When something -- like smoke -- flows between these two plates, the electric charge is interrupted and the alarm is triggered. Photoelectric smoke detectors have a small light inside.

Duct smoke detector maintenance requirements are not included in the NFPA standard that covers HVAC systems (NFPA 90A or 90B); however, the International Code Council’s 2015 Mechanical Code does ...

The MSR-50 Series of duct ... smoke detectors. The MSR-50RM provides a hidden magnet test switch and a push-button reset, and the MSR-50RK includes a key-operated detector test and reset. Both models ...

Allegro’s A5303 device can be used with an infrared optical chamber to sense light scattered from smoke particles. A networking capability allows units to be interconnected so that if any unit senses ...