One of the first pieces of work which a plumber is called upon to do, when building operations commence, is to run in the terra-cotta sewer from the street sewer into the foundation wall.
When the street sewer is laid, Y-branches are left every few feet. A record of the branches and their distance from the manhole is kept generally in the Department of Sewers or Public Works. Therefore, the exact measurement of any branch can be obtained and the branch found by digging down to the depth of the sewer. A branch should be chosen so that the pipe can be laid with a pitch, the same way as the main sewer pitches. This can be done by getting the measurements of two of these branches and choosing the one that will serve best. When there is a brick sewer in the street and no branches left out, the sewer must be tapped wherever the house sewer requires it (see Fig. 35).
Digging Trenches.—After the measurements and location of the house sewer and sewer branches are properly located, the digging of the trench is started. The methods employed to dig the trench vary according to the nature of the ground, that is, whether it is sand, rock, or wet ground. A line should be struck from sewer to foundation wall to insure a straight trench.
Sandy Ground.—If the ground is sandy, the sides of the trench will have to be sheathed or planked and the planks braced so as to prevent the bank caving in. As the trench is dug deeper, the planks are driven down. When the trench is very deep, a second row of planking is necessary. The planks must be kept well down to the bottom of the trench and close together, otherwise the sand will run in. It is well to test the planking as progress is made by tamping the sand on the bank side of the planks.
Gravel.—Where the ground is mostly gravel and well packed, the above method of planking is unnecessary. The bank should have a few stringers and braces to support it. When only a few planks are used the term "corduroy the bank" is used (see Fig. 37).
Rock.—Where rock is encountered, blasting is resorted to. The plumber should not attempt to handle a job requiring the use of powder. It is dangerous in the hands of a person not used to handling it and the work should be sublet.
A sketch of the two methods above for planking trenches is given and a little study will make them clear.
The pipe should be laid on the bottom of the trench to a pitch of at least 1⁄4 inch per foot fall. In laying, the start should be made at the street sewer with hubs of pipe toward the building. The trench should be dug within a few inches of the bottom of the pipe, then as the pipe is laid the exact depth is dug out, the surplus dirt being thrown on the pipe already laid. The body length of pipe should be on solid foundation. A space dug out for each hub as shown in Fig. 38 allows for this, also allows for the proper cementing of joints. To get the proper pitch of pipe, take for example 1⁄4 inch per foot, a level 2 feet long with a piece of wood or metal on one end 1⁄2 inch thick will answer. The end with the 1⁄2-inch piece on should be on the lower hub and the other end resting on the hub of the pipe about to be put in place. When the bubble shows level, then the pipe has the 1⁄4-inch fall per foot. If a tile trap is used, it should be laid level, otherwise the seal will be weakened or entirely broken.
Cutting.—The cutting of tile is not difficult, but must be done carefully or the pipe will crack or a piece will be broken out, thus making the pipe worthless. To cut tile or terra-cotta pipe, stand the pipe on end with the hub down, fill the pipe with sand to the point of cutting. With a sharp chisel and hammer cut around the pipe two or three times and the pipe will crack around practically straight.
Cementing.—If the pipe is free from cracks, the only possible way roots can get into the inside of terra-cotta pipe is through the cement joint. There are two ways of making these joints. Both ways are explained below and are used today on terra-cotta work.
First.—The bottom of the hub of pipe in place is filled with cement and the straight end of the next piece of pipe is laid in place, then more cement is placed into the hub until the space between the hub and the pipe is filled. In a trench, a trowel is rather unhandy to work with, while the hands can be used to better advantage. The cement can be forced into place with the hands and then surfaced with a trowel. The rest of the operation is to swab out the inside joint to remove any cement that perchance was forced through the joint (see Fig. 39). The cement used should be 1⁄2 cement and 1⁄2 clean sharp sand.
Second.—Half of the space between the hub and the pipe is first packed with oakum and then the other half filled with cement of the same proportions as that used above.
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.
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.
|Weight per ft.,
Terra-cotta pipe should not be permitted in filled-in ground.
Roots of trees find their way into the pipe through cracks or cement joints. When the roots get inside of the pipe they grow until the pipe is stopped up. As the roots cannot be forced or wired out, the sewer must be relaid. The writer has seen a solid mass of roots 10 feet long taken out of a tile sewer.
In case terra-cotta is laid in filled-in ground, there is only one way to insure the pipe from breaking. The pipe should be laid on planks. Then, if the ground settles, the pipe will not be broken.
