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, which, however, is of little consequence so long as the means for pro ducing 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.
Local vent stacks are round or rectangular, and are made of galvanized sheet iron. Unlike the soil or supply pipe system, the stack system is made proportional; that is, the area of the stack at any point is an approximation to the aggregate area of all the vent branches that have been connected into it up to that point. The local vent stack is sometimes carried into the same shaft which incloses the smoke-pipe from the boilers. In other cases it is connected with an exhaust fan driven by power, usually supplied by an electric motor, thus insuring a constant air-current. Bowl or local ventilation is not generally installed in dwellings. The closet does not receive such frequent usage in private houses as in larger buildings such as hotels, offices, etc.; and in the smaller structures there is no hot flue that can be depended upon for purposes of aspiration. If led to the open air, the vent will act very well in warm weather; but during the winter months it will be likely, through reversal of the current, to gyring in cold air and disseminate the odor through the apartment.
Soil Pipe and Fittings. Under the head of specialties, many forms of patented soil-pipe traps and fit tings have been placed on the mar ket from time to time, with a view to lessening labor and cost and simplifying the work of roughing-in for plumbing fixtures. Of these, a singular instance of the use of one type will be noticed. Fig. 167 illus trates a well-known line used in roughing-in for the toilet-rooms of a double-flat building. Being drawn
in perspective, the function and merit of every fitting shown is self evident. Fig. 168 gives in plan view the roughing-in shown in Fig. 167. The location of the fixtures on the floor below thz plan of piping, is indicated in solid lines by a, b, and c. On other floors, corresponding fixtures for the stack shown, are of course superimposed as a matter of economy and convenience. Fig. 169 is a broken general view of the waste and vent stacks for the laundries and kitchen sinks of the same building, the roughing-in work and some of the fixtures being shown. The regular standard soil-pipe and fittings can be made to answer for any case, although incon venience and additional ex pense are of ten incurred in working fit tings of stand ard dimen sions in close quarters. .
There are several weights of soil pipe and fittings used, varying with the building or with the requirements of city or state sanitary laws, etc. The weight known as standard is sometimes used on buildings under four stories in height, and for vent pipes and soil-pipe extensions above the highest fixture. Extra heavy pipe and fittings are used in tall buildings and in most ordinary work, for all soil and waste purposes below the highest fixture. The standard length of soil pipe for all ters, is five feet, exclusive of hub.
Fig. 170 shows a regular single-hub length. Fig. 171 represents the double-hub length employed to avoid the use of double-hub fittings and extra joints where less than full lengths are required in cases where the cost of regular extension pieces would exceed the price of double-hub pipe. Fig. 172 is a quarter-bend with double hub. It is of the long-sweep or long-radius pattern. The whole list of standard regular fittings is made in the long-radius pattern. They should be used where possible; but the shorter-radius type, sponding to that shown in Figs. 173 to 180, is most generally employed because the little room available enables the plumber to lay lines in places where cramped con ditions make the use of the long radius impossible.
One-sixteenth, one eighth, one-sixth, one fourth, and return bends embrace the regular list of soil-pipe bends, giving a range in angles from 221 to 180 degrees in the same plane; and, by winding them, giving a twist to the joints, almost any angle with the original direction can be obtained.
A wider range of bends is offered in the recessed and threaded cast-iron drainage fittings for use with wrought pipe. Omitting the pitched ells and tees for regular fall, 51 degrees is the most obtuse fitting regularly made.