running horizontally, in order to obtain the flat surface for bedding, but where it is necessary to cut for vertical pipes, it is well to set a vertical line of blocks on end and clamp them to the flat tiles. All openings for doors and windows are made with wooden studs (or with steel bars, if the door frames are of cast iron) to receive the frames and finish. For thinner partitions, blocks of solid porous terra cotta 2 inches thick may be used, but they must be clamped or banded together.

Partition

A patented partition may be obtained of Fig. 246. Terra Cotta Bloc thin terra cotta plates, reinforced by twisted

steel wires run on either side of the plates and imbedded in the plaster. Thin plates having plaster of Paris for a base, and clamped or banded with iron, are also used for partition blocks where extra lightness is required.

For all of these blocks, mortar composed of lime with a little cement should be used for setting, and the finished plaster surfaces are best when hard-setting plaster is used.

Metal-Lath Partitions. To save floor space, very thin partitions may be made by using small steel bars for studding; these are usually-inch channel bars set vertically about a foot apart and turned at a right angle to be fastened top and bottom. On one side metal lathing is stretched and wired to the bars. This is covered with a very heavy coat of hard plaster, which squeezes through the lathing and makes a good surface to receive the plaster of the other side of the partition, the whole forming, when completed, a solid wall of plaster and metal about 1 inches thick, Fig. 247. It is necessary in this case to use a very hard-setting plaster, as this gives the partition its stiffness. Special patented studs of sheet steel, made with prongs to hold the lathing, and of various depths, Fig. 248, are used in a similar manner. Door and window frames are placed in these thin partitions by setting up a rough wooden frame to which the channel bar is screwed, as in Fig. 249, and as a nailing for chair rails, picture moldings, and other finish, strips of wood are laced to the lathing, flush with the plastering, before the plaster is applied, Fig. 250.

Fig. 247. Section of Steel and Lath Partition

Metal Lathing. Metal lathing, which is of great importance both for fireproofing, and for the finishing of fireproof buildings, may be obtained in a variety of patterns and devices.

Wire Cloth. The original metal lathing was the common wire cloth, and this is still one of the principal forms in which it is found. Improvement in the manufacture of wire cloth has been made by stiffening the cloth in various ways by the use of rods or ribs of metal. These are attached to, or woven into, the lath

Fig. 248. ing which is then known as stiffened lathing.

Steel Stud

Clinton Lath. A well-known form of stiffened lathing is the Clinton lath, which contains corrugated steel furring strips, attached to the cloth by metal clips and running across the roll every 8 inches. These strips not only serve to stiffen the lathing when stretched over furrings, but, if the lathing is applied directly to a plain surface, such as planking or brick walls, the stiffening keeps the lathing away, and gives room for the clinch of the plaster.

Fig. 249. Door Finish in Thin
Partition

Roebling Lath. The Roebling stiffened lathing contains V-shaped ribs of various depth, which are woven into the cloth at 7-inch intervals. These ribs serve for a furring, and are made from 3 to 1 inches in depth. For special uses, ribs of 1-inch steel rods are used instead of the V-shaped steel. Wire cloth for lathing is run in a variety of meshes, 3X3. and 2×2 to the inch being the common meshes, and they may be obtained plain, painted, or galvanized. Painted lathing is very satisfactory, and is more generally used than any other kind.

Fig. 250. Wood
Furring in Thin
Partition

Expanded-Metal Lath. This form of lathing is made from strips of thin and tough sheet steel, which are cut at regular intervals and then "expanded" by being wrenched or pushed into open meshes, large or small as the cuts are made long or short. This expanding also turns the metal on edge, making a flat and stiff sheet of lathing much larger than the original piece of metal, Fig. 251. Having a degree of stiffness, this lathing does not require stretching, and it is used extensively for wrapping

steel beams or columns, for fireproofing or finishing, for thin partitions and for concrete floors.

Bostwick Sheet-Metal Lathing. An objection is sometimes made to wire or expanded-metal laths, because they require an excessive amount of plaster for ordinary uses. This

may be overcome by the use, when feasible, of the Bostwick sheet-metal lath, shown in Fig. 252, which is made from sheet steel by punching out loops at regular intervals. In this, and in many other forms of sheet-metal lathing, the surface is corrugated, besides being punched, to give stiffness and to keep the lathing away from the surface to which it is applied. Sheet-metal lathing is especially adapted to the forming of coves or round corners, but for fireproofing, the open lathing, requiring a greater amount of plaster with the metal more thoroughly imbedded, is to be preferred.

Rib-Stiffened Lathing. Almost all manufacturers of expandedmetal lathing make some form of lath having ribs or stiffeners of different depths, some only enough to give a clinch to the plaster, others deep and stiff enough to give an amount of strength such that the material may be used for a light roof or partition without the usual joists or studding.

This method of stiffening or furring is more valuable to expanded or sheet-metal lathing than to wire lathing, inasmuch as it can be formed up integral with the lath, this producing great stiffness, if desired. This material is known to the trade as "Hy-rib", "SelfSentering", "Corr-Mesh", or by some other title more or less. descriptive of the product.

HEATING, LIGHTING, AND PLUMBING

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 possible to make spaces for pipes, and so more careful

consideration must be given to their placing in the early stages of the construction; and, again, the necessity of leaving no continuous channel or connection from one floor to another, which would allow the passage of fire, requires that the pipes be run in exposed situations so 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 done 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 also because the expansion and contraction of the great height of pipe would destroy the lead calking 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 allowance 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 need to be smooth and well put together so that when bronzed or finished they will not be unsightly.

Gas Pipes and Electric Conduits. Before the plastering is begun, the pipes for gas and the conduits for electric wires must be run. These, being small, may be concealed, although the idea of exposing gas piping is coming more into vogue, especially where thin partitions are used. When the partitions are made of hollow blocks, it is customary to channel them so that the rising pipes and conduits may easily be carried through; while the horizontal pipes are usually bedded in the concrete filling over the floor construction, Fig. 253.

There are some types of construction where the horizontal pipes are run under the floor beams, the suspended ceiling 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, to allow for the pipes; but if this is done, a separate flue outside the column casing, as in Fig. 254, should be made, since the insertion of

pipes or conduits directly into the column casing destroys its fireproof value to a large extent, besides subjecting the steel to the action of injurious gases.

Heating Pipes. The pipes for heating the building, are, as a rule, run outside of the plaster, and are bronzed to match the radiators and other exposed piping. The number and size of the pipes depend upon the system of heating used. For a large building, the heating is generally put in charge of an system subject to the approval of the architect, but some stated conditions will in general be found to apply to most buildings.

engineer who devises a

Heating System. In almost every large building, the exhaust steam from the engines necessary to run elevators and dynamos suffices to heat the rooms, and this heat may be made available in either one of two ways. The exhaust steam may be forced or drawn through the radiators so that it transmits heat directly to the building; or it may be carried to a coil in a water tank in the basement where it will heat the water, causing it to circulate through the pipes and radiators instead of the steam. By the latter method a more nearly uniform distribution of heat is obtained, and any danger of back pressure on the engines is avoided. It is important to see that the tank is placed low enough to prevent any backing-up of the water to the engine.

Fig. 254. Conduit Pipes in
Column Casing

The circulation of hot water to the radiators 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 require a much more complicated system of piping, but the main features are the same. The most effective service is, of course, 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 floor, and from a horizontal run in this story to bring down the hot water to supply the radiators, the pipe being continued to the heater.