A heat detector is a fire alarm device designed to respond when the heat energy of a triggered fire increases the temperature of a heat-sensitive element. The thermal mass and elemental conductivity regulate the rate of heat flow into the elements. All heat detectors have this thermal delay. The heat detector has two main classifications of operation, "rate-of-rise" and "fixed temperature". The heat detector is used to help reduce the damaged property. It is triggered when the temperature increases.
Video Heat detector
Detektor panas suhu tetap
This is the most common type of heat detector. The temperature detector remains in operation when the heat-sensitive eutectic alloy reaches the point of change of the eutectic point from solid to liquid. The thermal lag delays heat accumulation on the sensitive element so that the fixed temperature device will reach its operating temperature sometime after the ambient temperature exceeds that temperature. The most common fixed temperature point for electrically connected heat detectors is 136.4 Â ° F (58 Â ° C). Technological developments have enabled the perfection of the detector to activate at a temperature of 117 ° F (47 ° C), increasing the available reaction time and safety margins.
Maps Heat detector
Heat rate detector
The Rate-of-Rise heat detector operates at a rapid increase in element temperature of 12 ° to 15 ° F (6.7 ° to 8.3 ° C) increase per minute, regardless of the initial temperature. This type of heat detector can operate under lower temperatures than is possible if the threshold is fixed. It has two heat-sensitive thermocouples or thermistors. One thermocouple monitors heat transferred by convection or radiation while the other responds to ambient temperature. The detector responds when the first sensing temperature increases relative to the other.
The rate of increase in the detector may not respond to low energy release rates from slow-growing fires. To detect slowly develop a fire combination detector adds a fixed temperature element which will ultimately respond when the temperature element remains to reach the design threshold.
Hot detector options
Hot detectors generally have labels on them that read "Not a live safety device". That's because the heat detector is not meant to replace the smoke detector in the bedroom or in the hallway outside the bedroom. The heat detector will keep telling you about fires in the kitchen or utility area, for example , laundry room, garage, or attic, where smoke detectors should not be installed because dust or other particles will affect smoke detectors. and cause false alarms. This will allow additional time to evacuate buildings or extinguish the fire, if possible.
A mechanical heat detector is an independent fire warning station that - unlike smoke detectors - can be installed in any area of ​​the house. Portability, ease of installation, and outstanding performance and reliability make it the right choice for home fire protection when combined with the required smoke detector. Because detectors are not interconnected, heat activation identifies the location of fires, facilitating evacuation from the home.
Each type of heat detector has its advantages, and it can not be said that one type of heat detector should always be used than the other. If a person puts a heat detector level rise above a large enclosed oven, then every time the door is opened an interruption alarm can be generated due to a sudden transient heat. Under these circumstances the threshold detector remains probably the best. If a room full of highly inflammable materials is protected with a fixed heat detector, then a fast-burning fire may exceed the alarm threshold due to thermal lag. In this case a heat detector rate increase may be preferred.
See also
Source of the article : Wikipedia
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