Tapping Main.—The water service for a building is put in at the same time as the sewer is connected and run into the house. For a 11⁄4-service pipe a 1⁄2-inch tap is furnished. The water company taps the main, at the expense of the plumber, and inserts a corporation cock.
Digging Trench.—The trench for the water main should be dug at least 41⁄2 feet deep or below frost level and the trench should be kept straight. When the sewer is put in at the same time, one side of the sewer trench can be cut out after it is filled up to the level of the water main. The water pipe can then be laid on this shelf at least 2 feet away from the original trench of sewer. Sometimes the surface of the ground must not be disturbed. In this case small holes are dug and the pipe is pushed through or driven through under that portion not dug. These places are often tunnelled (see Fig. 42).
In digging in city streets, care should be taken not to destroy any of the numerous pipes encountered.
The trench should be dug straight out from the house so the pipe can be laid and the main tapped straight out from the building. The water companies keep a record of these taps so that in case of trouble the street can be opened and the water shut off. In laying the water service, the pipe from the curb to the main should be laid first. This takes in all the pipe in the street. At the main there is a shut-off in the tap. Another stop with T or wheel handle must be placed just inside the curb line. This is called a curb cock (see Fig. 43). One trench either outside or inside of the curb should be at least 15 feet long so that a full length of pipe can be laid in the trench. It is generally impossible to open a trench the full length the pipe is to be run. A trench 10 feet long is dug, then 8 feet left, and another 10- or 8-foot trench is dug and the two are connected with a small tunnel and pipe pushed through. When the pipe has been put in place between the curb and main, the water is turned on and the pipe flushed out. The valve at the curb should now be shut off, and if there are any leaks they will show. The street part is now ready to fill in. At this point Fig. 43 should be studied. Note the piece of lead attached to the pipe and corporation cock. This piece of lead should be extra heavy and always laid in place the shape of the letter S or goose neck. In case the street should settle, this piece of lead will allow for it. These "lead connections" or "goose necks" are made as follows: 3 ft. of 5⁄8 lead pipe; 1-inch brass solder nipple (wiped on); one brass corporation cock coupling (wiped on).
Laying Pipe.—This lead connection can be screwed on the pipe after the pipe is laid, then bent and coupled on the main with the coupling.
After the pipe has been tested as far as the curb, the trench in the street can be filled as described later. The pipe from the curb to the building can now be laid. If necessary to push the pipe through a tunnel, the end of the pipe should first be capped. Start by screwing a length in the curb cock. If the other end of the pipe comes in a tunnel an additional length must be put on before putting in place so that an end will come in the open trench. When the building is reached and before the stop cock is put on, the valve at the curb should be opened full and the pipe flushed out. The valve can then be put on and water turned on to test the pipe.
Setting Curb Box.—A cast-iron box, adjustable length, with cover should extend from the curb cock to the surface. This makes it possible with a long rod to control the water service into the building. To set a curb box some flat stones should be laid around the curb cock and the box set on these stones. Then the space around the box and pipe should be closed in with brick or other covering to keep the sand from washing in on the curb cock. The box should be adjusted for height and then held in place by placing the curb key rod in place and holding the rod and box while the trench is filled. The refill should be tamped evenly on all sides of the box.
Refill.—In refilling the trench around the corporation cock and goose neck, the greatest care should be taken. The writer has seen cases when indifferent workmen have tossed heavy stones in the ditch and broken off the corporation cock or destroyed the goose neck. After the pipe is covered with 18 inches of refill and tunnels have been filled, water can be run in the trench and will settle the refill.
There are a number of special points concerning water services and taps at mains that should not be overlooked. Take for example a water service pipe which must be run through ground where electricity is escaping under trolley tracks, around power houses, etc. The electricity will enter the pipe and wherever it leaves the pipe a hole is burned. The surface of the pipe in a short time will be full of small pith marks and will soon leak. A good way to add to the life of the pipe under these conditions is to make a star of copper and solder it on to the pipe in the street. Another piece of copper should be put on the pipe near the building. The electricity will leave the pipe by way of the points on the star. This method may not be a cure for electrolysis, but will add to the life of the pipe. Another method employed is to put the pipe in the center of a square box, then fill the box with hot pitch. When this is hardened the pipe will have a covering that will keep out any moisture and bar electricity to a marked degree.
Materials Used.—Galvanized steel pipe does not last under ground.
Galvanized iron, heavy lead, and brass are used. Wooden pipes were once used and stood years of service. No service smaller than 11⁄4 should be used.
When the water service pipe passes through the foundation wall, the pipe should not be built in, but a small arch should be built over the pipe or a piece of XX cast-iron pipe can be used as a sleeve (Fig. 44).
Points to Remember.—