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NC-v4 EAp2:Minimum energy performance

100% OA Laboratory System

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Charles Daze
Project Engineer
Burns & McDonnell
LEEDuser Premium Member
2 thumbs up

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

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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Thu, 10/06/2016 - 15:05

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.

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