I have a HVAC system with labs on it requiring 100% outside air systems. Following all the guidance in 90.1 these spaces require a dedicated Sys 5/7 because they are over 5,000 cfm. Also my proposed design varies lower than 50% during unoccupied times with air quality sensing.
It is my understanding that the baseline should not vary less than 50% and I can show savings for that difference.
I have seen other comments on the internets about that difference in airflow not being allowed to be OA. Is this accurate? This seems illogical to me on a 100% lab system. Why would be baseline get savings potential of being able to return lab air?
Anyone have any insight on modeling Lab systems for LEED.
-Thanks
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 6, 2016 - 11:05 am
Sounds like you are citing the exception to G3.1.3.13. There is more to this than the 50% limit, so make sure the Baseline is modeled accordingly.
Under 90.1-2007 the OA must be identical. In 90.1-2010 the OA will vary (Baseline is minimum 62.1-2010 calculated and Proposed is as designed).
I would think that this is an area where you could demonstrate savings through an exceptional calculation.