ASME B16.38-2007 pdf download

ASME B16.38-2007 pdf download.Large Metallic Valves for Gas Distribution.
1 SCOPE 1.1 Valve Types This Standard covers requirements for manually oper- ated metallic valves innominalsizes 2 1 ⁄ 2 (DN65) through 12 (DN 300) having the inlet and outlet on a common centerline. These valves are intended for controlling the flow of gas from open to fully closed positions, for use in distribution and service lines where the maximum gage pressure does not exceed 125 psig (8.6 bar). Valve seats, seals, and stem packing may be nonmetallic. 1.2 Application This Standard sets forth the minimum capabilities, characteristics, and properties that a newly manufac- tured metallic valve must possess in order to be consid- ered suitable for use in piping systems indicated above, carrying natural gas, manufactured gas [includes syn- thetic natural gas (SNG)], and liquefied petroleum gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof. 1.3 Referenced Standards Standards and specifications adopted by reference in this Standard and the names and addresses of the spon- soring organizations are shown in Mandatory Appendix I. It is not considered practical to refer to a specific edition of each of the standards and specifications in the individual references. Instead, the specific edition references are included in Mandatory Appendix I. A product made in conformance with a prior edition of reference standards will be considered to be in confor- mance, even though the edition reference may be changed in a subsequent revision of the standard. 1.4 Quality Systems Nonmandatory requirements relating to the product manufacturer’s Quality System Program are described in Nonmandatory Appendix A. 1.5 Convention For the purpose of determining conformance with this Standard, the convention for fixing significant digits where limits, maximum or minimum values, shall be 1 “rounded off” as defined in ASTM Practice E 29. This requires that an observed or calculated 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 mea- surement. 1.6 Codes and Regulations A valve used under the jurisdiction of a Federal Regulation, such as CFR Title 49, Part 192; the ASME Code for Pressure Piping, such as ASME B31.8; or the National Fuel Gas Code, Z223.1, is subject to any limita- tion of that code or regulation. 1.7 Definitions NPS: nominal pipe size NVS: nominal valve size one bar: 100 kPa PTFE: materials that comply with ASTM D 4894, Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Extrusion Materials All pressures, unless otherwise stated, are gage pres- sures. 2 CONSTRUCTION 2.1 Conformance 2.1.1 Each completed and assembled valve at the time of manufacture and marked with the designation B16.38 shall be capable of meeting the requirements set forth in this Standard. 2.1.2 Classes 125 and 150 valves (depending upon their design) shall meet the requirements of one of the following standards: MSS SP-67, MSS SP-70, MSS SP-72, MSS SP-78, MSS SP-80, MSS SP-84, ASME B16.34, and ASME B16.42 (see Mandatory Appendix I). 2.2 Tamperproof Features Where valves are specified to be tamperproof, they shall be designed and constructed to minimize the possi- ble removal of the core of the valve with other-than- specialized tools, e.g., tools other than common wrenches, pliers, etc.
2.3 Configuration 2.3.1 Closure Indication 2.3.1.1 Valves designed for one-quarter turn operation shall be designed to visually show the open and closed position of the valve. A rectangular stem head or a position indicator shall indicate the closed position of the valve port when the longitudinal axis of the stem head or indicator is perpendicular to the axis of the connecting pipe. If a separate indicator is employed, it shall be designed such that it cannot be assembled to incorrectly indicate the position of the valve. 2.3.1.2 Valves shall close by clockwise stem rota- tion unless otherwise specified by the purchaser or by the reference standard in para. 2.1.2. The direction for closing shall be indicated. 2.3.2 Valve Ends. Valve ends shall conform to the following standards where applicable: (a) for threaded valve ends, ANSI/ASME B1.20.1 (b) for flanged gray cast iron valve ends, ASME B16.1 (c) for flanged ductile cast iron valve ends, ASME B16.42 (d) for flanged steel valve ends, ASME B16.5 (e) for flanged, butt-welding, and socket-welding valve ends, ASME B16.34 2.3.3 Dimensions. Face-to-face and end-to-end dimensions of valves (other than ball, butterfly, or dia- phragm valves) with flanged ends or butt-welding ends shall conform to the dimensions contained inMSS SP-72. Face-to-face dimensions for butterfly valves shall be in accordance with dimensions contained in MSS SP-67. End-to-end dimensions of threaded end valves shall be in accordance with the manufacturer’s standard dimensions. 2.4 Marking Each valve, in addition to the markings required by the applicable valve standard of para. 2.1.2, shall bear the marking “B16.38” or “B16.38T” if tamperproof fea- tures are included according to para. 2.2. Alternative to the latter, the marking “T” may be shown on the operating head or stem. 2.5 Injection Sealant A valve that utilizes injection of sealant through a fitting that leads to the sealing surfaces shall be capable of having sealant injected in both the full-open and -closed positions at an inlet pressure of125 psig (8.6 bar). 2.6 Pressure-Containing Materials Materials for valve bodies, plugs, bonnets, unions, and other pressure-containing parts shall be in accor- dance with the applicable standards of para. 2.1.2. 2 2.7 Gas Resistance All materials, including lubricants and sealants, shall be resistant to deterioration when exposed to fuel gases such as listed in para. 1.2. 2.8 Temperature Resistance The materials used for valve bodies, plugs, bonnets, unions, and other pressure-containing parts, excluding handles, shall have a solidus temperature in excess of 600°F (427°C).