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Exit passageways shall be maintained free of obstructions at all times. Not more than fifty percent of the total number of vertical exits provided for a building may be served by a single exit passageway, except as provided in subdivision (h) of section 27-370 of this article.
(a) Capacity. The capacity of exit passageways shall be as listed in table 6-1.
(b) Width. The width of an exit passageway serving one vertical exit shall be equal to the width of the vertical exit. The width of an exit passageway serving two or more vertical exits shall be equal to seventy-five percent of the width of all of the vertical exits that it serves. Width shall be measured in the clear between the narrowest points at any projections such as radiators, door swings, or pilasters.
(c) Height. Exit passageways shall have a clear height of seven feet six inches for at least seventy-five per cent of the floor area, with no point less than seven feet in height. No projection below the ceiling shall be located so as to obstruct full view of exit signs.
(e) Construction. The construction of exit passageways shall be as required by table 3-4 for the applicable construction class of the building.
(f) Openings. No openings other than exit doors shall be permitted in exit passageways, except as provided in subdivision (h) of this section.
(g) Interior finish. The interior finish of exit passageways shall be in accordance with the requirements of table 5-4.
(h) Street floor lobbies. Street floor lobbies may be used as exit passageways when they comply with the requirements of subdivisions (a) through (g) of this section subject to the following modifications:
(1) VERTICAL EXITS SERVED. One hundred per cent of the total number of vertical exits provided for a building may be served by a street floor lobby, if egress is provided in two different directions from the discharge points of all vertical exits to open exterior spaces that are remote from each other.
(2) WIDTH. Street floor lobbies serving as exit passageways shall be increased in width to accommodate the occupant load of all communicating spaces on the lobby floor that exit through them. The capacity per unit of width shall be as listed in table 6-1.
(3) OPENINGS. Openings between street floor lobbies serving as exit passageways and elevators or communicating spaces shall comply with the following:
a. Doors.
1. Doors to stairways and elevators, and unsprinklered communicating spaces classified in occupancy group B-2, D-2, F-1 or F-2 shall be self-closing fire doors having a one and one-half hour fire protection rating.
2. Doors to unsprinklered communicating spaces classified in occupancy group G, H or J, or sprinklered communicating spaces classified in occupancy group B-2, D-2, F-1 or F-2 may be either:
(a) self-closing fire doors having a three-quarter hour fire protection rating, or
(b) glass or other noncombustible doors installed in conjunction with automatic fire doors having a one and one-half hour fire protection rating, with sprinkler heads installed over the doors on the room side.
3. No other door openings shall be authorized except as otherwise provided in this section.
b. Other openings. Other openings to spaces classified in occupancy group C, E, F, G, H or J shall be permitted, provided they have a maximum length of eight feet and a maximum height of eight feet, are glazed by one-quarter inch polished plate glass or equivalent and are protected by automatic fire doors having a one and one-half hour fire protection rating and by automatic sprinklers complying with the construction requirements of subchapter seventeen of this chapter over the openings on the room side.
c. Separations and limitations. Openings permitted by subparagraphs a and b of this paragraph shall not exceed in total length fifty per cent of the length of such enclosure wall except where the length of such wall is less than sixteen feet. Adjoining openings shall be separated from each other a minimum of three feet by construction having a two hour fire-resistance rating.
d. Notwithstanding the restrictions in subparagraphs a, b, and c of this paragraph, the following openings may be authorized:
1. A space classified in occupancy group C, E, F-3 or, F-4 within fire separations having a minimum fire-resistance rating of one hour, with an area not exceeding twenty-five hundred square feet, may have an unlimited length of show window under the following conditions:
(a) The maximum depth of show window shall be three feet.
(b) Automatic sprinklers complying with the construction requirements of subchapter seventeen of this chapter, shall be provided in the show window display area.
(c) The show window display area shall be protected on all sides, except for the glazed window, by construction having a two hour fire-resistance rating with access provided by means of a fireproof self-closing door having a three-quarter hour fire protection rating.
(d) The show window shall be glazed by one-quarter inch polished plate glass or equivalent.
(e) Glass or other noncombustible doors may be used for entrance to or egress from the space within fire separations when installed in combination with automatic fire doors having a one and one-half hour fire protection rating. Such automatic fire doors shall be located on the room side and shall be held open by approved door-holding devices actuated to release automatically upon the activation of smoke detecting devices, whether of the photoelectric cell or other approved type. In addition, automatic sprinkler heads, complying with the construction requirements of subchapter seventeen of this chapter, shall be provided over the door openings on the room side.
