Inverted Y.—The inverted Y is used in venting to good advantage. The use of these fittings is illustrated in the sketches.
Waste Pipes.—Waste pipes are the pipes that run to or convey the discharge of waste matter to the house drain, from wash trays, baths, lavatories, sinks, and showers.
The usual size of waste pipes is 2 inches. Waste pipes are made of the same material as soil pipe. Lead and brass pipe are also in common use. All exposed waste pipes in bath and toilet rooms are brass, nickel-plated. The waste pipes under kitchen sinks and wash trays are either lead or plain heavy brass. All waste pipes are run with a pitch towards the house trap and should be properly vented as explained under venting. The pipes should be easy of access, with clean-outs in convenient places. The waste pipes under a tile or cement floor should be covered with waterproof paper and a metal V-shaped shield over the entire length. If the waste pipes are over a decorated ceiling they should be in a copper-lined or lead-lined box. This box should have a tell-tale pipe running to the open cellar with the end of the tell-tale pipe left open. If waste pipes are to take the discharge from sinks in which chemicals are thrown, either chemical lead or terra-cotta pipe should be used. If terra-cotta is used, it should have at least 6 inches reinforced concrete around it and the joints of pipe made of keisilgar.
Size of Waste Pipes
| Urinals................... | 2 inches |
| Kitchen sink........... | 2 inches |
| Slop sink................ | 3 inches |
| Receptacles............ | 11⁄2 inches |
| Bath tubs................ | 11⁄2 inches |
| Lavatories.............. | 11⁄2 or 11⁄4 inches |
| Wash trays............. | 2 inches |
Tell-tale Pipe.—The tell-tale pipe is a small pipe that extends from the trough, pan, or box that is under a line of pipe or fixtures to the open cellar. When water is seen running out of this pipe, it shows that a leak exists somewhere in the line of pipe that is in the box or trough. The use of this pipe saves the destruction of walls and ceilings.
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