Fig. 36.--Laying of plank for trench dug in sandy ground.Fig. 36.—Laying of plank for trench dug in sandy ground.
Fig. 36.--Laying of plank for trench dug in sandy ground.Fig. 36.—Laying of plank for trench dug in sandy ground.
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 tampingthe 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 (seeFig. 37).
Fig. 37.--Arrangement of plank for gravel.Fig. 37.—Arrangement of plank for gravel.
Fig. 37.--Arrangement of plank for gravel.Fig. 37.—Arrangement of plank for gravel.
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 least1⁄4inch 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 islaid 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 inFig. 38allows for this, also allows for the proper cementing of joints. To get the proper pitch of pipe, take for example1⁄4inch per foot, a level 2 feet long with a piece of wood or metal on one end1⁄2inch thick will answer. The end with the1⁄2-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 the1⁄4-inch fall per foot. If a tile trap is used, it should be laid level, otherwise the seal will be weakened or entirely broken.
Fig. 38.--Laying terra-cotta pipe.Fig. 38.—Laying terra-cotta pipe.
Fig. 38.--Laying terra-cotta pipe.Fig. 38.—Laying terra-cotta pipe.
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 untilthe 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 (seeFig. 39). The cement used should be1⁄2cement and1⁄2clean 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.
Fig. 39.--Showing use of the swab.Fig. 39.—Showing use of the swab.
Fig. 39.--Showing use of the swab.Fig. 39.—Showing use of the swab.
Fig. 40.--Pushing pipe through tunnel.Fig. 40.—Pushing pipe through tunnel.
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 thencement 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 inFig. 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 (seeFig. 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.
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 inexperiencedmen 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.
SizeThickness,inchesWeight per ft.,poundsDepth ofsocketAnnular space31⁄2711⁄21⁄441⁄2915⁄83⁄855⁄81213⁄43⁄865⁄81517⁄83⁄883⁄42323⁄8913⁄162323⁄8107⁄83521⁄83⁄81214521⁄41⁄21511⁄86021⁄21⁄21811⁄48523⁄41⁄22013⁄810031⁄2
Terra-cotta pipe should not be permitted in filled-in ground.
Roots of trees find their way into the pipe through cracksor 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 a1⁄2-inch tap is furnished. The water company taps the main, at the expense of the plumber, and inserts a corporation cock.
Fig. 42.--Showing water main and sewer in same ditch.Fig. 42.—Showing water main and sewer in same ditch.
Fig. 42.--Showing water main and sewer in same ditch.Fig. 42.—Showing water main and sewer in same ditch.
Digging Trench.—The trench for the water main should be dug at least 41⁄2feet 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 cutout 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 (seeFig. 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 (seeFig. 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 pointFig. 43should 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 letterS 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. of5⁄8lead 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.
Fig. 43.--Water main from street to foundation wall.Fig. 43.—Water main from street to foundation wall.
Fig. 43.--Water main from street to foundation wall.Fig. 43.—Water main from street to foundation wall.
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 controlthe 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 lastunder ground.
Galvanized iron, heavy lead, and brass are used. Wooden pipes were once used and stood years of service. No service smaller than 11⁄4should 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).
Fig. 44.--Free space around pipe passing through wall.Fig. 44.—Free space around pipe passing through wall.
Fig. 44.--Free space around pipe passing through wall.Fig. 44.—Free space around pipe passing through wall.
Points to Remember.—
Fig. 45.--Sub-soil drain.Fig. 45.—Sub-soil drain.
When a building is erected on a site that is wet or springy, some means of carrying off the surplus water in the ground must be provided for, or the basement of the building will be flooded with water. For the thorough understanding of the methods employed in laying a drain of this kind, I will go over it carefully and the beginner can read it and then study it, and understand just how it is done. A site may appear to be dry on the surface of the ground and yet be very wet under the surface. If no information can be had regarding the site, it is always well to drain the site if it is on a slope or near a body of water and on the water shed of a river or lake. If a building is a large one and the foundation goes down very deep, the site should always be drained. The drain is laid under the basement floor and around the outside of the foundation wall on a level with or lower than the basement floor. The value of draining a building site when the building is first started is very often overlooked. The cost of the drain will be saved in a few years as the basement will be free from all excessive dampness. The expense of installing a sub-soil after the building is up and in use is great as well as inconvenient. The drain is called "sub-soil drain" on account of its location under the ground and on account of its dutyof taking off all surplus water that is underground. With the surface water taken off by the surface drains and the sub-soil drained by the sub-soil drains, a wet building site can be made practically dry (seeFig. 45).
