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A residential heat detector. A heat detector is a fire alarm device designed to respond when the convected thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. All heat detectors have this thermal lag. Heat detectors have ...
Fire alarm systems are required in most commercial buildings. They may include smoke detectors, heat detectors, and manual fire alarm activation devices (pull stations). All components of a fire alarm system are connected to a fire alarm control panel. Fire alarm control panels are usually found in an electrical or panel room.
For smoke detectors according to EN 54-7 and fire detectors with smoke sensor (parts 12, 20 and 30 of EN 54) the test fires TF2, TF3, TF4 and TF5 are used. The EN 54-20 defines the following test fires with reduced fuel quantity for aspirating smoke detectors with enhanced or very high sensitivity (class A or B):
In dwellings, smoke detectors are often stand-alone devices. In non-domestic buildings, fire detection will typically take the form of a fire alarm system, incorporating one or more of the following automatic devices: Heat detector; Smoke detector; Flame detector; Fire gas detector
A conventional fire alarm control panel employs one or more electrical signalling circuits (each a pair of wires), connected to initiating devices (usually smoke detectors, heat detectors, duct detectors, manual pull stations, and sometimes flame detectors) wired in parallel. These sensors are designed to dramatically decrease the circuit ...
A 48 V system can provide more power, improve energy recuperation, [7] and allow up to an 85% decrease in cable mass. [10] 12-volt systems can provide only 3.5 kilowatts, while a 48 V power could achieve 15 to 20 kW or even 50 kW. 48 volts is below the level that is considered safe without special protective measures. [11]
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Linear heat detection (LHD) (also known as linear detection wire or linear heat detection cable or linear heat) is a very commonly used method of fire detection. It can detect a fire anywhere along the length of the cable, and can be of lengths in excess of a kilometer. Applications can range from building fire alarm systems to mobile plant ...