2. A space classified in occupancy group C, E, F-3, or F-4 within fire separations having a minimum fire-resistance rating of one hour, with an area not exceeding three thousand square feet, may have a maximum total length of unprotected openings upon a corridor or exit passageway not exceeding fifty percent of the space frontage along such corridor or exit passageway under the following conditions:
(a) The entire space shall be provided with automatic sprinklers complying with the construction requirements of subchapter seventeen of this chapter.
(b) The show window shall be glazed by one-quarter inch polished plate glass or equivalent.
(c) All corridor or exit passageway doors shall be self-closing, noncombustible, and smokeproof.
3. Show windows or other openings of unlimited lengths and heights shall be permitted on any corridor or exit passageway without requirements for fire-resistance doors under the following conditions:
(a) The entire floor area, including the corridors or exit passageways, shall be provided with automatic sprinklers complying with the construction requirements of subchapter seventeen of this chapter.
(b) The occupancy of all spaces on the floor shall be limited to occupancy groups C, E, F-3 and F-4.
(c) The widths of the corridors or passageways shall exceed the requirements of table 6-1 or subdivision (b) of this section, whichever is applicable, by at least fifty percent.
(d) All doors opening on the corridors or exit passageways shall be smokeproof, noncombustible self-closing doors.
(e) Show windows or other openings shall be glazed by one-quarter inch polished plate glass or equivalent.
(f) Each corridor or exit passageway shall be provided with a fresh air intake, a positive smoke exhaust system and smoke detectors which, when activated, shall permit circulation only of fresh air.
(4) OCCUPANCY. Street floor lobbies serving as exit passageways may be occupied by newsstands, candy and tobacco stands, information booths or similar occupancies, if such stands or booths are constructed of noncombustible materials, or of materials which comply with the requirements of section 27-348 of article five of subchapter five of this chapter for interior finish for exit passageways, provided that such stands or booths:
a. do not occupy more than one hundred square feet or five percent of the net floor area of the lobby, whichever is greater; and
b. do not reduce the required clear width of the lobby at any point; and
c. if constructed of combustible materials are protected by no less than two automatic sprinkler heads. Water for such sprinkler heads may be supplied from the domestic water supply system.
Exit doors and doors providing access to exits shall comply with the following:
(a) Exit doors. Doors for required exits shall be self-closing swinging doors with a one and one-half hour fire protection rating, except in occupancy group J-3 buildings and except that:
(1) Exterior street floor exit doors having an exterior separation of more than fifteen feet need not have a fire-protection rating.
(2) Doors into stairs and exit passageways shall have at least a three-quarter hour fire protection rating.
(b) Corridor doors. Doors that provide access to interior corridors required to have a one hour fire-resistance rating shall be self-closing swinging fire doors with a three-quarter hour fire-protection rating, except that in buildings classified in occupancy group G, in which an acceptable interior fire alarm system is installed and in which regular supervised fire drills are held, the doors to rooms or spaces devoted exclusively to nonhazardous uses in occupancy group G need not be fire-rated, provided they are swinging, self-closing one and three-quarter inch solid core wood, and have a maximum area of seven hundred twenty square inches of one-quarter inch thick wired glass vision panels. Other corridor doors except those provided for in subdivision (d) of section 27-369 of this article, shall be self-closing, swinging, noncombustible or one and three-quarter inch solid core wood doors, except that in buildings classified in occupancy group H-2 the doors need not be self-closing. Noncombustible mail slots having an area not exceeding forty square inches may be provided in corridor doors when the opening is protected by a closure activated by gravity or a spring device so as to keep it closed when not in use. Noncombustible louvers may be installed in corridor doors opening into toilets, service sink closets, and electric closets. Notwithstanding the foregoing restrictions in this subdivision, doors not prohibited by subdivision (d) of this section may open from spaces into corridors when in compliance with all of the provisions of paragraph three of subdivision (h) of section 27-370 of this article.
(c) Smoke stop doors. Smoke stop doors shall be self-closing, swinging doors of metal, metal covered, or one and three-quarter inch solid core wood with clear wire glass panels having a minimum area of six hundred square inches per door and a maximum area of twelve hundred ninety-six square inches per door, except that in buildings not over two stories high, smoke stop doors may be of one and three-eighths inch solid core wood with clear wire glass panels, unless the doors are also used as horizontal exits in which case they shall comply with the provisions of subdivision (b) of section 27-373 of this article. In addition, smoke stop doors may be constructed of tempered glazing or the equivalent and be protected by sprinkler heads constructed in accordance with subchapter seventeen of this chapter and installed a maximum of six feet (6'-0") on centers on each side of the opening. Smoke stop doors may be double-acting but shall close the opening completely with only such clearance as is reasonably necessary for proper operation. Smoke stop doors shall normally be in the closed position, except that they may be left open if they are arranged to close automatically by an approved device which is actuated by an interior fire alarm system meeting the requirements of subchapter seventeen of this chapter or upon smoke detection. Tempered glass smoke stop doors shall be marked where required in accordance with the rules of the board of standards and appeals.