Materials Used in Sub-soil Construction.—The object of the drain is to collect water and carry it away from the building by means of pipes. Terra-cotta pipes, with or without hubs, are used. Perforated tile pipe is sometimes used. This pipe is unglazed terra-cotta pipe with 1-inch holes in the sides about 3 or 4 inches from the center. These holes allow the surplus water to enter the bore of the pipe and thus be carried off beyond the building site.
When the sub-soil of a small building needs draining, the trenches made for the house drain and its branches are used as a drain in the following manner: The trenches are dug deeper than is required for the house drain. The trenches are then filled to the correct level with broken stones. There is space between these stones for the water to find passage to a point away from the building. When this method is employed, some provision must be made to prevent the house drain from settling. When locating the drain, we must consider approximately the amount of water that is likely to be in the soil and required to be carried off. If there is considerable water, the pipes should extend all around the outside of the building foundation wall, also a main pipe running under the cellar bottom with six branches, three branches on each side.
If there is not a great deal of surplus water in the soil, the drain around the outside of the foundation wall should be put in and one drain line running through the basement will be sufficient.
Laying the Pipe.—The drain pipe should be handled with care, for it is easily broken. The trench should be laid out and dug, then the pipe can be laid in it with a grade toward the outlet or discharge. If pipes with a hub on one end areused, the hub should not be cemented. A little oakum is packed in the hub to steady the pipe and keep sand out, the bottom of joint is cemented, a piece of tar paper can be laid over the top of the joint to keep the sand out. With joints made this way, the water can find its way to the bore of the pipe and yet the sand will be kept out of the pipe. As soon as the water gets into the bore of the pipe it has a clear passageway to some discharge point away from the building. If tile pipes without any hubs are used, some covering should be put around the joint to keep out the sand and still allow the water to find its way into the pipes.
Discharge of Sub-soil Drain.—The water that accumulates in a sub-soil drain must be carried off to some point away from the building. As the pipes are generally under the cellar bottom and under the house drain, it is very evident that this drain cannot discharge into the house drain sewer, directly. If the building site is on a hill, the drain can be carried out and discharged on the surface at a point that is somewhat lower than the level of the pipe under the building. Where this cannot be done, it will be necessary to have the different lines of pipes discharge into a pit. The water is accumulated in this pit until it is filled, then it will automatically empty itself as later explained.
Pit Construction.—The pit for the sub-soil water is constructed of cement. A pit 2 feet square or 2 feet in diameter and 3 feet deep will answer all requirements. A pit of this depth will allow a pitch for all lines of pipe, and is large enough for ordinary installations. The pit is built up to the surface of the cemented floor of the basement and covered with a removable iron cover.
Cellar Drainer or Pump.—A cellar drainer is employed to empty the above-mentioned pit. The cellar drainer works automatically. When the pit is filled with water, the drainer operates and empties the pit and dischargesthe water into a sink or open sewer connection. When the pit is emptied, the drainer shuts off. The cellar drainer is operated by water pressure. When the valve is opened, a small jet of water is discharged into a larger pipe. The velocity of this small jet of water creates a suction and carries along with it some of the water in the pit. This suction continues until the tank is empty. There should always be a strainer on the suction pipe, also on the supply pipe, to prevent any particles of dirt getting into the valve. The pipes leading to and from the drainer should empty into an open sink where it can be seen. There is a possibility of the drainer valve leaking and then the water pressure will leak through it, causing a waste of water. If this leakage can be seen where it discharges, then the trouble can be rectified. The cellar drainer is connected directly with the water pressure and should have a valve close to the connection to control the supply.
The accompanying drawing of storm and sanitary drains should be studied in detail by the reader. The location of each trap and fitting should be studied carefully and the reason that it is put in that particular place should be thoroughly understood. Below, each plan has been taken and gone over in detail, bringing out the reasons for fittings and traps, also the arrangement of the piping.
