ASME B31.8-2018 pdf download.Gas Transmission and Distribution Piping Systems.
801 GENERAL 801.1 Approved Standards and Specifications Standards and specifications approved for use under this Code and the names and addresses ofthe sponsoring organizations are shown in Mandatory Appendix A. It is not considered practicable to refer to a specific edition of each ofthe standards and specifications in the individual Code paragraphs. 801.2 Use of Standards and Specifications Incorporated by Reference Some standards and specifications cited in Mandatory Appendix A are supplemented by specific requirements elsewhere in this Code. Users of this Code are advised againstattempting directapplication ofany ofthese stan- dards without carefully observing the Code’s reference to that standard. 801.3 Standard Dimensions Adherence to American National Standards Institute (ANSI) dimensions is strongly recommended wherever practicable. Paragraphs or notations specifying these and other dimensional standards in this Code, however, shall not be mandatory, provided that other designs of at least equal strength and tightness, capable of withstanding the same test requirements, are substituted. 801.4 SI (Metric) Conversion Forfactors usedinconvertingU.S. Customaryunits to SI units, see Nonmandatory Appendix J. 802 SCOPE AND INTENT 802.1 Scope (a) This Code covers the design, fabrication, installa- tion, inspection, and testing of pipeline facilities used for the transportation of gas. This Code also covers safety aspects of the operation and maintenance of those facilities. (See Mandatory Appendix Q for scope diagrams.) This Code is concerned only with certain safety aspects ofliquefied petroleum gases when theyare vaporized and used as gaseous fuels. All ofthe requirements ofNFPA 58 andNFPA59 andofthisCodeconcerningdesign,construc- tion, and operation and maintenance of piping facilities shall apply to piping systems handling butane, propane, or mixtures of these gases.
(b) This Code does not apply to (1) design and manufacture of pressure vessels covered by the BPV Code 1 (2) piping with metal temperatures above 450°F (232°C) (For low-temperature considerations, see section 812.) (3) piping beyond the outletofthe customer’s meter set assembly (Refer to ANSI Z223.1/NFPA 54.) (4) pipingin oil refineries ornatural gasoline extrac- tion plants, gas treating plant piping other than the main gas stream pipingin dehydration, and all otherprocessing plants installed as part of a gas transmission system, gas manufacturing plants, industrial plants, or mines (See other applicable sections of the ASME Code for Pressure Piping, B31.) (5) vent piping to operate at substantially atmo- spheric pressures for waste gases of any kind (6) wellhead assemblies, including control valves, flow lines between wellhead and trap or separator, off- shore platform production facility piping, or casing and tubing in gas or oil wells (For offshore platform produc- tion facility piping, see API RP 14E.) (7) the design and manufacture ofproprietaryitems of equipment, apparatus, or instruments (8) the design and manufacture of heat exchangers (Refer to appropriate TEMA 2 standard.) (9) liquid petroleum transportation piping systems (Refer to ASME B31.4.) (10) liquid slurry transportation piping systems (Refer to ASME B31.4.) (11) carbon dioxide transportation piping systems (12) liquefied natural gas piping systems (Refer to NFPA 59A and ASME B31.3.) (13) cryogenic piping systems 802.2 Intent 802.2.1 Adequacy for Normal Conditions. The re- quirements of this Code are adequate for safety under conditions usually encountered in the gas industry.
803.3 Distribution Systems distribution main: a segment of pipeline in a distribution system installed to convey gas to individual service lines or other mains. gas main: see distribution main. gasservice line: the piping installed between a main, pipe- line, orothersource ofsupplyand the metersetassembly. [See para. 802.1(b)(3).] high-pressuredistribution system:agas distributionpiping system that operates at a pressure higher than the stan- dard service pressure delivered to the customer. In such a system, aservice regulatoris requiredon eachservice line to control the pressure delivered to the customer. low-pressure distribution system: a gas distribution piping system in which the gas pressure in the mains and service lines is substantially the same as that delivered to the customer’s appliances. In such a system, a service regu- lator is not required on the individual service lines. 803.4 Gathering Systems gasstorageline:apipelineusedforconveyinggasbetween a compressor station and a gas well used for storing gas underground. gathering line: a segment of pipeline installed in a gath- ering system. gathering system: one or more segments of pipeline, usually interconnected to form a network, that meets one or more of the following criteria: (a) transports gas from one or more production facil- ities to the inletofa gas processing plant. Ifno gas proces- sing plant exists, the gas is transported to the most downstream of one of the following: (1) the point of custody transfer of gas suitable for delivery to a distribution system (2) thepointwhereaccumulationandpreparationof gas from separate geographic production fields in reason- able proximity has been completed (b) transports gas within the gathering system for production or gathering uses such as compressor fuel gas, gas lift, heating, or other processes, the source of which is within the gathering system (i.e., upstream of a transmission system).