(d) Prohibited doors. Vertically sliding doors, rolling shutters, and folding doors shall not be used as exit doors or as corridor doors, except that overhead garage doors may serve as exits from buildings classified in occupancy group J-3, and except that sliding or rolling doors or gates may be used in F-2 places of assembly provided they are kept open when the place of assembly is occupied. Revolving doors may be used only to the extent permitted by subdivision (m) of section 27-371 of this article. Automatic horizontally sliding fire doors shall be permitted only in horizontal exits in fire divisions required to have a four hour fire-resistance rating as specified in table 5-3.
(e) Door opening widths. The capacity of exit and corridor door openings shall be as listed in table 6-1. Door jambs or stops and the door thickness when open shall not reduce the required width by more than three inches for each twenty-two inches of width. The maximum width of any swinging door leaf shall be forty-eight inches. The minimum nominal width of corridor and exit door openings shall be thirty-six inches, except that where a door opening is divided by mullions into two or more door openings, the minimum nominal width of each such opening shall be thirty-two inches. The minimum nominal width of other door openings shall be as follows:
(1) Door openings to all habitable and occupiable rooms-thirty-two inches.
(2) Door swinging in pairs (no mullion), opening-forty-eight inches.
(3) Door openings to rooms used by bedridden patients and all single door openings used by patients in buildings classified occupancy group H-2-forty-four inches.
(4) Door openings to toilet rooms in buildings to which the public has free access shall be thirty-two inches.
(5) Door openings giving access to at least one toilet, lavatory and bathtub or shower in each dwelling unit, in buildings or spaces classified in occupancy group J-1 or J-2, when such dwelling unit is accessible to individuals in wheel chairs-thirty-two inches.
(6) Door openings giving access to all toilets, lavatories and bathtubs or showers serving single room occupancies which are accessible to individuals in wheelchairs-thirty-two inches.
(7) Door openings for people having physical disabilities shall additionally comply with the requirements of reference standard RS 4-6.
(f) Door heights. The minimum nominal door opening height for exit and corridor doors shall be six feet eight inches. Door jambs, stops, sills, and closers shall not reduce the clear opening to less than six feet six inches.
(g) Door swing. Exit doors, corridor doors from rooms or spaces classified in high hazard occupancy group A, or from factories as defined in the labor law, and corridor doors from rooms required to have more than one door under the provisions of section 27-365 of article four of this subchapter, shall swing in the direction of exit travel, except:
(1) Doors from rooms of instruction in buildings classified in occupancy group G, having an occupant load of less than seventy-five persons.
(2) Exterior street floor exit doors from lobbies in buildings classified in occupancy groups J-2 and J-3.
(3) Exterior street floor exit doors from spaces in occupancy group C or E not exceeding two thousand square feet in area, and occupied by less than fifty persons, where the maximum travel distance to a door does not exceed fifty feet.
(h) Floor level. The floor on both sides of all exit and corridor doors shall be essentially level and at the same elevation for a distance, perpendicular to the door opening, at least equal to the width of the door leaf, except that where doors lead out of a building the floor level inside may be seven and one-half inches higher than the level outside.
(i) Closed doors. Exit doors and corridor doors shall normally be kept in the closed position, except that corridor doors in buildings classified in occupancy group H-2 shall be exempt from this requirement.
(j) Door and window hardware. Doors and windows shall be equipped with hardware as follows:
(1) Fire protection requirements.
a. Exit doors and corridors shall be readily openable at all times from the side from which egress is to be made and shall not require a key to operate from that side, except that:
1. Locks may be used in penal and mental institutions and areas, where required for security.
2. Locks may be used in banks, museums, jewelry stores and other places where extra safeguards are required, subject to the approval of the commissioner, and provided the locks are equipped with electrical release devices for remote control in case of emergency.
3. Stairways leading from the top floor to a roof may be provided with locked wire mesh gates openable by key in buildings classified in occupancy group G. The use of a hook and eye closing device on the inside of all doors to roofs shall be permitted.
b. Doors opening into interior stair enclosures shall not be locked from either side with the following exceptions:
1. Doors may be located to prevent access to the stair at the street floor.
2. In buildings classified in occupancy group E, less than one hundred feet in height, the doors may be locked on the stair side on each floor above the street floor.
