house, lodging house, hotel, workshop, factory, school, church, hospital and asylum hereafter erected, shall be concreted not less than four inches thick.

Where wood floors are to be laid in such cellars or lowest stories, the sleepers shall be placed on top of the concrete. (Id., sec. 57, rev. from L. 1882, ch. 410, § 480, as amend.)

§ 58. Cellar Ceilings.- The ceiling over every cellar or lowest floor in every residence building more than four stories in height, hereafter erected, when the beams are of wood, shall be lathed with iron or wire lath and plastered thereon with two coats of brown mortar of good materials, or such other fireproof covering as may be approved by the Commissioner of Buildings having jurisdiction. (Id., sec. 58, rev. from L. 1882, ch. 410, § 480, as amend.)

Part 9.- Wood Beams, Girders and Columns.

§ 59 Wood Beams.- All wood beams and other timbers in the party wall of every building built of stone, brick or iron shall be separated from the beam or timber entering in the opposite side of the wall by at least four inches of solid mason work. No wood floor beams or wood roof beams used in any building hereafter erected shall be of a less thickness than three inches. All wood trimmer and header beams shall be proportioned to carry with safety the loads they are intended to sustain. Every wood header or trimmer more than four feet long, used in any building, shall be hung in stirrup irons of suitable thickness for the size of the timbers. Every wood beam, except header and tail beams, shall rest at one end four inches in the wall, or upon a girder, as authorized by this Code. The ends of all wood floor and roof beams, where they rest on brick walls, shall be cut to a bevel of three inches on their depth. In no case shall either end of a floor or roof beam be supported on stud partitions, except in frame buildings. All wood floor and wood roof beams shall be properly bridged with cross bridging, and the distance between bridging or between bridging and walls shall not exceed eight feet. All wood beams shall be trimmed away from all flues and chimneys, whether the same be a smoke, air or any other flue or chimney. The trimmer beam shall not be less than eight inches from the inside face of a flue, and four inches from the outside of a chimney breast, and the header beam not less than two inches from the outside face of the brick or stone work of the same; except that for the smoke flues of boilers and furnaces where the brickwork is required to be eight inches in thickness, the trimmer beam shall be not less than twelve inches from the inside of the flue. The header beam, carrying the tail beams of a floor, and supporting the trimmer arch in front of a fireplace, shall be not less than twenty inches from the chimney breast. The safe carrying capacity of wood beams for uniformly distributed loads shall be determined by mutiplying the area in square inches by its

depth in inches and dividing ths product by the span of the beam in feet. This result is to be multiplied by seventy for hemlock, ninety for spruce and white pine, 120 for oak and by 140 for yellow pine. The safe carrying capacity of short span timber beams shall be determined by their resistance to shear in accordance with the unit stresses fixed by section 139 of this Code. (Id., sec. 59, rev. from L. 1882, ch. 410, sec. 488, as amend.)

§ 60. Anchors and Straps for Wood Beams and Girders.— Each tier of beams shall be anchored to the side, front, rear or party walls at intervals of not more than six feet apart, with good, strong, wrought-iron anchors of not less than one and one-half inches by three-eighths of an inch in size, well fastened to the side of the beams by two or more nails made of wrought iron at least one-quarter of an inch in diameter. Where the beams are supported by girders, the girders shall be anchored to the walls and fastened to each other by suitable iron straps. The ends of wood beams resting upon girders shall be butted together end to end and strapped by wrought-iron straps of the same size and distance apart, and in the same beam as the wall anchors, and shall be fastened in the same manner as said wall anchors. Or they may lap each other at least twelve inches and be well spiked or bolted together where lapped.

Each tier of beams front and rear, opposite each pier, shall have hardwood anchor strips dovetailed into the beams diagonally, which strips shall cover at least four beams and be one inch thick and four inches wide, but no such anchor strips shall be let in within four feet of the centre line of the beams; or wood strips may be nailed on the top of the beams and kept in place until the floors are being laid. Every pier and wall, front or rear, shall be well anchored to the beams of each story, with the same size anchors as are required for side walls, which anchors shall hook over the fourth beam. (Id., sec. 60, rev. from L. 1882, ch. 410, § 488, as amend.)

