In 1955 a decision was made to publish separate code sections of B31, Code for Pressure Piping. Consequently, Section 2 of B31.1-1955 was updated and revised to publish as USAS B31.2—1968, Fuel Gas Piping. No edition of this code section was published after 1968. This code was withdrawn in 1988.
USAS B31.2 covers the design, fabrication, installation, and testing of piping systems for fuel gases such as natural gas, manufactured gas, and liquefied petroleum gas (LPG); air mixtures above the upper combustible limit; LPG in the gaseous phase; or mixtures of these gases.
This code applies to fuel gas piping systems both within and between the buildings, from the outlet of the consumer meter assembly, and to and including the first pressure-containing valve upstream of the gas utilization device.
This code does not apply to:
Vacuum piping systems
Fuel gas piping systems with metal temperatures above 450°F or below —20°F
Fuel gas piping systems within petroleum refineries, loading terminals, natural gas processing plants, bulk plants, compounding plants, or refinery tank farms, and so forth within the scope of USAS B31.3
Fuel gas piping systems in power and atomic energy plants within the scope of USAS B31.1
Fuel gas piping systems within the scope of USAS B31.8
Fuel gas piping systems within the scope of USAS Z21.30
Piping systems within the scope of USAS Z106.1
Proprietary items of equipment, apparatus, or instruments, such as compressors, gas-generating sets, and calorimeters
Design and fabrication of pressure vessels covered by the ASME Boiler and Pressure Vessel Code
Support structures and equipment such as stanchions, towers, building frames, pressure vessels, mechanical equipment, and foundations
Piping systems for conveying premixed fuel gas-air mixtures which are in the combustible or inflammable limits or range
Effective Edition, Addenda, and Code Cases
USAS B31.2 is no longer used. It can be used for installations which were constructed in compliance with 1968 edition of this code, if permitted by the authorities having the jurisdiction. #Little_PEng