This Code covers the design, fabrication, installation, and testing of piping systems for fuel gases such as natural gas, manufactured gas, liquefied petroleum gas (LPG)-air mixtures above the upper combustible limit, liquefied petroleum gas (LPG) in the gaseous phase, or mixtures of these gases.
Included within the scope of this Code are fuel gas piping systems both in buildings and between buildings, from the outlet of the consumer's meter set assembly (or point of delivery) to and including the first pressure containing valve upstream of the gas utilization device. (See Figure B-1 in Appendix B).
Piping systems within the scope of this Code include all components such as pipe, valves, fittings, flanges (except inlet and outlet flanges that are a part of equipment or apparatus described in Par. 200.1.4), bolting and gaskets. Also included are the pressure containing parts of other components such as expansion joints, strainers and metering devices and piping supporting fixtures and structural attachments.
Piping systems covered by this Code may be used only at pressures permitted by the various limitations contained in this Code. Vacuum piping systems are not covered by this Code. See Subdivision 222.5.
This Code does not apply to:
(a) Fuel gas piping systems with metal temperature above 450°F or below −2°F.
(b) Fuel gas piping systems in petroleum refineries, loading terminals, natural gas processing plants, bulk plants, compounding plants, or refinery tank farms, etc. within the scope of USAS B31.3.
(c) Fuel gas piping in power and atomic energy plants, within the scope of USAS B31.1.
(d) Gas gathering, transmission, and distribution piping systems (including compressor stations, metering stations, pressure regulating stations, etc.) for natural, manufactured, or diluted liquefied petroleum gases within the scope of USAS B31.8.
(e) Fuel gas piping systems within the scope of USAS Z21.30. (For the convenience of the Code user, the scope of USAS Z21.30-1964 is included in Appendix C.)
(f) Piping systems for conveying liquefied petroleum gas (LPG) in the liquid phase nor to containers or storage system for liquefied petroleum gases within the scope of USAS Z106.1.
(g) Proprietary items of equipment, apparatus, or instruments, such as compressors, gas generating sets and calorimeters.
(h) Design and fabrication of pressure vessels covered by the ASME Boiler and Pressure Vessel Code.
(i) Support structures and equipment such a s stanchions, towers, building frames, pressure vessels, mechanical equipment, and foundations.
(j) Piping systems for conveying premixed fuel gas-air mixtures which are in the combustible or inflamable limits or range.