ASME B16.1:2005 pdf download Gray Iron Pipe Flanges and Flanged Fittings (Classes 25, 125, and 250)
SCOPE
1.1 GeneralThis Standard covers Classes 25, 125, and 250 GrayIron Pipe Flanges and Flanged Fittings. It includes:(a) pressure-temperature ratings;(b) sizes and method of designating openings ofreducing 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 inthis Standard are shown in Appendix Il, which is partof this Standard. It is not considered practical to identifythe specific edition of each referenced standard and specification in the text, when referenced. Instead, the specific editions of the referenced standards andspecifications are listed in Appendix Il
1.3 Quality Systems
Requirements relating to the product manufacturer’sQuality System Programs are described in Appendix A1.4 Relevant Units
This Standard states values in both SI and USCustomary units. As an exception, diameter of bolts andflange bolt holes are expressed in inch units only. Thesesystems of units are to be regarded separately. Withinthe text, the U.S.Customary units are shown in parenthesis or in separate tables. The values stated in each tableare not exact equivalents; therefore it is required thateach 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.
1.5 Service Conditions
Criteria for selection of materials suitable for particu-lar fluid service are not within the scope of this Standard1.6 Convention
For the purpose of determining conformance withthis Standard, the convention for fixing significant digitswhere limits,maximum and minimum yalues are specified. shall be rounded as defined in ASTM E 29.This requires that an observed or calculated value shall berounded off to the nearest unit in the last right handdigit used for expressing the limit. Decimal values andtolerance do not imply a particular method of mea-surement.
1.7 Denotation
1.7.1 Pressure Rating Designation. Class, followedby a dimensionless number, is the designation forpressure-temperature ratings as follows:
1.7.2 Size.NPS, followed by a dimensionless num-ber, is the designation for nominal flange or flange fittingsize. NPS is related to the reference nominal diameter,DN, used in international standards. The relationshipis, typically, as follows:For NPS 2 4, the related DN is: DN = 25 x (NPS)
2 PRESSURE-TEMPERATURE RATINGS2.1 General
Pressure-temperature ratings are maximum allow-able working pressures in bar units at the temperaturein degrees Celsius shown in Table 1 for the applicablematerial and class designation. Table I-1 of Appendix Ilists pressure-temperature ratings using psi units forpressure at the temperature in degrees Fahrenheit. Forintermediate temperatures, linear interpolation is per-mitted. Interpolation between class designations is notpermitted.
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. Proper controls mustbe exercised in the selection and application for these