ported from the ceiling above by means of some kind of an expansion hanger, two common types of which are shown in Figures 43 and 44, the two shown in each case being, one for wooden beams and the other for iron. The rods can be cut to the length desired after the pipe is in place. There is sufficient movement of the rod at the top to allow for the small play of the pipe due to expansion. A simple and cheap form of hanger frequently used for small pipes in buildings with wooden floors is made of a piece of light chain looped under the pipe and hung from the nails in the floor beams. The chain can be cut to length with wire nippers. In case of very large pipes in the basement of buildings, they are
Expansion Pipe Hangers.
sometimes supported by some kind of a standard erected from the floor.
Arrangement of pipes.—In laying out the main piping connections of the power plant of a large building great care must be taken to arrange the pipes as systematically as possible so that they take up no more room than necessary, and also to properly provide for the drainage of all pipes into proper receptacles. This is frequently a difficult matter, but one can hardly give too much consideration to the subject, as the successful operation of a plant depends largely upon the way piping connections are arranged. It is impossible to give any detailed rules, as each plant is a prob-
