Exhaust / Supply air Interlocks

[russgs]

Could someone help clarify a code issue with me ?

In a large institution like a High School, if one were to add a small (~400 cfm) range hood, what kind of mechanical interlocks between the exhaust and supply would be required to satisfy building code? Would you have to ensure that the main air handling system for the school be operating before the range hood could come on?

Thanks for any help you can give.

 

[ChasBean1]

International Mechanical Code 2009, Section 508, “Commercial Kitchen Makeup Air” (shortened): says makeup shall be about equal to the amount exhausted, it should be automated to start with the exhaust, and the temperature difference between the make-up air stream and the conditioned space should not exceed 10°F.

Under Sec. 505, "Domestic Kitchen Exhaust Equipment" there is an exclusion for make-up air if the amount exhausted is 400 cfm or less.

Maybe you can put it in the Home Ec. class and call it domestic...

 

[Ziggypump]

I've run into problems with issues like this. Be sure to check your state code to back up what Chas said, and verify with the local inspector.

I had a job where there was less than 400 cfm exhaust, but still need to put an a huge exhaust fan, hood, and makeup air system.

Always check with the local inspector if the situation is borderline with the code. Just because you understand the code one way, doesn't mean that the inspector does, and he has the ability to shut down the building.