Gas Leak Detection & Alarm Systems

A detector monitors gas concentration in the surrounding air; when it crosses the alarm threshold it signals the control panel. The panel raises audible and visual alarms and commands the solenoid valve on the gas line to close, and may start ventilation depending on the facility's design.

Because LPG is heavier than air it accumulates near the floor, so detectors are mounted at low level close to likely leak sources such as appliances, connections and regulator areas. A ceiling-mounted detector in an LPG application gives a false sense of protection.

• Near appliances and connection areas, not in a corner away from the likely gas path.
• Away from direct airflow from extracts or air conditioning that would divert gas from the sensor.
• In a position reachable for testing, calibration and replacement.
• As far as practical from direct steam and grease in kitchens, to limit sensor fouling.

• Accepting inputs from several detectors and identifying the alarm location.
• Driving audible and visual alarms where staff are actually present.
• Commanding the solenoid valve on the main line to close.
• Providing status indication that reveals detector fault, not only alarm state.
• Manual reset only after the cause has been verified as cleared.

An alarm alone prevents nothing if no one hears and acts on it. The system is therefore tied to a solenoid valve that closes automatically on alarm, selected to match the facility's required operating logic, with a manual shut-off button at a clear exit position.

A detector's sensor ages, and periodic testing is the only way to know it still works. A typical programme covers response testing, verifying the signal reaches the panel, actually testing valve closure, tracking sensor life and replacing it when required, and documenting all of it.

• Mounting the detector at ceiling level in an LPG application.
• Relying on an audible alarm with no automatic shut-off.
• Locating the sounder where nobody hears it during operation.
• Never testing the system after installation.
• Disabling a detector because of repeated alarms instead of resolving their cause.