Gentex 7139LS Wall Mount with 9ft Line Cord Photoelectric Smoke Alarm with Visual Signaler
The Gentex7139LS photoelectric single/multiple station smoke alarm is designed to give reliable early warning of the presence of smoke where both audible and visual alarms are required.
Wall mount unit
9 foot line cord
90dBA temporal 3 evacuation piezo horn
177 candela strobe with â€œFIREâ€ lettering
9VDC Battery Back-up with audible low-battery chirp
Horn frequency 3100Hz
Patented three position test switch
5-to-1 signal-to-noise ratio
Fully insect screened
Quick-disconnect wiring harness
The strobe is listed per ANSI/UL 1971
1 year manufacturer warranty
NOTE: The visual strobe alarm and relay contacts will not function when the unit is running off of the battery backup.
How does it work?
The smoke alarm operates on the light scattering principle, a superior method of detection in smoldering fires, utilizing a pulsing LED light source and a photodiode sensor in a fully screened sensing chamber. Every 4 to 5 seconds the pulsing LED emits an infrared beam that bypasses the photodiode under normal conditions. However, when smoke enters the sensing chamber, the infrared beam is deflected onto the sensor by the smoke particles. The LED pulse rate increases to 8 times the normal rate, after the photodiode confirms that smoke is present for 2 consecutive pulses, it will produce the signal necessary to trip an alarm.
Upon activation, the smoke alarm will emit a 90dBA local audible signal and activate the high intensity strobe. During the alarm period the strobe will flash at a brightness of 177 candela 60 times per minute. After the smoke has cleared from the smoke alarm, the unit will revert to the normal stand-by condition.