A Different Approach to Using IFCs to Facilitate Interoperability in the Building Industry

What are Industry Foundation Classes (IFCs)?

The International Alliance for Interoperability (IAI) has pioneered an international technical effort by industry leaders in 19 countries to define a single building information framework as one authoritative semantic definition of building elements, their properties and inter-relationships called the "IFC Model." This effort has resulted in the open publication of a rich set of building element definitions designed specifically to facilitate the unambiguous exchange of data between software applications. The importance of the IFC Model is evident from the fact that it has been endorsed as an ISO standard for use by industry stakeholders.

The full IFC Model is available for reference on the IAI international website. For a more detailed and non-technical explanation of IFCs, we recommend the AECbytes article entitled "The IFC Building Model: A Look Under the Hood."

How the IFCs Have Been Defined

The IAI has, from its inception, relied heavily on the use-case methodology, which is used in software system analysis to identify, clarify, and organize the requirements as defined and elaborated by industry practitioners. For example, in defining the processes specific to calculating a building's heating and cooling requirements, engineers provide detailed definitions of all the data that is inherent to this process. In this example, leading industry organizations, such as the American Society of Heating, Refrigeration and Air-Conditioning Engineers in the US, the Chartered Institution of Building Services Engineers in the UK, and the DIN standards organization in Germany, are all consulted for concise, unambiguous, locale-independent definitions that are captured within the IFC Model. The resulting data definitions contained in the model consist of things from the very generic (for example, a fan used to move air in the building) to the very detailed (for example, the flow characteristics at each point in the distribution system, captured in enough detail to allow for a comprehensive fluid flow simulation and analysis).

Who are these industry experts? Many work for companies that are industry leaders, such as Hellmuth, Obata + Kassabaum, Inc. (HOK) and Jaros Baum & Bolles (JB&B) in the US; Obermeyer Planen + Beraten GmbH in Germany; Building Design Partnership (BDP) in the UK; Kajima Corporation in Japan; Woods Bagot in Australia; Olof Granlund in Finland; Ingérop in France; Rambøll in Denmark; and Selvaag in Norway, along with many others. These companies are sponsoring the IAI's efforts, both financially and by allocating significant resources, to identify and implement improved work processes that can break down the barriers to productivity gains in the delivery of projects for their clients. They expect that their voluntary involvement in the IAI, working closely with fellow industry professionals, data modelers, software developers, and members of academia, can deliver on the promise of interoperability. They provide the rich language of building design, construction and operation that forms the basis for data modelers to codify their practice in the IFC Model.

The results of this rigorous and unprecedented collaborative effort have led to an ISO-endorsed building model definition that has been developed to meet the process-specific needs of the users of building data in the AECO (architectural, engineering, construction, owner/operator) industry.

The True Value that IFCs Bring to our Industry

One of the greatest contributions of the IFC Model is the AECO specific, non-graphical definitions that have been captured from building industry domain experts. It is our contention that the true value of the IAI's work is the agreements that have been reached globally on the semantics of a building model (elements, assemblies, relationships, and processes) versus the IFCs per se.

In our opinion, the laudable efforts by CAD and BIM vendors to support IFCs have thus far focused primarily on architectural graphical elements that require physical coordination within a 3D space. CAD vendors have spent huge amounts of time at great cost to work out the intricacies of this exchange between their respective products, each with its own internal BIM. However, there is currently little benefit to end-users by adding IFC exchange focused on the graphical representations of building elements that they can already exchange today via DWG, DXF, DWF, etc. In fact, this is actually a disservice to the industry in the sense that the benefits of IFC-model exchange become mired in the evaluation of the fidelity of the graphics elements rather than focusing on the exploitation of the non-graphical data in other processes. A focus instead on the real value associated with capturing and communicating non-graphical properties adds true intelligence to the graphics and accommodates many more AECO processes.

In our view, the IFC Model offers AECO companies an industry agreed-upon set of definitions with which to describe their project and business processes. Herein lies the real opportunity for achieving major breakthroughs in attacking the runaway costs of inadequate interoperability in our industry. This cost overhead totals in excess of $15bn annually, according to the National Institute of Standards and Technology (NIST) as quantified in its August, 2004 report entitled "Cost Analysis of Inadequate Interoperability in the U.S. Capital Facilities Industry."

Using the IFC Model as a "Data Dictionary" for Project Information—A Different Approach to Unlocking their Potential

Based on our industry research, it is clear that specifically discussing how industry professionals might directly use IFCs is a meaningless exercise. It is a bit like talking to a car buyer about how the fuel injection system actually works when they are actually interested in the trade off between driving performance and fuel economy. We believe that the IAI has, in the past, been too focused on IFCs as a technology in and of itself, rather than relegating it to its rightful role as an enabler for delivering improved information sharing among the processes practiced daily by architects, engineers, contractors and building owners.

