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Concealed spaces within partitions, walls, floors, roofs, stairs, furring, pipe spaces, column enclosures, etc. that would permit passage of flame, smoke, fumes, or hot gases from one floor to another floor or roof space, or from one concealed area to another, shall be firestopped to form an effective draft barrier, or shall be filled with noncombustible material in accordance with the requirements of this section. Firestopping shall not be required where a concealed space is sprinklered in accordance with the construction provisions of subchapter seventeen of this chapter, or is constructed as a shaft.
(a) Firestopping materials. In buildings of construction group I, firestopping or fill shall be of noncombustible material that can be shaped, fitted, and permanently secured in position. In buildings of construction group II, firestopping may be of combustible material consisting of wood not less than two inches nominal thickness with tight joints, two layers of one inch nominal thickness assembled so that there are no through joints or of one-half inch exterior type plywood with joints backed, except that noncombustible firestopping shall be used in concealed spaces of fire divisions and where in contact with fireplaces, flues, and chimneys. Noncombustible firestopping may be masonry set in mortar, concrete, three-quarter inch thick mortar or plaster on noncombustible lath, plasterboard at least three-eighths of an inch thick, fire-rated wallboard at least five-eighths of an inch thick, sheet metal at least No. 14 U.S. std. gage thick, solid web metal structural members, asbestos-cement board at least one-quarter of an inch thick, or equivalent rigid noncombustible material. Mineral, slag, or rockwool may be used for firestopping when compacted to a density of at least three and one-half pounds per cubic foot into a confined space of least dimension not more than one-third its second dimension.
(1) The performance of through-penetration fire stops shall be measured and specified according to reference standard RS 5-19.
(2) The commissioner may accept reference standard RS 5-19 test data results from an independent laboratory acceptable to the commissioner pursuant to subdivision (c) of section 27-131, when such data is submitted by a registered architect or licensed professional engineer to justify the usage of fire stops or the details of their installation not specified herein.
(b) Hollow partitions and furred spaces. All hollow partitions and furred out spaces shall be firestopped at each floor level. Firestops shall be the full thickness of the hollow space or furred out space.
(c) Stairs. Concealed spaces within stair construction shall be firestopped between stringers at the top and bottom of each flight of stairs so as not to communicate with concealed spaces in the floor, roof or intermediate landing construction.
(d) Ceiling spaces. Floor or roof assemblies required to have a fire-resistance rating shall have any concealed spaces therein firestopped in accordance with section 27-327 of this subchapter.
(e) Exterior cornices. Exterior cornices and eaves, constructed of combustible materials or with combustible framing, shall be firestopped at the ends of fire divisions and party walls, and at maximum intervals of twenty feet. If not continuous, they shall have closed ends and at least four inches separation between adjoining sections.
(f) Trim and finish. Where combustible trim and finish is permitted all hollow spaces shall be firestopped at ten foot intervals or shall be solidly filled with noncombustible materials.
(g) Duct and pipe spaces. Ducts and pipes enclosed in construction that does not meet the requirements of this code for shaft construction shall be firestopped at every floor level.
(h) Inspection of firestopping. The installation of all required firestopping shall be subject to the controlled inspection requirements of section 27-132 of article seven of subchapter one of this chapter, except that the architect or engineer need not be retained by the owner. Firestopping shall not be concealed from view until inspected.
In buildings of construction group I, partitions and furring shall be constructed of noncombustible materials, except that nonbearing partitions that are not required to have a fire-resistance rating, and furring may be constructed of fire retardant treated wood as provided in subdivision (d) of section 27-328 of article three of this subchapter, and except that such partitions and furring, may be constructed of combustible materials in spaces classified in occupancy group E, J-2, or J-3, provided the following conditions are met:
(a) the space containing the combustible partitions does not exceed five thousand square feet in area within a noncombustible enclosure having a fire-resistance rating of at least one hour.
(b) the space is in a single tenancy.
(c) glass or slow burning plastic is used for glazing.
Folding partitions shall not be used as partitions that are required by this code to have a fire-resistance rating.
(a) Construction group I. In buildings of construction group I, folding partitions may be used if they are constructed of noncombustible materials, or of fire retardant treated wood, or are constructed of noncombustible frame covered with fabric that has a class A interior finish rating. Where partitions of combustible materials are permitted by section 27-346 of this article, folding partitions may also be constructed of combustible materials. Where doors constructed of materials having a class C interior finish rating are permitted by section 27-348 of this article, folding doors may be constructed of combustible materials.
(b) Construction group II. In buildings of construction group II, folding partitions may be constructed of combustible materials, surfaced with interior finish materials meeting the requirements of section 27-348 of this article.
(a) Definition. For the purposes of this section, interior finish shall mean those materials that form the exposed interior surfaces of a building and that are part of or affixed to walls, fixed or folding partitions, ceilings, and other construction elements.
