ASME B31.4 Liquid Trasportation and ASME B31.5 Referigeration Piping code scope of work


Section B31.4 of the ASME Pressure Piping Code prescribes requirements for the design, materials, construction, assembly, inspection, and testing of piping trans¬porting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, liquid alcohol, liquid anhydrous ammonia, and liquid petroleum products between producers’ lease facilities, tank farms, natural-gas processing plants, refineries, stations, ammonia plants, terminals, and other delivery and receiving points.

The scope of ASME B31.4 also includes the following:
  • Primary and associated auxiliary liquid petroleum and liquid anhydrous ammonia piping at pipeline terminals (marine, rail, and truck), tank farms, pump stations, pressure reducing stations, and metering stations, including scraper traps, strainers, and prover loops
  • Storage and working tanks, including pipe-type storage fabricated from pipe and fittings, and piping interconnecting these facilities
  • Liquid petroleum and liquid anhydrous ammonia piping located on property which has been set aside for such piping within petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plants
  • Those aspects of operation and maintenance of liquid pipeline systems relating to the safety and protection of the general public, operating company personnel, environment, property, and the piping systems
ASME B31.4 does not apply to
  • Auxiliary piping such as water, air, steam, lubricating oil, gas, and fuel
  • Pressure vessels, heat exchangers, pumps, meters, and other such equipment, including internal piping.
  • Piping designed for internal pressures
  • At or below 15 psi (100 kPa) gauge pressure regardless of temperature.
  • Above 15 psi (100 kPa) gauge pressure if design temperature is below -20°F (-29°C) or above 250°F (120°C).
  • Casing, tubing, or pipe used in oil wells, wellhead assemblies, oil and gas separators, crude oil production tanks, other producing facilities, and pipelines interconnecting these facilities.
  • Petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plant piping, except as covered within the scope of the code.
  • Gas transmission and distribution piping.
  • The design and fabrication of proprietary items of equipment, apparatus, or instruments, except as limited by this code.
  • Ammonia refrigeration piping systems provided for in ASME B31.5, Refrigeration Piping Code.
  • Carbon dioxide gathering and field distribution systems.
The rules of this code provide for protection of the general public and operating company personnel, for reasonable protection of the piping system against vandal¬ism and accidental damage by others, and for reasonable protection of the environment.


This section of ASME B31, Pressure Piping Code, contains requirements for the materials, design, fabrication, assembly, erection, testing, and inspection of refrigerant and secondary coolant piping for temperatures as low as -320°F (-195.5°C), except when other sections of the code cover requirements for refrigeration piping.

ASME B31.5 does not apply to the following:
  • Self-contained or unit systems subject to the requirements of Underwriters’ Labo¬ratories (UL) or other nationally recognized testing laboratories.
  • Water piping.
  • Piping designed for external or internal gauge pressure not exceeding 15 psig (100 kPa).

ASME B31.1 Power  Piping  code scope of work
ASME B31.2 Fuel gas and ASME  B31.3 Process piping code scope of work

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