Safety Valve

Definition - What does Safety Valve mean?

A safety valve is a valve mechanism which automatically releases a substance from a boiler, pressure vessel or other system when the pressure or temperature exceeds predetermined limits.

Safety valves are designed for severe conditions in:

  • Petroleum refineries
  • Chemical manufacturing
  • Petrochemical plants
  • Food, drinks, cosmetics
  • Natural gas processing
  • Power generation plants

Safety valves are also known as pressure relief valves (PRV), pressure safety valves (PSV) and relief valves.

Corrosionpedia explains Safety Valve

A safety valve automatically actuates when the pressure of the inlet side of the valve increases to a predetermined pressure. This opens the valve disc and discharges the fluid or gas. When the pressure decreases to the prescribed value, the valve disc is closed.

A safety valve is a so-called final safety device, which controls pressure and discharges certain amounts of fluid automatically without any electric power support. Safety valves are used in industry for thermal protection and flow protection. Their main use is preventing pressure vessels and heat exchangers from exploding or suffering damage.

The safety valve operates by releasing a volume of fluid or gas from within the plant when a predetermined maximum pressure is reached, thereby reducing the excess pressure in a safe manner. As the safety valve may be the only remaining device to prevent catastrophic failure under overpressure conditions, it is important that any such device is capable of operating at all times and under all possible conditions.

Safety valves should be installed wherever the maximum allowable working pressure (MAWP) of a system or pressure-containing vessel is likely to be exceeded. In steam systems, safety valves are typically used for boiler overpressure protection and other applications such as downstream of pressure-reducing controls. Although their primary role is safety, safety valves are also used in process operations to prevent product damage due to excess pressure.

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