Duct Smoke Detector Installation and Sampling Tube Geometry

A duct cutaway showing the sampling and return tubes in the airstream with airflow direction, a duct smoke detector with power, alarm and trouble LEDs, a remote test station, a 24 VDC supervised power supply, a Form C relay output to an air handler shutdown circuit, and tube placement at 1/6 to 1/3 of the duct height from the top and bottom.