Fig. 161. Showing Layout of Soil, Waste, and Vent Pipes of Several Groups of

Fig. 161. Showing Layout of Soil, Waste, and Vent Pipes of Several Groups of.

Superimposed Fixtures in Same Building.

Slope. With due respect for appearance, all the fall possible should be given lateral soil and Waste lines. About 3/16 inch to the foot (one degree) is taken as the minimum. With cast pipe and leaded joints, much more than this can be given, by gaining change of direction in setting the joints. With screwed fittings for wrought pipe, tapped, pitched one degree from the nominal angle, less latitude to vary the fall is offered. Considerable variation is possible, however, by cutting pitched threads on the pipe. In positions where the cutting of one pitched thread entails the work of cutting another with the pitch just opposite that of the first in order to follow the perpendicular again, the work is irksome and is seldom resorted to. Cast fittings, threaded, for drainage work, are recessed in the ends, so that, when screwed on the pipe, the pipe and interior of the fitting are of the same diameter, thus presenting no jog or broken edges to favor stoppage. Stoppage of drains of any kind is likely from many causes; and during installation, trap-screw ferrules, or tees with brass plugs, according to the kind of pipe being used, should be provided along the line, as shown in Fig. 162, so as to make the work of cleansing as convenient and inexpensive as possible.

Fig. 162. Trap Screw Ferrules Installed at Intervals to Facilitate Cleaning of

Fig. 162. Trap-Screw Ferrules Installed at Intervals to Facilitate Cleaning of Drain Pipe.

Sizes of Soil and Waste Pipe. The usual sizes for soil and waste work are: 5-inch for ordinary house main (horizontal); 4-inch for 1 to 4 closets; 5-inch horizontal branch from 5-inch stack for a battery of five or more closets; 5-inch stack for any ordinary number of fixtures; main vent stack, same size as soil-stack; loop vent, same size as stack; crown-vent stacks, 2 or 3-inch; slop-sink stacks, 3 or 4-inch; closet connection, 4-inch; closet crown vent, 2-inch; slop-sink connection, 3-inch; slop-sink vent, 2-inch; urinal stacks, 3-inch; urinal branch wastes, 2-inch; urinal trap vents, 1 1/2 to 2-inch; bath stacks, 3-inch; bath-waste connection, 2-inch; lavatory wastes, 2-inch. The 2-inch refers to the size of cast pipe used in the case of lavatories and baths; the lead trap and connections of these, and often of other fixtures, are made l 1/2-inch. Small lavatories often have l 1/4-inch waste. The crown vent is usually one size less than the trap for all but closets and slop sinks. Of late, bath-waste outlets are frequently made 2-inch. Kitchen-sink stacks are made 3-inch; single sinks or branch waste for one sink or set of. trays, 2-inch, with 2-inch trap and l 1/2-inch crown vent.

Local Ventilation. A local vent is a pipe leading air from the bowl of a closet or through the outlet of a urinal to carry away odors with a current of air fed by the air of the room. In Fig. 163 are shown two openings for urinals where the roughing-in provides for local ventilation for the urinal bowls in a way that is equivalent to the local vent pipe to a closet bowl. V is a general vent stack, and W the urinal waste stack. Instead of putting in crown vents for the traps, the branch waste becomes a vent at the junction of the trap branches, and loops back into the general vent stack. There is sufficient ventilation in this case for two reasons - the traps are close to the line; and the current up the main local vent stack is induced and maintained by a fan motor, which, in drawing the odors from the urinal bowl, creates more or less suction on the house side of the trap seals and counteracts the tendency toward siphonage on the sewer side. The roughing-in. shown, is hid by marble slabs in the finished work.

Fig. 163. Local Ventilatio'n for Two Urinals.

Fig. 163. Local Ventilatio'n for Two Urinals..

Fig. 164. Part Section of

Fig. 164. Part Section of.

Locally Vented Urinal and Connection.

A section of the marble back, with urinal and vent and waste connection, is shown in Fig. 164, which makes clear what is meant by local urinal ventilation. The difference between it and local closet ventilation, is that as the trap for the urinal is not in the urinal proper, the current from the room passes through the urinal outlet except while it is flushing; while in the closet the local vent connection is made to the bowl above the visible water-level, because the trap below interferes with connecting it otherwise.

Another plan of local-Venting a urinal is shown in Fig. 165, in which the urinal trap answers as a trap to the floor drain as well, and the local-vent current passes down through the grating of the floor-slab drain and up through the urinal waste to the point where the urinal proper connects. Between the trap and urinal connection, the pipe is a waste and local vent combined, its continuation above the urinal Vent connection being simply a local vent pipe, the area of which being equal to the combined area of the urinal outlet and floor-slab grating, a current also passes from the urinal bowl through its outlet into the local vent pipe. The only fault to be found with this arrangement is the abnormal distance of the trap from the fixture.

Fig. 165. Locally Vented Trap for Urinal and Floor Drain Combined.

Fig. 165. Locally Vented Trap for Urinal and Floor Drain Combined..

which, however, is of little consequence 30 long as the means for producing a current in the local vent stack is doing its duty. Fig. 166 shows the openings left for a battery of closets that are to be set on a tile floor. The uprights connect into a branch soil line below. The illustration is given to show a system of venting which can be used with closets that do not permit of crown venting.