ASME B16.42:2021 pdf download

ASME B16.42:2021 pdf download.Ductile Iron Pipe Flanges and Flanged Fittings
1 SCOPE
This Standard covers minimum requirements for Classes 150 and 300 cast ductile iron pipe flanges and flanged fittings. The requirements covered are as follows: (a) pressure–temperature ratings (b) sizes and method ofdesignatingopenings ofreduc- ing fittings (c) marking (d) material (e) dimensions and tolerances (f) bolts, nuts, and gaskets (g) tests
2 GENERAL
2.1 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix I, whichispartofthis Standard. Itisnotconsideredpractical to identify in the text the specific edition of each refer- enced standard and specification. Instead, the specific editions are identified in Mandatory Appendix I. 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 ofbolts and flange bolt holes are only expressed in inch units. These systemsofunitsaretoberegardedseparatelyasstandard. In this Standard, the U.S. Customary units are shown in parentheses or in separate tables following the SI tables. Thevaluesstatedineachsystemarenotexactequivalents; therefore, it is required that each system ofunits be used independently of the other. Except for the diameters of bolts and flange bolt holes, combining values from the two systems constitutes nonconformance with the Stan- dard.2.4 Service Criteria for selection ofmaterials suitable forparticular fluid service are not within the scope of this 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 orcalculatedvalueberoundedofftothenearestunitinthe lastright-hand digitused forexpressingthe limit. Decimal values and tolerances do notimply a particular method of measurement. 2.6 Denotation 2.6.1 Pressure Rating Designation. Class, followed by a dimensionless number, is the designation for pressure– temperature ratings, as follows: (a) Class 150 (b) Class 300
3 PRESSURE–TEMPERATURE RATINGS
3.1 General Cast ductile iron pipe flanges and flanged fittings covered by this Standard shall be designated Class 150 or Class 300. Except as provided in para. 3.5, ratings are maximum allowable workingpressures, expressed as gage pressure, at the service temperature from −29°C (−20°F) minimum to 343°C (650°F) maximum for ASTM A395 or 260°C (500°F) maximum for ASTM A536 Grade 65-45-12 (see Tables 3.1-1 and 3.1-1C). These minimum and maximum temperatures may be further limited by refer- encing regulations, codes, or specifications. For inter- mediate temperatures, linear interpolation is permitted. The method used for establishing pressure– temperature ratings is shown in Nonmandatory Appendix B. 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 foralignmentand 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 independent, although interrelated, components: the flanges, the gasket, and the bolting, which are assembled by another influence, the assembler. Proper controls must be exercised in the selection and application for all these elements to attain a joint that has acceptable leak tightness. Special techniques, such as controlled bolt tightening, are described in ASME PCC-1. Ifthe two flanges in a flanged jointdo nothave 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 rating shall be the material temperature of the pres- sure-retainingstructure. Itmaybeassumedthatthemate- rial temperature is the same as the fluid temperature. Use ofa pressure rating at a material temperature other than that ofthe contained fluid is the responsibility ofthe user and subjectto the requirements ofany applicable code or regulation.