ASME B16.1-2010 pdf free download.Gray lron Pipe Flanges and Flanged Fittings Classes 25, 125, and 250.
2 GENERAL
2.1 References
Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix 11, which is part of this Standard. It is not considered practical to identify the specific edition of each referenced standard and specification in the text, when referenced. Instead, the specific editions of the referenced standards and specifications are listed in Mandatory Appendix II.
2.2 Quality Systems
Requirements relating to the product manufacturer’s Quality System Programs are described 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. Within the text, the U.S. Customary units are shown in parenthesis 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, combining values from the two systems constitutes nonconformance with the standard.
2.4 Service Conditions
Criteria for selection of materials suitable for particular fluid service are not within the scope of this Standard.
3.2 Flanged Joints
A flanged joint is composed of independent interrelated components; the flanges, the gasket, and the bolting, that 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 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.
3.4 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.
3.5 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 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. Care should also be exercised to ensure that piping loads transmitted to gray iron flanges are controlled.
4 SIZE
4.1 Nominal Pipe Size
As applied in this Standard, the use of the phrase “nominal pipe size” or the designation NI’S followed by a dimensionless number is for the purpose of identifying the end connection of piping, flanges, or flanged fittings. The number is not necessarily the same as the flange or flanged fitting inside diameter.