Beam Detectors

Fire detectors are designed to detect one or more criteria of fire like smoke, heat, flame, spark etc. None of the detector is suitable for all type of application.

As per IS 2189 guidelines spot type smoke detectors can be used only up to 10 meters of ceiling height. When the ceiling height exceeds 10 meters, line type detectors like beam detector or aspiration type smoke detector should be used, if the fire hazard is smoky in nature.

There are two basic types of beam detectors viz., reflective beam detector and transmitter receiver type / end to end type, both operates on the principle of light obscuration. An infra red light beam is projected from transmitter to receiver and the signal strength will be monitored for smoke.

The transmitter receiver type required power on both ends whereas in the reflective type detector only one end to be powered as both receiver and transmitter electronics sit inside the same enclosure and reflective mirror reflects the light back to the receiver.

The beam detector will not respond to changes in environmental conditions such as dust and dirt accumulation on the transmitter and / or receiver’s optical assemblies. These are compensated for by automatic drift compensation. When the detector is first turned on through the setup program, it assumes the current light signal level as a reference point for a normal condition.  Sudden and total obscuration of the light beam is not the typical smoke signature , so crossing of crane or similar objects will not be considered as alarm. Beam detectors require visible smoke to detect alarm.

Area of application

High ceiling areas such as atriums, lobbies, sports arenas, museums, church, as well as factories and warehouses might be the candidates for beam smoke detectors.