ASME B16.5-2009 pdf download.Pipe Flanges and Flanged Fittings
1 SCOPE 1.1 General (a) This Standard covers pressure–temperature rat- ings, materials, dimensions, tolerances, marking, test- ing, and methods of designating openings for pipe flanges and flanged fittings. Included are (1) flanges with rating class designations 150, 300, 400, 600, 900, and 1500 in sizes NPS 1 ⁄ 2 through NPS 24 and flanges with rating class designation 2500 in sizes NPS 1 ⁄ 2 through NPS 12, with requirements given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units (2) flanged fittings with rating class designation 150 and 300 in sizes NPS 1 ⁄ 2 through NPS 24, withrequire- ments given in both metric and U.S. Customary units with diameter of bolts and flange bolt holes expressed in inch units (3) flanged fittings with rating class designation 400, 600, 900, and 1500 in sizes NPS 1 ⁄ 2 through NPS 24 and flanged fittings with rating class designation 2500 in sizes 1 ⁄ 2 through NPS 12 that are acknowledged in Nonmandatory Appendix E in which only U.S. Custom- ary units are provided (b) This Standard is limited to (1) flanges and flanged fittings made from cast or forged materials (2) blind flanges and certain reducing flanges made from cast, forged, or plate materials Also included in this Standard are requirements and recommendations regarding flange bolting, gaskets, and joints.
1.4 User Accountability This Standard cites duties and responsibilities that are to be assumed by the flange or flanged fitting user in the areas of, for example, application, installation, system hydrostatic testing, operation, and material selection. 1.5 Quality Systems Requirements relating to the product manufacturer’s Quality System Program are described in Nonmanda- tory Appendix D. 1.6 Relevant Units This Standard states values in both metric 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 stan- dard. Within the text, the U.S. Customary units are shown in parentheses or in separate tables. The values stated in each system are not exact equivalents; there- fore, 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. 1.7 Selection of Materials Criteria for selection of materials suitable for particu- lar fluid service are notwithin the scope ofthis Standard. 1.8 Convention For the purpose of determining conformance with this Standard, the convention for fixing significant digits where limits, maximum and minimum values, are specified shall be rounded as defined in ASTM Practice E 29. This requires that an observed or calculated value shall 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.
2.4 Rating Temperature The temperature shown for a corresponding pressure rating is the temperature ofthe pressure-containing shell of the component. In general, this temperature is the same as that of the contained fluid. Use of a pressure rating corresponding to a temperature other than that of the contained fluid is the responsibility of the user, subject to the requirements ofapplicable codes and regu- lations. For any temperature below −29°C (−20°F), the rating shall be no greater than the rating shown for −29°C (−20°F) (see also paras. 2.5.3 and 5.1.2). 2.5 Temperature Considerations 2.5.1 General. Use of flanged joints at either high or low temperatures shall take into consideration the risk of joint leakage due to forces and moments devel- oped in the connected piping or equipment. Provisions in paras. 2.5.2 and 2.5.3 are included as advisory with the aim of lessening these risks. 2.5.2 High Temperature. Application at tempera- tures in the creep range will result in decreasing bolt loads as relaxation of flanges, bolts, and gaskets takes place. Flanged joints subjected to thermal gradients may likewise be subject to decreasing bolt loads. Decreased bolt loads diminish the capacity of the flanged joint to sustain loads effectively without leakage. At tempera- tures above 200°C (400°F) for Class 150 and above 400°C (750°F) for other class designations, flanged joints may develop leakage problems unless care is taken to avoid imposing severe external loads, severe thermal gradi- ents, or both.