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A gaseous fire loop system is tested by:
  • A
    checking the sensor with external pressurised gas.
  • B
    checking the wiring harness for faults but not the sensor.
  • C
    heating up the loop.
  • D
    checking the continuity of the system.

Refer to figure.

The Gas-filled fire detection system is based on the principles of gas laws. The sensing element consists of a stainless steel tube that is filled with an inert gas and a gas absorbing material. The gas filled tube reacts to the heat during a fire. The built up pressure, due to the fire making the gas expand, activates the detector when a predetermined value is reached. A leak in the system causes the gas pressure to drop, resulting in a fault alert. An advantage of this system is that a leak will not trigger a false fire warning.

  • Testing of the gas-filled loop system involves heating up the gas-fille container to the predetermined temperature at which gas pressure will trigger the fire warning. An integrity switch is also incorporated.

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