Ventilation.—The house drain may have no fresh-air inlet, or the fresh-air inlet may be obstructed; the vent pipes may be absent, or obstructed; the vertical pipes may not be extended.
Condition.—Pipes may have holes, may be badly repaired, bent, out of shape, or have holes patched up with cement or putty; pipes may be corroded, gnawed by rats, or they may be obstructed, etc.
The above are only a few of the many defects that may be found in the plumbing of a house. It is, therefore, of paramount importance to have the house plumbing regularly, frequently, and thoroughly examined and inspected, as well as put to the various tests, so as to discover the defects and remedy them.
Plumbing Tests.—The following are a few minor points for testing plumbing:
(1) To test a trap with a view to finding out whether its seal is lost or not, knock on the trap with a piece of metal; if the trap is empty, a hollow sound will be given out; if full, the sound will be dull. This is not reliable in case the trap is full or half-full with slime, etc. Another test for the same purpose is as follows: hold a light near the outlet of the fixture; if the light is drawn in, it is a sign that the trap is empty.
(2) Defects in leaded joints can be detected if white lead has been used, as it will be discolored in case sewer gas escape from the joints.
(3) The connection of a waste pipe of a bath tub with the trap of the water-closet can sometimes be discovered by suddenly emptying the bath tub and watching the contents of the water-closet trap; the latter will be agitated if the waste pipe is discharged into the trap or on the inlet side of trap of the water-closet.
(4) The presence of sewer gas in a room can be detected by the following chemical method: saturate a piece of unglazed paper with a solution of acetate of lead in rain or boiled water, in the proportion of one to eight; allow the paper to dry, and hang up in the room where the escape of sewer gas is suspected; if sewer gas is present, the paper will be completely blackened.
The main tests for plumbing are: (1) the Hydraulic or water-pressure test; (2) the Smoke, or sight test, and (3) the Scent, or peppermint, etc., test.
The Water-pressure Test is used to test the vertical and horizontal pipes in new plumbing before the fixtures have been connected. It is applied as follows: the end of the house drain is plugged up with a proper air-tight plug, of which there are a number on the market. The pipes are then filled with water to a certain level, which is carefully noted. The water is allowed to stand in the pipes for half an hour, at the expiration of which time, if the joints show no sign of leakage, and are not sweating, and if the level of the water in the pipes has not fallen, the pipes are water-tight. This is a very reliable test, and is made obligatory for testing all new plumbing work.