ISO 23251 is an international standard that provides detailed guidance on the design, sizing, and selection of pressure-relieving and depressuring systems for petroleum, petrochemical, and natural gas industries. It is technically identical to the widely used API Standard 521 .
In the high-stakes world of oil & gas, refining, and petrochemical processing, managing pressure is a matter of life and death. When process systems experience overpressure, the consequences can be catastrophic—ranging from equipment damage to fatal explosions. iso 23251 pdf
: The standard warned of the "Fire Case"—a scenario where an external fire could heat the vessel even further. The engineer used the PDF’s formulas to ensure the relief system could handle two-phase flows and gas expansion during such an emergency. ISO 23251 is an international standard that provides