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Fire towers may be used as exits in lieu of interior stairs provided they comply with all of the requirements for interior stairs, except as modified below.
(a) The enclosing walls of fire towers shall be of incombustible materials or assemblies having a fire-resistance rating of at least four hours. Such walls shall be without openings, except for doors serving as means of egress.
(b) At each story served by a fire tower, access to the stairways of such fire tower shall be provided through outside balconies or fireproof vestibules. Such balconies or vestibules shall be at least three feet eight inches in width and shall have unpierced floors of incombustible materials and shall be provided with substantial guard railings at least four feet high, without any openings greater than five inches in width.
(c) Such balconies or vestibules of fire towers shall be level with the floors of the structure and the platforms of the stairs connected by such balconies. Such balconies or vestibules shall be separated from the structure and the stairs by self-closing swinging doors with a one and one-half hour fire protection rating, capable of being opened from both sides without the use of a key or other unlocking device.
(d) Balconies or vestibules of fire towers shall open on a street or yard, or on a court open vertically to the sky for its full height, having a minimum net area of one hundred five square feet and a minimum dimension of seven feet. The opening from the vestibule to the street, yard or court shall have a minimum area of eighteen square feet and a minimum dimension of two feet six inches. It shall be unlawful to leave openings in the court walls surrounding an interior fire tower, other than the openings from the vestibules, within fifteen feet of the balcony, except that self-closing windows with a three-quarter hour fire protection rating may be used if such windows are at least ten feet from the balcony, provided that the area of the court is at least twelve feet by twenty-four feet.
(e) Fire towers shall terminate at grade level and shall exit directly to the street independently of corridors serving other stairways, except when the fire tower terminates in the ground floor corridor outside of the inner vestibule and within ten feet of the building line.
(f) Fire tower stairs shall comply in all other respects with the applicable requirements of section 27-375 of this code.
(a) Capacity. The capacity of ramps shall be as listed in table 6-1.
(b) Maximum grade. Ramps shall not have a slope steeper than 1 in 8, except that in buildings classified in occupancy group H the slope shall not exceed 1 in 12, and except as provided in subchapter eight of this chapter for places of assembly.
(c) Design.
(1) CHANGES IN DIRECTION. Ramps shall be straight, with changes in direction being made at level platforms or landings, except that ramps having a slope not greater than one in twelve at any place, may be curved.
(2) LENGTH. The sloping portion of ramps shall be at least three feet but not more than thirty feet long between level platforms or landings.
(3) PLATFORMS. Level platforms or landings, at least as wide as the ramp, shall be provided at the bottom, at intermediate levels where required, and at the top of all ramps. Level platforms shall be provided on each side of door openings into or from ramps having a minimum length in the direction of exit travel of three feet, and when a door swings on the platform or landing a minimum length of five feet.
(4) DOORS. Door openings into or from ramps shall comply with the requirements for stairs in subdivision (g) of section 27-375 of this article. No door shall swing over the sloping portion of a ramp.
(5) GUARDS AND RAILINGS. Guards and railings of ramps shall comply with the applicable requirements of subdivision (f) of section 27-375 of this article except that only ramps having a slope steeper than one in twelve need comply with the requirements for handrails and intermediate handrails shall not be required.
(6) SURFACE. Interior ramps exceeding a slope of one in ten and all exterior ramps shall be provided with nonslip surfaces.
(7) Ramps for people having physical disabilities shall additionally comply with the requirements of reference standard RS 4-6.
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 1987/058.
Escalators may be used as exits in lieu of interior stairs provided they comply with all of the requirements of subchapter eighteen of this chapter and with the applicable requirements for enclosed interior stairs, except as modified below:
(a) Capacity. The capacity of escalators as listed in table 6-1 shall be based on the following:
Minimum Width (in.) at:
Step | Balustrade
1
| Enclosure
2
| Units of Exit Width |
24 | 32 | 52 | 1 1/2 |
40 | 48 | 68 | 2 1/2 |
Notes for Table:
1
Measured twenty-seven inches above front edge of tread.
