ASME B16.18-2012 pdf download – Cast Copper Alloy Solder Joint Pressure Fittings.
The largest opening in the fitting governs the tolerance to be applied to all openings.
Tables 3 through 19 and Tables 1-3 through 1-19 offer dimensions for pressure fittings covered by this Standard.
8.3 Ovatity
Maximum ovality shall not exceed 1% of the maximum diameters shown in Table 3 or Table 1-3. The average of the maximum and minimum diameters must be within the dimensions shown in the table.
8.4 Gaging of Solder Joint Ends
8.4.1 Standard Gaging Method. The standard method of gaging the diameter tolerances for male and female ends shall be by the use of plain plug and ring gages designed to hold the product within the limits established in Table 3 or Table 1-3.
8.4.2 Optional Gaging Method. For gaging the diameter tolerance of male and female ends, the manufacturer may use direct reading instruments instead of ring and plug gages as specified in para. 8.4.1. When gaging the diameters of male and female ends using direct reading instruments, refer to para. 8.3.
8.5 Standard Gaging Method of Threaded Ends
The standard method of gaging the external and internal threaded ends shall be in accordance with the requirements of ANSI/ASME B1.20.1.
8.6 Alignment
The maximum-allowable deviation in the angular alignment of any opening shall be 0.06 in./ft (5 mm/rn) (0.5%).
9 THREADED ENDS
9.1 Thread Type
Fitting threads shall be right hand, conforming to ANSI/ASME Bl.20.1, Pipe Threads, General Purpose (Inch). They shall be taper threads (NPT).
9.2 Countersink or Chamfer
All internal threads shall be countersunk a distance not less than one-half the pitch of the thread at an angle approximately 45 deg with the axis of the thread, and all external threads shall be chamfered at an angle of 30 deg to 45 deg from the axis, for easier entrance in making a joint and protection of the thread. Countersinking and chamfering shall be concentric with the threads.
9.3 Threading Tolerances
Tolerance for an internal threaded end having an internal shoulder shall be from the gage reference point (notch) to one turn small. Tolerance for an internal threaded end without shoulder and for an external threaded end shall be from one turn small to one turn large.
9.4 Thread Length
The length of threads specified in all tables shall be measured to include the countersink or chamfer.
10 CONFIGURATION OF THREADED ENDS
At the manufacturer’s option, female ends of fittings may be furnished with a polygon or bead with or without ribs, and male ends of fittings may be furnished with a polygon, ribs, or flats.
11 PRODUCTION TESTING
Each fitting shall be tested for evidence of leakage by one of the following methods:
(a) Each fitting shall be pressurized with air, or other compressed gas, at 60 psi (410 kPa) while under water for a minimum duration of 5 sec.
(b) Each fitting shall be hydrostatically tested with water at 250 psi (1 720 kPa) for a minimum duration of 15 sec.