ASME B16.1:2020 pdf download

ASME B16.1:2020 pdf download.Gray Iron Pipe Flanges and Flanged Fittings
1 SCOPE
This Standardcovers Classes 25, 125, and250 GrayIron Pipe Flanges and Flanged Fittings. It includes (a) pressure–temperature ratings (b) sizes and method ofdesignatingopenings ofreduc- ing fittings (c) marking (d) materials (e) dimensions and tolerances (f) bolting and gaskets (g) pressure testing
2 GENERAL
2.1 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix I, whichispartofthis Standard. Itisnotconsideredpractical to identifythe specificeditionofeach referenced standard andspecification inthe text, whenreferenced. Instead, the specific editions of the referenced standards and specifi- cations are listed in Mandatory Appendix I. 2.2 Quality Systems Requirements relating to the product manufacturer’s Quality S ys tem Pro grams are des crib ed in Nonmandatory Appendix A. 2.3 Relevant Units This Standard states values in both SI and U.S. Customary units. As an exception, diameter of bolts and flange bolt holes are expressed in inch units only. These systems of units are to be regarded separately as standard. Within the text, the U.S. Customary units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, it is required that each system of units be used independently of the other. Except for diameter of bolts and flange bolt holes, combining values from the two systems constitutes nonconformance with the Standard. 2.4 Service Conditions 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.
3 PRESSURE–TEMPERATURE RATINGS
3.1 General Pressure–temperature ratings are maximum allowable workingpressures in bar (psi) units atthe temperature in degrees Celsius (Fahrenheit) shown in Table 3.1-1 for the applicable material and class designation. For inter- mediate temperatures, linear interpolation is permitted. Interpolationbetweenclass designations isnotpermitted. 3.2 Flanged Joints Aflanged jointis composed ofindependentinterrelated components: the flanges, gasket, and bolting, which are assembled manually. Proper controls must be exercised in the selection and application for these elements to attain a joint that has acceptable leak tightness. Special techniques, such as controlled bolt tightening described in ASME PCC-1, may be used to achieve a tight joint in service. 3.3 Rating Temperature Temperatures shown for the 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. 3.4 Low-Temperature Ratings Pressure ratings fortemperatures below−29°C (−20°F) should be determined in accordance with low-tempera- ture properties ofgray iron (ASTM A126) as governed by applicable code or regulation. 3.5 Ductility Grayiron has little ductility; therefore, the resistance of these flanges and flanged fittings to excessive forces and suddenly applied loads is significantly less than for more ductile materials, such as steel. The following precautions are recommended: (a) These flanges and flanged fittings should not be usedwhere suddenlyappliedloads such as rapid pressure fluctuation may occur. (b) Alignment of flange faces is essential along with control of assembly bolt torque so as not to over- stress the gray iron flanges.