Dear eQuest Experts -

I am working on a model for a laboratory building where the laboratory
exhaust exceeds 5,000 cfm (combined, not for a single space).

ASHRAE 90.1-2007, Section G3.1.1, exception d, states that "for laboratory
spaces with a minimum of 5,000 cfm exhaust, use system type 5 or 7 that
reduce the exhaust and makeup air volume to 50% of design values, during
unoccupied periods." This is a requirement for the Baseline case.

I am using system type 5 but am not too sure how to model this requirement
for flow rates. Does anyone have an insight to this or know of any specific
instructions for meeting this requirement?

As always, thank you for being such a helpful and knowledgeable group.

Regards,

Jeff Ross-Bain, PE, LEED AP BD+C, BEMP