Smoke And Heat Detectors

Smoke Detector

page23image2013462096

page22image2013280000

 

 

 

 

 

 

 

Smoke detectors are essential because they provide an early warning of a fire and therefore occupants can evacuate the building immediately because of the early warning.

Smoke detectors detect most fires much more rapidly than heat detectors. They automatically detect a fire by sensing smoke particles. The smoke particles may be visible or invisible to the human eye.

Common Smoke Detectors

 

Most smoke detectors work either by optical detection (photoelectric) or by physical process (ionization) .

Anatomy of a typical smoke detector

 

 

page23image1994697008

 

Ionization detectors

Analyze particles in the air. When the it senses abnormal conditions, the system actives the alarm.

 

page23image1994696528

 

Photoelectric detectors

Uses light sensors to detect the presence of smoke

 

 


Heat Detector

 

Heat detectors are available in two general types: rate-of-rise and fixed temperature.

 

page28image2017464000

 

 

Rate-of-rise heat detectors activate the alarm when the room temperature increases at a rapid rate.

 

 

page29image1994625392

 

Fixed-temperature heat detectors activate the alarm when the detector components melts at a set temperature. Some need to be replaced after they have activated an alarm.