UL 51:2018-10 Power-Operated Pumps and Bypass Valves for Anhydrous Ammonia, LP-Gas, and Propylene.
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.
Exception: 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.
2.1 Except as indicated in 2.2, a component of a product covered by this standard shall comply with the requirements for that component. See Appendix A for a list of standards covering components generally used in the products covered by this standard.
2.2 A component is not required to comply with a specific requirement that:
a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard, or
b) Is superseded by a requirement in this standard.
2.3 A component shall be used in accordance with its rating established for the intended conditions of use.
2.4 Specific components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specified limits, and shall be used only under those specific conditions.
2.5 Electrical components, including motors and wiring, when incorporated by a manufacturer in the assembly of a pump for LP-Gas or propylene, and the means provided in the pump assembly for electrical connections, shall comply with the requirements for equipment for use in hazardous locations, Class I, Group D, in the National Electrical Code, NFPA 70, Articles 500 and 501.
2.6 Electrical components, including motors and wiring and connections shall comply with the requirements for equipment for use in hazardous locations, Class I, Group D, in the National Electrical Code, NFPA 70, Articles 500 and 501.
Exception: When incorporated by a manufacturer in the assembly of a pump for anhydrous ammonia, the above described electrical components need only to comply with the requirements for ordinary (nonhazardous) locations or for outdoor use locations, if the assembly is appropriately marked to designate the limitations in location and use involved with the electrical features.UL 51 pdf download.