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 1-1/2-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 16-2/3. 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 16-2/3 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.
[Illustration: CAST-IRON SCREW FITTINGS FIG. 54.]
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 1-1/2 inches Bath tubs 1-1/2 inches Lavatories 1-1/2 or 1-1/4 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.
VENTS
[Illustration: FIG. 55.--Circuit vent.]
Vents are the most important pipes in the plumbing system. Modern plumbing successfully attempts to make living in crowded and thickly populated districts, as well as in isolated buildings, free from all unpleasant odors and annoyances. This could not be accomplished without the use of vents. Vents relieve all pressure in the system by furnishing an outlet for the air that is displaced by the waste discharged from the fixtures. Another of its functions is to supply air when syphonic action starts, thereby stopping the action that would break the seal of the trap under fixtures. The pipe extending from top fixture connection, up to and through the roof, is called the ventilation pipe. All vents that do not pass directly through the roof terminate in this ventilation pipe.
To explain the use of vents, we might well start in the basement of a dwelling house. Suppose there is a set of wash trays in the laundry; the 2-inch trap of these trays should have a 1-1/4-inch vent pipe leading from the crown of the trap up along side of the stack. On the first floor a 1-1/4-inch pipe from the crown of the kitchen sink trap will lead into it. Here the pipe should be increased to 2 inches. On the second floor the 1-1/4-inch pipes leading from the lavatory and bath traps come into it. The vent stack now extends up into the attic and connects with the ventilation pipe. In a general way, the above is an example of venting. The old method of venting was very complicated and is almost beyond describing with the pen.
[Illustration: FIG. 56.--Loop vent.]
In common use today, there are several kinds of venting, namely: circuit and loop venting, crown venting, and continuous venting.
The _circuit venting_, Fig. 55, is used in connection with the installation of closets. Take a row of toilets in which the waste connection of each closet discharges into a Y-branch, and there will be a series of Y-branches. One end of this series of branches discharges into the main stack while the other end continues and turns up at least to the height of the top of the closet and then enters the main vent stack. When this main vent runs up along side of the main stack and forces the vent pipe connected to the series of Y-branches to travel back, it is called a loop vent. This type of vent supplies air to the complete line of toilets and is very efficient.
[Illustration: FIG. 57.--Continuous vent.]
[Illustration: FIG. 58.]
CONTINUOUS VENTING, Figs. 57 and 58, applies more to fixtures other than toilets. A P-trap is used and enters a T in the stack. The lower part of the T acts as and connects with the waste pipe while the upper half is and connects with the vent pipe. A study of the figures will aid the reader to understand thoroughly the above explanations. In continuous venting the waste of the lowest fixture is discharged into the vent pipe and extended to the main waste stack where it is connected. This is done to allow any rust scales that occasionally drop down the vent pipe, and render it unfit to perform its duty, to be washed away into the sewer.
CROWN VENTING, Fig. 59, is as its name implies, a vent that is taken from the crown of the trap, thence into the main vent.
Each one of these methods of venting is used and considered good practice, provided it is properly installed and correctly connected with the use of proper fittings.
[Illustration: FIG. 59.--Crown venting.]
THINGS TO REMEMBER.--
_First_, venting is to prevent traps from syphoning.
_Second_, also to allow free passage 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 brass 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 partition. 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.