Please, I need a bit of help on this for a job this week. FireLite addressible panels have the option to set devices as Supervisory or Supervisory AR. Code states that duct detectors shall be supervisory. Should it auto reset or not? What about a CO detector in a auto body shop that might be prone to frequent alarm. Can that Auto Reset once the mechanics clear the air?
And here’s an interesting follow-up question. If a duct detector is supervisory, should it shut down the RTU in question or not? Furthermore, should it shut down every RTU in the building or not?
A duct detector being alarm vs. supervisory doesn’t impact the RTU shutdown function, just how the panel reports the condition to the rest of the building/outside world.
Correct. I suppose I worded that poorly. Let me try a different way.
Lets say a supervisory duct detector #1 is in active supervisory inside RTU #1. Should that duct detector trigger an RTU shut down? Or does RTU shut down only occur once a nearby smoke goes into full alarm?
And then the follow up on that question is, if Duct Detector #1 is supposed to shut down RTU#1, then should it also shut down RTU #2, 3 and 4 elsewhere in the facility?
Section 606.4 of the 2024 IMC states that smoke detectors required by section 606.2 must shut down the air distribution system, and the smoke detectors required by section 606.2 are all duct smoke detectors (but open area smoke detectors are allowed as an alternative, provided that they are arranged equivalently).
Similarly, section 11.4.3.1 of NFPA 90A requires smoke detectors required by section 11.4.2 to shut off fans, and section 11.4.2 has similar requirements to the IMC regarding duct smoke detectors.
NFPA 90A section 11.4.3.1 requires the smoke detectors to de-energize the “respective fans.” IMC section 606.4 requires the smoke detectors to shut down the “air distribution system,” which is defined in chapter 2 to be made up of one or more air handling units. I’m not familiar with HVAC systems, so I don’t know how this specifically applies in this case.