Purpose:
Know the various types and workings of fire detectors so that it can place it as needed.
Fire Detector Function:
Fire detectors function to determine the occurrence of fire as early as possible. Usually combined with fire alarm or system or automatic shutdown system (fixed).
Fire Detector Type based on response to fire.
Heat Detector
Fixed Temperature Detector
The detector will work when the surrounding reaches a certain temperature.
For example: 52 ° C (125 ° F), 57 ° C (135 ° F), 68 ° C (155 ° F).
88 ° C (190 ° F), 102 ° C (216 ° F), etc.
Detector of temperature rise (Rate of rise temperature)
This detector works when indoor temperature occurs a certain temperature rise every minute. Usually works at a temperature rise of 1 ° C (34 ° F) per minute, some are working on a temperature rise of 15 ° F per minute.
Detector fixed temperature combination & temperature rise
The detector works if there is a certain temperature rise per minute.
If the temperature rise does not reach a predetermined price, it will work at a certain temperature.
Smoke Detector
Photoelectric smoke detector
Work on the basis of changes in light intensity.
Light will become blurred or less intensity when subjected to smoke. The reduction in intensity will cause the detector to work.
Ionized smoke detector
The smoke particles will cause ionic changes in a room on the detector. Radioactive sources as energy to ionize. Commonly used: Americium 241, 4.5 microcuri.
Flame Detector
This detector will detect fire on the basis of the emitted light and the flame modulation frequency. The types are as follows:
Ultraviolet ray detector
The ultraviolet light detector will capture ultraviolet light from the fire. Medium length ultravioletnya light must be under 2900 Angstroom, so as not to capture the ultraviolet light from the sun.
Infrared ray detector
The infrared ray detector will capture the flickering of infrared rays coming from the fire. Frequency of the flicker is between 5-30 Hz. While infrared rays themselves have wavelengths above 7000 Angstroom.
Fire Detector Mechanism.
Heat Detector
The detecting mechanism on the heat detector can be divided as follows:
Based on metal development.
Bimetal.
Metals are easy to melt (low melting point metal fusible links).
Development of air volume.
Thermocouples.
Laser light.
Smoke Detector
The detecting mechanism of the smoke detector can be distinguished as follows:
The reflected beam (ref lected beam type) file.
For this type of photoelectric smoke detector.
Bipolar chamber for ionization smoke detectors.
One-pole (unipolar chamber) rooms for ionization smoke detectors.
Blinking beam (less light intensity) for photoelectric type.
Laser light.
Flame Detector
Ultraviolet Light Detector
The electronic gas tube unit (gas discharge tube unit).
The photosensitive diode of silicon carbide (photosensitive silicon carbide diode).
Timer unit.
Area of protected area.
The area covered by each detector varies according to the design of the detector itself. Generally the area of the protected area is between 10-1000 feet per facet.
Detector mount circuit.
Fire detectors usually require electric power to turn on the system work. Electric power is generally with a voltage of 24 In the standby state, the installation circuit there are 2 (two) kinds, namely:
Open circuit
This circuit has a parallel relationship system.
Closed Circuits
This circuit has a series relation system.
Cover.
The greater the level of fire hazard in a protected room, the lower the temperature indicated by the detector to be selected.
At some detector temperature detector can be seen in the head detector (detector head).
Any experiments, examinations, abnormalities encountered and treatments should be recorded in a special book called:
"FIRE DETECTOR JURNAL"
There should be special officers who are experts in the field of detectors assigned to maintain the detectors.
Indonesian and Original Terms In English
Used In This Summary
Detector = Detector
Heat detector = Heat detector, Thermal detector
Detector temperature fixed = Fixed temperature detector
Detector temperature rise = Rate of rise detector
Smoke detector = Smoke detector
Photoelectric = Photoelectric
Flame detector = Flame detector
Metals are easy to melt = Low melting point metal
Thermocouple = Thermocouple
Shaded refracted beam = Reflected beam
Rays diffuse = Seatered light
Flick flame = Flame flocker
