NFPA 20 VENTILATION 1

[jtucker17]

Good morning. I am looking for guidance to help determine fan capacity for a venitlation fan on a diesel driven fire pump. In NFPA-20, Section 11.3.2, there is guidance on the maximum differntial pressure allowed between the inside and outside of the building, but that does not answer capacity. Is there another NFPA code that addresses the design of the ventilation system? Is there a minimum time period in which the air in the building needs to be 'turned over'? Any help is greatly appreciated.

 

[JLSeagull]

Check NFPA 496 to see if applicable to your situation.

 

[pipesnpumps]

Add up the air drawn into from:
a) the combustion air drawn into the engine, and
b) the radiator fan air drawn into the room (and blown across the radiator to the outside).

Once you get this cfm, then you need to adjust the number.

If the diesel pump is in a room adjacent to other areas, then subtract ~5% or so to keep the room negative relative to other spaces.

The number you come up with is the amount of air that needs to be brought into the room by whatever means is appropriate. You should try to create somewhat of a crossflow in the room. In other words, dump the supply air into the opposite side of the room from the radiator fan.

That is my two cents anyway.

 

[chicopee]

The first question should have been what is the purpose of the ventilation fan?