The Home Medical Library Volume V Part 16

DIFFERENT FORMS AND FITTINGS.]

_Iron Pipe_ is joined to _Iron Pipe_ by lead-calked joints. These joints are made as follows: the spigot end of one pipe is inserted into the enlarged end, or the "hub," of the next pipe. The s.p.a.ce between the spigot and hub is half filled with oak.u.m or dry hemp. The remaining s.p.a.ce is filled with hot molten lead, which, on cooling, is well rammed and calked in by special tools made for the purpose. To make a good, gas-tight, lead-calked joint, experience and skill are necessary. The ring of lead joining the two lengths of pipe must be from 1 to 2 inches deep, and from 1/2 to 3/4 of an inch thick; 12 ounces of lead must be used at each joint for each inch in the diameter of the pipe. Iron pipes are sometimes connected by means of so-called rust joints. Instead of lead, the s.p.a.ce between the socket and spigot is filled in with an iron cement consisting of 98 parts of cast-iron borings, 1 part of flowers of sulphur, and 1 part of sal ammoniac.

[Ill.u.s.tration: FIG. 17.]

All connections between _Lead Pipes_ and between _Lead_ and _Bra.s.s_ or _Copper_ pipes must be made by means of "wiped" solder joints. A wiped joint is made by solder being poured on two ends of the two pipes, the solder being worked about the joint, shaped into an oval lump, and wiped around with a cloth, giving the joint a bulbous form.

All connections between _Lead Pipes_ and _Iron Pipes_ are made by means of bra.s.s ferrules. Lead cannot be soldered to iron, so a bra.s.s fitting or ferrule is used; it is jointed to the lead pipe by a wiped joint, and to the iron pipe by an ordinary lead-calked joint.

_Putty_, _Cement_, and _Slip_ joints should not be tolerated on any pipes.

[Ill.u.s.tration: FIG. 18.]

=Traps.=--We have seen that a trap is a bend in a pipe so constructed as to hold a quant.i.ty of water sufficient to interpose a barrier between the sewer and the fixture. There are many and various kinds of traps, some depending on water alone as their "seal," others employing mechanical means, such as b.a.l.l.s, valves, lips, also mercury, etc., to a.s.sist in the disconnection between the house and sewer ends of the pipe system.

The value of a trap depends: (1) on the depth of its water seal; (2) on the strengths and permanency of the seal; (3) on the diameter and uniformity of the trap; (4) on its simplicity; (5) on its accessibility; and (6) on its self-cleansing character.

The depth of a trap should be about three inches for water-closet traps, and about two inches for sink and other traps.

Traps must not be larger in diameter than the pipe to which they are attached.

The simpler the trap, the better it is.

Traps should be provided with cleanout screw openings, caps, etc., to facilitate cleaning.

The shapes of traps vary, and the number of the various kinds of traps manufactured is very great.

Traps are named according to their use: gully, grease, sediment, intercepting, etc.; according to their shape: D, P, S, V, bell, bottle, pot, globe, etc.; and according to the name of their inventor: Buchan, Cottam, Dodd, Antill, Renk, h.e.l.lyer, Croydon, and others too numerous to mention.

The S trap is the best for sink waste pipes; the running trap is the best on house drains.

[Ill.u.s.tration: FIG. 19.

FORMS OF TRAPS.]

[Ill.u.s.tration: FIG. 20.

FORMS OF TRAPS.]

=Loss of Seal by Traps.=--The seals of traps are not always secure, and the causes of unsealing of traps are as follows:

(1) _Evaporation._--If a fixture in a house is not used for a long time, the water const.i.tuting the seal in the trap of the fixture will evaporate; the seal will thus be lost, and ingress of sewer air will result. To guard against evaporation, fixtures must be frequently flushed; and during summer, or at such times as the house is unoccupied and the fixtures not used, the traps are to be filled with oil or glycerin, either of which will serve as an efficient seal.

(2) _Momentum._--A sudden flow of water from the fixture may, by the force of its momentum, empty all water in the trap and thus leave it unsealed. To prevent the unsealing of traps by momentum, they must be of a proper size, not less than the waste pipe of the fixture, the seal must be deep, and the trap in a perfectly straight position, as a slight inclination will favor its emptying. Care should also be taken while emptying the fixture to do it slowly so as to preserve the seal.

(3) _Capillary Attraction._--If a piece of paper, cotton, thread, hair, etc., remain in the trap, and a part of the paper, etc., projects into the lumen of the pipe, a part of the water will be withdrawn by capillary attraction from the trap and may unseal it. To guard against unsealing of traps by capillary attraction, traps should be of a uniform diameter, without nooks and corners, and of not too large a size, and should also be well flushed, so that nothing but water remains in the trap.

_Siphonage and Back Pressure._--The water in the trap, or the "seal,"

is suspended between two columns of air, that from the fixture to the seal, and from the seal of the trap to the seal of the main trap on house drain. The seal in the trap is therefore not very secure, as it is influenced by any and all currents and agitations of air from both sides, and especially from its distal side. Any heating of the air in the pipes with which the trap is connected, any increase of temperature in the air contents of the vertical pipes with which the trap is connected, and any evolution of gases within those pipes will naturally increase the weight and pressure of the air within them, with the result that the increased pressure will influence the contents of the trap, or the "seal," and may dislodge the seal backward, if the pressure is very great, or, at any rate, may force the foul air from the pipes through the seal of the traps and foul the water therein, thus allowing foul odors to enter the rooms from the traps of the fixtures. This condition, which in practice exists oftener than it is ordinarily thought, is called "back pressure." By "back pressure" is therefore understood the _forcing back_, or, at least, the _fouling_, of the water in traps, due to the increased pressure of the air within the pipes back of the traps; the increase in air pressure being due to heating of pipes by the hot water occasionally circulating within them, or by the evolution of gases due to the decomposition of organic matter within the pipes.