3. In buildings classified in occupancy group E, one hundred feet or more in height, and existing office buildings one hundred feet or more in height, the doors may be locked on the stair side above the street floor except that at intervals of four stories or less, doors shall be openable from the stair side without the use of a key to permit reentry at such floors. In addition, the door on every floor where a keyed switch is required by the provisions of subchapter eighteen of this chapter shall be openable from the stair side without the use of a key to permit reentry at such floors.
4. When a locked door is provided with an automatic fail safe system for opening such door in the event of the activation of any automatic fire detecting device or when any elevator in readiness as provided in section 27-989 of subchapter eighteen of this chapter is activated, such door shall be deemed as openable from the stairside. The installation of such automatic fail safe system shall comply with the requirements of reference standards RS17-3A and RS17-3B, whichever is applicable. Stair reentry signs required under section 27-394 of article nine of this subchapter shall specify that reentry is provided only during fire emergencies.
c. Latch bolts shall be provided on all exit doors and corridor doors to hold them in a closed position against the pressure of expanding gases except that this requirement shall not apply to doors in stair enclosures in buildings classified in occupancy group G.
(2) Security requirements. The following provisions shall apply to all buildings erected or altered after December sixth, nineteen hundred sixty-eight that may be classified in residential occupancy group J-2. Existing buildings in such group shall comply with the requirements of article eleven of subchapter two.
a. Building entrance doors and other exterior exit doors shall be equipped with heavy duty lock sets with auxiliary latch bolts to prevent the latch from being manipulated by means other than a key. Latch sets shall have stopwork in the inside cylinder controlled by a master key only. Outside cylinders of main entrance door locks shall be operated by the tenants' key, which shall not be keyed to also open the tenant's apartment door. A light or lights shall be provided at or near the outside of the front entranceway of the building providing not less than five foot candles intensity measured at the floor level for the full width of the entranceway.
b. Doors to dwelling units shall be equipped with a heavy duty latch set and a heavy duty dead bolt operable by a key from the outside and a thumb-turn from the inside. Those doors shall also be equipped with a chain guard so as to permit partial opening of the door. Dwelling unit entrance doors shall also be equipped with a viewing device located so as to enable a person on the inside of the entrance door to view a person immediately outside.
c. All openable windows shall be equipped with sash locks designed to be openable from the inside only. Grilles lockable from the inside only may be placed on the inside or outside of windows that are accessible from grade but that do not serve to provide access to exits.
d. Buildings classified in occupancy group J-2 containing eight or more dwelling units shall be provided with an intercommunication system located at the door giving access to the main entrance hall or lobby, consisting of a device or devices for voice communication between the occupant of each dwelling unit and a person outside said door to the main entrance hall or lobby and permitting such dwelling unit occupant to release the locking mechanism of said door from the dwelling unit.
(k) Panic hardware.
(1) Exit doors shall be equipped with fire exit bolts when providing an exit from:
a. Buildings classified in occupancy group G, except exit doors opening directly outdoors at grade from rooms having an occupant load of less than seventy-five persons,
b. F-1 places of assembly,
c. F-2, F-3 and F-4 places of assembly having an occupant load exceeding three hundred persons, except places of assembly having doors that are not equipped with locks and are openable at all times.
(2) Fire exit bolts shall be of an approved type, and shall release when a pressure exceeding fifteen pounds is applied to the releasing device in the direction of exit travel. The bars or panels shall extend at least two-thirds of the width of the door and shall be placed at least thirty inches, but not more than forty-four inches above the floor.
(l) Power operated doors. Power operated doors or power assisted manually operated doors, may be used as exit or corridor doors provided they remain closed in case of power failure but shall be manually operable. No power operated door shall be credited as a required exit unless it swings in the direction of exit travel.
(m) Revolving doors. Revolving doors shall not be used as exits in buildings classified in occupancy group F-1 or F-2, G, or H; nor shall revolving doors be used in any occupancy as interior doors providing access to exits, at the foot of stairs, or at the head of basement stairs. Where revolving doors are used as exits, they shall comply with the following:
(1) They may provide not more than one unit or exit width for each revolving door and not more than fifty per cent of the required exit capacity at any location, provided that the revolving doors are located adjacent to, or within twenty feet, of swinging doors that provide the remaining required exit capacity at that location.
