Hvac Duct Smoke Detector Requirements

The duct smoke detector is equipped with an auxiliary relay.

Hvac duct smoke detector requirements. A heating ventilating or air conditioning hvac fan motor overheats and resulting smoke is sensed by the duct smoke detector installed in the main supply duct. Nfpa 72 also states that a duct smoke detector is not allowed to replace an area smoke detector mainly because if the air handling unit ahu is not running the detector would not detect smoke. Summary duct smoke detector requirement air moving systems supplying air in excess of 2 000 cfm to enclosed spaces within buildings shall be equipped with an automatic shutoff. Ventilation fan systems used to remove air from the inside of the building to the outside of the building.

Duct smoke detection may be useful in preventing injury and property dam age in instances such as the following. The ashrae handbook of smoke control engineering nfpa life safety book for health. Duct smoke detectors are not required if the occupied space is served by an area smoke detector system. A duct smoke detector should shut off a typical blower and fresh air and turn on the exhaust duct detectors aren t a replacement for room sensors if the duct system is designed to carry more than 2000 cfm 5 tons nominal of air you need one in the return if imc is being followed and the supply if nfpa is being followed.

Duct smoke detection nfpa 90a code requirements there are exceptions to the two basic requirements.