On page 97 is represented the simplest type of drainage system that can be installed in the small house, but since it uses anti-siphon traps and no back-venting, it will not be possible to make use of it in all cities or towns which have plumbing rules prohibiting it. The average small house does not have room for more than one bath, a kitchen-sink, a set of laundry-tubs, and a toilet for the servant, generally placed in the cellar.
For purposes of economy it is essential to place all of these fixtures on the same soil-line, the main pipe which extends vertically from the horizontal house-drain in the cellar up through the roof. If the bathroom is so located that the vertical line which serves its fixtures cannot serve the kitchen-sink or the laundry-tubs, then a special waste-line or small vertical pipe draining fixtures other than water-closets, must be carried up and through the roof, which is extravagant of material. As this waste-line will be only 2 inches in diameter, it is necessary to increase its diameter to 4 inches before projecting it from the roof, since it may become clogged in the winter with frost.
PLUMPING SYSTEM USING ANTI-SYPHON TRAPS-.
But the main soil-line is 4 inches in diameter and needs no in-creaser on it. The main house-drain is also made 4 inches in diameter, and is generally laid under the cellar floor with a pitch of 1/4 inch to the foot. At the junction of the vertical soil-line with it, and also at any other point where there is a marked change in direction, the house-drain should be equipped with clean-out holes, covered with brass screw-caps. Just where the house-drain leaves the house, a house-trap is installed (see illustration), and back of this an inlet for fresh air to permit the circulation of air in the system. The foundations should be arched over the house-drain where it passes through them, so that any settlement of the masonry will not come upon the pipe and cause it to be broken.
The material of which the house-drain, soil-line, and waste-line are made is usually cast iron, and of a grade known as extra heavy. The joints are the bell-and-spigot type, which are stuffed with oakum and then closed tight with 12 ounces of fine, soft pig lead for each inch in diameter of the pipe. Branches are usually of galvanized wrought iron or lead, but lead should be limited in use in modern plumbing, although the term plumbing originated from the Latin word for lead. The common limitations upon the length of branches of lead pipe are: 8 feet for 1 1/2-inch pipe, 5 feet for 2-inch pipe, 2 feet for 3-inch pipe, 2 feet for 4-inch pipe. The parts of the branch pipes which are visible are generally made of brass nickel-plated. The joints between lead pipe and lead pipe, and between lead pipe and brass pipe, are made by the common wiped joint. Joints between lead pipe and cast-iron pipe are made by first wiping the lead pipe to a brass ferrule, a piece of pipe in shape like a bell with the top cut off, and then inserting and caulking this into the cast-iron pipe. The joints between wrought-iron pipes are made with the screw joint, and between wrought iron and cast iron with the screw joint, by using connections of malleable cast iron which have been threaded.
The usual sizes for branch wastes from the fixtures are as follows: for water-closets 4 inches, for bathroom-tubs 1 1/2 inches, for lavatories 1 1/2 inches, for kitchen-sinks 2 inches, for laundry-tubs 1 1/2 inches, and when in sets of three 2 inches. The size of the waste from the bathroom-tub can be increased to 2 inches with great advantage, if the additional slight expense is not objectionable.
The vertical soil-lines should be supported at each floor by metal straps placed under the hub and fastened to the floor-joists. It is very important to properly flash the base of the projecting portion of the soil-line above the roof. Wherever the branch soil-line to the water-closet is connected, a short TY connection may be employed in order to avoid the projection of the parts of the pipe beyond the plane of the ceiling in the floor below. However, no short TY connections should be made in any horizontal pipes.
A very important economical consideration should be noted in laying out the arrangement of the bathroom fixtures in this connection. The horizontal branch soil-lines and waste-lines must be carried through the floor construction, and they should be so arranged that they can run parallel with the floor-joists; otherwise deep cuts will have to be made in them. In the case of the branch soil-line it is essential to place the water-closet as near to the main soil-stack as possible, for with a 4-inch pipe the joists must be framed around it rather than be cut, since so deep a gouge would weaken too much the strength of them.
A similar consideration must be given to the framing in stud partitions which are bearing the loads of the floors above, for too deep cuts in them, to allow for the passage of pipes, will weaken them greatly. In this connection it ought to be noted that an ordinary 4-inch soil-pipe cannot be carried in a stud partition made with 2 by 4 studs, since the outer edges of the joints of the pipe will project beyond the face of the plaster, and for this reason some convenient place should be planned for them in closets, or 2 by 6 studs should be used in the partition through which they are run.