Duct smoke detectors are easy to forget because they live inside the HVAC, but they are a routine inspection item and a common source of findings. Here is what to check and when.
Test them on the NFPA 72 schedule
Duct smoke detectors should be tested on the NFPA 72 schedule like any other initiating device. HVAC season is when problems tend to surface — if a unit is seeing more airflow than it did six months ago, it is worth confirming the detector is clean, sealed, and still alarming on test.
Don’t overlook the sampling tube
The most overlooked part is the sampling tube. Wrong length, bent, or missing entirely and the detector cannot sample the airflow properly — which defeats the whole point. The tube has to match the duct width. We stock OEM and aftermarket tubes for 6 in, 12 in, 24 in, 36 in, and wider ducts.
Stock duct detectors and tubes
We stock commercial duct smoke detectors and the sampling tubes to match. Duct detectors show up right alongside batteries and resistors on the most common fire alarm inspection failures — get ahead of them before the inspector does.
