Nevertheless, it is a poor practice, and never to be followed if it is possible to construct the work otherwise. While the practice is bad under any conditions, certain methods of performing this work are far better than others. In Fig. 93 two different methods of making the connection .are to be seen, into the heel of the bend, and into the upper part of the horizontal arm. The latter is far preferable to the former. When connected into the heel, the opening is in such a position that paper and other matter may fall into the entrance and result eventually in its stoppage. When so connected the connection is often made so low that soil and other waste has an opportunity to set back into the waste pipe whenever the water-closet is flushed. When connected as high up as possible on the horizontal arm, however, neither of these faults is encountered.
Fig. 93. - Connection of Waste Pipe into Lead Bend.
The connection of a fixture waste into the vertical part of the lead bend is preferable to the heel connection, but not so good as into the horizontal arm.
In any of these connections, however, another serious fault is to be found. In the wiping of the connection onto the lead bend, small spines of solder are extremely liable to project through into the interior of the bend and cause much trouble by the catching of paper, etc., upon them. When other fixture wastes connect into the lead bend, another serious feature presents itself in the fact that the stoppage of the lead bend results in the disabling of all fixtures connected to it.
No fixture waste should ever pass through more than one trap before reaching the house drain, the effect of double trapping being to cause air-lock between the two traps, which acts to impede the flow of waste through the pipe. Where an abrupt change is made in the direction of a pipe, on the drainage system, a cleanout should be used at that point. End cleanouts should be used as seen in Fig. 89, at the ends of horizontal lines. In running such horizontal lines no dead end should ever be left. By dead end is meant an extension of drainage pipe beyond the last entrance of waste into it. Thus, in Fig. 89, if the house drain were extended beyond the point where the cleanout is, and no waste entered this extension, it would become a dead end. The dead end not only serves no useful purpose, but soon fills with filth, and aids materially in fouling the drainage system.
In the running of drainage pipes, whether on main or branch lines, all offsets should be made at 45° if posssible, this giving a much easier passage for the waste than abrupt offset, such as 90°. Formerly it was customary in making an opening into a pipe for a new fixture waste or branch line of waste to use a saddle fitting, such fitting usually being held in position over the opening cut in the pipe, by wrought-iron clamps, the joint between the fitting and the pipe being made with putty. For obvious reasons this practice is now prohibited, it being a most unsanitary method.
The proper method of performing such work is to break out the pipe at the desired point, and insert the necessary fitting. On such work as this the use of insertable fittings has in recent years become universal. There are several such fittings on the market, and in Fig. 94 two of them are shown. It being desired to insert the fitting A to receive a new line of waste, the pipe at this point is broken out and the spigot end of the insertable fitting calked in.
The fitting A is then set in position, and the part F unscrewed until its hub and the spigot of A are together. The several joints are then calked. The part B of the insertable fitting is provided with a coarse cast thread in which the thread on G works. Such a fitting saves much time and makes more satisfactory work, for in many instances in the insertion of fittings into old pipe, several joints on each side of the fitting have to be sprung in order to get the new fitting into position, and it is then necessary to recalk these joints. The other insertable fitting of Fig. 94 is made on a different principle. It consists of a long hub of large diameter, D, into which a ring of soft lead, E, may be calked when the fitting C has been placed in position.
Fig. 94. - The Use of Insertable Fittings.
From what has been stated in previous chapters, it will be seen that in any plumbing system it is necessary that at least one 4-inch pipe shall pass through the roof. Whenever a vent passes through the roof it should extend at least two feet above it.
If a flat roof is used for other purposes than the mere covering of the building, such pipes should extend at least five feet above it.