AHU Shutdown

[ed downey]

I was wondering if someone could help me with a code reference. What is the cfm requirement that an air handling unit must be shut down when a duct detector senses smoke? I believe it is 2,000cfm and I believe that it is called out in NFPA 72. Could someone confirm or correct this and provide the NFPA section.

Thanks,
Ed Downey

 

[jimwalker]

Re: AHU Shutdown

While on AC shut downs ,does anyone use them on residential homes ?

 

[drhalleron]

Re: AHU Shutdown

It is 2000 cfm and it's in NFPA 90A (Standard for the Installation of Air-Conditioning and Ventilating Systems) section 6.4.2.1

 

[ron]

Re: AHU Shutdown

6.4.2* Location.
6.4.2.1 Smoke detectors listed for use in air distribution systems shall be located as follows:
(1) Downstream of the air filters and ahead of any branch connections in air supply systems having a capacity greater than 944 L/sec (2000 ft3/min)
(2) At each story prior to the connection to a common return and prior to any recirculation or fresh air inlet connection in air return systems having a capacity greater than 7080 L/sec (15,000 ft3/min) and serving more than one story

6.4.2.2 Return system smoke detectors shall not be required where the entire space served by the air distribution system is protected by a system of area smoke detectors.

6.4.2.3 Smoke detectors shall not be required for fan units whose sole function is to remove air from the inside of the building to the outside of the building.

 

[ed downey]

Re: AHU Shutdown

Thank You