Science
Publication Date
04/23/2008
Defense Date
03/28/2008
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
BIM,interoperability,OAI-PMH Harvest
Language
English
Advisor
Kensek, Karen (
committee chair
), Knowles, Ralph (
committee member
), Schiler, Marc (
committee member
)
Creator Email
sumedhak@usc.edu
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-m1183
Unique identifier
UC1216340
Identifier
etd-Kumar-20080423 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-64743 (legacy record id),usctheses-m1183 (legacy record id)
Legacy Identifier
etd-Kumar-20080423.pdf
Dmrecord
64743
Document Type
Thesis
Rights
Kumar, Sumedha
Type
texts
Source
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Repository Name
Libraries, University of Southern California
Repository Location
Los Angeles, California
Repository Email
cisadmin@lib.usc.edu
Tags
BIM
interoperability