Shut down exaust fan in hospital

[LUIS FERNANDEZ]

Is there any code requirement, for shutting down an exaust fan with a control module from the fire alarm systems serving various rooms like toilets and equipment room if the AHU unit serving the area shuts down on fire alarm condition.

 

[infinity]

How many CFM's is the fan? I believe that the cutoff is under 2500 CFM for not requiring shutdown. I may be wrong however.:roll:

 

[mcelweec@gmail.com]

in kitchens they sometimes require the exhaust to turn on in an alarm condition.

 

[skeshesh]

How many CFM's is the fan? I believe that the cutoff is under 2500 CFM for not requiring shutdown. I may be wrong however.:roll:

I think it's 2000 but can't remember absolutely and done have a referrence right now.

 

[shamsdebout]

I think it's 2000 but can't remember absolutely and done have a referrence right now.

I am pretty sure its 2000 CFM or more, I do not have a reference either :grin:.

 

[milehiwire]

2000 or more is for supply I do believe and not exhaust.

 

[steve66]

Yes, you would have to shut down the AHU if it provides over 2000 cfm, but not normally toilet or equipment room exhaust fans.

But a high rise building with a fire command center might have different requirements that I'm not familar with. It's not a high rise, is it??

Steve

 

[STHOMAS]

Typically exhaust fans do not need to be shut down. Over 2k cfm supply fans do need detection and automatic shut down. Engineered smoke control systems require a Rational Analysis Report which will dictate if exhaust fans need to shut down, but usually no-one cares if it does not affect pressure differentials required for smoke-control.

During a fire event if hot smoke and gasses are exhausted that is a good thing, but if the fan is not rated for high temp, served with e-power and in accordance with CBC smoke-control requirements, it is acceptable to let the fan die on its own.

 

[skeshesh]

2000 or more is for supply I do believe and not exhaust.

Detection is needed for 2000cfm+ supply & 5000+cfm return I believe but I dunno about shutdown... again no ref (i'm gonno ask one of the mechanical eng guys after lunch I don't believe its in NFPA72...)

 

[milehiwire]

detection is needed for 2000cfm+ supply & 5000+cfm return i believe but i dunno about shutdown... Again no ref (i'm gonno ask one of the mechanical eng guys after lunch i don't believe its in nfpa72...)

nfpa 90a.............