The usual methods of joining tile pipes is to fill the annular space between the hub and spigot with cement mortar and bank it full in front of the joint.

When the inside of the hubs and the end of the pipes are unglazed, this method makes a very fair joint. However, most tile pipe now made have both the hub and spigot salt glazed, consequently, under such conditions, mortar will not adhere to the pipe and the joints soon leak.

Salt glazed pipe can be made water-tight by first calking the hub half full of oakum, and then cementing the joint as in the first instance. The oakum should not be loosely packed in the hub, but should be calked in hard enough to make the joint water-tight; the cement gives the joint the necessary strength. When tile pipe joints are made with cement mortar without first calking the joints with oakum, great care should be exercised to remove any cement that might be worked through to the inside of the pipe. The cement can be removed by placing in the drain a large swab that completely fills the bore of the pipe, and drawing it along a couple of feet each time a length of pipe is laid.

Tile pipe joints are sometimes made with asphalt; the joints are first made tight by calking with oakum and then poured full with hot asphalt. For many purposes asphalt joints are preferable to cement joints; they are tighter, more flexible, and not so likely to be broken by a settlement of the ground or by jarring of the pipe when the trench is being filled.

Where Tile Sewer Pipe May Be Used

Tile pipe should be used for house sewers only when a natural bed of earth or rock can be obtained to lay it on. It should not be used even then if it is exposed to frost, discharges into a cesspool or passes near a well, spring or other source of water supply.

Objections To Use Of Tile Pipe

The chief objection to the use of tile pipe for house sewers is the unsatisfactory joints between the lengths. During dry weather or in localities where the ground water is low, sewage escapes from the sewer into the earth and might wear a channel to some nearby well, cistern, or other source of water supply. During wet weather, or in localities where the ground water is high, water enters the sewer through the joints, a condition that might be serious in case the sewage is treated at a disposal plant.*

* At Grinnell, Iowa, the flow of sewage in wet weather is from three to four times the volume of water pumped from the city wells. No permanent water level, steepage at depths varying from 10 to 40 feet.

Another not uncommon source of trouble from leaky-joints are roots of trees that enter in search of water and in course of time completely obstruct the drain.

An Iron Pipe House Sewer possesses many advantages over the tile pipe sewer: It is not so easily broken by settlement of the earth; the joints are perfectly gas and water tight and can not be broken by carelessness in filling the trench; the sewer is not so likely to be affected by upheavals from frost; it can safely be laid close to wells, cisterns or other sources of water supply, in any kind of soil, and it costs but a trifle more than the tile pipe sewer. Iron pipe sewers should be constructed of cast iron pipe; wrought iron or steel pipes are not suitable for this purpose, owing to their comparatively short life when buried in the earth.

Cast-iron pipe sewers may be standard or extra heavy in weight, and either plain or coated. Coated pipe is covered both inside and out with a protective coating of pitch or asphalt, applied hot. This coating is beneficial in many ways - it prolongs the life of the pipe by protecting it from contact with the earth and sewage, and reduces the frictional resistance by forming a smooth surface.

Cast-iron pipe should be sound, cylindrical, smooth, free from cracks, sand holes or other defects, of a uniform thickness and of the following average weights per lineal foot:

Standard weight pipe can be made tight when great care is exercised in cutting the pipe and calking the joints. Nevertheless, it should be used only on the smaller and least important of installations.

Cast-iron fittings should conform in all respects to all requirements of their respective grades of pipe.

Joints of cast-iron pipe may either be lead calked or rust joints.

Lead Calked Joints are made by calking a ring of oakum tightly into the hub of a pipe or fitting, and then filling the hub with molten lead. The lead contracts in bulk on cooling, and must be calked with a hammer and calking iron to expand it against pipe and hub to make a gas and water-tight joint. One pound of pure soft pig lead for each inch in diameter of the pipe is found sufficient for each joint under ordinary conditions; however, when a cut piece of pipe is being calked, a greater depth of lead is needed to compensate for the loss of the ring on the spigot end of the pipe.

Rust Joints are used in the drainage systems of chemical works, where the acids would affect lead joints; also they are used in cases where a line of pipe will be subjected to such a range in temperature that the alternate expansion and contraction would work lead out of the joints.

Rust joints are made by calking a ring of oakum into the hub, and filling the hub with a mixture composed of:

Flower of sulphur.....1 part

Sal-ammoniac......I part

Iron borings......98 parts

When a slow-setting rust mixture is desired, 198 parts of iron chips are used in place of 98 parts. A preparation is now sold that is easier to apply, quicker to set, and is stronger than a rust joint. While it is more costly than a rust mixture, it is cheaper to use in the end on account of the greater quantity of work that can be done by its use.

Cutting Cast-Iron Pipe

Cast-iron pipe is usually cut with a cold chisel and hammer. Recently, however, a special pipe-cutting tool (Fig. 1,) was put on the market that makes a cleaner, quicker and safer cut than a cold chisel.

It will cut the lightest standard pipe any distance from the end without cracking it.