Copper and Bronze Fittings (Wrought and Cast)

What it is

Copper water and drainage systems are joined with fittings that are soldered or brazed. Wrought fittings are formed from copper tube or sheet. They are thin-walled, smooth and bright. Cast fittings are poured from copper alloy (bronze or brass) and are heavier and rougher. Cast is common for tees with threaded outlets, adapters and fittings with complex shapes. DWV fittings have long-radius turns and drainage pattern sweeps for waste lines.

How to identify

Wrought fittings look like copper tube, with smooth curves and a uniform wall. Cast fittings have a sand-cast texture, a yellow or reddish tone and thicker walls. Most fittings are stamped with the maker, size and sometimes the standard. DWV fittings have pitch built into turns and wide sweeps.

End connection markings

Sizes are by nominal copper tube size. For types K, L and M and DWV, the actual tube outside diameter is the nominal size plus 1/8 in, so 1/2 tube is 5/8 in OD and 1 tube is 1-1/8 in OD. See the copper tube types sheet and the ACR tube size chart for refrigeration tube, which is sized by actual OD.

Key points

• Street fittings (FTG x C) save a coupling and space. They go into another fitting's cup.
• Use lead-free solder (no more than 0.2 percent lead) and lead-free flux on potable water. Cast fittings for potable water must be lead-free alloy.
• Wrought fittings heat faster than cast fittings. Cast fittings need more heat to bring the cup to solder temperature.
• DWV fittings are for drainage. Do not use them on pressure water lines.
• Brazed joints are used for higher temperature service and refrigeration. Check the fitting maker's limits for brazing cast fittings.

Common mistakes

• Ordering a coupling when a street fitting was needed, or the reverse.
• Mixing up nominal and actual tube size.
• Using drainage fittings on pressure piping.
• Overheating a cast fitting and cracking it, or underheating so solder does not flow.

Governing standards: ASME B16.22 (wrought copper solder joint pressure fittings); ASME B16.18 (cast copper alloy solder joint pressure fittings); ASME B16.29 (wrought copper DWV fittings); ASTM B32 (solder); NSF/ANSI/CAN 61 and 372 (lead-free).

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.