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Existing Building - DOAS Serving Corridor?

J

jmepd

Registered User
Joined
Oct 14, 2019
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3
Location
USA
I have water source heat pumps located in a hallway (in corridor plenum) serving classrooms. Supply duct from water source heat pumps goes into classroom thru a fire damper. Return is just a transfer air grille with a fire damper back into the corridor plenum.

This is an existing building and the DOAS is supply fresh air in the corridor and all of the water source heat pumps are bringing in the outside air from the corridor plenum but are not ducted from the DOAS.

If I am replacing the DOAS and the water source heat pumps one-for-one on this existing building (considered an alteration level 1), does the existing building code code allow for the DOAS to still supply the corridor without ducting to each water source heat pump unit?
 
Do you know if this is a rated corridor??

Does the building have a fire sprinkler system??
 
Thank you.

The corridor is a rated corridor. It will be used as a means of egress. I don't believe it has a fire sprinkler system. We would be making sure building bms system shuts down all units when any smoke detectors sense smoke.
 
Not sure how it was done originally, if there is a rated corridor??

Give it the rest of the day for some others to answer.
 
IMC 601.2.1 allows the ceiling above a corridor to be used as a return plenum if certain conditions are met, but I don't see where it allows it for a fresh air plenum.

I would think that blowing outside air from a DOAS into a ceiling plenum would pressurize the corridor slightly from leakage around tiles, etc., which would help keep smoke from getting into the corridor. On the other hand, using a ceiling plenum for return air would create a slight negative pressure in the corridor which could draw smoke into the corridor. I don't always understand code logic, or I may be missing something.
 
“””Thank you.

The corridor is a rated corridor. ”””


Rated corridor penetration problem???
 
Any thoughts since it is a rated corridor??


"""""Return is just a transfer air grille with a fire damper back into the corridor plenum."""""
 
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