Thanks for your comment, David. I agree with you about new technologies and using old ones in new ways. Of course, this shouldn't be an argument against innovation or improving how we conceive and engineer our buildings.
I would also add another concern that needs much more discussion and recognition. It's the "problem" of energy modeling. Designers often think, and clients understandably expect, that when a team does a sophisticated energy model that that it will accurately predict actual building energy use. Since energy is a financial cost, owners also expect that energy models can predict financial performance as well.
In practice, models have proven to be poor predictors of energy use. There are inherent inaccuracies in the modeling process that makes models unreliable predictors. This fact may lead to unintentional misrepresentations by the design team, and create new liability exposures.
Here are the issues with energy models:
1. Models are not like construction drawings. CDs are accurate predictors of what the final building will be. When we do energy models as part of the design process, we may mistakenly expect that they are accurate predictors just like the drawings and specs are.
2. Models need to be seen as decision tools, not as prediction tools. This is the most important point. A good model tells us that a certain strategy will achieve RELATIVE performance over some alternative.strategy. Assuming that this is equivalent to an ABSOLUTE performance is a big mistake.
3. Green buildings tend to produce successful experiences for users. The down side here is that the intensity of occupancy use is often substantially higher than the building program anticipated. Buildings may stay open longer, have greater occupant loads and therefore use more energy than the model predicts. This is not a flaw in the model or a deficiency in the design but a measure of the success of the building. We could "re-model" the building after a year of actual use and compare the results with the energy bills, but who has the budget for that, unless we insist on post-occupancy re-commissioning?
And then there are unexpected infiltrations, janitors who prop open exterior doors while taking smoke breaks, maintenance staff who arbitrarily change HVAC set points, hard winters and hot summers, and all the other unpredictable normalities of building use.
Now try explaining this to a client who told his Board that Building X will save Y thousands of dollars in energy per year, probably because your team told him so.
Does this mean models are bad, or (as we hear in the press) than green buildings are failures? Of course not. But we need to understand the limitations of models, be VERY CAREFUL in what we say models will do, and make a very strong case for re-commissioning the building systems after the first year.
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Billy Tindell
Chicago IL
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Original Message:
Sent: 04-04-2011 16:07
From: David Brotman
Subject: Re: Green Litigation
Billy, Your point is well taken. I agree that the "risks are really just the same old risks." However, the plethora of new products and techniques promoting sustainability multiplies the risk exposure by a significant factor.
The following comments made by Christopher G. Hill address the issue quite well:
While the move to sustainable building is a laudable one, this new paradigm brings with it new legal risks that have yet to be explored. New technologies are being created and old methods are being used in new ways. This alone creates liability risks for the simple reason that we do not have years (or even decades) of engineering data...
...the new world of sustainable or "green" construction presents both great opportunities for construction attorneys and their clients. Those in the construction world who master this new construction paradigm will flourish in this new environment. This opportunity comes with risks (some new, others old but in new packages). Form contracts, insurance, and technology have yet to catch up with the desire to build a more sustainable future.
Your notion that due diligence will help mitigate the risks is right on. My suggestion that we share the horror stories we become aware of, is an effort to further that due diligence.
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David Brotman FAIA
Former AIA Regional Director
Sunset Consultants
Malibu CA
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