(2) They shall be collapsible, and designed and constructed so that:
a. Each wing is independently supported by a hanger with a corrosion resistant safety release which, when pressure of between sixty to eighty pounds is exerted simultaneously on the wings on opposite sides of the door pivot, the door wings will fold back on themselves in the direction of egress.
b. Each wing is provided with at least one push bar and glazed with at least 7/1932 in. plate or tempered glass.
c. The inside diameter of the enclosure is at least six feet six inches.
d. The freely operable maximum rate of revolving speed is controlled so that it is not greater than fifteen rpm.
e. The upper surface of the floor finish within the door enclosure is flush with the adjacent floor area, and permanently secured in place.
(3) The owner shall be responsible at all times for the operation and maintenance of revolving doors, and shall have the doors inspected at intervals not to exceed six months. All parts of the doors, including the safety releases and speed control mechanism, shall be maintained in good working order. Inspection reports shall be made in writing and kept on file at the premises for at least two years.
(n) Turnstiles. No turnstile or other device designed to restrict travel shall be placed so as to obstruct any required exit, except that approved turnstiles that turn freely in the direction of exit travel may be used in any occupancy where revolving doors are permitted. Turnstiles shall be not more than thirty-six inches nor less than thirty inches high and shall be of such design as to provide twenty-two inches clear width as the turnstile rotates. Each turnstile may be credited with a capacity of one unit of exit width. Not more than fifty per cent of the required exit capacity may be provided by turnstiles at any location. The balance of the required exit capacity shall be provided by swinging doors located within twenty feet of the turnstiles. Turnstiles over thirty-six inches high shall meet the applicable requirements of this code for revolving doors.
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 1987/058.
Areas of refuge shall comply with the following:
(a) Separation. Areas of refuge shall be separated from the area which they serve by construction having at least a two hour fire-resistance rating.
(b) Floor area. Areas of refuge shall provide clear public space or space occupied by the same tenant or owner, adequate in size to hold the occupant load it receives from the floor area it serves as computed by the provision of section 27-367 of article four of this subchapter, in addition to its own occupant load, allowing at least three square feet per person, except that in buildings classified in occupancy group H-2 for patient areas only, the allowance shall be at least thirty square feet per person.
(c) Required exits. Areas of refuge shall be provided with at least one vertical exit. When an area of refuge is located higher than the eleventh floor of a building, the vertical exit shall be supplemented by at least one elevator.
(d) Locking. Doors providing access to areas of refuge shall be kept unlocked at all times when any floor area served by the area of refuge is occupied.
A horizontal exit to an area of refuge may consist of doors through walls or partitions having at least a two hour fire-resistance rating; of a balcony or exterior vestibule leading around the end of a fire division to another fire area or building; or it may be a bridge or tunnel between two buildings. Horizontal exits shall comply with the following:
(a) Capacity. The capacity of horizontal exits shall be as listed in table 6-1. Only the widths of doors swinging in the direction of exit travel to the area of refuge shall be counted.
(b) Door requirements. Doors shall be swinging, self-closing doors having a fire protection rating of one and one-half hours, except that door in fire divisions having a three hour or four hour fire-resistance rating shall have opening protective as required by table 5-3. Each swinging door shall swing in the direction of exit travel, and when travel is in both directions, as when two areas of refuge serve as areas of refuge for each other, at least two door openings shall be provided, the doors of which shall swing in opposite directions. Signs shall be placed over each door on the side from which egress is made, indicating the exit door.
(c) Balconies, bridges and tunnels. When serving as horizontal exits, balconies, bridges, and tunnels shall comply with the following:
(1) Their width shall be equal to at least the width of the doors opening on them, but in no case less than three feet eight inches.
(2) They shall be enclosed at each end by doors complying with subdivision (b) of this section.
(3) The floor level at doors shall be the same as that of the building except that the floor level of open balconies or open bridges shall be approximately seven and one-half inches lower.
(4) Where there is a difference in level between the areas connected, the floors of the horizontal exit shall be ramped not more than one inch in ten inches.
(5) Exterior wall openings within thirty feet horizontally of any open bridge or balcony or below any open bridge or balcony shall be provided with opening protectives having a three-quarter hour fire protection rating.
(6) Balconies shall not face or open on yards or courts less than twelve feet wide, and shall be constructed as required for exterior corridors.
(7) Exterior bridges shall be constructed of noncombustible materials. Interior bridges or tunnels shall be constructed of materials providing a two hour fire-resistance rating.
Enclosed interior stairs, ramps, or escalators may provide access to an area of refuge located on a floor nearer to the street floor, when complying with the following:
(a) Limitation. They shall be supplemental vertical exits serving no other purpose than to connect a floor area with an area of refuge.
(b) Capacity. The capacity of supplemental vertical exits shall be as listed for stairs in table 6-1.
