The term soil pipe is used in a popular manner to designate all iron drainage piping, and it is also applied to the cast-iron piping used on the vent system. As a matter of fact, soil pipe is that part of the iron pipe of the drainage system through which the waste from water-closets flows. Other pipe, even though of the same size as the soil pipe, but carrying waste from other fixtures, is called waste pipe. However, the term soil pipe has come to be used so universally to designate all cast-iron pipe, whether used as soil, waste, or vent, that it will be more convenient to refer to it occasionally in this general way.

In Fig. 89 is shown a system of soil piping to which reference will be made later. In this system the main back-air or vent pipes are of cast iron. Wrought iron is being used very largely for this purpose at the present time, and it appears to be replacing the cast iron on this part of the system, in many sections.

In fact the use of wrought-iron pipe for vent work has become almost universal. Long, straight lines of wrought-iron pipe are more quickly run than cast iron, and closer connections can be made.

Several matters which might properly be considered here have already been taken up, such as the supporting of horizontal soil piping, etc. Vertical lines of soil and waste pipe should be supported at each floor by a clamp placed under the hub of a pipe or fitting, and firmly screwed to the timber. This support not only prevents the settling of the stack, but also prevents any side motion of the pipe.

All first-class plumbing ordinances now require the use of extra heavy cast-iron pipe on the drainage system in preference to standard pipe. The reason for this is that the standard pipe being much lighter has more sand holes and defects than the extra heavy.

Unless the standard pipe is cast perfectly, one part of the circumference will be very thin, while the section directly opposite will be correspondingly thick. When in this condition it takes only a slight blow to break the pipe. In the cutting of standard pipe and in the calking of joints, split lengths of pipe and split fittings are much more liable to result than in the use of extra heavy pipe. Many times such defective pipe and fittings are not cast aside as they should be, but made use of, the defects being patched up with tar so that they may not be detected. Principally to make such practices impossible, some ordinances demand the use of soil pipe which has no asphaltum coating.

The weights of different materials used on the plumbing system are, viz.:

Weights Of Cast-Iron Pipe

2-inch

Standard C.-I. Pipe Weighs

3 1/2

lbs.

per foot

3-inch

,,

,,

,,

,,

4 1/2

,,

,,

,,

4-inch

,,

,,

,,

,,

6 1/2

,,

,,

,,

5-inch

,,

,,

,,

,,

8

,,

,,

,,

6-inch

,,

,,

,,

,,

10

,,

,,

,,

2-inch

Extra Heavy

,,

,,

,,

5 1/2

,,

,,

,,

3-inch

,,

,,

,,

,,

,,

9 1/2

,,

,,

,,

4-inch

,,

,,

,,

,,

,,

13

,,

,,

,,

5-inch

,,

,,

,,

,,

,,

17

,,

,,

,,

6-inch

,,

,,

,,

,,

,,

20

,,

,,

,,

7-inch

,,

,,

,,

,,

,,

27

,,

,,

,,

8-inch

,,

,,

,,

,,

,,

33 1/2

,,

,,

,,

10-inch

,,

,,

,,

,,

,,

45

,,

,,

,,

Weights Of Wrought-Iron Pipe

Diameter.

Thickness.

Weight per ft.

1 1/2

inches

.14

inch

2.68

lbs.

2

,,

.15

,,

3.61

,,

2 1/2

,,

.20

,,

5.74

,,

3

,,

.21

,,

7.54

,,

3 1/2

,,

.22

,,

9

,,

4

,,

.23

,,

10.66

,,

4 1/2

,,

.24

,,

12.34

,,

Diameter.

Thickness.

Weight per ft.

5

inches

.25

inch

14.50

lbs.

6

,,

.28

,,

18.76

,,

7

,,

.30

,,

23.27

,,

8

,,

.32

,,

28.18

,,

9

,,

.34

,,

33.7

,,

10

,,

.36

,,

40.06

,,

Weights Of Brass Pipe

Diameter.

Thickness.

Weight per ft.

1 1/2

inches

.14

inch

2.84

lbs.

