ASME B16.1-2010 pdf download.Gray Iron Pipe Flanges and Flanged Fittings.
1 SCOPE 1.1 General This Standard covers Classes 25, 125, and 250 Gray Iron Pipe Flanges and Flanged Fittings. It includes: (a) pressure-temperature ratings; (b) sizes and method of designating openings of reducing fittings; (c) marking; (d) materials; (e) dimensions and tolerances; (f) bolting and gaskets; (g) pressure testing. 1.2 References Standards and specifications adopted by reference in this Standard are shown in Appendix II, which is part of this Standard. It is not considered practical to identify thespecificeditionofeachreferencedstandardandspec- ification in the text, when referenced. Instead, the spe- cific editions of the referenced standards and specifications are listed in Appendix II. 1.3 Quality Systems Requirements relating to the product manufacturer’s Quality System Programs are described in Appendix A. 1.4 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. Within thetext, theU.S. Customaryunits are showninparenthe- sis or in separate tables. The values stated in each table 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, com- bining values from the two systems constitutes noncon- formance with the standard. 1.5 Service Conditions Criteria for selection of materials suitable for particu- lar fluid service are notwithin the scope ofthis Standard.
2 PRESSURE–TEMPERATURE RATINGS 2.1 General Pressure–temperature ratings are maximum allow- able working pressures in bar units at the temperature in degrees Celsius shown in Table 1 for the applicable material and class designation. Table I-1 of Appendix I lists pressure–temperature ratings using psi units for pressure at the temperature in degrees Fahrenheit. For intermediate temperatures, linear interpolation is per- mitted. Interpolation between class designations is not permitted. 2.2 Flanged Joints A flanged joint is composed of independent interre- lated components; the flanges, the gasket, and the bolt- ing, that are assembled manually.
2.3 Rating Temperature Temperatures shown for the corresponding pressure rating 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. 2.4 Low-Temperature Ratings Pressure ratings for temperatures below −29°C (−20°F) should be determined in accordance with low- temperature properties of gray iron (ASTM A 126) as governed by applicable code or regulation. 2.5 Ductility Gray Iron 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 used where suddenly applied loads such as rapid pres- sure 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. Care should also be exercised to ensure that piping loads transmitted to gray iron flanges are controlled. 3 SIZE 3.1 Nominal Pipe Size As applied in this Standard, the use of the phrase “nominal pipe size” or the designation NPS followed by a dimensionless number is for the purpose of identi- fying the end connection of piping, flanges, or flanged fittings. The number is not necessarily the same as the flange or flanged fitting inside diameter. 3.2 Reducing Fittings Reducing fittings shall be designated by NPS for the openings in the sequence as indicated in the sketches of Fig. 1.