Hi eQuesters!

I am modeling a Laboratory building with Fume Hoods (Climate zone 4A).

Even though Supply Air is 100% Outside Air, the AHU for the laboratory
space doesn't have Energy Recovery because, as the Fumehood

operates, there won't be much exhaust air to recover heat from.

Question is.. What about the Baseline? Should I install Energy
Recovery for the Baseline?

Per ASHRAE 90.1 Appx.G 3.1.2.10, the baseline Laboratory AHUs should be
installed with Energy Recovery (SA>2400L/s & OA 70%).
However, there are two 'Exceptions(see below)' that makes me wonder
whether I should apply Energy Recovery for the Baseline.

*b.* Systems exhausting *toxic, flammables, or corrosive fumes* or paint of
dust. This exception shall only be used if exhaust air energy recovery is
not used in the proposed design.---> *I assume laboratory exhaust air fits
into the underlined characteristics.*

*f.* Where the largest exhaust source is less than 75% of the design
outdoor airflow. This exception shall only be used is exhaust air energy
recovery is not used in the proposed design.--> *As the main exhaust
happens through Fume Hood, the AHU will seldom get the exhaust air more
than 75% of OA.*
**
What do you think equesters?

Any comment will be greatly appreciated!

Thank you.

Kim