# Commercial Kitchen Exhaust Q



## Bob Badger (Apr 19, 2009)

Dnkldorf said:


> Is there something I am missing on roof top exhausts for kitchens, like a fire code somewhere that doesn't allow roof top exhausts for a kitchen?


Not that I am aware of, I work on Kitchens with roof exhaust often.

If you really want to help the guy out make sure to provided the required sq, inches of intake air. The fan manufacturer can tell you what size intake to match the fan.

If you do not provide intake air you can cause problems with the venting of of gas fired equipment and even make it hard to open doors to outside that swing out.

Remember, fans do not 'make air' they can only exhaust as much air from a space as is being supplied to that space.


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## 10492 (Jan 4, 2010)

Bob Badger said:


> If you really want to help the guy out make sure to provided the required sq, inches of intake air. The fan manufacturer can tell you what size intake to match the fan.
> 
> If you do not provide intake air you can cause problems with the venting of of gas fired equipment and even make it hard to open doors to outside that swing out.


 
One door leads to the air conditioned hall, and another has a screen door leading outside. It should be enough make-up air to avoid a negative pressure. I am guessing maybe a 1000CFM or close would do the trick.

With the current exhaust at 6' off the floor, and 14' cielings, it gets hot in there and the heat can't get out.


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## wildleg (Apr 12, 2009)

Sounds like this restaurant should have a proper hood installed with fire suppression and a microswitch, hood shunt, etc ? (every restaurant I worked on had roof exhaust except one, and that one had a huge bunch of problems cause the fire marshal didn't like the exhaust out the side of the building - there were all kinds of clearance issues to glass, combustibles above, etc)


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## MDShunk (Jan 7, 2007)

Just be careful with the supplementary exhaust. You start pulling too much out that new fan, and the hood's fan will have a hard time keeping the cooking smoke going the right way, and you'll grease up the ceilings in a hurry.


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## nitro71 (Sep 17, 2009)

It's been so long since I did a hood. Do I have this right: In case of fire, the exhaust on the hood keeps running. Outlets behind stove or heat source are shunt tripped or contactor shut off. Make up air is shut off. Is that the correct way it should work?

How about AC units?


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## 10492 (Jan 4, 2010)

nitro71 said:


> It's been so long since I did a hood. Do I have this right: In case of fire, the exhaust on the hood keeps running. Outlets behind stop are shunt tripped or contactor shut off. Make up air is shut off. Is that the correct way it should work?
> 
> How about AC units?


To be honest, I dunno. I am planning on using the feed to the side wall exhaust, and run it up to the roof exhaust. Figured I leave the original switch right where it's at, the way it's wired in.


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## JohnR (Apr 12, 2010)

You got to listen to the Badger, sounds like your makeup air is non existent.
try installing that exhaust fan as a supply makeup. 



sorry I'm tired.......can't think.....


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