We are working on a project which includes 2, 1350sf, culinary classrooms with many industrial cooking equipment in them. The kitchen exhaust rate are as high as 1,000,000 cfh for each of these classroom. The kitchen exhaust are demand controlled and work on a cascade mode with 6 fans.

Would these system be considered HVAC? There is no way to comply with the HVAC 45dBA limit in these classrooms including the kitchen exhausts. The only way around I see would be to include an override switch to turn the exhaust off in case quiet is required.