Fig. 46.Fig. 46.
The first thing to note inFig. 46is the number and kinds of fixtures to be drained. There is in the basement a set of three-part wash trays. This will require a 2-inch waste and a 11⁄2-inch vent. There is in the drawing a 2-inch waste extending to the fixtures above. On the same line is a rain leader with a trap showing also a 4-inch floor drain. There are two 4-inch rain leaders on the opposite corners of the plan, in the rear of the building. There is a 4-inch soil stack for fixtures above and a 4-inch soil stack in the basement on the same line for a basement toilet. On the front there are rain leaders in each corner. These will be connected outside of the house trap (this feature should be noted). The outlets that are to discharge into the house drain are as follows:
Two 4-inch rain leaders.One 2-inch sink waste.One 2-inch wash tray waste.One 4-inch floor drain.One 4-inch soil pipe.One 4-inch closet connection.Two 4-inch front rain leaders to discharge into house sewer.
If we were to install this job, we would first locate each pipe that enters the house drain. The lowest outlet would be particularly noted, in this case the 4-inch floor drain. From this drain we must make sure that at least1⁄4inch to the foot fall is secured. We must then locate the house sewer where it enters the foundation wall, then the work can be started. I will not attempt to list the material that is necessary for this work, at this time. With all the material at hand the house drain is started. All of this work is installed under the ground, therefore trenches must be dug for all the piping. The plumber must lay these trenches out and in doing so he must have in mind all connections and the fittings he can use so that the trenches can be dug at the right angle. The trenches must be dug allowing a pitch for the pipe. The height of the cellar is 8 feet below the joists. A stick is cut 8 feet long which can be used to get the trenches below the cement floor at the right depth. After the digging is completed, the house trap, which is a 6-inch running trap, is caulked into a length of 6-inch cast-iron pipe. This piece of pipe is pushed out toward the sewer bringing the trap near the foundation wall, on the inside. The fittings and traps and pipe are caulked in place as fast as possible. When possible, the joints are caulked outside of the trench in an upright position. There are a number of different ways to caulk this pipe together, and to make it clear to the beginner just how it is done the following exercise is suggested. This job brings in the caulking of pipes, traps, and fittings in variouspositions. Two or three can work on this job together.Fig. 47shows how the pipe and fittings are put together, which needs no further explanation. Therefore, we will go over in detail only the caulking of the joints in the various positions.
Fig. 47.Fig. 47.
Fig. 47.Fig. 47.
Material Needed.—One length of 4-inch extra heavy cast-iron pipe, single hub; two lengths of 4-inch extra heavy cast-iron pipe, double hub; one running trap, one full Y, one 4-inch1⁄4bend; two 4-inch clean-out screws with iron body; one 4-inch vent cap; one 4-inch1⁄8bend; 30 pounds of block lead; 2 pounds of oakum.
Tools Required.—Ladle, asbestos pourer, hammer, cold chisel, yarning iron, two caulking irons, furnace and pot.
The beginner should start at the trap and caulk the joints with the trap held in place. The cold chisel should be sharp as it is used to cut the cast-iron pipe.
To caulk the straight end of cast-iron pipe into the hubend and make a water-tight joint when the pipe is in a vertical position, the spigot end of the pipe is entered into the hub end of another piece. A wad of oakum is taken and forced into the hub with the yarning iron. This piece of oakum is forced to the bottom of the hub, then another piece is put in. The oakum is set and packed by using the yarning iron and hammer. The hub is half filled with oakum. The oakum is forced tight enough to make a water-tight joint. If the oakum used comes in a bale, pieces of it will have to be taken and rolled into long ropes about 18 inches long, the thickness of the rope corresponding with the space between the hub and the pipe. If rope oakum is used, the strands of the rope can be used. After the oakum is well packed into place and the pipe is lined up and made straight, molten lead is poured in and the hub filled. When the lead has cooled, set the lead with the caulking tool and hammer, making one blow on each side of the joint. This sets the lead evenly on every side. If there is any surplus lead, it can now be cut off, using the hammer and cold chisel. The caulking iron is again taken and the lead next to the pipe is tamped, striking the iron with the hammer at an angle to drive the lead against the pipe. After this has been done all around, the caulking iron is held in such a position that the lead around the hub will receive the force of the blow. After this has been done, the center of the lead is caulked and the joint should be tight. With a little practice, this can be done very rapidly. The lead should be poured in while it is very hot. The caulking must not be done by hitting heavy blows as there is a possibility of splitting the hub and thereby rendering the joint unfit for use.
