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School classroom lab exhaust hood

Renzo

Member
Joined
Oct 30, 2014
Messages
1
Location
Northwest Houston
As you know I'm a mechanical contractor. I've installed kitchen exhaust as well as restroom exhausts. I have a school that is asking for an exhaust hood to be installed in the classroom to vent out foul smells from their non hazardous demonstrations. They mainly want to control smells. The classroom is approx 200 sqft. It has 24x24 lay in tiles for a ceiling and they would like the hood to be about 24"x 48" installed in the middle of the classroom over a island type counter. I don't think a kitchen exhaust is necessary. Any advice? Thanks in advance
 
Welcome

Sounds like a more of a "want" then "required"

They want to ventilate the room to the outside. Not sure if is going cause other problems, such as a/ c, but does not get cold where you are, to often.

Install it. Not sure about using a kitchen hood, may not push enough air.

How many sq ft is the room ??
 
A couple of things to consider:

What kind of "stuff" is making the smell? Some materials disperse quite rapidly and a large cfm is necessary, others are a bit heavier than ambient air and need more cfm to move the "stuff" smell.

Height above the "stuff" is a factor, more cfm is necessary for higher distances.

What kind of "stuff" will go up the hood? Some materials may not be hazardous but over time can be corrosive.

What different kinds of "stuff" will be used? Over time a combo of "stuff" could be quite corrosive to the hood materials.
 
You need a fume hood, not a kitchen or bathroom exhaust fan. Kitchen and bathroom fans are not designed to remove the byproducts from chemical reactions done in a chemistry classroom and based on the demonstrations being done, could cause premature failure or become a potential fire hazard.
 
What is ceiling height?

Consider weight of hood vs T-bar ability to support it vs independent support.

What of roof flashing and type of duct material you propose to use?

Tie-in to Fire alarm systen via duct detector may be required.
 
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