What is the term for the pressure at which a pressure relief valve starts to open?

The term "cracking" refers to the specific pressure at which a pressure relief valve begins to open. This is a critical concept in systems that utilize pressure relief valves to ensure safety and prevent overpressure situations. The cracking pressure represents the point where the force exerted by the pressure of the fluid exceeds the spring tension holding the valve closed, allowing it to start opening and venting excess pressure.

Understanding this term is essential for managing systems where pressure regulation is crucial. The cracking pressure is a design specification and is fundamental to the valve's function in protecting equipment and maintaining operational safety. Knowing this can help millwrights select the appropriate valve for specific applications based on the expected operating conditions and safety margins required.