buildings, or to other parts of the same building, the exposed surfaces should be covered with some fire-resisting material fol· lowing all lines and angles of the walls.

Concealed spaces in walls should be avoided as much as pos sible. Where plastered brick or stone walls are desired, the plaster should be put directly on the walls; where it is not possible to put plaster directly on the walls, wire netting or ex panded metal laths should be used; where a wood covering is used, the wood should be directly against the walls, following al! lines and angles of the same; wooden laths should be avoided.

THICKNESS Of Walls as per LAWS OF NEW YORK STATE, AND RECOMMENDED BY THE NATIONAL BOARD OF FIRE UNDER

WRITERS, JUNE, 1893.

35 feet to 50 feet high. 12 inches (dwellings, etc., 26 feet or less between bearing walls).

12 inches above basement (dwellings).

··

for 25 feet up: 12 inches above.
for 20

up to 60 feet: 12 inches

above.

up to 75 feet: 16 inches

24 inches for 35 feet up: 20
above.

28 inches for 25 feet up: 24

up to 90 feet: 16 inches above.

Each additional 25 feet in height or part thereof next above curb should be increased 4 inches in thickness, the upper 115 feet of wall remaining as above.

Non-bearing walls in dwellings, etc., may be 4 inches less in thickness to a minimum thickness of 12 inches.

WALLS 25 FEET OR LESS IN WIDTH BETWEEN WALLS OR BEARINGS (FACTORIES, WAREHOUSES, Stores, Stables).

28 inches for 25

up to 75 feet: 16 inches above.

Each additional 25 feet in height or part thereof next above curb should be increased 4 inches in thickness, the upper 100 feet of wall remaining as above.

Walls over 25 feet in width between walls or bearings. (Fac tories, warehouses, stores, stables.) Bearing walls should be 4 inches more in thickness than specified above, for every 12%

feet or fraction thereof that said walls are more than 25 feet apart.

All buildings that are over 105 feet in depth, without a cross wall, or proper piers or buttresses, shall have the side or bearing walls increased in thickness 4 inches more than above that the said walls of buildings are over 105 feet in depth.

Factories, Warehouses, Stores, over 25 feet in width between walls, in which there are brick partition walls, or girders supported on iron or wooden columns, or piers of masonry, the partition walls or girders shall be so placed that the space between any two partition walls or girders shall not exceed 25 feet, In case iron or wooden girders, supported by iron or wooden columns, or piers of masonry, are substituted in place of brick partition walls, the building should not exceed 10,000 feet area on the ground floor, except in case of fireproof buildings.

Curtain walls of brick, built in between iron or steel columns. and supported wholly or in part on iron or steel girders, shall not be less than 12 inches thick for fifty feet of the uppermost height thereof, and every lower section of fifty feet shall have a thickness of 4 inches more than is required for the section next above it down to the tier of beams nearest to the curb level. GENERAL TABLE OF THICKNESS OF SOLID

BRICK

Walls.

In place of solid brick walls, the walls above the first floor can be of heavy brick piers 8 feet to 10 feet apart between centers with large windows between the piers; any intervening spaces to be filled in with brick; but this construction should not be used

7th Floor.

8th Floor.

9th Floor.

10th Floor.

11th Floor.

12th Floor.

in building of more than 3 stories in height when used for all walls, but where used for only one wall, between bearing walls can be carried up to 6 stories.

ROOFS. A gravel roof made of small round stones laid on properly prepared and spread good coal tar is a most desirable one for roofs having a slight pitch, and is, to a certain extent, fireproof.

Composition roofs are now made in such a manner as to practically eliminate the old objection to them, that is, the liability of their cracking; the materials used and the way of mixing them as well as the manner of laying them is now such that many of these roofs are lasting and, to a decided extent, fireproof. Where acid fumes, such as destroy metal, are in evidence, these roofs are especially desirable.

Trinidad asphalt and asbestos roofs withstand great heat, and are a good type of roofing for buildings subject to constant heat and acid fumes, besides being lasting and not liable to become expensive through repairs.

Tin and copper make the best sheet metal roofs, but they should be well laid and soldered.

Sheet iron does not make a lasting roof, as it is easily affected by the weather and soon goes into holes.

