Factory Installed Duct Detectors

[Kloozy]

I have 2 RTUs that aren’t big enough to require duct detection. However they have factory installed duct detectors. Am I required to monitor these devices?

This is big warehouse with your typical FA system. 15 of the 17 RTUs are being monitored. But all 17 came with factory installed detectors.

In the past I’ve always had to monitor these detectors. However when I asked, was told they were too small to require it. I can’t find any code directly stating anything beyond CFM minimums. Trying to figure out, is it required to monitor all installed detection? Imo, whether the detection is required is a moot point once it’s installed.

But I’ve been wrong once or twice hoped maybe one of you guys would know. Thanks.

 

[MichaelGP3]

I have witnessed a California city's electrical inspector represent that in a situation like yours if all of the fan units cumulative output into a common space was over 2000 cfm then all of those fan units are required to have duct smoke detectors connected to the building's fire alarm. This was around 25 or 30 years ago.

 

[CadmanNY]

In my jurisdiction, duct detectors are not required (regardless of the CFM rating) if the building has a full fire alarm system (smokes in every nook & cranny).
In instances where we do need them, the factory-installed units are abandoned in favor of system devices since we need to have independent fan restart and the factory units do not allow for it.

 

[Eaglesionu]

I have witnessed a California city's electrical inspector represent that in a situation like yours if all of the fan units cumulative output into a common space was over 2000 cfm then all of those fan units are required to have duct smoke detectors connected to the building's fire alarm. This was around 25 or 30 years ago.

I second this. In my experience, if the CFM rating of all units feeding a common space is greater than 2000CFM then they must be tied to the fire alarm.