ISO 23251:2006 is applicable to pressure-relieving and vapour-depressuring systems. Although intended for use primarily in oil refineries, it is also applicable to petrochemical facilities, gas plants, liquefied natural gas (LNG) facilities and oil and gas production facilities. The information provided is designed to aid in the selection of the system that is most appropriate for the risks and circumstances involved in various installations. ISO 23251:2006 is intended to supplement the practices set forth in ISO 4126 or API RP 520-1 for establishing a basis of design.
ISO 23251:2006 specifies requirements and gives guidelines for examining the principal causes of overpressure; and determining individual relieving rates; and selecting and designing disposal systems, including such component parts as piping, vessels, flares, and vent stacks.
ISO 23251:2006 does not apply to direct-fired steam boilers.