§ 61. Wood Columns and Plates.- All timber columns shall be squared at the ends perpendicular to their axes.

To prevent the unit stresses from exceeding those fixed in this Code, timber or iron cap and base plates shall be provided.

Additional iron check plates shall be placed between the cap and base plates and bolted to the girders when required to transmit the loads with safety. (Id., sec. 61.)

§ 62. Timber for Trusses.- When compression members of trusses are of timber they shall be strained in the direction of the fibre only. When timber is strained in tension it shall be strained in the direction of the fibre only. The working stress in timber struts of pin-connected trusses shall not exceed seventy-five per cent. of the working stresses established in section 139, this Code. (Id., sec. 62.) § 63. Bolts and Washers for Timber Work.- All bolts used

in connection with timber and wood beam work shall be provided with washers of such proportions as will reduce the compression on the wood at the face of the washer to that allowed in section 139, this Code, supposing the bolt to be strained to its limit. (Id., sec. 63.)

Part 10.- Chimneys, Flues, Fireplaces and Heating Pipes.

§ 64. Trimmer Arches. All fireplaces and chimney breasts where mantels are placed, whether intended for ordinary fireplace uses or not, shall have trimmer arches to support hearths, and the said arches shall be at least twenty inches in width, measured from the face of the chimney breast, and they shall be constructed of brick, stone or burnt clay. The length of a trimmer arch shall be not less than the width of the chimney breast. Wood centres under trimmer arches shall be removed before plastering the ceiling underneath. If a heater is placed in a fireplace, then the hearth shall be the full width of the heater. All fireplaces in which heaters are placed shall have incombustible mantels. No wood mantel or other woodwork shall be exposed back of a summer piece; the ironwork of the summer piece shall be placed against the back or stone work of the fireplace. No fireplace shall be closed with a wood fireboard. (Id., sec. 64.)

§ 65. Chimneys, Flues and Fireplaces. All fireplaces and chimneys in stone or brick walls in any building hereafter erected, except as herein otherwise provided, and any chimney or flue hereafter altered or repaired, without reference to the purpose for which they may be used, shall have the joints struck smooth on the inside, except when lined on the inside with pipe. No parging mortar shall be used on the inside of any fireplace, chimney or flue. The firebacks of all fireplaces hereafter erected shall be not less than eight inches in thickness, of solid masonry. When a grate is set in a fireplace a lining of firebrick, at least two inches in thickness, shall be added to the fireback, unless soapstone, tile or cast iron is used, and filled solidly behind with fireproof material. The stone or brickwork of the smoke flues of all boilers, furnaces, bakers' ovens, large cooking ranges, large laundry stoves, and all flues used for a similar purpose shall be at least eight inches in thickness, and shall be capped with terra-cotta, stone or cast iron.

The inside four inches of all boiler flues shall be firebrick, laid in fire mortar, for a distance of twenty-five feet in any direction from the source of heat. All smoke flues of smelting furnaces or of steam boilers, or other apparatus which heat the flues to a high temperature, shall be built with double walls of suitable thickness for the temperature, with an air space between the walls, the inside four inches of the flues to be of firebrick. All smoke flues shall extend at least three feet above a flat roof, and at least two feet above a peak roof.

On dwelling houses and stables, three stories or less in height, not less than six of the top courses of a chimney may be laid in pure cement mortar and the brickwork carefully bonded and anchored together in lieu of coping.

In all buildings hereafter erected every smoke flue, except the flues herein before mentioned, shall be lined on the inside with cast iron or well-burnt clay, or terra-cotta pipe, made smooth on the inside, from the bottom of the flue, or from the throat of the fireplace, if the flue starts from the latter, and carried up continuously to the extreme height of the flue. The ends of all such lining pipes shall be made to fit close together, and the pipe shall be built in as the flue or flues are carried up. Each smoke pipe shall be inclosed on all side with not less than four inches of brickwork properly bonded together.

All flues in every building shall be properly cleaned and all rubbish removed, and the flues left smooth on the inside upon the completion of the building. (Id., sec. 65, rev. from L. 1882, ch. 410, § 489, as amend.)

§ 66. Chimney Supports.- No chimney shall be started or built upon any floor or beam of wood.