Metal roofs should not be used where there is any probability of acid fumes attacking them, as under such conditions they will soon deteriorate and become worthless. They should be kept thoroughly painted with iron oxide paint to prevent rusting; lead paint will not adhere as firmly and securely as the iron oxide, and thus an additional expense is incurred in keeping the roofs in a good painted condition where the lead paints are used.

Slate is liable to break, and so make apertures through which sparks can lodge in the wood sheathing under the slate; this objection to these roofs can be overcome to a great extent by laying the slate in mortar.

Cotton duck for roofing, soaked in water, and painted with white lead and linseed oil before being thoroughly dry, and after drying painted with several coats of white lead and fireproof paint, and then covered with sand, makes a good waterproof and practically fireproof roof.

Through the action of age, water, heat, and cold, shingle roofs curl, warp, crack, and rot, and thus lodgment holes for sparks are formed; they also present a large inflammable surface to exposure. Such roofs should be removed or some steps taken to reduce the hazerd: as, for instance, they can be painted with several coats of fireproof paint, or the shingles can be laid in lime mortar (this tends to hold them in place and prevents their warping).

Brick arched roofs or fire tile roofs on properly protected steel girders are from the fire hazard point of view the best roofs. Barn, mansard, and hipped roofs are not desirable on account of the increase of exposed surface, additional weight, and the joisted and general class of construction.

CORNICES.-Brick, stone, and terra cotta are especially desirable on account of their forming an integral part of the building and being non-combustible.

Cast iron when entirely disconnected from the cornice of any other building is not objectionable, but where it is continuous with and forming one cornice with that of contiguous buildings it is a weak feature, from the fact that by the falling of the cornice of the adjoining building the cornice on the other buildings would be seriously damaged; also, if there are openings leading into the cornice from the building, in case of fire a suction chamber for carrying the fire from building to building is immediately formed, hence under these conditions this form of cornice is not very desirable.

An open, unboxed wooden roof overhang is the best class of cornice for "slow-burning," "mill," or any other form of construction for factory purposes where brick of terra cotta cornices are not built.

Boxed wooden cornices, especially where exposed to other buildings, or where continuous with similar cornices of contiguous buildings, constitute a very weak and hazardous point, and should be removed or made open wherever possible.

All wooden cornices should be preferably of open construction. Where hollow metal or hollow wooden cornices are continuous with the cornices of other buildings, a "break" in the cornice should be made at each wall, said "break" to be made of brick, heavy iron, wood standard tin clad, or asbestos parti

tion entirely filling the full open end of the cornice. These "breaks" or "stops" will prevent the fire in one building communicating to a contiguous building through the opening in the cornice.

SKYLIGHTS.-Frames should preferably be "hipped," i. e., the sides at an angle so that the topmost point will form an angle and thus be entirely different in form from the flat style. The glass should be thick, wired glass or ribbed glass.

Area should not exceed 50 feet when the frame is of wood; when the area is in excess of this the entire frame should be of iron.

All flat or hipped skylights should be protected by wire netting of a mesh not larger than 1⁄2 inch and the wire should not be less than No. 12; this netting should be in a rigid iron frame supported by iron standards from 6 to 12 inches high.

Monitor or lantern skylights should have the same kind of roofing as the main roof.

FLOORS.-Under all conditions, hollow fireproof brick or tile floors supported by iron or steel girders fully covered by tiles or fire-brick, and covered by a cement, or a hardwood flooring, or brick-arched floors, or "slow-burning" constructed floors, are to be desired.

Wherever any heavy work or trucking is done, wooden floors should be double.

Where any specially hazardous processes are carried on (as in foundries, varnish works, burner rooms in acid works, hot rooms, japan dry rooms, boiler rooms, etc.), the floors should be of earth, cement or concrete.

All floors should be tight against walls, allowing no air space between the walls and floors.

Where iron posts, beams, girders, etc., are used, they should be fireproofed by thoroughly encasing them in fireproof bricks or tiles, or covering them by layers of asbestos or mineral wool and cement held in place by wire netting, or by some other approved method.

Floor beams should at least have a bearing at each end of 4 inches.

The butts or ends of all beams and rafters entering a brick wall should be cut on a splay of inches in their width, so as to make them self-releasing.