English: Flaring of gas at the chemical plant Rheinland Raffinerie in Wesseling, Germany:

In the chemical industry, flares are usually used for the safe removal of combustible gases that do not occur continuously. The use is often as a high torch.

When industrial plant equipment items are over-pressured, the pressure relief valve is an essential safety device that automatically release gases and sometimes liquids. Those pressure relief valves are required by industrial design codes and standards as well as by law.