Fig. 307. - Diagram Illustrating the terms "Sewer" and "Drain".

If we examine the basement plan, we find that there are sinks in the scullery from which the wastes will have to be carried away; this will necessitate the drain being laid deep enough to drain the gully, which must be placed in the area at z to receive the wastes from the two sinks. This should be a flushing-rim grease gully, which may be cleansed from a flushing-tank fixed at E. If we refer to the first-floor plan we shall find a dressing-room over the scullery, so the waste-pipe F from the lavatory basin may be carried down to feed the cistern, as also that from the overflow n from the cistern fixed on the second floor. In the same area at a is a Sykes's gully with three unions, one for the waste from the clean-water sink d in the scullery, another for the waste from the foul-water sink in the scullery, another for the waste from the bath at B on the first floor, and from the lavatory basin at 0 in the bath-room.

Fig 308.   Drainage for a Block of Four Houses.

Fig 308. - Drainage for a Block of Four Houses.

The two branch drains from A and E will join in manhole No. 5, and from this will be laid a drain to the rain-water pipe R, with a through connection to an upcast ventilator at v. The drain from the south side of the house will enter the intercepting chamber at p1.

On the west side of the house there are no waste-pipes from the basement, but there is the servant's w.c, and if we examine the plans closely we shall find that the cloak-room w.c. and the W.c. on the first floor are immediately over this, so that one soil-pipe h will serve for the three closets. At J is the waste-pipe from the cloak-room lavatory. These two branch drains will form a junction with the main drain in manhole No. 2, into which the branch from the rain-water pipe at the corner r may he connected.

At the angle where the main drain is required to turn, so that the branch drains from the north side may be picked up, a manhole (No. 3) should Informed having a suitable curved channel. On this side of the bouse, on the ground-floor, there is a maid's pantry, in which is a sink k for washing china, glass, silver, etc, and immediately over this room on the second floor is a housemaid's closet with slop-sink l. As this is the head of the main drain, it i-desirable that there should be a flushing-tank connected with it; this can conveniently be done by dividing the manhole No. 4 into two chambers, the lower one receiving the branch drain from L, and in the upper fixing a syphon flush ing-leg, utilizing the waste-water from K and the rain water from R R for flushing purposes. The pipe at l, l>eing constructed as a soil-pipe. will serve as a ventilator.

The various sanitary appliances denoted on the plan, together with the methods of designing and constructing the drain, and a consideration of the materials to be used, are referred to in subsequent chapters.

The illustration just described will serve for most types of houses, modifications being introduced to suit the special circumstances met with in each case, provided the principles are not departed from. In the arrangement of town houses, and especially in London, it is not, however, always possible to carry the drains entirely outside, as usually there is no access to a tack road, so that the drain must be carried under the house from back to front. The best method of doing this is by using iron pipes, and following the directions as to ventilation bid down in the Model By-laws (see No. 62), but there are also other means which will be subsequently pointed out.