(c) Construction. Supplemental vertical exits shall comply with all of the construction requirements for interior stairs as provided in section 27-375 of this article.
(d) Openings. There shall be no openings in supplemental vertical exit enclosures other than the exit doors and doors leading into the area of refuge.
(e) Identification. Every supplemental vertical exit shall have a sign at the entrance designating its destination reading, "EXIT TO AREA OF REFUGE ON......FLOOR."
Interior stairs shall comply with the following requirements:
(a) Capacity. The capacity of interior stairs shall be as listed in table 6-1.
(b) Width. The width of interior stairs shall be the clear width between walls, grilles, guards, or newel posts. Stair stringers may project into the required width not more than two inches on each side of the stair. No interior stair shall be reduced in width in the direction of exit travel. Interior stairs shall be at least forty-four inches wide except as follows:
(1) Interior stairs may be not less than thirty-six inches wide when serving not more than thirty occupants per stair on any floor in buildings classified in occupancy groups J-1 and J-2 or when serving buildings classified in occupancy group J-3 and exceeding four stories in height, or when serving not more than sixty occupants per stair on any floor in buildings classified in occupancy groups E, B, and D.
(2) Interior stairs may be not less than thirty inches wide when serving mezzanines having an occupant load not exceeding twenty-five persons or when located in buildings classified in occupancy group J-3 not more than three stories in height. Interior stairs in four story buildings classified in occupancy group J-3 shall be a minimum of thirty-three inches in width.
(c) Headroom. The clear headroom shall be at least seven feet, except that in buildings classified in occupancy groups J-2 and J-3, the minimum clear headroom may be six feet eight inches. Headroom in a flight of stairs shall be measured vertically between two parallel inclined planes, one of which contains the line of the nosing or upper front edge of each tread and extends to its intersection with a landing and the other of which is through any point directly above the first plane that limits the headroom of the stair.
(d) Landings and platforms. Landings and platforms shall be provided at the head and foot of each flight of stairs, except at the head of basement stairs in oneand two-family dwellings, and shall comply with the following:
(1) The minimum width of landings and platforms perpendicular to the direction of travel shall be equal to at least the width of the stairs except that on a straight-run stair, the distance between risers of upper and lower flights at intermediate landings or platforms need not be more than forty-four inches.
(2) The maximum vertical rise of a single flight of stairs between floors, between landings or platforms, or between a floor and a landing or platform shall not exceed eight feet in buildings classified in occupancy groups F and H, and twelve feet in all other occupancy groups. No flight of stairs shall have less than two risers.
(3) Landings and platforms shall be enclosed on sides by walls, grilles or guards at least three feet high.
(e) Risers and treads. Risers and treads shall comply with table 6-4 and with the following:
(1) The sum of two risers plus one tread exclusive of nosing shall be not less than twenty-four nor more than twenty-five and one-half inches.
(2) Riser height and tread width shall be constant in any flight of stairs from story to story.
(3) Winders shall not be permitted in required exit stairs except in one- and two-family dwellings and except as permitted in subdivision l of this section. The width of winder treads when measured eighteen inches from the narrower end shall be at least equal to the width of treads above or below the winding section.
(4) Curving or skewed stairs may be used as exits when the tread and riser relationship is in accordance with table 6-4 when measured at a point eighteen inches in from the narrow end of the tread; and no tread shall be more than three inches narrower or three inches wider at any point than the width established eighteen inches in from the narrow end.
(f) Guards and handrails. Stairs shall have walls, grilles, or guards at the sides and shall have handrails on both sides, except that stairs less than forty-four inches wide may have a handrail on one side only. Handrails shall provide a finger clearance of one and one-half inches, and shall project not more than three and one-half inches into the required stair width.
(1) Stairs more than eighty-eight inches wide shall have intermediate handrails dividing the stairway into widths that maintain the nominal multiples of twenty-two inches, but the widths shall not be greater than eighty-eight inches nor less than forty-four inches.
(2) The height of handrails above the nosing of treads shall be not more than thirty-four inches nor less than thirty inches.
(3) Handrails shall be returned to walls and posts when terminated, except in one- and two-family dwellings.
(4) Handrails shall be designed to support loads in compliance with the requirements of subchapter nine of this chapter.
(5) Handrails in all stairs shall be of materials having a flamespread rating not exceeding one hundred fifty.
