Part 14 (1/2)

The fresh-air inlet should run as directly as possible into the outer air, at least 15 feet from any window. The pipes terminate in a number of different ways, some with a return bend, above the ground, some with a cowl cap, some with a strainer. When necessary to run pipe through the sidewalk, a box of brick is made with a heavy bra.s.s strainer fitted level with the sidewalk into which the pipe runs. If the pipe is run into the box on the side a little up from the bottom, the possibility of becoming stopped up or filled up is not great. The fresh-air inlet sometimes terminates above the roof of the building.

Special care should be given this fresh-air inlet as it supplies fresh air to the entire system and thus keeps the pipes in a much better sanitary condition.

Sometimes when the house drain is full of sewage, air is pushed out of the fresh-air inlet and disagreeable odors are evident. This is why it should be located as far as possible from any window.

Special care should be taken on the part of the plumber not to locate the fresh-air inlet nearer than 15 feet to the fresh-air intake of the heating system.

[Ill.u.s.tration: FIG. 60.--Fresh-air inlet.]

When the pipe pa.s.ses through the foundation wall, the same care should be exercised as with other pipes. That is, if the pipe is 4 inches, a sleeve 6 inches should be cut in the wall for the 4-inch pipe to pa.s.s through.

POINTS TO REMEMBER ABOUT FRESH AIR.--

_First_, never should be smaller than 4 inches.

_Second_, one size smaller than trap.

_Third_, location, directly back of trap.

_Fourth_, leads to outer air.

_Fifth_, keep away from windows and intake of heating system.

_Sixth_, always have end of pipe covered with strainer, cowl, or return bend.

_Seventh_, make as few bends as possible.

_Eighth_, supplies fresh air to system.

DRUM TRAP

The use of the drum trap is very handy to the plumber as well as efficient and practicable when installed. The trap can be purchased without any outlets or inlets, so the plumber can put them in according to the necessary measurements. The making of these traps with lead is explained in the chapter on Wiping Joints. The open end has a bra.s.s clean-out screw on it. When this clean-out screw comes below the floor, another bra.s.s screw cap and f.l.a.n.g.e is screwed on the floor above the trap so that the clean-out screw in the trap is easily accessible.

[Ill.u.s.tration: FIG. 61.--Drum trap.]

These drum traps are called bath traps as they are used mostly on bath wastes. They should never be installed with the clean-out exposed to the sewer side of the trap. In the best practice, heavy bra.s.s drum traps are used.

NON-SYPHONING TRAP

[Ill.u.s.tration: FIG. 62.--Flask trap.]

[Ill.u.s.tration: FIG. 63.--Clean-sweep trap.]

After years of experimenting to produce a trap that would not syphon without venting, we find in use today a large variety of non-syphoning traps. Traps that will hold their seal against all practical forms of syphonic action, or other threatening features, have been made and used and serve the purpose for which they are intended. Various means to prevent the breaking of the seal of these traps are employed. While some depend on a ball or other kind of valve, others rely on part.i.tions and deflections of various kinds. All of these perform the functions for which they are designed, yet the devices employed offer an excellent obstruction for the free pa.s.sage of waste; therefore, in time, these traps become inoperative. It should be borne in mind that any traps with a mechanical seal or an inside part.i.tion are not considered sanitary. The inside part.i.tion might wear out or be destroyed and thus break the seal without the knowledge of anyone and allow sewer gas to enter the room. The mechanical device may also be displaced or destroyed, leaving the trap without a seal. If the trap were cleaned out often or examined occasionally, these traps could be used with a greater degree of safety. Some of the forms of non-syphon traps in common use are:

The _Flask Trap_, Fig. 62. This trap gets its name from its shape. There is an inside wall upon which the seal depends.

This trap is like the bag trap, only the two inside walls of the pipe are combined into one. This wall should be of heavy cast bra.s.s, free from sand holes.