UL 51:2018 PDF Download

1 Scope

1.1 These requirements cover power-operated pumps and bypass valves for use in liquid transfer operations in non-refrigerated systems in installations for:

a)    Anhydrous ammonia systems installed in accordance with the Safety Requirements for the Storage and Handling of Anhydrous Ammonia, CGA/GAS G-2.1 (ANSI K61.1);

b)    Liquefied petroleum gas (LP-Gas) systems installed in accordance with the Liquefied Petroleum Gas Code, NFPA No. 58; and

c)    Propylene systems.

1.2 These requirements do not cover:

a)    Pumps or compressors intended for handling anhydrous ammonia or LP-Gas or propylene in the gaseous phase and

b)    Pumps, compressors or bypass valves for anhydrous ammonia, LP-Gas, or propylene for use in chemical, petro-chemical, petroleum, or utility power plants; nor pipeline or marine terminals; nor related storage facilities at such plants or terminals.

1.3 Equipment covered by these requirements is for use with LP-Gas, propylene, or anhydrous ammonia as covered by the Standards and Codes in 1.1 and shall have a minimum service pressure rating in accordance with Table 1.1.

A pump without an integral bypass valve with a higher differential pressure obtained in the Differential Pressure Test, Section 17, is permitted to have a lower minimum service pressure rating if it is marked in accordance with 25.2.

Table 1.1 - Minimum service pressure for rating pumps and bypass valves