Fig. 40.  Pushing pipe through tunnel. Fig. 40. - Pushing pipe through tunnel.

If the pipe must be run through a tunnel and there are perhaps three or four joints that cannot be reached, they should be put into place as follows: The pipe should be laid in the trench from the sewer in the street as far as the tunnel, then start at the other end of the tunnel. Lay the first piece of pipe on a board, lengthwise with the board, nail two cleats in the shape of a > (Fig. 40) for the pipe to rest in; push this pipe and board into the tunnel and then cement into its hub a second piece; push the two pieces in 2 feet, cement a third length into the second piece and push the three pieces along 2 feet. A workman can be on the sewer side of the tunnel and receive the end of the pipe as it is pushed through the tunnel, and steer the pipe into the hub. The joints in the tunnel will not be as secure as those outside. This explains how pipe is run through a tunnel.

Connecting

The proper method of connecting the house sewer with the street sewer is shown in Fig. 35. The connection should be made above the spring of the arch. The pipe should extend well into the sewer so the sewage will discharge into water and not drop on sides.

Inserting

To insert a tee in a line of pipe already laid, pursue the following method (see Fig. 41): Cut or break out one joint, preserve the bottom of the hub of pipe that is in. Cut away the top of the hub on the pipe to be inserted, then place the pipe in position and turn around until the part of the hub on the piece inserted is on the bottom. The bottom part of the pipes now will have a hub to receive the cement. The top part will have to be cemented carefully, as it is within easy access. This can be done without difficulty.

Fig. 41.  Inserting length of pipe. Fig. 41. - Inserting length of pipe.

While laying the pipe a stopper is used to prevent the sewer gases and foul odors from escaping. This stopper sometimes is of tile, sometimes a plug of paper or burlap. This stopper is sometimes cemented in by inexperienced men and the trouble created can only be guessed at. If a stopper is used, the workman must see that it is taken out.

Refilling

After the pipe is laid and cemented, it should be covered and allowed to stand 24 hours to give the cement time to harden. The dirt should then be thrown in and settled by means of a tamper or by flooding with water. The planks should not be taken out until the trench is well filled. To pull the plank, a chain or shoe and lever will have to be used. Where the tunnels are, dirt will have to be rammed in with a long rammer, care being taken not to disturb the pipe. If the refill is not well rammed and tamped, the trench will settle and cause a bad depression in the street surface.

Terra-Cotta Pipe

Terra-cotta pipe should be straight, free from fire cracks, and salt-glazed. The inside of the hub and outside of the plain end should not be glazed. This allows the cement to take hold.