Gas Fitting Pipe And Fittings Threading Measuring And Testing


Gas is in common use in all classes of buildings today. Dwellings use it for cooking and illuminating, factories, office buildings, and public buildings for power. In some parts of the country natural gas is found. In these places it is used freely for heating fuel. The actual making of gas is something that every plumber should understand. If space permitted I would describe a gas plant with all of its by-products. However, we shall d

al only with the actual installation of gas piping in buildings. Gas mains are run through the streets the same as water mains are run. Branches are taken off these mains and extended into the buildings requiring gas. The gas company generally installs the gas service pipe inside of the basement wall and places a stop cock on it free of charge. This stop that is placed on the pipe is a plug core type, the handle for turning it off is square, and a wrench is required to turn it. The square top has a lug on it. There is also a lug corresponding to it on the body of the valve. When the valve is shut off, these two lugs are together. Each lug has a hole in it large enough for a padlock ring to pass through. This gives the gas company absolute control of the gas in the building.

Setting of the Meter.—Every building that is supplied with gas has a meter that registers the amount of gas consumed. This meter is placed on the service pipe on the house side of the above-mentioned stop cock. This meter is furnished free of charge with a trivial charge made for setting up. The actual setting of this meter is not made until the piping throughout the building has had a thorough and satisfactory test and is found free from all leaks. The meter must be set level on a substantial bracket and in a place, if possible, where it will not require an artificial light to read its dial. The dry meter is usually used in dwellings. The interesting construction and mechanism of this meter cannot be discussed here.

Fig. 77.--Gas-meter dials. Fig. 77.—Gas-meter dials.

The reading of the dials on a gas meter comes in the province of the plumber and he should be able to read them. The sketch shows the dial plate of a meter. The ordinary house meter has only three recording dials. Large meters have five or more. To read the amount of gas consumed according to the meter we will read the dials as they are indicated on Fig. 77. We will call the four dials No. 1, No. 2, No. 3 and No. 4. In each of these dials a complete revolution of the index hand denotes 1,000, 10,000, 100,000 and 1,000,000, cubic feet respectively. The index hands on No. 1 and No. 3 revolve in the same direction, while No. 2 and No. 4 revolve in the opposite direction. Two ciphers are added to the figures that are indicated on the dials and the statement of the meter will be had. To tell just how much gas has been consumed in a given time, the statement of the meter is taken at the beginning of this given time and at the end of the time. The difference in the figures indicates the number of cubic feet of gas that have been consumed. A gas cock should be placed on the house side of the meter. The dials of meter read 658,800 cubic feet. The dial having the highest number is read first No. 4 dial points to 6, this indicates that No. 3 dial has revolved 6 times. Dial No. 3 reads 5, therefore the reading of dial No. 3 and No. 4 is 65. Dial No. 2 reads 8 making the readings of the three dials 658. Dial No. 1 reads 8 making the readings of the four dials 6588 add two ciphers to this figure and 658,800 is the correct reading.

Fig. 78. Fig. 78.
Fig. 79. Fig. 79.

Pipe and Fittings.—The pipe used in gas fitting is wrought iron or steel. In special places, rubber hose is used. Brass pipe is occasionally used to advantage. The fittings used in iron pipe gas work should be galvanized. No plain fittings should be allowed. The plain fittings very often have sand holes in them and a leak will result. Sometimes this leak does not appear until after the piping has been in use some time and the expense of replacing the fitting can only be guessed at. By using galvanized fittings, this trouble will be eliminated. All fittings used should be of the beaded type. The fitting and measurement of this work is practically the same as described under iron pipe work. To have the beginner get a clearer idea of gas-piping a building, the piping of the small building sketched will be gone over in detail and studied. One of the first important steps that a gas fitter is confronted with is the locating of the various lights and openings. With these located as shown on the plan, Figs. 78, 79 and 80, we will proceed to work out the piping. The first floor rise will be 1-inch, the second floor will be 1-inch. The horizontal pipe supplying the first floor outlets will be 3⁄4-inch pipe. The horizontal pipe on the second floor will be 3⁄4-inch. The balance of the pipe will be 3⁄8- or 1⁄2-inch. At this point your attention is called to the sketch of piping, sizes, and measurements. This sketch should be studied and understood in detail. The good mechanic will employ a sketch of this kind when installing any piping. The poor mechanic will take two or three measurements and get them out, put them in, and then get some more. This method is extremely costly and unworkmanlike. There is no reason, except the ability of the workman, why he cannot take a building like the sketch and get all the piping measurements for the job, then get them out, go to the job and put them in. The amount of time saved in this way is so great that a workman should not consider himself a full-fledged mechanic until he can get the measurements this way, and get them accurately. With a tape line, gimlet, and plumb-bob, a mechanic is fully equipped with tools to get his measurements. If the measurements are taken with a tape line, the same tape line should be used when measuring the pipe and cutting it. When laying out the piping, never allow a joist to be cut except within 6 inches of its bearing. It is good policy never to cut timber unless absolutely necessary and then only after consulting with the carpenter. When joists have to be notched they should be cut only on the top side. The pipe as it is put in place should be braced rigidly. Wherever there is an outlet pipe extending through the wall, the pipe should be braced from all sides so that when the fixture is screwed in it will be perfectly rigid.

