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 an 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.

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.

Whenever a branch line of soil or waste pipe is extended 15 feet or more from the main soil or waste stack into which it is connected, the branch should be carried through the roof.

Soil, waste, or vent pipe should ordinarily not be carried on the outside of any building. Such a prohibition is imperative in a cold climate, but there is not so much to be said against it when practiced in a warm climate, where there is no trouble from frost to be feared. When a building adjoins another of greater height having doors or windows overlooking the lower building, the openings of all roof pipes coming through the roof of the lower building should be at least 12 feet from windows and doors in the higher building, and no roof pipe should be closer than 6 feet to any chimney opening. It is quite customary to use a wire basket or other protector to cover the open end of a roof pipe, but there is something to be said against the practice. The meshes of the basket being somewhat close together furnish opportunity for the collection of frost over the basket in cold weather, resulting in the entire or partial stoppage of the vent opening. The practice, however, would not be open to objection in warm climates and would act as a protection against the entrance through the roof pipe of leaves, etc.

The roof connection is made in a variety of ways, either with sheet lead or with patented roof flanges. In Figs. 95 to 100 are shown several of these connections. Fig. 95 shows a device that is, perhaps, used more extensively than others. It consists of a castiron hub riveted to a copper flange, the latter being nailed to the roof as shown.

The roof flange of Fig. 96 is also a patented device, consisting of a lead body attached to a copper flange, having at its upper end an iron ring into which a lead ring is calked. The use of the soft lead ring obviates the necessity of carrying a pot of molten metal to the roof with which to make the lead joint. Fig. 97 shows a flange which may be used on roofs of any pitch, the joint being made by a

rubber ring which encircles the pipe. Unless the surface of the pipe is smooth, the rubber is not liable to make perfect contact around the entire circumference, in which case leakage of water down the outside of the pipe will follow. Moreover, the life of rubber is not of long duration, when exposed to the air and weather, and soon loses its elasticity. Fig. 98 shows a method often followed by the workman in making his own roof flange, as does Fig. 100 also. In Fig. 98 the sheet lead is flanged over and down into the

FIG. 101.-Connections between Lead-, Wrought- and Cast-Iron Pipes.

hub. When the lead joint is poured and calked, a very satisfactory piece of work results. In Fig. 100 the sheet lead forms an upright collar around the pipe, and after the joint is poured and calked the end of the collar is rounded over as shown. Fig. 99 shows a very satisfactory roof flange, in the use of which leakage of roof water down the pipe is an impossibility. A very popular feature of this device is the fact that no lead joint has to be poured and calked on the roof. This is a point much appreciated by the workman, as it is often difficult, particularly on steep roofs, to melt and pour