PIPES AND CONDUITS.
The running of pipes and conduits in fireproof buildings brings forward a system, differing in some essentials from the ordinary piping of buildings with wooden floors. In the first place, less cutting of material is available to make spaces for pipes, and so more careful consideration must be given to this matter in the early stages of the construction; and again the necessity of leaving no continuous nels or connection from one floor to another, which would allow the passage of fire, will require that the pipes be run in exposed tions as far as possible, so that the floor material may be filled closely around each pipe. This is a point that the superintendent will need to keep constantly in mind and be sure that it is clone in every case. Plumbing Pipes. The main soil, waste and vent pipes should be of wrought iron with screw joints, not only on account of the great weight of the high stacks of pipes, but because the expansion and contraction of the great height of pipe would destroy the lead caulking usual with cast-iron pipes. The pipes must be securely fastened to the solid frame of the building, and all joints well screwed together with ample chance for expansion. Brass supply pipes should be used throughout, nickeled or bronzed to taste when showing. As the pipes will all show, the soil and waste pipes will need to be smooth and well put together so that when bronzed or finished they will not be unsightly.
Gas and Electric Piping. Before the plastering is begun, the pipes for gas and the conduits for electric wires, must be run. These, being small, may be concealed, if desired, although the idea of exposing gas piping is becoming more in vogue, especially where thin partitions are used. When hollow blocks are used for the parti tions it is customary to channel them for the rising pipes and conduits; while the horizontal pipes arc usually bedded in the concrete filling over the floor construction. (Fig. 247.) Some times the horizontal pipes are run un der the floor beams, the suspended ceil ing being dropped low enough to allow free circulation for the pipes.
Sometimes the pipes are run between the floor beams; but if the girders are framed flush, it will be necessary to punch holes in them, and lateral branches cannot be easily managed. Where no partitions are available in which to run vertical pipes, as often occurs in the lower stories, the casing of the steel columns may be enlarged, so as to allow of pipes being run up, but if this is clone, a rate flue outside the column casing, as in Fig. 24S, should be made, as the insertion
of pipes or conduits directly into the column easing destroys its fireproof value to a large extent, beside subjecting the steel to the action of injurious gases.
Heating Pipes. The pipes for heating the building will in general be run outside of the plaster, and will be bronzed to match the radiators and other exposed piping. The number and size of the pipes will depend upon the system of heating used. For a large building, the heating is generally put in charge of an engineer who devises a system subject to the approval of the architect, but some stated conditions will in general be found to apply to most buildings.
Heating System. In almost every large building, the exhaust steam from the engines necessary to run elevators and dynamos will suffice to heat the rooms, and this may be clone in two ways. The exhaust steam may be forced or drawn through the radiators and transmit heat directly to the building, or it may be carried to a coil in a water tank in the basement, heating the water, and causing it to circulate through the pipes and radiators instead of the steam. By the latter method a more uniform distribution of heat will be obtained and any danger of back pressure on the engines will be avoided. This tank must be placed low enough to prevent any backing up of the water to the engine, and the circulation of hot water to the radia tors may be laid out in a manner similar to the circulation from an ordinary heater, which has been previously described. The greater height and multiplication of radiators will require a much more complicated system of piping, but the main features will be the same. The most effective service will of course be obtained by putting as few radiators as possible on a direct circulation, but as this adds very much to the expense it is quite usual to run one or two large mains up to the top story and from a horizontal run in.this story, to bring down the hot water to supply the radiators, continuing this pipe to the heater. This of course gives a better supply to the top stories than the lower ones, so the difference is made up by putting larger radiators in the lower stories.