2
Clear width above handrails.
(b) Acceptable exits. Only escalators moving in the direction of exit travel may be credited as exits, except that any escalator may be credited when it is connected to an automatic fire detection system that will cause it to stop simultaneously with the detection of fire. The detection system shall comply with the construction provisions of subchapter seventeen of this chapter. Where an escalator provides exit facilities from only one floor of a building, the automatic detection system shall be located on that floor. Where escalators provide exit facilities from more than one floor, the detection system shall be located on all floors so served, and shall cause escalators on all floors of the section of the building that they serve to stop operating. The stopping mechanism shall operate to bring the escalator to a gradual, rather than an abrupt stop.
(c) Escalators not used as exits. Escalators that do not serve as exits, and that connect more than two stories of a building, shall be completely enclosed with noncombustible construction having a three-quarter hour fire-resistance rating, except that in buildings completely protected by an automatic sprinkler system complying with the construction requirements of subchapter seventeen of this chapter, such escalators may, alternatively, be protected by one of the methods specified in subchapter eighteen of this chapter.
Pedestrian walkways consisting of conveyor belts shall be considered as exit passageways if level, or as ramps if inclined, and shall be acceptable as exits if they comply with the applicable requirements for exit passageways or ramps, and with the following:
(a) Capacity. The capacity shall be as listed under exit passageways or ramps, as the case may be, in table 6-1.
(b) Acceptable exits. Only walkways moving in the direction of exit travel may be credited as exits, except that any moving walkway may be credited when it is connected to an automatic fire detection system that will cause it to stop simultaneously with the detection of fire on the floor it serves. Such detection system shall comply with the construction provisions of subchapter seventeen of this chapter.
(c) Design and construction. Walkways shall comply with the requirements of subchapter eighteen of this chapter.
(d) Enclosure. Walkways that do not serve as exits, but are inclined so as to require an opening in any floor, shall be enclosed as required for escalators in subdivision (c) of section 27-378 of this article.
Fire escapes constructed on existing buildings when altered or as a second means of egress for group homes as permitted by section 27-368 of this article shall comply with the following:
(a) Capacity. The capacity of fire escapes shall be as listed in table 6-1 for stairs.
(b) Stairs. The minimum width of fire escape stairs shall be twentytwo inches. Treads shall have a minimum width of eight inches, exclusive of a required one inch nosing. The maximum height of risers shall be eight inches. No flight of stairs shall exceed twelve feet in height between landings.
(c) Landings. Landings shall be provided at each story served by fire escapes. The minimum width of landings shall be three feet, and the minimum length shall be four feet six inches. Floor openings in landings shall be at least twenty-two inches by twenty-eight inches.
(d) Handrails and guards. Handrails having a minimum height of thirty-two inches above the tread nosing shall be provided on both sides of stairs, and guards having a minimum height of thirty-six inches shall be provided on all open sides of landings, openings in guards shall be of such dimensions as to prevent the passage of a five inch dia. ball.
(e) Construction. Fire escapes shall be constructed of noncombustible materials adequately protected against deterioration by corrosion or other effects of exposure to the weather, and shall be designed to comply with the requirements of subchapter nine of this chapter.
(f) Access. Access to fire escapes shall be by doors or windows having a minimum clear opening of twenty-four inches in width and thirty inches in height. Such doors or windows shall have a fire protection rating of three-quarters of an hour except in buildings classified in occupancy group J-2.
(g) Discharge. The top landing of fire escapes shall be provided with a stair or gooseneck ladder leading to the roof, except that this requirement shall not apply to buildings having a roof pitch of more than twenty degrees. The lowest landing of fire escapes shall be not more than sixteen feet above grade and shall be provided with a stair to grade which may be counterbalanced.
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