Both also have exceptions that allow the deletion of the return duct smoke detectors if the area served is supplied with area smoke detectors and they are configured to control the hvac system in the same way that the duct detectors would have.
Hvac duct mounted smoke detector.
It is preferred that the occupied and non occupied areas and spaces have smoke detectors simply because the fans in air handlers or that move air through duct work may not be operational at all times so having smoke detectors in the duct work will not offer the amount of protection that smoke detectors would offer in the spaces or area served whether those areas or spaces are occupied or not.
Nfpa 72 also states that a duct smoke detector is not allowed to replace an area smoke detector.
Hvac duct smoke detection.
Duct smoke detection equipment a duct smoke detector is a device or group of devices used to detect the presence of smoke in the airstream of ductwork sections of the hvac air handling systems typically used in commercial buildings.
The duct smoke detectors are constructed of a black high impact polymer with a clear plastic cover and attach directly to the hvac system duct.
The duct smoke detector should be compatible with building automation and fire alarm systems.
If you are to ensure the rating of the wall at duct penetrations dampers you must provide coverage per the international building code ibc 2015.
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.
The perforated sampling tube which spans the duct is placed in the airflow upstream of the exhaust tube which causes a pressure differential in the duct detector.
The duct smoke detector samples air for early detection of smoke and products of combustion present in air moving through hvac ducts.
Nor should it serve as an early warning detection system.
Therefore they should complement the buildings fire detection system and not serve as the primary fire detection system.
A duct smoke detector should shut off a typical blower and fresh air and turn on the exhaust.
Tool free plug in sampling tubes speed and simplify installation.
Furthermore intentions for using duct smoke detectors should not be a substitute for area smoke detectors.
Innovairflex duct smoke detectors combine an impressive collection of innovations to greatly simplify hvac system monitoring.
For fire smoke dampers should i use an in duct spot type smoke detector or a duct detector sampling tube style duct detectors are listed for a minimum air velocity of 100 fpm feet per minute.
The duct smoke detector is fitted to the side the top or the bottom of the ventilation duct and has two tubes which extend into the air duct through holes in the duct wall.
One unit can accommodate multiple installation footprints to overcome mounting constraints.
Typical smoke detection devices used for duct application include smoke detector sensors within a housing mounted.
The table below lists the available detector models.