Fig. 80. Fig. 80.

The measurements on the piping sketch, Fig. 81, are taken from the accompanying sketch of a dwelling, and if they were to be actually put in, they would fit. The reader would do well to copy this sketch and follow the piping and check the measurements according to the plan, and note how the different risers, drops, etc., are drawn. It is not necessary in a sketch of this kind to draw to a scale. After the different measurements are the letters C.C., E.C., E.E., C.B. and E.B., meaning center to center, end to center, end to end, center to back, and end to back, respectively. Offsetting pipe is a very convenient way of getting the pipe or fittings back to the wall for support. To offset pipe properly and with little trouble, take a piece of scantling 2 by 4 and brace it between the floor and ceiling. Bore a few different-sized holes through it and you will have a very handy device for offsetting pipe. There is a little trick in offsetting pipe that one will have to practice to obtain. The pipe must be held firmly in the place where the pipe is to be bent. Large offsets and bends should not be made; 2 to 4 inches is as large as should be used. Larger offsets that are required should be made with fittings. Always make the offsets true and have the ends perfectly straight. Before putting a piece of pipe permanently in place, always look or blow through it, to ascertain if its bore is obstructed or not. Sometimes dirt or slag will collect and cause stoppage.

Fig. 81.--Pipe sketch. Fig. 81.—Pipe sketch.

Reading the Pipe Sketch.—Vertical lines represent vertical pipes (see Fig. 81). Horizontal lines represent horizontal pipes running parallel to the front. Diagonal lines represent horizontal pipes running from back to front. Any line that is drawn perpendicular to any other line stands for a horizontal pipe. A diagonal line separating a vertical line or horizontal line or set of lines represents a different horizontal plane. With this explanation the sketch will be made clear to one after drawing it. The reader should now take each measurement and check it on the plan. This is easily done by using a scale rule. The height of the ceiling is 81⁄2 feet on the first floor, the second floor is 8 feet. The first floor joists are 10 inches, the second floor joists are 9 inches. An outlet is indicated by a small circle. In the piping sketch, this circle is connected with the riser or drop by a horizontal line. At the junction of these two lines a short perpendicular line is drawn, and indicates the direction of the outlet.

Let me again emphasize the need to understand thoroughly this piping sketch, and to become so familiar with it that it can readily be put to use. The value of a mechanic is determined by the quality and the quantity of work that he can turn out; and a mechanic who can lay out his work and see it completed before he starts, and then proceeds to install his work, is by far of more value to his employer than the man who can see only far enough ahead to cut out two or three measurements and spends most of his time walking between the vise and place of installing the pipe.

Testing.—The system of gas piping must be tested before the pipes have been covered by the advance of building operations. If the job is of considerable size, the job can be tested in sections, and if found tight the sections can be covered. The necessity of having the piping rigidily secured can be appropriately explained here. If the test has been made and the system found tight and some pipe that is not securely anchored is accidentally or otherwise pushed out of place and bent by some of the mechanics working about the building, a leak may be caused and yet not discovered until the final test is made after the plastering is finished. The expense and trouble thus caused is considerable and could have been avoided by simply putting in the proper supports for the pipe.

