ASME B16.40-2008 pdf free download.Manually Operated Thermoplastic Gas Shut offs and Valves in Gas Distribution Systems.
1.1 General
(a) This Standard covers manually operated therrnoplastic valves in nominal valve sizes through 12. These valves are intended for use below ground in thermopbstic fuel gas distribution mains and service lines. The maximum operating pressure (MOP) at which such dis• trihuhon 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 W°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 manufactured valves for use in below-ground piping systems for fuel gas Iincludes synthetic natural gas (SNG)I and liquefied petroleum (l..P) gases (distributed as a vapor. with or without th admixture of air) or mixtun. tlwwof,
1.2 References
Standards and specifications referenced under this Standard are shown in Mandatory Appendix II.
1.3 Conversion
For the purpose of determining conformance with this Standard, the convention fur fixing significant digits. where limits maximum or minimum values are sped- fled, shall he “rounded off” as defined In ASTM Practice E 29. This requires that an obsened or cakulaled value shall be rounded off to the nearest unit in the last right-hand digit used for expressing the limit. L)eci,nal 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 zale design: for a given valve design,each variationin material, size, or configuration of molded pressure-containing parts shall constitute a different basic valvedesign, except where minor design variations are pro-duced by differences in machining of the same moldedpiece(s) to produce different end sizes or dimensionalratios (DRsj.
DR: the dimensional ratio defined as the pipe outsidediameter (O.D.) divided by the pipe wall thickness,t.DR= O.D./t.
DRz: the valve DR equivalent is the designated valveDR based on the lowest DR of the ASTM D 2513 pipeends used in long-term hydrostatic testing under thisStandard.
fasteners: nuts,bolts, washers, clip rings, and otherdevices used in the assembly of valves.
lnabricated vaIves: valves that require pressure lubricationto 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 gagepressure.
prodnuction pressure tests: pressure tests that include seatand closure-member and shell tests.
seat and closure-nember fest: an internal pressure test ofclosure-sealing elements (seats, seals,and closure mem-bers,such as gate, disc, ball, or plug).
shell fest: an internal pressure test of the pressure-con-taining envelope.
oaIze design pressure: the pressure calculated by themethod described in Mandatory Appendix I using thevalve shell material’s Hydrostatic Design Basis (HDB)at 73F (23C).
1.6 Quality Systems
Nonmandatory requirements relating to the productmanufacturer’s Quality System Program are describedin Nonmandatory Appendix A.
2 CONSTRUCTION
2.1 General
(a) The workmanship used in the manufacture and assembly of each valve shall provide gas tightness, safety and reliability of performance, and freedom from injurious 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 qualified to the requirements for pipe and fttigs as listed in ASTM D 2513.