# Make Up Air



## jwilly3879 (Jun 14, 2018)

Large Type I hood being installed (2500 cfm) and the contractor wants to pull make up air from the attic space. I referred him to 2015 IMC sections 508 and 401. He insists they do it this way all the time. 

Any suggestions?


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## cda (Jun 14, 2018)

health concern?


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## cda (Jun 14, 2018)

Require an air balance test and see what happens?


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## cda (Jun 14, 2018)

403.2 ?

and table 403.3.1.1  """  footnote b """"""


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## jwilly3879 (Jun 15, 2018)

The issue I have is that the attic is insulated with cellulose with soffit and gable vents. At 2500 cfm quite a breeze would be created, sucking cellulose into the hood.


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## steveray (Jun 15, 2018)

Tell him everything in the attic will need to be plenum rated.....That should end that...


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## cda (Jun 15, 2018)

Seems like IMC says outside air??


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## Francis Vineyard (Jun 15, 2018)

If the air in an unconditioned attic is not outdoor then what is it?

In unusually tight construction we can draw combustion air and fresh air in HVAC returns from attics, but not makeup air for exhaust?


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## Sifu (Jun 15, 2018)

The 2009 ICC Commercial Kitchen Hood Application Guide suggests checking with the local health departments to see if there is a filtering requirement since the make-up air discharges into food handling spaces.


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## cda (Jun 15, 2018)

Francis Vineyard said:


> If the air in an unconditioned attic is not outdoor then what is it?
> 
> In unusually tight construction we can draw combustion air and fresh air in HVAC returns from attics, but not makeup air for exhaust?




Depends on where you are at, could be full of squirrel air, raccoon air, bee air.

I would rather breath LA city air than any attic air.


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## steveray (Jun 15, 2018)

How are they meeting this?

508.1.1 Makeup air temperature. The temperature differential
between makeup air and the air in the conditioned space
shall not exceed 10ºF (6ºC) except where the added heating
and cooling loads of the makeup air do not exceed the capacity
of the HVAC system.


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## jwilly3879 (Jun 15, 2018)

steveray said:


> How are they meeting this?
> 
> 508.1.1 Makeup air temperature. The temperature differential
> between makeup air and the air in the conditioned space
> ...



Haven't even seen the contractor yet, that is the next question I will be asking. This is a municipal job so the whole Town Board is involved and in a big rush.
The first battle was over the sprinkler system. Thread was Titled "Community Hall" this is a continuation of the same project with all the same headaches.
Sometimes I feel like I am swimming upstream dragging an anchor.

Have asked this question to the Technical support group at DOS. They are quite helpful and carry more weight with the powers that be than a lowly employee.


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## jwilly3879 (Jun 15, 2018)

Francis Vineyard said:


> If the air in an unconditioned attic is not outdoor then what is it?
> 
> In unusually tight construction we can draw combustion air and fresh air in HVAC returns from attics, but not makeup air for exhaust?



The concern there is if the attic vents can provide 2500 cfm.


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## cda (Jun 15, 2018)

jwilly3879 said:


> Haven't even seen the contractor yet, that is the next question I will be asking. This is a municipal job so the whole Town Board is involved and in a big rush.
> The first battle was over the sprinkler system. Thread was Titled "Community Hall" this is a continuation of the same project with all the same headaches.
> Sometimes I feel like I am swimming upstream dragging an anchor.
> 
> Have asked this question to the Technical support group at DOS. They are quite helpful and carry more weight with the powers that be than a lowly employee.




I love city buildings!!!!


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## Francis Vineyard (Jun 15, 2018)

steveray said:


> How are they meeting this?
> 
> 508.1.1 Makeup air temperature. The temperature differential
> between makeup air and the air in the conditioned space
> ...


Note the exception.

Commentary "Makeup air that is not introduced directly into or close to the exhaust hood must be tempered to within 10ºF . . . "

To begin with commercial kitchen tend to run hot from cooking operations and it's a waste to draw conditioned outside fresh air from other areas or the dining area.


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## Francis Vineyard (Jun 15, 2018)

jwilly3879 said:


> The concern there is if the attic vents can provide 2500 cfm.



See 508.1.2 Air Balance.


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## cda (Jun 15, 2018)

jwilly3879 said:


> Haven't even seen the contractor yet, that is the next question I will be asking. This is a municipal job so the whole Town Board is involved and in a big rush.
> The first battle was over the sprinkler system. Thread was Titled "Community Hall" this is a continuation of the same project with all the same headaches.
> Sometimes I feel like I am swimming upstream dragging an anchor.
> 
> Have asked this question to the Technical support group at DOS. They are quite helpful and carry more weight with the powers that be than a lowly employee.





And you still have a job??

You must be doing something right.


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