ASME B16.34:2004 pdf download Valves—Flanged, Threaded, and Welding End
1.1 General This Standard applies to new construction and covers pressure-temperature ratings, dimensions, tolerances, materials, nondestructive examination requirements, testing, and marking for cast, forged, and fabricated flanged, threaded, and welding end and wafer or flangeless valves of steel, nickel-base alloys, and other alloys shown in Table 1. Wafer or flangeless valves, bolted or through-bolt types, that are installed between flanges or against a flange are treated as flanged-end valves. Alternative rules for NPS 2 1 ⁄ 2 and smaller valves are given in Mandatory Appendix V.
1.2 Applicability
1.2.1 Standards and Specifications. Standards and specifications adopted by reference in this Standard and the names and addresses of the sponsoring organiza- tions are shown in Mandatory Appendix VIII. It is not considered practical to refer to a specific edition of each of the standards and specifications in the individual clause references. Instead, the specific edition references are included in Mandatory Appendix VIII. A product made in conformance with a prior edition of reference standards and in all other respects conforming to this Standard shall be considered to be in conformance even though the edition reference may have been changed in a subsequent revision of this Standard.
1.2.2 Time of Purchase, Manufacture, or Installation. The pressure-temperature ratings included in this Stan- dard are applicable, upon publication, to all valves cov- ered within its scope that meet its requirements. For unused valves, valves which have been maintained in inventory, the manufacturer may certify conformance to this edition provided that it can be demonstrated that all requirements of this edition have been met. However, where such components were installed under the pres- sure-temperature ratings of an earlier edition of ASME B16.34, those ratings shall apply except as may be gov- erned by an applicable Code or regulation.
1.2.3 User Accountability. This Standard cites duties and responsibilities that are to be assumed by the valve user in the areas of, for example, application, installa- tion, system hydrostatic testing, operation, and material selection.
1.2.4 Quality Systems. Requirements relating to avalve manufacturer’s Quality System Program aredescribed in Nonmandatory Appendix C.
1.2.5 Relevant Units. This Standard states valves inboth metric and U.S. customary units. These systems ofunits are to be regarded separately. The U.S. customaryunits are shown in parentheses or are listed in separatetables. The values stated in each system are not exactequivalents; therefore it is required that each system ofunits be used independently of the other. Combiningvalues from the two systems constitutes nonconform-ance with the Standard.
1.3 Service Conditions
Criteria for selection of valve types and materials suit-able for particular fluid service are not within the scopeof this Standard.
1.4 Convention
For the purpose of determining conformance withthis Standard, the convention for fixing significant digitswhere limits, maximum and minimum values, are speci-fied shall be “rounding off” as defined in ASTM PracticeE 29. This requires that an observed or calculated valueshall be rounded off to the nearest unit in the last right-hand digit used for expressing the limit. Decimal valuesand tolerance do not imply a particular method of mea-surement.