Return bends are used on fresh-air inlets. Tees are used for vents only. Ys are used wherever possible. The use of a Y-branch together with an 1⁄8 bend for a 90° connection with the main line is always preferable to a TY or, as they are commonly called, sanitary T. A tapped fitting gets its name because it is tapped for iron pipe thread. Tapped fittings are used for venting and should not be used for waste unless the tap enters the fitting at an angle of 45°.
These fittings and pipe are joined by first caulking with oakum and pouring, with one continuous pour, the hub full of molten metal. When cool, the lead should be set and then caulked around the pipe and around the hub.
The amount of lead and oakum required for various-sized joints is as follows:
| Pipe size............. | 2 | 3 | 4 | 5 | 6 | 8 | 10 | 12 | 15 |
| Pounds of lead.... | 11⁄2 | 21⁄4 | 3 | 33⁄4 | 41⁄2 | 6 | 71⁄2 | 9 | 111⁄4 |
| Oakum (ounce)... | 4 | 6 | 8 | 10 | 12 | 16 | 20 | 24 | 30 |
Rust Joints.—The plumber is called upon to run cast-iron pipe in places where lead and oakum will not be of service for the joints. In cases of this kind, a rust joint is made. This "rust" is made according to the following formula:
- 1 part flour of sulphur.
- 1 part sal-ammoniac.
- 98 parts iron borings (free from grease).
This mixture is made the consistency of cement, using water to mix thoroughly and bring all parts into contact with each other. When it hardens, it becomes very hard and makes a tight joint which overcomes the objections to lead and oakum joints.
WROUGHT-IRON AND STEEL PIPE
This pipe comes in about 18-foot lengths and fittings of the following makes and shapes, and their use is fully explained. The lengths of pipe come with a thread on each end and a coupling screwed on one end. The lengths come in bundles up to 11⁄2-inches and in single lengths over that size. Screw pipe fittings, it will be noted, are called by a different name than cast-iron ones. The fittings in common use today are the 90 degree ell, 45, 22, and 162⁄3. The Y and TY, tucker fittings, and inverted Ys are used in practically the same way as the cast-iron fittings. The 90 degree ell, 45, 22, and 162⁄3 are used to change the run of pipe that many degrees. All 90 degree fittings, ells, and Ts are tapped to give the pipe a pitch of 1⁄4 inch to the foot. It is better to use two 45 ells to make a 90 bend when it is possible.