ASME B16.42:2016 pdf download

ASME B16.42:2016 pdf download.Ductile Iron Pipe Flanges and Flanged Fittings
2 GENERAL
2.1 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix II, which is part ofthis Standard. Itis notconsidered practi- cal to identify the specific edition of each standard and specification in the individual references. Instead, the specific edition reference is identified in the Appendix. 2.2 Quality Systems Requirements relating to the product manufacturers’ quality system programs are described in Nonmandatory Appendix A. 2.3 Relevant Units This Standard states values in both SI (Metric) and U.S. Customary units. As an exception, diameters of bolts and flange bolt holes are only expressed in inch units. These systems of units are to be regarded sepa- rately as standard. Within the text, the U.S. Customary units are shown in parentheses or in separate tables that appear in Mandatory Appendix I. The values stated in each system are not exact equivalents; therefore, it is required that each system of units be used indepen- dently of the other. Except for the diameters of bolts and flange bolt holes, combining values from the two systems constitutes nonconformance with the Standard. 2.4 Service Criteria for selection of materials suitable for particu- lar fluid service are notwithin the scope ofthis Standard.2.5 Convention For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed or calculated value 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.
3 PRESSURE–TEMPERATURE RATINGS
3.1 General Cast ductile iron pipe flanges and flanged fittings covered by this Standard shall be designated as one of the following: Class 150 or Class 300. Except as provided in para. 3.5, ratings are maximum allowable working pressures, expressed as gage pres- sure, at the service temperature from −29°C (−20°F) to 343°C (650°F). Ratings in Table 1 are in Metric units. For intermediate temperatures, linear interpolation is permitted. Methods for establishing pressure– temperature ratings are givenin Mandatory Appendix I.3.2 Ratings of Flanged Joints Ratings in this Standard apply to flanged joints that conform to the limitations on bolting in para. 6.2 and on gaskets in para. 7.8, and which are made up in accor- dance with good practice for alignment and assembly. See also para. 3.4. Use of the ratings for flanged joints not conforming to these limitations is the sole responsibility of the user. A flanged joint is composed of separate and indepen- dent, although interrelated, components: the flanges, the gasket, and the bolting, which are assembled by another influence, the assembler. Proper controls must be exer- cised in the selection and application for all these ele- ments to attain a joint that has acceptable leak tightness. Special techniques, such as controlled bolt tightening, are described in ASME PCC-1. If the two flanges in a flanged joint do not have the same pressure–temperature ratings, the rating of the joint at any temperature is the lower of the two flange ratings at that temperature. 3.3 Rating Temperature Temperatures shown for corresponding pressure rat- ing shall be the material temperature of the pressure- retaining structure. It may be assumed that the material temperature is the same as the fluid temperature. Use of a pressure rating at a material temperature other than that of the contained fluid is the responsibility of the user and subject to the requirements of any applicable code or regulation.