1.1 This Standard sets forth minimum requirements for safety valves, categorized as pressure-relief valves, safety relief valves and hydrostatic relief valves for anhydrous ammonia and liquefied petroleum gas (LP-Gas). These safety valves are typically installed on tanks built in accordance with ASME Pressure Vessel Code, Section VIII, Division 1, or the Boiler, pressure vessel, and pressure piping code, CSA B51, in nonrefrigerated systems in facilities covered by the applicable Codes and Regulations as determined by the Authority Having Jurisdiction (AHJ) such as:
a) In the United States:
1) Requirements for the Storage and Handling of Anhydrous Ammonia, ANSI/CGA G-2.1;
2) Liquefied Petroleum Gas Code, NFPA 58; and
3) Utility LP-Gas Plant Code, NFPA 59.
b) In Canada:
1) Natural gas code, CSA B149 Series; and
2) Provincial or other Regulations.
1.2 These requirements do not apply to relief valves for use on cylinders constructed in accordance with Department of Transportation (DOT) specifications or to safety valves for use on tanks constructed in accordance with Canadian Transport Commission (CTC) Specifications.
1.3 The suitability of an accessory in combination with a relief valve shall be judged under the applicable requirements of this standard and NFPA 59.