BIM's Impact on Sustainable Design - A Case Study

[Brian Kimsey]

CH2MHill is presenting a case study to open the session - a LEED Silver hanger project for the National Guard, designed in BIM.

This my first time blogging. I'm still trying to figure out how to manager the posting and when to use comments!

I've discussed in some comments below what tools the design team used, and how they measured the sustainability of the project.

The daylighting studies showed that a traditional design using clerestory lighting above the level of the hanger doors offered very effective daylighting. The team used Lumen Macro 2000 for photometrics, etc. Light shelves (8 feet wide) on the south facing facades were also used, along with translucent panels. Again, the user interface was difficult.

I missed the dates during which this project was designed, but I am guessing early 2000s. The tools originally used for the project have been followed up (for comparisons purposes only??) by CH2MHill with current tools. New versions of the tools they used, and new tools they have added, are more interoperable and much more sophisticated.

The dynamic 3D model engineering review, using a "NavisWorks-like" tool in Bentley TriForma is being presented. Clashes and colisions were caught. There are limitations on using the tool for code clearances, etc.

Note: they could have benefitted from the Solibri Model Checker tool that GSA is championing for code checking.

Visualization was a very successful BIM tool for presenting the design options to the client.

CH2MHill is now in a discussion about the efficiency of using BIM. They state that they are as efficient now in BIM as they were in 2D.

Energy consumption has dropped each year since completion, as the system has been "tweaked". Overall, it is now operating at about 45 percent below expectations b ased on ASHRAE.

A question was asked "who owns the BIM". CH2MHill is confusing "owns" with "is responsible for". The Owner "owns" the model, in my estimation. Of course, I am an owner.... The National Guard seems to agree. Of course, we (the Owner) only "own" it for use one time, on the intended project.

Overall for this hanger project, except for the CH2MHill learning curve on this early BIM project, there was no real "BIM penalty" experienced.

Primavera's ePM solution was used on the project, and interfaced well with Bentley.

Since construction completion, the model has been used for budgeting scheduled maintenance, for generating an FM database, for integrating specs with the model and tagging O and M data to the model components.

End of blog!

[Andrew Fisher]

The 4D reference was a bit unclear. I agree that '4D' typically refers to the combination of X, Y and Z spatial dimensions and a time dimension. Similary '5D' has been a reference to a '4D' project that includes a fifth 'dimension' of cost.
(although I'd argue that to be truly 5D, a program would need to weigh cost against time and know the future prices of things like steel, but that could be a whole other dicussion)
The key to all this xD however is really how we define BIM. Brent Mauti defined BIM as a 'multidisciplinary model where everything can be counted.'

I can fill in a few other details from my notes at this session:
The project was 130k SF of new construction on an existing site in Colorado. The project was designed in 2003-2004 and construction completed in 2006.

The discussion around LEED certification was interesting. The owner position was that an estimated ten thousand dollars would be needed to pursue LEED points and that this money could be better applied as further sustainable improvements. CH2MHill speakers countered that the documentation effort would be a small additional effort. I think this is an atypical scenario -- with a private sector client there would be an owner advantage to certification. The same could be said of government clients, but in this particular situation client and designer were not seeking LEED points during the process, but 'spirit' program recognition. Going back now to document for LEED purposes would not be as simple as it could have been during the design.

[Brian Kimsey]

I agree with you entirely. They used "4D" in a way I've never heard used before.

[Brian Frels / RTKL]

I question the presenter’s definition of 4D. It is my understanding that in order to be 4D the definition of "time" must be incorporated. Examples might be phasing, or schedules of work to be completed etc. Adding information to model components is in fact BIM but it is not necessarily 4D. Am I missing something?

[Brian Kimsey]

HAP Energy Analysis software by Carrier was used. Again, the design team didn't find it very user friendly. Better tools are now available.

[Brian Kimsey]

Newer versions integrate the design and analysis tools in the structural software.

[Brian Kimsey]

Some BIM tools that they designers used: Structural design analysis, energy analysis, daylighting tools, CM database tied to the models, etc. Midas was the structural tool. It was not very well integrated with the BIM platform (Bentley). Problems resulted with the Midas model was imported back into the Bentley central model.

[Brian Kimsey]

There is a "Spirited" discussion of the Spirit sustainability program vs. LEED. The National Guard (the client for this builidng) is using Spirit and sees it adding the same value as LEED with less investment of resources.

[Brian Kimsey]

Initially the project was being designed in 2D, and then 3D was used just for visualization. "4D" was then used - intelligence applied to components of the project, but not a true BIM. Later in it's evolution a full BIM was developed.