All connections between Lead Pipes and Iron Pipes are made by means of brass ferrules. Lead cannot be soldered to iron, so a brass 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.
Fig. 18.
Traps.—We have seen that a trap is a bend in a pipe so constructed as to hold a quantity 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 balls, valves, lips, also mercury, etc., to assist 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.