Experience with Cement Water Main Jointing Materials

Abstract

The joining of lengths of pipe together so as to form a continuous channel for the distribution of liquids or air under pressure has been a problem since man first started to carry, under control, these substances from one place to another. In olden days, the hollowed out log was joined together with a sleeve of wood of larger diameter. The ends of the pipe were tempered and driven into the sleeve. Pipe made of lead also dates back to ancient history, and was made continuous by burning or fusing the metal itself. In modern times, pipe made of steel, cast iron, brass, copper, cement, asbestos and wood have been joined together with every imaginable type of joint. Many times the failure of a pipe line, although constructed of excellent material, has been caused by a poorly designed joint, or by the use of an inferior material making the joint. The engineer who designs a water system should take many things into consideration, such as climatic conditions, depth of line, wet or dry trenches, temperature of water, amount of traffic, pressure to be carried, and maybe others, before he specifies his jointing materials. Here, in the West and South, very little attention need be given to frost and severe weather. A 30to a 36-inch cover, as a rule, will be sufficient, while localities that have colder weather to contend with might require a cover of twice this depth. The deep trench has its advantages and disadvantages. The first cost is, of course, greater. A leaky joint, or pipe, is more difficult to locate and repair, while, on the other hand, expansion and contraction are minimized and traffic jar is lessened. Wet trenches are another source of trouble, causing conditions that tend to destroy bolt and thread type of joints, and also, causing some of the compounds used in joint making to soften and fail.