[Ill.u.s.tration: FIG. 21.

NON-SYPHONING TRAP.

Copyright by the J. L. Mott Iron Works.]

A condition somewhat similar, but acting in a reverse way, is presented in what is commonly termed "siphonage." Just as well as the seal in traps may be forced back by the increased pressure of the air within the pipes, the same seal may be _forced out_, pulled out, aspirated, or siphoned out by a sudden withdrawal of a large quant.i.ty of air from the pipes with which the trap is connected. Such a sudden withdrawal of large quant.i.ties of air is occasioned every time there is a rush of large column of water through the pipes, e. g., when a water-closet or similar fixture is suddenly discharged; the water rushes through the pipes with a great velocity and creates a strong down current of air, with the result that where the down-rushing column pa.s.ses by a trap, the air in the trap and, later, its seal are aspirated or siphoned out, thus leaving the trap without a seal. By "siphonage" is therefore meant the emptying of the seal in a trap by the aspiration of the water in the trap due to the downward rush of water and air in the pipes with which the trap is connected.

To guard against the loss of seal through siphonage "nonsiphoning"

traps have been invented, that is, the traps are so constructed that the seal therein is very large, and the shape of the traps made so that siphonage is difficult. These traps are, however, open to the objection that in the first place they do not prevent the fouling of the seals by back pressure, and in the second place they are not easily cleansable and may retain dirt in their large pockets. The universal method of preventing both siphonage and back pressure is by the system of vent pipes, or what plumbers call "back-air" pipes.

Every trap is connected by branches leading from the crown or near the crown of the trap to a main vertical pipe which runs through the house the same as the waste and soil pipes, and which contains nothing but air, which air serves as a medium to be pressed upon by the "back-pressure" air, or to be drawn upon by the siphoning, and thus preventing any agitation and influence upon the seal in the traps; for it is self evident that as long as there is plenty of air at the distal part of the seal, the seal itself will remain uninfluenced by any agitation or condition of the air within the pipes with which the trap is connected.

The vent-pipe system is also an additional means of ventilating the plumbing system of the house, already partly ventilated by the extension of the vertical pipes above the roof and by the fresh-air inlet. The princ.i.p.al objection urged against the installation of the vent-pipe system is the added expense, which is considerable; and plumbers have sought therefore to subst.i.tute for the vent pipes various mechanical traps, also nonsiphoning traps. The vent pipes are, however, worth the additional expense, as they are certainly the best means to prevent siphonage and back pressure, and are free from the objections against the c.u.mbersome mechanical traps and the filthy nonsiphoning traps.

CHAPTER VII

=Plumbing Pipes=

=The House Drain.=--All waste and soil matter in the house is carried from the receptacles into the waste and soil pipes, and from these into the house drain, the main pipe of the house, which carries all waste and soil into the street sewer. The house drain extends from the junction of the soil and waste pipes of the house through the house to outside of the foundations two to five feet, whence it is called "house sewer." The house drain is a very important part of the house-plumbing system, and great care must be taken to make its construction perfect.

_Material._--The material of which house drains are manufactured is extra heavy cast iron. Lighter pipes should never be used, and the use of vitrified pipes for this purpose should not be allowed.

_Size._--The size of the house drain must be proportional to the work to be performed. Too large a pipe will not be self-cleansing, and the bottom of it will fill with sediment and slime. Were it not for the need of carrying off large volumes of storm water, the house drain could be a great deal smaller than it usually is. A three-inch pipe is sufficient for a small house, though a four-inch pipe is made obligatory in most cities. In New York City no house drains are allowed of smaller diameter than six inches.

[Ill.u.s.tration: FIG. 22.

SYSTEM OF HOUSE DRAINAGE, SHOWING THE PLUMBING OF A HOUSE. (H.

BRAMLEY.)]

_Fall._--The fall or inclination of the house drain depends on its size. Every house drain must be laid so that it should have a certain inclination toward the house sewer, so as to increase the velocity of flow in it and make it self-flushing and self-cleansing. The rate of fall should be as follows:

For 4-inch pipe 1 in 40 feet " 5 " " 1 " 50 "

" 6 " " 1 " 60 "

_Position._--The house drain lies in a horizontal position in the cellar, and should, if possible, be exposed to view. It should be hung on the cellar wall or ceiling, unless this is impracticable, as when fixtures in the cellar discharge into it; in this case, it must be laid in a trench cut in a uniform grade, walled upon the sides with bricks laid in cement, and provided with movable covers and with a hydraulic-cement base four inches thick, on which the pipe is to rest.

The house drain must be laid in straight lines, if possible; all changes in direction must be made with curved pipes, the curves to be of a large radius.

_Connections._--The house drain must properly connect with the house sewer at a point about two feet outside of the outer front vault or area wall of the building. An arched or other proper opening in the wall must be provided for the drain to prevent damage by settling.

All joints of the pipe must be gas-tight, lead-calked joints, as stated before. The junction of the vertical soil, waste, and rain-leader pipes must not be made by right-angle joints, but by a curved elbow fitting of a large radius, or by "Y" branches and 45 bends.

When the house drain does not rest on the floor, but is hung on the wall or ceiling of the cellar, the connection of the vertical soil and waste pipes must have suitable supports, the best support being a brick pier laid nine inches in cement and securely fastened to the wall.

Near all bends, traps, and connections of other pipes with the house drain suitable hand-holes should be provided, these hand-holes to be tightly covered by bra.s.s screw ferrules, screwed in, and fitted with red lead.