When drains are to be tested for leakage it is necessary to stop them at the inspection eye, either with expanding stops or patent bag stoppers. In the latter case an air pump would be required to inflate the bag (see Fig. 209). Expanding stops (Fig. 210) are more generally used, as being more convenient.

Stopper Relaxed.

Stopper Relaxed.

Stopper

Stopper.

Expanded.

Smoke Rocker.

Smoke Rocker.

Fig. 210.

Smoke Rockets (Fig. 210) should be kept in store by the builder. They have cross bars attached to them, so that they can be laid in a drain-pipe without actually resting on the pipe itself.

Drain Grenades are made of thin glass hermetically sealed. They are charged with a small quantity of pepperment or other chemical filling. They can be discharged into a drain in various ways.

Malacca cane rods are in constant use for drain cleansing. It is only, however, with a lockfast joint, such as that shown in Fig. 211, that there can be little, if any, possibility of parts being left in the drain.

Drain Stoppers Or Plugs 243

Fig. 211.

The "steel cable drain rods"(Fig. 212) are more pliable and more readily put into work, but while they are easily drawn they cannot be driven.

Lime and Sand Screens and Sieves vary in size according to requirements, but are usually about 6 feet high, with 1/4, 3/8, and 1/2-inch meshes of rectangular shape.