We just received comments on a review of this credit I am trying to understand. For this project, we actually had an approved MV plan from LEED NC credit EAc5. The plan is very detailed and addresses how to trend and look for variations in performance of each component (chillers, boilers, air handlers, heat recovery wheels, motors, etc.). The comment said, “the ongoing commissioning program should include elements of planning, system testing, performance verification, corrective action response, ongoing measurement, and documentation to proactively address operating problems. This includes evidence that rigorous functional testing of equipment (e.g., by changing parameters, setpoints or conditions and observing and documenting the system or equipment response through various modes and conditions over time) is being performed in the project building…. Note that system monitoring and preventive maintenance activities alone are not sufficient for achieving this credit, nor are repetition of the energy auditing activities associated with Option 2 of EAc2.1”
What I don’t understand is where is the value in additional functional testing. If something is going off, it would show up in the trends. Why push the setpoints around if maintaining them where they are is maintaining your energy consumption and efficiency targets? We could repeat some of the Functional Performance Tests from the initial building Cx process, but again, where is the value? (I can see that this would confirm some of the safety and fault procedures, but how is that related to the intent of this credit?) I know the ref guide says “monitoring” is not enough, but it also says that “portable data loggers are likely necessary,” and I have yet to see a variable that would contribute to ongoing Cx that can’t be put into a BMS if you want to.
Also, wouldn’t it make sense if following through on your plan approved for LEED-NC EAc5 actually earned you the related LEED-EBOM credit? Why get an M&V plan in one LEED rating system if it won’t play in another?
Jacob Arlein
Director of Energy ServicesEnvironmental Building Strategies
64 thumbs up
February 21, 2012 - 5:36 pm
Unfortunately what you think makes sense and meets the credit intent is not always what works for LEED. They have strict requirements for each credit, and rarely accept another approach, however compelling the argument is.
With that said, I think there certainly is some benefit to functional testing above and beyond what can come out of trending. Trending is limited by the time frame of each data point. When functional testing the system you can see how the system reacts immediately to the changes placed on it. I am not sure how often you are trending, but every 15 minutes is what I have encountered in the past. Also, by only reading and interpreting data you are making assumptions on what the system is doing, by functional testing it you are viewing exactly what is occurring which will allow you to spot issues and errors in the system.
Finally, your energy consumption goals are estimates, though based on historic information they will always be estimates. You system could have significant issues and still potentially meet or be near your energy consumption targets because other factors like occupancy or monthly outside air temps are favorable.