Caulking Joint in Horizontal Position.—It is necessary in a great many cases to caulk a joint in a position where the lead would run out of the joint unless provision were made to hold it in. To caulk a joint in a position of thiskind, the pipe is lined up and secured, then the oakum is put in and forced to the bottom of the hub. Then a joint runner, which is an asbestos rope about 2 feet long and about 1 inch in diameter, is fitted around the pipe and forced against the hub where it is clamped by means of an attached clamp. The clamp is put on the top of the pipe and so arranged that a channel will be left in a V shape. This channel allows the hot lead to run between the asbestos runner and the hub. When the lead has had a chance to cool, the asbestos runner is taken off. Where the clamp was, there will be a triangular piece of lead sticking out beyond the face of the hub. This piece has to be cut off, but no attempt should be made to do so until it has been caulked in place and well set; also the rest of the lead should be set. Then the cold chisel can be used and this extra piece of lead taken off. The caulking of the lead in this position is the same as in the previous position and should be carried out closely. The beginner should understand that it is necessary to have not only the joints tight so that running water will not leak out of them, but that the joints must stand a water test. The testing of soil stacks is explained under another heading. The lines of cast-iron pipe depend to a considerable extent upon these joints to make the whole line rigid.
Caulking of Fittings.—The caulking of fittings, while done the same as a straight pipe, is far more difficult. The improper making of these joints is the cause of many leaks. A long sweep fitting is caulked without a great deal of difficulty. If a short bend fitting is used, the matter of caulking is difficult. The fitting is so short that it is almost impossible to get a caulking iron into the throat. The mechanics will have to work at the throat from each side until this part has been sufficiently caulked. I call attention to this point, for I know it to be a failure in a large number of jobs when it comes to put the test on. Inorder to caulk the fittings, they must be put in their exact location and positions before the lead is poured in, for after the lead is once in the fitting cannot be moved. When there is a series of fittings on a line, their positions in relation to each other must be considered before the lead is poured.
Fig. 48.Fig. 48.Fig. 49.Fig. 49.Fig. 50.Fig. 50.Fig. 51.Fig. 51.
Fig. 48.Fig. 48.
Fig. 49.Fig. 49.
Fig. 50.Fig. 50.
Fig. 51.Fig. 51.
Fig. 48shows the same fixture and stack connections asFig. 46. Two 4-inch lines run through the cellar, one a sanitary drain, the other a storm drain. Each 4-inch line has an intercepting trap. On the sewer side of these traps the two lines are brought together, beyond which point the two front rain leaders connect; each of the two front leaders is trapped separately.
Fig. 52.Fig. 52.
Fig. 52.Fig. 52.
Fig. 49differs from the preceding one in only two points. First, the two front leaders are brought into the cellar and connected into the storm drain on the house side of the intercepting trap. Second, the storm and sanitary drainsare connected on the outside of the building.
Fig. 50shows the same fixtures collected into a 4-inch house drain, and the rain leaders run entirely on the outside of the building. This plan is a good one as all the storm water is kept entirely outside the building. If the storm drains are kept 5 feet away from the cellar walls (seePlumbing Code) the pipes can be of tile. Another good feature of this plan is that all the pipes under the cellar are 4-inch.
Fig. 51is similar toFig. 46, the difference being in the location of the floor drain and the connection of the two rear rain leaders, into the house drain.
InFig. 52the drains shown take the waste and storm water from the apartment building, also a building set in the rear. The leader pipes in this case are trapped on the outside of the wall. The building in the rear you will note has a separate fresh air inlet and house trap, and the house sewer is continued through the front house and connected into the house drain of the front building, on the sewer side of the intercepting trap.
These drawings should be studied carefully and the student should in each case list correctly all of the material required for the installation of these jobs.