ASME B16.40-2008 pdf download.Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Systems.
1 SCOPE 1.1 General (a) This Standard covers manually operated thermo- plastic valves in nominal valve sizes 1 ⁄ 2 through 12. These valves are intended for use below ground in thermoplas- tic fuel gas distribution mains and service lines. The maximum operating pressure (MOP) at which such dis- tribution piping systems may be operated is in accor- dance with the Code of Federal Regulations (CFR) Title 49, Part 192, Transportation of Natural and Other Gas by Pipeline; Minimum Safety Standards, for temperature ranges of −20°F to 140°F (−29°C to 60°C). (b) This Standard sets qualification requirements for each basic valve design as a necessary condition for demonstrating conformance to this Standard. (c) This Standard sets requirements for newly manu- factured valves for use in below-ground piping systems for fuel gas [includes synthetic natural gas (SNG)] and liquefied petroleum (LP) gases (distributed as a vapor, withorwithoutthe admixtureofair) ormixtures thereof. 1.2 References Standards and specifications referenced under this Standard are shown in Mandatory Appendix II. 1.3 Conversion For the purpose ofdetermining conformance with this Standard, the convention for fixing significant digits, where limits maximum or minimum values are speci- fied, shall be “rounded off” as defined in ASTM Practice E 29. This requires that an observed or calcu- lated value shall be rounded off to the nearest unit in the last right-hand digit used for expressing the limit. Decimal values and tolerances do not imply a particular method of measurement. 1.4 Relevant Units The values stated in either inch or metric units are to be regarded separately as standard. Within the text, the values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the Standard.
1.5 Definitions basic valve design: for a given valve design, each variation in material, size, or configuration of molded pressure- containing parts shall constitute a different basic valve design, except where minor design variations are pro- duced by differences in machining of the same molded piece(s) to produce different end sizes or dimensional ratios (DRs). DR: the dimensional ratio defined as the pipe outside diameter (O.D.) divided by the pipe wall thickness, t. DR p O.D./t. DRv: the valve DR equivalent is the designated valve DR based on the lowest DR of the ASTM D 2513 pipe ends used in long-term hydrostatic testing under this Standard. fasteners: nuts, bolts, washers, clip rings, and other devices used in the assembly of valves. lubricated valves: valves that require pressure lubrication to effect a leak-tight seal (by the insertion through fit- tings of lubricant to the sealing surfaces of the valve). NVS: nominal valve size. pressure: unless otherwise stated, pressure is gage pressure. production pressure tests: pressure tests that include seat and closure-member and shell tests. seat and closure-member test: an internal pressure test of closure-sealing elements (seats, seals, and closure mem- bers, such as gate, disc, ball, or plug). shell test: an internal pressure test of the pressure-con- taining envelope. valve design pressure: the pressure calculated by the method described in Mandatory Appendix I using the valve shell material’s Hydrostatic Design Basis (HDB) at 73°F (23°C). 1.6 Quality Systems Nonmandatory requirements relating to the product manufacturer’s Quality System Program are described in Nonmandatory Appendix A.
2 CONSTRUCTION 2.1 General (a) The workmanship used in the manufacture and assemblyofeachvalveshallprovide gas tightness, safety and reliability of performance, and freedom from injuri- ous imperfections and defects. (b) Design details not addressed in this Standard are the responsibility of the manufacturer. 2.2 Materials 2.2.1 Valve Shell. The pressure-containing valve shell shall be made from either polyethylene (PE) or polyamide 11 (PA-11) materials specified in and quali- fied to the requirements for pipe and fittings as listed in ASTM D 2513. 2.2.2 Parts Other Than the Valve Shell. Parts other than the valve shell, which contribute to pressure con- tainment or retaining differential pressure across the closure element, shall be resistant to the gases in para. 1.1(c). Such parts shall be designed to withstand normal valve-operating loads and, in addition, shall provide long-term pressure-containment integrity consistent with the valve shell. The sustained pressure tests ofpara. 6.3.3 shall qualify the design and material selected for these parts, which include, but are not limited to, the closure member, stems or shafts (if they are designed to retain pressure), and fasteners retaining shell sections. 2.2.3 Lubricants and Sealants. Lubricants and seal- ants shall be resistant to the action of gases referred to in para. 1.1(c). Lubricated valves, as defined in para. 1.5, are not within the scope of this Standard. 2.2.4 Responsibility. When service conditions, such as gases having high hydrogen content or compounds likely to form condensate, dictate special materials con- siderations, it is the users’ responsibility to specify this information to the manufacturer.