Does NFPA 72 require Duct Smoke Detectors?

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DownRiverGUy

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Canton, MI
Hey guys,

Working on a renovation job where we are putting in smoke detectors in ALL rooms of the building.

Now my Mechanical thinks that we can get away with not using duct smoke detectors in the job. The Michigan mechanical code says that if all the room already have smoke detectors that you don't need duct smoke detectors (however the detectors have to be able to kill the mechanical equipment).

Now I didn't see anything in the building owners spec to require duct detectors so that just leaves the NFPA.

I've check and couldn't find anything that requires me to have duct smoke detectors in there. You guys agree that I don't need them if all the other spaces are served by spot smoke detectors? Can anyone give me a code reference stating the contrary?

Thanks in advance guys! :D
 
Duct detectors are not required in most jurisdictions if every room that the HVAC unit feeds is also completely covered by area smoke detection. It is correct that the alarm of any area smoke detector must shut down the associated unit just as the duct smoke detector would do. Verify with the local Fire marshall and mechanical inspector. Also, the "5 tons" is not totally correct, it is based on units above 2000 cfm.
 
sometimes the duct detector might need to shut off power to the unit if it detects smoke the system sensor (?) duct detector that i used on a simplex fire alarm had a set of contacts that i could connect a pan relay too that had 3 wires a C, NO, NC i used the NC that fed control wiring to VFD's. when the alarm went off it opened the contacts and shut the machine off :)
 
Is the project under either the International Building Code or Life Safety Code?

I think you will find requirements in there, in addition to the mechanical code.
 
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