To test the piping, an air pump and a gage connected with the pipes are placed in a convenient position. The job should now be thoroughly gone over, making sure that all plugs and caps are on and that no outlet is open, also that all pipe that is to be put in has been installed. After this has been attended to, the pump is operated until 10 pounds is registered on the gage. The connection leading to the pump and the piping is now shut off. If the gage drops rapidly, there is a bad leak in the system. This leak should be found without difficulty and repaired. If the gage drops slowly, it denotes a very small leak, such as a sand hole or a bad thread. This kind of leak is more troublesome to find. When it has been found, the pipe or fitting causing the leak should be taken out and replaced. If black caps have been used to cap the outlets, the chances are that a sand hole will be found in one of them. Nothing but galvanized fittings should be used. In case the small leak mentioned above cannot be found by going over the pipe once, there are other means of locating the leak. Two of the methods used, I will explain. If the job is small, each fitting is painted with soap suds until the fitting is found that causes the leak. If the leak is not in the fittings, then the pipe can be gone over in the same way. As soon as the soap suds strikes the leak, a large bubble is made and the leak discovered. It is possible that there are more leaks, so the gage is noted and if it still drops, the search should be continued. The pump should be operated to keep the pressure up to 10 pounds while the search is being made for the leak. When the gage stands at 10 pounds without dropping, the job is then tight. The pump and gage fitting should be gone over first to ascertain if they leak. The other method employed to discover leaks is to force a little ether or oil of peppermint (not essence) into the system by means of the pump. A leak can readily be noted by the odor. To make this method successful, the ether or peppermint should not be handled by the men who are to hunt for the leak. The bottle containing the fluid should not be opened in the building except to pour some into the piping, otherwise the odor will get into the building and as the odor comes out of the leak it will not be noted. For the benefit of the gas fitter, the piping should be tested again after the plastering is completed. The next test is made when the fixtures are put on, and as the piping is tight any leak that develops in this test indicates that the fixtures leak. There are in common use various methods to stop leaks in gas pipe when they are found. If a piece of piping or a fitting is defective, it should be taken out and replaced. This should be remembered so that while the piping is being installed any defects should be noted and the defective fitting or pipe thrown out. Before the gas job is accepted, the gas company will inspect it and look for traps and sags in the pipe. Therefore, the piping should be installed without any traps and it should be arranged to pitch toward the meter, or toward a convenient place from which any condensation can be taken out. If provision is not made for this condensation, it will accumulate and stop the flow of gas.


The sketches show clearly the methods employed to make a shower-bath waste and stall water-tight. The shower bath, as a separate fixture, is in use and the demand for it as a separate fixture is increasing rapidly. This demand comes from the owners of private houses. The plumber must therefore devise some way to make these connections tight and prevent any leak from showing in the room below. This fixture is so constructed that all waste pipes and trap come under the floor level with no way of getting to them from below. Therefore the piping for this fixture must be of a permanent nature. No pipe or trap made of material that is liable to give out in a short time should be allowed under a shower-bath fixture or stall. The two sketches, Figs. 82 and 83 illustrate two methods of connecting and making tight a shower stall. A plumber should always consider it his special duty to make his work complete and free from all objections. He should always prepare for any emergency that may occur in the future. This is rather a big task, yet the plumber when accepting all of his responsibilities has a big task. I state this to the beginner and emphasize the all-important fact that he must learn to perform and think deeply of the elements of plumbing to be able later on to handle successfully the problems that present themselves in the plumbing trade.

Fig. 82.--Shower stall with lead pan extending outside of stall. Fig. 82.—Shower stall with lead pan extending outside of stall.

The heavy brass trap shown in the sketch has proved itself very satisfactory and can be made to fit almost any condition of piping or building construction. A flashing of sheet lead is soldered on the trap and carried out to the outside edge of the stall where it is turned up 1 inch, or to the floor level. When the flashing is carried out for only a foot on each side of the trap, the possibilities of a leak are greater.

Fig. 83.--Shower stall with lead pan extending six inches beyond strainer. Fig. 83.—Shower stall with lead pan extending six inches beyond strainer.