Similar to boiler maintenance checklists, pressure safety valves exist to protect your employees or the people in a home, the steam boiler process, and the factory or residential home. Steam boilers are pressurized systems that can be dangerous to human beings. If the pressure inside a boiler gets too high, it becomes unstable and can break down the heating system.
What is a pressure safety valve?
A pressure safety valve “is a type of Pressure Relieving Device (PRD) that is used to release gases or liquids, and thus relieve pressure, in the case that the pressure in a vessel reaches a (pre-determined) setpoint,” writes Croft Supply, an oil and gas industry equipment supplier. The safety valve releases fluid when the steam boiler hits maximum pressure, reducing it. Spirax Sarco, a steam product seller that advises the company’s processes, states that steam systems use safety valves “for boiler overpressure protection and other applications such as downstream of pressure reducing controls.”
What is the difference between pressure relief and boiler safety valves?
Different industries use PRDs for various functions. The Croft Supply blog post mentioned above explains, “…a pressure safety valve should be used as a final measure to prevent accidents, rather than consistently maintaining pressure. Because of this, pressure safety valves are heavily regulated.” Some national standards use specific terminology for the rules and regulations of pressure relief devices. The terminology is notably different between US and Europe. The Spirax Sarco webpage explains, “… a valve referred to as a ‘safety valve’ in Europe is referred to as a ‘safety relief valve’ or ‘pressure relief valve’ in the USA.” Spirax Sarco also offers a list of definitions for the terminology used in the US and Europe. The first term is a general term that includes safety valves, relief valves, and safety relief valves.
- Pressure Relief Valve – “A spring-loaded pressure relief valve… designed to open to relieve excess pressure and to re-close and prevent the further flow of fluid after normal conditions have been restored.”
- Relief Valve – “A pressure relief device actuated by inlet static pressure having a gradual lift generally proportional to the increase in pressure over opening pressure.”
- Safety Relief Valve – “A pressure relief valve characterized by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on the application, and which may be used either for liquid or compressible fluid.”
The International Organization of Standardization designates the European standard. ISO 4126-1 defines a Safety Valve as “a valve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of the fluid… to prevent a (pre-determined) safe pressure being exceeded, and which is designed to re-close and prevent further flow of fluid after normal pressure conditions of service have been restored.”
Engineering Energy Equipment advises steam boiler users to consult a heating professional to choose the proper type of pressure safety valve for their specific machinery because the US enforces strict and complex regulations. The importance of a pressure safety valve is also so critical that an expert should be involved. EEE has experts in the Tampa area to assist you!
References
https://croftsupply.com/blog/what-is-a-pressure-safety-valve-/
https://www.spiraxsarco.com/learn-about-steam/safety-valves/safety-valves
