A digital computerised gas detector with carbon monoxide and narcotic gas detection. The gas alarm has a unique heating element, which ensures that the air around the sensors is ventilated and renewed which increases safety and reliability. The TriGas alarm responds to Propane/Butane (LPG) at the floor, carbon monoxide (CO and NO at the ceiling), as well as several other gases with anaesthetic effect, at floor and ceiling. The intelligent electronics tests the calibration every 40 seconds, and adapts to the environment in the caravan to avoid false alarms due to natural changes. The sensor automatically adjusts to the temperature, ensuring proper calibration when temperature is above 25C, again avoiding false alarms.