In downstream oil and gas, LPG: valve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of fluid so as to prevent a predetermined safe pressure being exceeded, and which is designed to re-close and prevent the further flow of fluid after normal pressure conditions of service have been restored (footnote 18: PNS ISO 14245:2013) [Section 3.42, Rule 3, DTI Department Administrative Order No. 22-11, Series of 2022, The New Technical Regulation Concerning the Mandatory Certification of Liquefied Petroleum Gas (LPG) Pressure Vessels, Systems, Services and Ancillary Products]
