square feet of wall surface and 47,400 cubic feet of space, including corridors, and is heated by 18 radiators containing 787 square feet of surface. By the author's formula given on page 68 the amount of surface required amounts to 730 square feet, but the exposure of the upper stories of this building is unusually severe.
It is frequently a very difficult matter to conceal risers in fireproof buildings on account of the floor plates of the columns and the beams, which frequently interfere with placing the risers very close to them. Figure 40, however, represents the manner in which they were enclosed in a building which was framed with box columns. In this case the tile fireproofing was put on over both column and riser. In concealing risers in the walls of wooden buildings it is necessary to protect the pipes carefully from immediate contact with the woodwork. In hanging risers in buildings
Methods of Running Risers in Columns.
great care must be taken that the pipe be cut to the proper lengths so that the fittings for the radiator connections will come exactly in the proper place.
Riser anchors.—As previously stated, risers are usually, especially in large buildings, anchored rigidly at certain points so that expansion shall be in both directions from these points. This should be carefully done so that the pipe will not slip, and the method to be employed to accomplish this depends largely upon the local conditions. Figures 41 and 42 show two methods of accomplishing this, the latter being especially adaptable where the riser can be run close to the floor beam, but to make it perfectly rigid it should be made strong and shrunk in place. The method indicated by Figure 41 can be adapted to anchoring the pipe to a column instead of to the floor beams. In some cases risers are also secured at the other floors so as to allow expansion, but at
