To ensure correct operation, install the duct detector using the following guidelines: Install the duct smoke detector on a flat section of HVAC duct between six and ten duct widths from any bends or obstructions. Install supply-side detectors at a point downstream from the supply fan and after the air filter.
Likewise, are duct detectors required at fire smoke dampers?
1. Duct smoke detectors will not be required at each fire smoke damper where the supply fan shall shut down and all the fire smoke dampers associated with the supply system automatically close upon actuation of an automatic alarm initiating device on the floor(s).
Moreover, are duct detectors required to be monitored?
Specifically for duct detectors, the test method table states, “Air duct detectors shall be tested or inspected to ensure that the device will sample the air stream. The test shall be made in accordance with the manufacturer’s instructions.”
Does a makeup air unit require a duct detector?
Occasionally the design professional will specify a duct detector on a makeup air unit due to concerns from smoke being generated outside of the building and pulled into the building by the unit, but that is the prerogative of the design professional and the owner, and minimum code does not require it.
How close can a smoke detector be to a return air grille?
One of the more common installation problems with smoke detectors is installing them too close to air vents. NFPA 72 recommends that they should not be installed closer than 3 feet from any supply air diffuser or return vent. If they are too close to the supply, smoke may not reach the detector.
How do you test a duct detector?
Spray aerosol smoke into the duct through the ¼ inch hole for five seconds. Wait two minutes for the duct smoke detector to alarm. If the duct smoke detector alarms, air is flowing through the detector.
What CFM requires a duct detector?
The International Mechanical Code requires a duct smoke detector in the return for units over 2,000 cfm and requires a detector in the supply duct for systems over 15,000 cfm.
What is a duct probe?
Duct probe smoke detectors products. Used where smoke detectors can not be directly mounted into the protected zone a probe duct detector enables the user to still detect fire by using the UG housing with a venturi pipe.