Question

Describe two functions of detectors and detection timing?

Answer 1

Detectors are used to detect fire in its very early stage and should raise the alarm in minimum time so that fire could be controlled easily.Detection time should be minimum and accurate for any fire alarm system.Two main functions of detectors and detection timing are as follows:

1) Fire Detection : One of the main use of detectors is identifying the fire emergency in a building and giving enough time to the occupants of building and fire fighting authorities.Its primary function is to anticipate the fire in the building through automatic sensors,so that enough time is available for evacuation.Control panel is the main component in fire detection.It monitors various sensors designed for fire detection and raises alarm based on critical condition.It may range from single input and single output device to computer programs that may cover from a building to an entire campus.Various type of detectors are :

(i) Thermal detector which works on the priciple of becoming active after a pre fixed temperature is reached in building

.(ii)Smoke detectors identifies the fire in its early flame statge like human sense of smell.

(iii) Flame detectors uses the principle of infrared, ultraviolet or combination to identify the fire by using energy radiated and wavelenth relation.

2) Output Of Alarm: Detection timing plays very important role here. It should be as minimum as posssible so that fire could be controlled in its early stage.Upon receiving the the fire signal through detectors, it is very important that alarm is put on and sent to concerned authority as soon as possible. Alarm is produced through various audio and visual components of alarm output system.Most common sounding device is bells.However in places like health care , soft sound devices like chimes are preferred.For producing a human voice output, speakes are most suitable devices. They are fixed on various floors of a bulding, making them suitable for tall storeyed buildings.Sometimes visual alarm is required where hearing impaired occupants are present.Fire alarm should also be transmitted to the fire fighting authorities in minimum time.Commonly an automated telephone or radio signal is transmitted to the fire monitoring authorities, providing the location of alarm.More advance fire systems also shut down all electrical devices after receving the alarm so that the damage can be minimised.