These industry professionals can readily identify the points of pain associated with their project deliverables and everyday work practices, such as the difficulty in verifying that a client's space program expectations are being properly met, or their inability to find a piece of information they know already exists somewhere in the overwhelming amount of project data that they are managing. However, very few of the professionals that we have spoken to are concerned about the specifics of how a particular emerging industry open data standard like IFCs might be exploited to assist them; understanding these technical details are not their concern nor interest. Thus, few industry practitioners are clamoring for IFC-compliant software tools or services despite the potential benefits and cost savings.

In analyzing project and business processes specific to the AECO industry, our research has identified that one of the most often overlooked causes of the lack of interoperability in the AECO industry is the absence of common terms and definitions. Utilizing a consistent "data dictionary" on a project provides a huge opportunity for consistency across sets of documents, re-use of project related data, and sharing of information between the members of an extended project team.

It is our assessment that IFCs alone, as an information framework, are unlikely to become a singly unifying model used in the building industry—there are too many processes and areas of specialization to be encompassed comprehensively within a single model framework. Rather, when used in conjunction with existing data structures and/or established data exchange formats, and when combined with the pragmatic capabilities of XML as a ubiquitous communications protocol, IFCs have the potential of becoming an essential part of an emerging "language" for information sharing in the building industry.

Having a common set of terms and definitions is a prerequisite for interoperability; it is the foundation of any meaningful communication. For it to be optimally useful and allow for improved productivity, it has to be focused specifically on what information is relevant to the needs of the communicating parties. This is where the activities of the IAI will have a significant impact on the AECO industry. By utilizing these standardized definitions of the processes captured in the IFC Model, software applications used in the AECO space have a much greater opportunity for meaningful communication. Furthermore, it offers any application the ability to meaningfully exchange selected project data with other standards initiatives that have found support in specific areas of the AECO industry, such as the civil engineering community's LandXML initiative, the structural industry's CIS/2 standard, etc.

This very basic tenet of standardized terminology was a fundamental prerequisite that led to achieving greater levels of automation in the aerospace and manufacturing industries. It has yet, however, to be applied to the heterogeneous AECO industry where the potential benefits might be even greater than in these other industries.

How Will IFCs Affect Your Business?

There are several innovators that are already starting to exploit the powerful "data dictionary" concepts found in the IFC Model. For example, in Norway, the IFC Model is being used to unambiguously exchange non-graphical data between the different spoken languages in the region. The IFC Model Based Operation and Maintenance of Buildings (Ifc-mBomb) project in the UK relies heavily on the exchange of simple property sets to facilitate the objectives of a procurement-based model. And in Singapore's ePlanCheck project, local authorities mine the semantics found in the IFC Model to perform building code compliance checking against local regulations.

We anticipate that more software applications will leverage the contents of the IFC Model, particularly from leading vendors who are committed to supporting open data standards. This trend will grow as more building owners follow the lead of the U.S. General Services Administration's (GSA) Public Building Service 2004 policy directive calling for submission of IFC based building model information in all concept design proposals for its future project programs. More discussion on the how building owners will impact the drive to achieve improved interoperability can be found in the AECbytes Viewpoint article entitled "The Building Owner as a Catalyst for Change in the Construction Industry".

These initial efforts represent the beginnings of a sea change in the AECO industry toward the use of richly defined (intelligent) building data and better structured project information, providing the ability to re-use data across different work processes and to share project information more easily between members of the extended project team.

Conclusion

Our supposition is that the true value of the IFC Model lies in the agreements that have been made about its non-graphical data. The scope of the collection of building-specific elements and semantics contained in the IFC Model is arguably more comprehensive than any other in the AECO industry. This, in and of itself, is of extremely high value. When viewed purely as a building-specific data dictionary, the potential for furthering the goals of interoperability is perhaps greater than the potential offered by the current focus on CAD/BIM data exchange.

This approach avoids the necessity to accept an unrealistic single homogeneous modeling framework as the basis for addressing the industry's need to improve interoperability. The great contribution that the IAI has made is to empower the AECO industry to continue to use its preferred combination of special purpose models to design, analyze, estimate, construct and manage buildings as discussed in our industry whitepaper entitled "Building Information Modeling Two Years Later—Huge Potential, Some Success and Several Limitations", while providing a framework for the meaningful exchange of information.

About the Authors

Jim Forester is Chief Data Architect of Newforma. He has been an active member of the Model Support Group and Technical Advisory Group of the International Alliance for Interoperability since its inception. Jim is a registered mechanical engineer and his professional background includes software development, design content, and consulting services to the AECO industry. Jim can be contacted via email at jforester@newforma.com.

Ian Howell is Chief Executive Officer of Newforma. Ian is an Australian architect, a co-founder and current board member of the International Alliance for Interoperability, and has extensive experience in applied technology in the building industry, both as a director at Autodesk and as vice president of Citadon. Ian can be contacted by email at ihowell@newforma.com.

Newforma is a venture-funded software development company serving architecture, engineering, construction, and owner-operator (AECO) companies. Newforma is striving to dramatically increase the effectiveness and productivity of the AECO industry by developing software that enables the seamless flow of information between every building project team member, in support of both project and business processes.

Note: The views expressed in Viewpoint articles are those of the individual authors and do not necessarily reflect those of AECbytes. Also, no advertising or sponsorship is accepted for Viewpoint articles.

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