Duct Smoke Detector Installation Requirements

The local authority having jurisdiction should be consulted prior to the installation of the damper and smoke detector.

Duct smoke detector installation requirements.

With all wiring in place install the detector head. With power source de energized and the smoke detector not installed wire all connections per engineering drawings. A duct smoke detector should shut off a typical blower and fresh air and turn on the exhaust. The international mechanical code imc specifies that if the space is air conditioned and the a c unit is over 2 000 cfm a duct smoke detector is required to be installed in the return air duct.

Energize the duct detector. To ensure correct operation install the duct detector using the following guidelines. Standard location when factory mounted will be on the side opposite the damper actuator. The duct detector should when possible be located a minimum of six duct widths downstream from a source of turbulence bends inlets or deflection plates.

Smoke alarms should be installed at least 10 feet 3 meters from a cooking appliance to minimize false alarms when cooking. At these locations air flow is less turbulent and the air smoke mixture should be more homogenous. Duct smoke detectors alarms and the code. Detector installation 5 1 verify air flow direction and velocity model d4120 detectors are designed to be used in air handling systems with air velocities of 100 to 4000 feet per minute.

Wall mounted alarms should be installed not more than 12 inches away from the ceiling to the top of the alarm. Ventilation fan systems used to remove air from the inside of the building to the outside of the building. Return air smoke detectors are not required when there is a protection of. For proper air sampling duct pressure should be a minimum of 0 01 inches of water.

Duct detectors aren t a replacement for room sensors. Install the duct smoke detector on a flat section of hvac duct between six and ten duct widths from any bends or obstructions. Duct widths from 6 inches to 12 feet can be accommodated. Refer to nfpa 90a 72 and 101 for more information.

If the duct system is designed to carry more than 2000 cfm 5 tons nominal of air you need one in the. Refer to the applicable figures below depending on your duct housing model number.