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· Be able to save, manipulate, scale, and reconfigure the object for use in future projects that have similar scopes of work. · Use the AHU (object) to design the ductwork, pipe, controls and electrical systems that will be needed to support the air-handling unit and make it work. · Export cost information stored in the BIM object about the unit and its components and connections to a third-party construction cost-estimating tool. · Export schedule information for use by a third-party construction management system to help develop the project construction schedule. · Interface the objects in the as-built model with a building automation system (BAS) and a computerized maintenance management system (CMMS). • Gather the relevant information from the appropriate sources such as manufacturers’ catalogs, codes, standards, etc. • Construct the object using the BIM tool’s UI, a stand-alone BIM object editor or other scripting language that can interface with the BIM authoring tool following the instructions provided by your software’s developer. • Apply the object to the BIM and test its usability and function inside the BIM. Also, test it with other analytic tools that will use the information associated with the object.Have another user audit the results and provide feedback on the utility of the object. • Make any enhancements or corrections identified to the object file before publishing it for use by others. Although this workflow seems simple, the act of creating a useful BIM object that is smart, flexible and can be used by many BIM tools and third-party analytic and diagnostic programs can be quite complex depending on the BIM tool being used, the information exchange formats required to make the object interoperable, the complexity of the object being created and the number of fixed and variable features and inputs required to make the object fit its intended purpose. An airhandling unit was chosen for this example because it is commonly one of the most customizable and highly configurable products an HVAC manufacturer produces. It’s a challenge to create a truly integrated and interoperable AHU BIM object that allows a typical user almost unlimited enumerations and configurations that would work across many BIM platforms and across many analytic platforms and operations and maintenance platforms throughout a facility’s life cycle. Luckily, it’s a challenge that most major equipment manufacturers, BIM tool developers, ASHRAE, the buildingSMART alliance, the International Organization for Standardization (ISO) and others are working diligently to meet. BIM objects are typically organized within a BIM authoring tool into catalogs, parts lists and libraries that classify and sort the objects according to an industry standard filing or numbering scheme such as the Construction Specifications Institute’s (CSI) MasterFormat or OmniClass2 numbering systems. A BIM object’s numbering scheme or categorization is only one part of the puzzle. The limitations on the use of the information stored with an object is currently determined by the authoring
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tool chosen to create the object, its database structure and its data exchange capabilities and the BIM authoring tool’s ability to share that information with other applications. BIM’s vision is that once an object is created and the information associated with it is entered into one application, the information may be accessed, exchanged and used seamlessly by any other application that has a need to use the information without having to manually recreate, reenter or transcribe the information into another format. This is where industry standardization of data structures and data exchange formats becomes important and necessary. The buildingSMART Alliance has developed the HVAC Information Exchange (HVACie) open information exchange protocol. The HVACie was produced with the help of industry experts from ASHRAE and the U.S. Army Corps of Engineers.3 The ISO Technical Committee 59, Subcommittee 13 has written and proposed a two-part standard to create a “uniform, internationally standardized definition for product catalogue data interchange.”4 Those standards were produced with input from the international building community including buildingSMART International. The work of ASHRAE and our colleagues and these other organizations in this area is just beginning. The positive impact of realizing the full potential and vision of BIM on our industry would be enormous. I encourage you to join the conversation and participate in the work of ASHRAE by joining a standards committee, guideline committee, technical committee or multidisciplinary task group.

references
1. buildingSMART Alliance. 2012. National BuildingInformation Modeling Standard—United States, Version 2. www. nationalbimstandard.org. 2. The Construction Specifications Institute. 2012. MasterFormat and OmniClass. www.csinet.org. 3. buildingSMART Alliance. 2012. HVAC Information Exchange (HVACie). http://tinyurl.com/hvacie. 4. ISO. 2012. ISO/CD 16757-1, Product Data for Building Services System Models—Part 1: Concepts, Architecture and Model. Under development by TC 59/SC13. http://tinyurl.com/8mttcf2.

resources
ARCAT BIM Objects Online Database: www.arcat.com/bim/ bim_objects.shtml. ASHRAE Building Information Modeling Guide: http://cms.ashrae. biz/bim/. Autodesk Revit Model Content Style Guide: http://seek.autodesk. com/revit.htm. Autodesk Seek Object Database: http://seek.autodesk.com. Bentley Mechanical Systems: http://tinyurl.com/9sccs2q. GSA BIM Guide Series: www.gsa.gov/portal/content/105075. National BIM Library: www.nationalbimlibrary.com/. SMARTBIM Online Object Database: http://tinyurl.com/9ag882x. Whole Building Design Guide to BIM Libraries: http://tinyurl. com/8dtlvey.

M. Dennis Knight, P.E., is CEO and founder of Whole Building Systems in Charleston, S.C. He is vice chair of the ASHRAE BIM Multidisciplinary Task Group, and he is an ASHRAE certified Building Energy Modeling Professional.
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ASHRAE Journal -November 2012

Table of Contents for the Digital Edition of ASHRAE Journal -November 2012