ASME B16.1:1998 pdf download CAST I RON PIPE FLANGES AND FLANGED FITTINGS Classes 25,125, and 250
1 SCOPE
1.1 GeneralThis Standard for Classes 25，125，and 250 CastIron Pipe Flanges and Flanged Fittings covers:(a) pressure-temperature ratings(b) sizes and method of designating openings ofreducing fittings
(c) marking(d) minimum requirements for materials
(e) dimensions and tolerances(f) bolt, nut, and gasket dimensions
(g) tests
1.2 References
Standards and specifications adopted by reference inthis Standard are shown in Annex l which is part ofthis Standard.
1.3 Quality Systems
Requirements relating to the product manufacturer’sQuality System Programs are described in Annex A
2 PRESSURE-TEMPERATURE RATINGS
2.1 General
Pressure ratings for various temperatures (includinglimitations) are shown in Table 1.
2.2 Ratings
Ratings are independent of the contained fluid andare the maximum nonshock pressures at the tabulatedtemperatures. Intermediate ratings may be obtained bylinear interpolation between the temperatures shown.
2.3 Rating Temperature
Temperatures shown for the corresponding pressurerating 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. Uscof a pressure rating at a material temperature otherthan that of the contained fluid is the responsibilityof the user and subject to the requirements of anyapplicable code.
2.4 Low-Temperature Ratings
Pressure ratings for temperatures below -20°F shouldbe determined in accordance with low-temperature properties of cast iron (ASTM A 126) as governed byapplicable codes.
3 SIZE
3.1 Nominal Pipe Size
The sizes of the flanges and fittings shown in Figs2 through 9 and scheduled in Tables 2 through 9 arcidentified by the corresponding nominal pipe sizes. NPSas used in this document means the nominal pipe size.
3.2 Reducing Fittings
Reducing fittings shall be designated by the size ofthe openings in their proper sequence as indicated inthe sketches of Fig. .
4 MARKING
4.1 Fittings
The manufacturer’s name or trademark and numeralsas shown below for each rating shall be cast on theexterior surface of all fittings.
4.2 Flanges
The manufacturer’s name or trademark shall be caston all loose flanges. In addition, numcrals 25 shall becast on Class 25 flanges. Rating numerals for otherclasses shall be cast on loose flanges that are subjectto the requirements of para. 4.3.
4.3 Material Class
In those sizes and classes where both Classes A andB iron can be uscd, the letter A or B shall be caston both flanges and fittings adjacent to the ratingnumerals. Flanges and fittings with no A or B Classiron marking shall be considered as Class A iron forrating purposes.
5 MATERIALS
5.1 Castings
The castings shall meet the requirements of ASTMA 126 as listed in para. 5.1.1.
5.1.1 The material requirements for flanges andflanged fittings shall be as follows:
ASME B16.1:1998 pdf download
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