2

,,

.15

,,

3.82

,,

2 1/2

,,

.20

,,

6.08

,,

3

,,

.21

,,

7.92

,,

3 1/2

,,

.22

,,

9.54

,,

4

,,

.23

,,

11.29

,,

4 1/2

,,

.24

,,

13.08

,,

5

,,

.25

,,

15.37

,,

6

,,

.28

,,

19.88

,,

Weights Of Lead Pipe

Diameter.

Weighl per ft.

1

inch

2

lbs.

1 1/4

,,

2 1/2

,,

1 1/2

,,

3

,,

2

,,

3 1/2

,,

3

,,

4 1/2

,,

4

,,

6

,,

As will be seen later, in the description of the Durham plumb-ing system, whenever wrought-iron pipe is used for drainage purposes, the fittings used in connection with it should be of cast iron. They should be of the style known as extra heavy cast iron, recessed, and threaded drainage fittings. These fittings should also be used on main vent lines of wrought iron, although it is true that in many cases they are not used on such work.

For fixture and branch vents of wrought iron it is permissible to use galvanized cast or malleable steam and water fittings. In the use of short nipples on either drainage or vent work, special care should be taken in order that they may not be split or crushed in any way. When the nipple is of such length that the distance between the two threaded ends, that is, the part unthreaded, is less than 1 1/2 inches, the nipple should be of "extra strong" pipe.

The term "roughing-in" is applied to the plumbing system when it has reached the point where the first test is to be applied. The "roughing-in" includes the entire soil-pipe system, house drain, soil and waste stacks, main vent lines, all branch wastes and vents. In fact, the "roughing-in" includes the entire plumbing system with the exception of exposed work above the floor, that is, the fixture itself its trap and waste to the floor, and the vent connection to the wall. Figs. 89 and 110 will give an idea of what is meant by "roughing-in."

In roughing-in, wherever waste pipes are to be run of more than six feet in length, lead pipe should not be used. The use of lead for drainage and vent work is fast going out of date, cast and wrought iron and brass taking its place. The labor involved in lead work, properly constructed, is greater than in the use of other materials; it is less rigid; long lines of lead pipe are liable to sag and form traps; and lead pipe is sometimes subject to the attack of rats, the generally accepted idea being that in their attack they are attempting to reach the water which they hear flowing through the pipes.

To such an extent has lead work been replaced in many parts of the country that the trade of the plumber of to-day has changed almost entirely from that which the old-time lead worker followed. There was a time not many years back when the plumber made his own traps, bends, etc., and a time when lead soil pipe was used. All that is now changed, and although the older plumbers may not agree to it, it would seem that this great change is for the better.

In the running of horizontal soil, waste, and vent pipes, they should have a grade of at least one-quarter inch to the foot, and more than this amount is preferable. Wherever possible, each fixture should have a separate entrance into its stack. This is a practice which is by no means generally followed, and it certainly does not receive the attention which it deserves. Referring to Fig. 90, . it will be noted that the bath tub and lavatory are served by the same line of lead waste pipe. This is not to be considered an unsanitary practice, and many times it would be almost impossible to construct the work otherwise. If the waste pipe should become stopped at any point between the lavatory connection and the stack, it may readily be seen that both lavatory and bath would be affected. If each had a separate connection the stoppage of one waste would not affect the other. It may be stated further that very often the plumber might obtain separate entrance for each fixture, but in a vast majority of cases the work is taken under contract, and the betterment of the work by making separate entrance would result in additional expense to him. In other instances the architect might easily lay out the work and make locations of pipes and fixtures such that separate entrances might easily be made. For instance, in the floor plan of Fig. 91, the relative locations of fixtures and stack are such that each fixture may waste independently into the stack, as will be seen in Fig.

Fig. 89.   System of Soil Piping.

Fig. 89. - System of Soil Piping.

Fig. 90.

Fig. 90. - "Roughing-in.".

Fig. 91.   Floor Plan of Bath Room.

Fig. 91. - Floor Plan of Bath Room.

Fig. 92.   Separate Entrance of Each Fixture into Stack.

Fig. 92. - Separate Entrance of Each Fixture into Stack.

92, which shows an elevation of the work of Fig. 91. Mention should be made of the practice which is almost universal in certain sections, of connecting the waste pipes from lavatories and bath tubs into the water-closet lead bend. This is a practice followed by a surprisingly large number of plumbers who pride themselves on the excellence of their work; and it is generally allowed both by the architect and the plumbing inspector.