(g) Stair doors. Doors providing access to stairs shall comply with the requirements of subdivision (a) of section 27-342 of article five of subchapter five of this chapter and subdivision (e) of section 27-371 of this article. The swing of stair doors shall not block stairs or stair landings, nor shall any door at any point of its swing reduce the effective width of the landing or stair to less than seventy-five percent of the required width of the landing or stair, or to less than the width of the door opening on them. The width of doors from a stair shall not be less than the number of units of exit width required for the capacity of the stair, but in no case shall the door width be less than required by subdivision (e) of section 27-371 of this article.
(h) Stair construction. Risers, treads, stringers, landings, platforms, and guards, exclusive of handrails, shall be built of noncombustible materials except that interior stairs in buildings of construction group II may be built of combustible materials in buildings classified in occupancy group B-2, C, D or E when the buildings are two stories in height or less, and in buildings classified in occupancy group J-2 or J-3 when the buildings are not more than three stories in height, and in the case of J-2 occupancy group, when occupied by not more than three families. Interior stairs shall have solid treads. All risers shall be closed except as otherwise provided in subdivision (i) of this section. When of combustible construction, the soffit of interior stairs shall be fire protected by material having a minimum fire resistive rating of one hour or five-eighths inches gypsum wall board or equivalent, or the space beneath shall be enclosed without openings by material having a one hour fire resistance rating unless permitted to have open risers by subdivision (i) of this section. Where two separate interior stairs are contained within the same enclosure (so called "scissor stairs"), each stair shall be separated from the other by noncombustible construction having a fire resistance rating equal to that required for the stair enclosure. Stairs, platforms, and landings shall be designed to support all loads in compliance with the requirements of subchapter nine of this chapter. Treads and landings shall be built of or surfaced with nonskid materials.
(i) Stair enclosures.
(1) Interior stairs shall be enclosed with construction complying with the requirements of table 3-4 except that:
(a) In buildings three stories or less in height excluding those classified in occupancy group J-1 or J-2 combustible construction group II, the enclosing construction may have a one hour fire resistant rating.
(b) Stairs in buildings or spaces classified in occupancy group J-3 and not more than three stories in height, need not be enclosed except as otherwise required in subdivision (a) of section 27-341 of article five of subchapter five of this chapter. Stairs may have open risers in one family dwellings and group homes.
(c) Unenclosed stairs in buildings classified in assembly occupancy group F may be permitted as provided in subchapter eight of this chapter.
(d) Stairs from floors or mezzanines may be unenclosed, with open or closed risers.
(e) In buildings classified in occupancy group J-2 occupied exclusively by not more than one family on each story without boarders, roomers or lodgers and not more than three stories in height, the enclosing construction may have a one hour fire-resistance rating which may be constructed of combustible material provided that the stair enclosure is protected with an automatic sprinkler system complying with the construction provisions of subchapter seventeen of this chapter.
(f) In buildings classified in occupancy group J-1 or J-2 not more than two stories in height of combustible construction group II, the enclosing construction may have a one hour fire-resistance rating which may be constructed of combustible material; however, where only one vertical exit is provided the stair enclosure shall be protected throughout with an automatic sprinkler system constructed in accordance with the provisions of subchapter seventeen of this chapter.
(g) Except as provided in subparagraphs (a), (e) and (f) of this paragraph, in all buildings or spaces classified in occupancy group J-1 or J-2, the enclosing construction shall be of masonry or an approved equivalent material having at least a two hour fire-resistant rating.
(2) Access stairs connecting not more than two stories which do not serve as a required exit may be constructed without an enclosure in buildings classified in other than occupancy group H-2. Such stairs shall be additional to and shall not obstruct or interfere with required exit facilities. When the first story below grade is served by an interior, unenclosed access stair, it shall be sprinklered in accordance with the construction provisions of subchapter seventeen of this chapter.
(3) The interior finish of interior stair enclosures shall be in accordance with the requirements of table 5-4.
(4) Stair enclosures shall be vented in accordance with the requirements for shafts in subdivision (d) of section 27-344 of article five of subchapter five of this chapter except that stair enclosures for buildings or spaces classified in occupancy group J-1 or J-2 shall be vented as follows:
a. In occupancy group J-2 buildings three stories in height and with not more than one dwelling unit per story or two stories in height with not more than two dwelling units per story, shall be provided with a skylight at least nine square feet in area, glazed with plain glass with a wire screen over and under and provided with fixed or movable ventilators having a minimum open area of forty square inches.
b. In occupancy group J-1 or J-2 buildings two stories in height with more than two dwelling units per story shall be provided with a skylight of at least twenty square feet in area, glazed with plain glass, with a wire screen over and under and provided with fixed or movable ventilators having a minimum open area of forty square inches.
c. In occupancy group J-1 buildings exceeding two stories in height and in occupancy group J-2 buildings three stories in height with more than one dwelling unit per story or exceeding three stories in height shall be provided with a skylight at least twenty square feet in area, glazed with plain glass with a wire screen over and under and provided with fixed or movable ventilators having a minimum open area of one hundred forty-four square inches. In lieu of the skylight and ventilators a window of equal area may be provided with fixed louvres having a minimum open area of one hundred forty-four square inches installed in or immediately adjacent to the window.
