Part 13 (2/2)

_Second_, also to allow free pa.s.sage of air.

_Third_, circuit vent--loop vent.

_Fourth_, continuous venting.

_Fifth_, crown venting.

_Sixth_, ventilation pipe extends from the top of fixture through roof.

CHAPTER XI

HOUSE TRAPS, FRESH-AIR CONNECTIONS, DRUM TRAPS, AND NON-SYPHONING TRAPS

The _house trap_ is a deep seal trap placed inside the foundation wall, and intersects the house drain and house sewer. The trap is placed at this point for a number of reasons: first, to keep sewer gases from entering the pipes in the house; second, this location is where the house drain ends. This trap should have two clean-outs, one on each side of the seal. The clean-outs should be of extra heavy cast-iron body with a heavy bra.s.s screw cap. The cap should have a square nut for a wrench to tighten or unscrew the cap. This cap should be brought up flush with the floor. When a house trap is being set, it is necessary to set it perfectly level, otherwise the seal of the trap is weakened and sewer gases can enter.

Sometimes the trap is located on the house sewer just outside of the foundation wall. In this case, a pit should be built large enough for a workman to get down to it to clean it out when necessary.

_A mason's trap_ was formerly used to a considerable extent, but is very poor practice to use today on modern work. This trap was built square of brick with a center part.i.tion. The brick soon became foul and the trap would be better termed a small cesspool than a trap.

POINTS TO REMEMBER ABOUT HOUSE TRAPS.--

_First_, should be a running trap.

_Second_, two clean-outs.

_Third_, deep seal, at least 2 inches.

_Fourth_, set level.

_Fifth_, set inside foundation wall.

_Sixth_, accessible at all times.

_Seventh_, same size as house drain.

_Eighth_, fresh air should connect with it.

FRESH-AIR CONNECTIONS

The term ”fresh-air inlet” is, as its name implies, an inlet for fresh air. It is placed directly on the house side of the main trap. The connections made vary considerably. A few good connections in common use are explained below.

When the trap is in place, one of the clean-outs can be used for the fresh air. If this is done, a Y-branch should be placed in the hub of the clean-out. The Y-branch should be used for the fresh air and the run should be used for a clean-out.

A Y-fitting can be inserted directly back of the trap and the branch used for the fresh air. An inverted Y makes a good fitting to use directly back of the trap. These branches should be taken off the top of the pipe. The branch taken off for the fresh-air inlet should not have any waste discharge into it and should not be used for a drain pipe of any description.

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