ASME B16.4:2016 pdf download

ASME B16.4:2016 pdf download.Gray Iron Threaded Fittings
1 SCOPE
This Standard for gray iron threaded fittings, Classes 125 and 250, covers (a) pressure–temperature ratings (b) sizes and method of designating openings of reducing fittings (c) marking (d) material (e) dimensions and tolerances (f) threading (g) coatings Mandatory Appendix I provides table values in U.S. Customary units.
2 GENERAL
2.1 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix II, which is part ofthis Standard. Itis notconsidered practi- cal 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 manufacturers’ quality system programs are described in Nonmandatory Appendix A. 2.3 Relevant Units This Standard states values in both SI (Metric) and U.S. Customary units. These systems of units are to be regarded separately as standard. Within the text, the U.S. Customary units are shown in parentheses or in separate tables that appear in Mandatory Appendix I. The values stated in each system are not exact equiva- lents; therefore, it is required that each system of units be used independently of the other. Combining values from the two systems constitutes nonconformance with the Standard.2.4 Service Conditions Criteria for selection of materials suitable for particu- lar fluid service are notwithin the scope ofthis 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: (a) Class 125 (b) Class 250 2.6.2 Size. NPS, followed by a dimensionless num- ber, is the designation for nominal fitting size. NPS is related to the reference nominal diameter, DN, used in international standards. The relationship is, typically, as follows
3 PRESSURE–TEMPERATURE RATINGS
(a) Pressure–temperature ratings for these fittings are shown in Tables 1 and I-1. (b) All ratings are independent of the contained fluid and are the maximum allowable working gage pressures at the tabulated temperatures. Intermediate ratings may be obtained by linear interpolation between the temper- atures shown. (c) The 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 tempera- ture. Use of a pressure rating at a material temperature other than thatofthe contained fluid is the responsibility of the user and subject to the requirements of any appli- cable code.
4 SIZE
4.1 Nominal Pipe Size As applied in this Standard, the use of the phrase “nominal pipe size” or the designation NPS followed by a dimensionless number is for the purpose of identi- fying the end connection of fittings. The number is not necessarily the same as the fitting inside diameter. 4.2 Reducing Fittings For reducing tees and crosses, the size of the largest run opening shall be given first, followed by the size of the opening at the opposite end of the run. Where the fitting is a tee, the size of the outlet is given last. Where the fitting is a cross, the largest side-outlet opening is the third dimension given, followed by the opposite opening. The straight-line sketches of Fig. 1 illustrate how the reducing fittings are read.