The best forms of slop sink are those of enamel lined or porcelain ware.
Owing to the nature of the waste which enters it the slop sink becomes a very foul and unsanitary fixture unless properly constructed. The most approved type is that having a flushing rim and provided with a flush tank. As the water enters the slop sink through the flushing rim its entire surface is thoroughly flushed and cleansed. The use of plain cast-iron slop sinks, flushed only by means of a common faucet, is very poor practice indeed. Such a fixture it is impossible to keep in a sanitary condition, and a foul-smelling room must result from its use.
Connections for Urinals.
The waste of the slop sink should be 3 in. in size; the size of the vent should be 2 in. The best form of trap for this fixture is one which is enameled over its entire interior and exterior surfaces, and which presents no metal surfaces which may corrode and foul. The slop-sink trap should be provided with a 2-in. cleanout, and it is excellent practice to provide a cleanout, when possible, at the end of the horizontal waste from the fixture, as shown in Plate 6.
The opening of the vent into the slop-sink trap is large and not so liable to stoppage as the vent opening of lead traps of smaller size. An excellent trap of comparatively recent construction is the adjustable slop-sink trap. It is of the half-S pattern, attached to a standard resting on the floor in the usual manner. The height of the outlet above the floor can be adjusted by means of a nipple, to meet roughing requirements, and the trap being of the half-S type, the continuous vent may be used in connection with it. On high-grade work the slop sink is often provided with a local vent.
This local vent should be of the same size as the local vent of the water closet; it should enter a heated flue, and in other respects be installed in a manner similar to the local vent of the water closet. When the slop sink is of the flushing-rim type, and is provided with a flush tank of adequate size and also local vent, it may be made a very sanitary fixture. The size of the slop-sink flush tank should be of 5 gallons capacity. In addition to the type of fixture described above, the waste-preventive slop hopper is used to a limited extent. This fixture is flushed automatically by the emptying of slops into it, the flushing being accomplished by the creation of a vacuum which produces siphonage. As intimated above, however, this fixture is used only to a limited extent.