What is a dead end?

A dead end is a part of the drainage system that is without ventilation. If the entire plumbing of a house is without ventilation, the entire system may be considered a dead end. Strictly speaking, we also consider as a dead end an unventilated projection of main waste pipe beyond the entrance of the branch.

What is a tell-tale pipe, what is its object, and where should it be carried to?

A tell-tale pipe is usually used where a storage tank is used. It runs up to within a few inches of the top of the tank, with its lower end dripping into a sink or other place that is exposed to view. When water has been pumped into the tank in sufficient quantity, it overflows down this tell-tale pipe, showing to the operator of the pump that the tank has been sufficiently filled.

What is a by-pass?

A by-pass on the drainage system permits the air from the sewer or cesspool to evade the seal of the trap by passing around it and escaping into the room, instead of passing through it. Why should all plumbing be open work? When enclosed there is more danger of leakages remaining undiscovered, there is always a collection of filth in corners and about the sheathing, no matter how much care is taken, and the air confined in these enclosures is very apt to be impure.

Why are the lead and iron pipes of a ventilated plumbing system longer lived than those of an unventilated system?

The ventilation prevents the accumulation of gas, carrying it off constantly into the air.

What is meant by air lock?

The confining of air between two traps. Air lock may occur both on the drainage and on the hot and cold water supply system.

How should a refrigerator waste be connected?

A refrigerator should never be connected directly with soil or waste pipes, even though trapped, but should drip into an open pan with an air space between pan and refrigerator. This pan should then be trapped and counter-vented before entering a soil or waste pipe.

What extra precaution should be used on refrigerator work, in case of evaporation of the trap seal, when the refrigerator is not in use?

A trap screw should be soldered into the bottom of the pan, to be closed during the months when the refrigerator is not in use.

How are Ts read?

Hold the T with the branch up, and the large end to the left. Then read the large end first, small end next, and branch last, as 1 x 3/4 x 1/2 inch.

What is the principle of the oxyhydrogen and airo-hydrogen flame?

These flames are produced by the mixture of proper proportions of oxygen and hydrogen gases, which mixture is highly explosive. The most intense flame is the oxyhydrogen, but for most work the airohydrogen flame is all that is necessary. It is made by forcing air into the supply of hydrogen at a point near where it is ignited, there being sufficient oxygen in the air to produce the explosive result.