(5) When dwelling units are located over a space classified in occupancy group C or E on the street floor, they shall be provided with a separate enclosed interior stair, or with an exterior stair.
(6) Impact resistance. Stair enclosures serving occupancy group E spaces (office spaces) in high rise buildings constructed pursuant to applications filed on or after July 1, 2006 shall comply with rules to be promulgated by the commissioner establishing minimum impact resistance standards. Such rules shall permit compliance with assemblies comprising approved reinforced construction boards affixed onto stud framing. The commissioner shall promulgate such rules on or before January 1, 2006.
(j) Openings and obstructions to stair enclosures. No piping of any kind, with the exception of piping required or permitted in subchapter seventeen of this code, shall be permitted within a stair enclosure. No openings of any kind, other than windows, fire department access panels, exit doors and openings specifically authorized in reference standard RS 5-18 shall be permitted within a stair enclosure. Pipes required or permitted by such subchapter seventeen and protected in accordance therewith which do not reduce the required clearances of the enclosure may be permitted. Ducts protected in accordance with the requirements of subchapter thirteen of this chapter, which do not reduce the required clearances of the enclosure, may be permitted. In addition, in buildings in occupancy group J-2, which are three stories or less in height and occupied by not more than two families on each story, a door from an apartment may open directly into a stair, and the door may swing into the apartment.
(k) Roof access.
(1) Except as otherwise provided for in paragraphs two and three of this subdivision, in buildings or in building sections more than three stories or forty feet high with roofs having a slope of less than twenty degrees, access to the roof shall be provided by at least one interior stair, except that access to setback roof areas may be through a door or window opening to the roof. Interior stairs extending to roofs shall be enclosed in bulkheads of fire-resistant construction meeting the requirements of subchapter five of this chapter.
(2) In buildings or in building sections classified in occupancy group J-1 or J-2 more than two stories in height, except as otherwise provided for in paragraph three of this subdivision, with roofs having a slope of fifteen degrees or less all interior stairs, except those terminating at a level of a setback roof, shall extend to the roof and shall be enclosed in bulkheads of fire-resistive construction meeting the requirements of subchapter five of this chapter. Stairs terminating at the level of a setback shall provide access to the setback roof areas through a door except where the setback is less than four feet in width, measured from the inside of the parapet wall, and less than ten feet in length.
(3) In buildings or in building sections classified in occupancy group J-1 or J-2 two stories in height and in occupancy group J-2 three stories in height with not more than one dwelling unit per story with roofs having a slope of fifteen degrees or less, access to the roof shall be provided through a scuttle at least twenty-one inches in width and twenty-eight inches in length and shall comply with subdivision (c) of section 27-338 of article four of subchapter five of this chapter. Scuttles shall be located within each stair enclosure with a stationary iron ladder leading thereto.
(l) Spiral stairs. Spiral stairs may serve as access stairs between two floors or levels in accordance with the provisions of paragraph two of subdivision (i) of this section. Such stairs may not serve as required exits, except that unenclosed spiral stairs when built of noncombustible materials and having a tread length of at least thirty inches may serve as exits from mezzanines or balconies having an occupant load not exceeding twenty-five persons.
TABLE 6-4
Maximum Riser Height and Minimum Tread Width
Maximum Riser Height and Minimum Tread Width
Occupancy Group Classification of Building | Maximum Riser Height (in.) | Minimum Tread
1
Width (in.) |
Residential J-3 (with closed risers) | 8 1/4 | 9 plus 1 1/4 nosing |
Residential J-3 (with open risers) | 8 1/4 | 9 plus 1/2 nosing |
Residential J-2 (with only three dwelling units) | 8 1/4 | 9 plus 1 1/4 nosing |
Assembly F | 7 1/2 | 9 1/2 plus nosing |
Institutional H-2 | 7 | 10 plus nosing |
All others
2
| 7 3/4 | 9 1/2 plus nosing |
Notes for Table 6-4:
1 Treads may be undercut a distance equal to the nosing. A nosing shall not be required when tread width is eleven inches or wider.
2 The proportions and dimensions of treads and risers may be adjusted in buildings classified in occupancy group G to suit the age of occupants, subject to the approval of the commissioner.
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