What role does a thermocouple play in a gas system?

A thermocouple functions primarily as a safety device in gas systems by detecting the presence of a flame. When a gas appliance is ignited, the thermocouple generates a small electrical current in response to the heat from the flame. If the flame goes out, the thermocouple ceases to produce this current, which triggers a safety mechanism to shut off the gas supply, preventing the risk of gas accumulation and potential hazards such as explosions or fires.

This role is crucial for ensuring the safe operation of gas appliances, as it directly contributes to risk management in gas systems. Other functions mentioned, such as measuring gas temperature, regulating gas flow, or preventing gas escape, are not the primary function of a thermocouple and are managed by different components in the gas system.