Table 5. Standard Dimensions Of Wrought-Iron Pipe

Wrought-iron pipes are made in lengths from about 15 to 20 feet.

All wrought-iron pipe which is 1 1/4 inches or less in diameter is butt welded; that is, the edges are joined face to face. All sizes above 1 1/4 inches are lap welded, the edges being lapped over each other.

All butt-welded pipe is tested at the mills to a pressure of 300 pounds per square inch, and lap-welded pipe is similarly tested to 500 pounds pressure per square inch.

Wrought-iron pipes having a greater thickness of metal than those above are made, and are known as extra strong and double extra strong. The extra thickness of metal reduces the bore of the pipe, the outside diameter of each nominal size is never changed. Thus, all grades of pipe will connect properly with standard fittings.

75. Tubes of brass or copper are made of all diameters and thicknesses. The size by which these tubes are designated is always the outside diameter, and the thickness of the metal must always be specified, in order to secure tubing which is suitable for the purpose in view.

Brass and copper tubes are made by two methods, and are accordingly designated as seamless drawn, or brazed tubing.

76. Seamless drawn tubing is made from a solid block of metal without a joint, and is much superior in strength to brazed tubing. Brazed tubing is similar in structure to butt-welded wrought-iron pipe, except that the joint is secured by brazing.

Brass tubing is also made in sizes which correspond in external diameter with the sizes of wrought-iron pipe, in order that it may be screwed into the same fittings that are used for wrought-iron pipe. Tubing of these sizes should always be designated as iron pipe sizes.

77. Wooden pipes are usually made from solid square timber. The bore is made by an auger, which is forced throughout the length of the piece. Another variety is made by winding a flexible wooden strip or ribbon upon a mandrel spirally in such a manner that the layers overlap one another and then securing them together with cement. It is made of all diameters and of all lengths up to 20 feet.

78. Cast-iron pipes for plumbers' use are made with a socket on one end and a spigot on the other. They are made in two grades, the standard and extra heavy, the latter having the greater thickness of metal. These pipes are made 5 feet long, exclusive of the socket, and may be had from 2 to 12 inches inside diameter. They are sold by the lineal foot. Pipes having a socket on each end, called double hub pipe, are sold by the piece.

The above cast-iron pipes are used chiefly for the drainage of buildings.

Cast-iron pipes used for conveying water under pressure, such, for example, as pipes from a reservoir to a building, are much heavier and longer than those for drainage purposes. Cast-iron pipes may be had either plain, i. e., as they come from the mold, or coated with some particular material, such as asphaltum. In ordering this kind of pipe, it should be stated whether plain or coated is wanted.

79. Earthenware drain pipes are of various qualities as to texture, varying from a porous material like that of common red brick (sometimes called terra cotta) to a hard and compact material which is glazed to make it water-tight, called salt-glazed or vitrified earthen pipe. The latter class is made in 2 and 3 foot lengths, and has a socket on one end. The sizes usually kept in stock by dealers are 3, 4, 5, 6, 7, and 8 inch inside diameters.