FIREPROOF CONSTRUCTION. C19 FIREPROOF CONSTRUCTION. or treatment of persons, the height of which ex- ceeds 35 feet, ;i ntl every other building the height of which exceeds 75 feet, except as otherwise pro- vided, must be built fireproof. The stairs and staircase landings must be built entirely of brick, stone, Portland cement, concrete, iron, or steel. No woodwork or other inflammable material shall be used in any of the partitions, furrings, or ceil- ings in anj' fireproof buildings, excepting, how ever, that when the height of the building does nut exceed twelve stories, or more than 150 feet, the doors and windows and their frames, the trims, the casings, the interior finish when filled solid at the back with fireproof material, and the floor boards and sleepers directly thereunder may be of wood, but the space lid ween the sleepers shall be solidly filled with fireproof materials and extend up to the under side of the floor- boards. When the height of a fireproof building exceeds twelve stories, or is more than 150 feet, the Hoor-surfaces shall be of stone, cement, rock, asphalt, tiling, or similar incombustible material, or the sleepers and floors may be of wood treated by some process approved by the Board of Build- ings to render the same fireproof. All outside window frames and sash shall be of metal, or of wood covered with metal. The inside window frames and sash, doors, trim, and other interior finish may be of wood covered with metal, or of wood treated by some process approved by the Board of Buildings to render the same fireproof. All hall partitions or permanent partitions be- tween rooms in fireproof buildings shall be built of fireproof material, and shall not be started on wooden sills or on wooden floor-boards, but be built on the fireproof construction of the floor and extend to the fireproof beams filling above. Tin' tops of all doors and window-openings in such partitions shall be at least 12 inches below the ceiling-line. Fireproof floors shall be constructed with wrought-iron or steel floor-beams tied together at intervals of not more than eight times the depth of the beam. Between the wrought-iron or sticl floor-beams shall be placed brick arches springing from ihe lower flange of the steel beams; or hollow tile arches of hard-burnt clay or porous terra-cotta of uniform density and hardness of burn : or arches of Portland cement concrete, segmental in form, which shall have a rise of not less than 1% inches for each foot of span between the beams: or between the said beams may be placed solid or hollow burnt-clay, stone, brick, or concrete slabs in flat or curved shapes, concrete, or other fireproof composition, and any of said materials may be used in com- bination with wire cloth, expanded metal, wire strands, or wrought-iron or steel bars; but in any such construction, and as a precedent condi- tion to the same being used, tests shall be made. These tests shall be made by constructing within inclosure walls a platform consisting of four rolled-steel beams, 10 inches deep, weighing each 25 pounds per lineal foot, and placed 4 feet be- tween the centres, and connected by transverse tie-rods, and with a clear span of 14 feet for the two interior beams, and with the two outer beams supported on the side walls throughout their length, and with both a filling between the said beams and fireproof protection of the exposed ports of the beams of the system to be tested, constructed as in actual practice, with the qua! ity of material ordinarily used in that system and the ceiling plastered below, as in a finished job. Such filling between the two interior beams shall I"- Loaded with a distributed load of 150 pounds per square foot of its area, and all car- ried by such filling; i In- platform so con tructed being subjected to the continuous heaf of a wood fire below, averaging not. less than 1700' !■'., for not less than four hours, dining which time no flume will have pa sed through the platform, and no part of the load shall have fallen through, and the beams shall lone been protected from the heal to the extent that after applying f. the tinder side of the platform at the end of the heat lest a stream of water directed against the bottom and discharged through a 1%-inch nozzle under (ill pounds pressure, for five minutes, and al'lcr ll ling I he top of the platform with water under low pressure, and then again apply- ing the stream of water through the nozzle under the 60 pounds pressure to the bottom for five minutes, and after a total load of 600 pounds per square foot uniformly distributed over the mid- dle bay shall have been applied and removed, after the platform shall have been cooled, the maximum deflection of the interior beams shall not exceed 2% inches. Any system failing to meet the requirements of the test of heat, water, and weight prescribed shall be prohibited from use in any building hereafter erected. No filling of any kind which may be injured by frost shall be placed between said floor-beams during freezing weather, and if the same is so placed during any winter month, it shall be temporarily covered with suitable material for protection from being frozen. On top of any arch, lintel, or other device which does not ex- tend to and from a horizontal line with the top of the floor-beams, cinder concrete or other suit- able fireproof material shall be placed to fill up solidly the space to a level with the top of the floor-beams, and shall be carried to the under side of the wood floor-boards in case such be used. All fireproof floor systems shall be of sufficient strength safely to carry the load to be imposed thereon without straining the material in any case beyond its safe working load. The bottom flanges of all wrought-iron or rolled-steel floor-beams and flat roof-beams, and all exposed portions of such beams below the abutments of the floor- arches, shall be entirely incased with hard-burnt clay, porous terracotta, or other fireproof ma- terial allowed to be used for the filling between the beams, to which such incasing material shall be properly secured. The exposed sides and bottom plates or flanges of wrought iron or rolled-steel girders supporting iron or steel floor- beams, or supporting floor-arches or floors, shall be entirely incased in the same manner. After the floors are constructed no opening greater than eight inches square shall be cut through said floors unless properly boxed or framed around with iron. And such openings shall be filled in with fireproof material after the pipes or con- duits are in place. All columns, including the lugs and brackets on same, used in the interior of any fireproof building, or used to support any fireproof floor, shall be protected with not less than two inches of fireproof material, securely applied. The extreme outer edge of lugs, brack ets, and similar supporting metal may project tc
