ASME B31.8 pdf download

ASME B31.8 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 of the sponsoring organizations are shown in Mandatory Appendix A. It is not considered practicable to refer to a specific edition of each of the 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 against attempting direct application of any of these standards 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 with. standing the same test requirements, are substituted.
801.4 SI (Metric) Conversion
For factors used in converting U.S. Customary units to SI units, see Nonmandatory Appendix J.
802 SCOPE AND INTENT
(16) 802.1 Scope
(a) This Code covers the design, fabrication, installation, 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.)
(4) Waler Vapor Con tent and Free Liquids. Free water and hydrocarbons at certain combinations of pressures and temperatures may produce hydrates, which are crystalline solids that may cause partial or complete pipeline blockages, that may lead to a disruption of pipeline operations.
Based on the characteristics of the gas stream (i.e., heating value, specific gravit temperature, free liquid, odorization, impurities, and other objectionable substances), appropriate precautions shall be considered to address any problems that might adversely affect the pipeline system or the end user.
(c) The most significant factor contributing to the failure of a gas pipeline is damage to the line caused by the activities of people along the route of the line. Damage will generally occur during construction of other facilities associated with providing the services associated with human dwellings and commercial or industrial enterprises, These services, such as water, gas and electrical supply, sewage systems, drainage lines and ditches, buried power and communication cables, streets and roads, etc., become more prevalent and extensive, and the possibility of damage to the pipeline becomes greater with larger concentrations of buildings intended for human occupancy. Determining the Location Class provides a method of assessing the degree of exposure of the line to damage.
(d) A pipeline designed, constructed, and operated in accordance with the requirements of Location Class 1 Isee para. 840.2.2(a)] is basically safe for pressure containment in any location; however, additional measures are necessary to protect the integrity of the line in the presence of activities that might cause damage. One of the measures required by this Code is to lower the stress level in relation to increased public activit This activity is quantified by determining Location Class and relating the design of the pipeline to the appropriate design factor.
(e) Early editions of this Code used the term “population density index” to determine design, construction, testing, and operation requirements. They also used the term “Location Class” in prescribing design pressure, type of construction, and maximum allowable operating pressure. To simplify use of this Code, the term “population density index” was eliminated. Construction Types A, B, C, and V were eliminated and replaced with the same terminology used for design—location class.