In no case shall a chimney be corbeled out more than eight inches from the wall, and in all such cases the corbeling shall consist of at least five courses of brick, but no corbeling more than four inches shall be allowed in eight-inch brick walls. Where chimneys are supported by piers, the piers shall start from the foundation on the same line with the chimney breast, and shall be not less than twelve inches on the face, properly bonded into the walls. When a chimney is to be cut off below, in whole or in part, it shall be wholly supported by stone, brick, iron or steel. All chimneys which shall be dangerous in any manner whatever, shall be repaired and made safe, or taken down. sec. 66, rev. from L. 1882, ch. 410, § 489, as amend.)

(Id.,

§ 67. Chimneys of Cupolas.- Iron cupola chimneys of foundries shall extend at least ten feet above the highest point of any roof within a radius of fifty feet of such cupola, and be covered on top with a heavy wire netting. No woodwork shall be placed within two feet of the cupola. (Id., sec. 67, rev. from L. 1882, ch 410, § 489, as amend.)

§ 68. Hot-Air Flues. Pipes and Vent Ducts.- All stone or brick hot-air flues and shafts shall be lined with tin, galvanized iron or burnt-clay pipes. No wood casing, furring or lath shall be placed against or cover any smoke flue or metal pipe used to convey hot air or steam. No smoke pipe shall pass through any wood floor. No stovepipe shall be placed nearer than nine inches to any lath and plaster or board partition, ceiling or any woodwork. Smoke pipes of laundry stoves, large cooking ranges and of furnaces shall be not less than fifteen inches from any woodwork, unless they are properly guarded by metal shields; if so guarded, stovepipes shall be not less than six inches distant, smoke

pipes of laundry stoves, large cooking ranges and of furnaces shall be not less than nine inches distant from any woodwork. Where smoke pipes pass through a lath and plaster partition they shall be guarded by galvanized iron ventilated thimbles at least twelve inches larger in diameter than the pipes, or by galvanized iron thimbles built in at least eight inches of brickwork. No smoke pipe shall pass through the roof of any building unless a special permit be first obtained from the Building Department for the same. If a permit is so granted, then the roof through which the smoke pipe passes shall be protected in the following manner: A galvanized iron ventilated thimble of the following dimensions shall be placed; in case of a stovepipe, the diameter of the outside guard shall be not less than twelve inches and the diameter of the inner one, eight inches, and for all furnaces, or where similar large hot fires are used, the diameter of the outside guard shall be not less than eighteen inches and the diameter of the inner one, twelve inches. The smoke-pipe thimbles shall extend from the under side of the ceiling or roof beams to at least nine inches above the roof, and they shall have openings for ventilation at the lower end where the smoke pipes enter, also at the top of the guards above the roof. Where a smoke pipe of a boiler passes through a roof, the same shall be guarded by a ventilated thimble, same as before specified, thirty-six inches larger than the diameter of the smoke pipe of the boiler. Tin or other metal pipes in brick or stone walls, used or intended to be used to convey heated air, shall be covered with brick or stone at least four inches in thickness. Woodwork near hot-air pipes shall be guarded in the following manner: A hot-air pipe shall be placed inside another pipe, one inch larger in diameter, or a metal shield shall be placed not less than one-half inch from the hot-air pipe; the outside pipe or the metal shield shall remain one and one-half inches away from the woodwork and the latter must be tin lined, or in lieu of the above protection, four inches of brickwork may be placed between the hot-air pipe and the woodwork. This shall not prevent the placing of metal lath and plaster directly on the face of hot-air pipes or the placing of woodwork on such metal lath or plaster, provided the distance is not less than seven-eighths of an inch. No vertical hot-air pipe shall be placed in a stud partition, or in a wood inclosure, unless it be at least eight feet distant in a horizontal direction from the furnace. Hot-air pipes in closets shall be double, with a space of one inch between them. Horizontal hot-air pipes shall be placed six inches below the floor beams or ceiling; if the floor beams or ceiling are plastered and protected by a metal shield, then the distance shall be not less than three inches.

Vent flues or ducts for the removal of foul or vitiated air in which the temperature of the air cannot exceed that of the rooms, may be constructed of iron, or other incombus