A  F&G safety system continuously monitors for abnormal situations such as a fire, or combustible or toxic gas release within the plant, and provides early warning and mitigation actions to prevent escalation of the incident and protect the process or environment.

Common sensors include combustible gas sensors, photoionization detectors, infrared point sensors, ultrasonic sensors, electrochemical gas sensors, and metal-oxide-semiconductor sensors (MOS sensors). More recently, infrared imaging sensors have come into use.