ASME B16.50-2018 pdf download.Wrought Copper and Copper Alloy Braze-Joint Pressure Fittings
1 SCOPE This Standard establishes requirements for wrought copper and wrought copper alloy braze-joint seamless fittings designed for use with seamless copper tube conformingto ASTM B88 (forwaterand general plumbing systems), ASTM B280 (for air conditioning and refrigera- tion service), and ASTM B819 (for medical gas systems). This Standard covers joints assembled with brazing materials conforming to AWS A5.8M/A5.8. This Standard is allied to ASME B16.18 and ASME B16.22. It provides requirements for fitting ends suitable for brazing. This Standard covers (a) pressure–temperature ratings (b) abbreviations for end connections (c) size and method ofdesignating openings offittings (d) marking (e) material (f) dimensions and tolerances (g) testing 2 GENERAL 2.1 ð18Þ 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. 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. Combining values from the two systems constitutes nonconformance with the Standard. 2.2 References Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix I, whichispartofthis Standard. Itisnotconsideredpractical to identify the specific edition ofeach standard and spec- ification in the individual references. Instead, the specific edition reference is identified in Mandatory Appendix I. 2.3 Quality Systems Requirements relating to the product manufacturer’s Quality S ys tem Pro grams are des crib ed in Nonmandatory Appendix B.
3 PRESSURE–TEMPERATURE RATINGS 3.1 Rating of System The internal pressure–temperature rating for a braze joint system is dependent on not only fitting and tube strength but also selection of valves and appurtenances. Pressure–temperature ratings forfittings and braze joints to the dimensions of Table 3.1-1, made with typical commercial brazing materials, shall be considered equal to the values given in Table 3.1-2. Theinternalpressure–temperatureratingofthesystem shall be the lowest ofthe values shown in Table 3.1-2 and those of the tube, valves, or appurtenances. 3.2 Fitting Bursting Strength Fittings manufactured to this Standard shall have an ambient-temperature bursting strength of at least 4 times the 38°C (100°F) internal pressure rating as shown in Table 3.1-2. 4 SCOPE 4.1 Size ThesizeofthefittingsshowninTable3.1-1 corresponds to standard water tube size as shown in ASTM B88. The sizeofthethreadedendscorrespondsto nominalpipesize as shown in ASME B1.20.1. Fittings are designated by the size of the openings in the sequence illustrated in Figure 4.1-1. 4.2 Abbreviations The followingsymbols are used to designate the type of fitting end: C: braze-joint fitting end made to receive copper tube diameter (female) F: internal ANSI standard taper pipe-thread end (female) NPTI FT FTG: braze-jointfittingend made to coppertube diameter (male) M: external ANSI standard taper pipe-thread end (male) NPTE 4.3 Definitions out-of-roundness: the maximum measured diameter minus the minimum measured diameter.
5 MARKING Each fitting shall be permanently marked with the manufacturer’s name or trademark in accordance with MSS SP-25 and the letters “BZ” in uppercase. Marking on fittings less than size 1 ∕ 2 or on any fitting where it would damage the brazing surfaces is not required. 6 ð18Þ MATERIAL (a) FittingsshallbemadefromcopperUNSNo.C10200, C12000, or C12200 or copper alloy UNS No. C23000, for which allowable stresses are found in ASME B31.1, ASME B31.9,orASMEBoilerandPressureVesselCode,SectionII, Part D. (b) Other coppers and copper alloys are permitted, provided (1) they meet the chemical requirements of 84% minimum copper and 16% maximum zinc (2) the fittings produced from the copper alloy meet all the mechanical and corrosion-resistant properties for the end purposes of the fittings Thecompositionofthecopperalloys shallcontainnothing that will inhibit joining to the tube or to other fittings. 7 LAYING LENGTHS Due to widely varying manufacturing processes, mean- ingful laying length requirements of fittings cannot be established. Consult the manufacturer for these dimensions. 8 TUBE STOPS Except for repair couplings, fittings shall be manufac- turedwithatubestop. Repaircouplings shallnotrequirea tube stop. The tube stop shall control joint length, even with an external (FTG) end having the minimum outside diameter shown in Table 3.1-1. Examples ofvarious tube stop configurations are shown in Figure 8-1. 9 INSPECTION TOLERANCE 9.1 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 orcalculatedvalueberoundedofftothenearestunitinthe last right-hand digit used for expressing the limit. Decimal values and tolerances do notimplya particular method of measurement.