ASME B16.1:2020 pdf download.Gray lron Pipe Flanges and Flanged Fittings.
ASME B16.1 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
(fl 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, 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 I.
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 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 of materials suitable for particular 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 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.
2.6 Denotation
2.6.1 Pressure Rating Designation. Class, followed by a dimensionless number, is the designation for pressure- temperature ratings as follows:
2.6.2 Size. NPS, followed by a dimensionless number, is the designation for nominal flange or flange fitting size. NPS is related to the reference nominal diameter, DN, used in international standards. The relationship is, typically, as follows.ASME B16.1 pdf download.