(b) Classification. Interior finish materials shall be classified in accordance with the surface flame-spread rating obtained as prescribed in the provisions of reference standard RS 5-5. Where an interior finish material is comprised of two or more materials laminated, glued, nailed, or otherwise secured together, the test rating for flame spread shall be based upon the composite of the materials in the form in which it will be used in construction. Interior finish materials shall be grouped in the following classes, in accordance with their surface flame spread characteristics:
Interior Finish Class | Flame-Spread Rating |
A | 0 to 25 |
B | 26 to 75 |
C | 76 to 225 |
D | Over 225 |
(c) Requirements. Interior finishes and exposed structural or construction materials shall have a flame-spread rating not greater than that designated by the class prescribed for the various occupancy groups in which they are used, as listed in table 5-4. Exceptions to these requirements are:
(1) Finish flooring and floor coverings, which are subject to the requirements of section 27-351.
(2) Wall coverings and coatings that are less than 0.036 in total thickness, when applied directly to a noncombustible, or fire-retardant treated wood, substrate.
(3) Exposed structural members and planking in buildings of class II-A construction, which may be left exposed in any room or space, except in exits.
(4) Twenty per cent (20%) of the aggregate wall and ceiling area of any room, space, or corridor required to have a class A or B rating may be finished with materials having a class C rating. This allowance shall include the area of doors, folding partitions, windows, glazing, skylights, luminous ceilings, trim, bases, chair rails, panels, moldings, etc. This exception shall not operate as a waiver of other requirements of this code relating to opening protectives.
(5) When a sprinkler system is provided in any room or space, and is installed in compliance with the construction provisions of subchapter seventeen of this chapter, interior finish materials may be one class higher in flame-spread rating than required by tables 5-4.
(d) Smoke density. No material shall be used for interior finish in the following locations if the material develops smoke in greater density than the rating shown, based upon a test conducted in accordance with the provisions of reference standard RS 5-5. Materials used for interior finish that cover not more than twenty percent of the aggregate wall and ceiling area of any room, space, or corridor shall be exempt from the above requirements.
Location or Occupancy | Smoke Developed Rating |
Exits, corridors | 25 |
Occupancy groups H-1 and H-2 | 50 |
Rooms in which the net floor area per occupant is ten square feet, or less | 100 |
(e) Toxicity. No material shall be used in any interior location that, upon exposure to fire will produce products of decomposition or combustion that are more toxic in point of concentration than those given off by wood or paper when decomposing or burning under comparable conditions.
(f) Attachment of interior finish.
(1) To be credited with the same rating, interior finish materials that were applied to a substrate when tested shall be applied at the building to an equivalent substrate.
(2) Interior finish materials shall be cemented or otherwise secured in place in the same manner and with materials equivalent to those used in flame-spread tests conducted in accordance with subdivision (b) of this section for the applicable classification.
(3) Where walls, ceilings, partitions, or other construction elements are required to have a fire-resistance rating or are required to be constructed of noncombustible materials, and the interior finish is secured to studs or furring, the surface of the interior finish facing the concealed space shall either have a class A rating, shall be applied to a substrate that has a class A rating, or shall have the concealed space completely filled with noncombustible material.
TABLE 5-4
Interior Finish Requirements Class
Interior Finish Requirements Class
Occupancy Group Classification of the Space | Occupancy Group Designation | Exits and Shafts | Corridors b | Rooms More Than 1500 Sq. Ft. in Area a | Rooms Less Than 1500Sq. Ft. in Area a, d |
High Hazard | A | A | A | B | B |
Storage | B-1 | A | A | B | C |
Storage | B-2 | A | B | B c | C |
Mercantile | C | A | B | B c | C |
Industrial | D-1 | A | A | B | C |
Industrial | D-2 | A | B | B c | C |
Business | E | A | B | C | C |
Assembly | F-1a | A | B | B | Bd |
Assembly | F-1b | A | B | B c | B c, d |
Assembly | F-2 | A | B | B c | B c, d |
Assembly | F-3 | A | B | B c | B c, d |
Assembly | F-4 | A | B | B c | C |
Educational | G | A | A | B | C |
Institutional | H-1, H-2 | A | A | B | B d |
Residential | J-1, J-2 | A | A | B | B f |
Residential | J-3 | B | D e | De | De |
Notes For Table 5-4:
a In determining the applicable requirements for rooms or enclosed spaces, the occupancy group classification of the room or enclosed space shall be the governing factor, regardless of the occupancy group classification of the building. For the purposes of this table, the area of a room shall be that floor area contained within enclosing construction in which interior doors or other interior openings represent not more than ten percent of the area of the enclosing construction. Interior doors or windows that are constructed of noncombustible materials and that are self-closing or automatic may be ignored in computing door or opening area. Rooms or spaces that have unprotected openings constituting more than ten percent of the area of enclosing construction shall not be considered as a room. Interior finish requirements for rooms are based upon rooms being enclosed in ceiling high partitions. Partitions, to be considered ceiling high, shall extend up to the floor or roof construction above or to a ceiling having at least a three-quarter hour fire-resistance rating. Partitions that do not comply with this requirement shall not be considered as enclosing the spaces, and the rooms or spaces on both sides thereof shall be considered as one.
b Rooms or spaces through which it is necessary for occupants of an adjacent room to pass in order to reach the only exit shall, for the purposes of this table, be considered as corridors. Where used in corridors, class B finish material shall not extend more than fifty feet between separations of class A finish material that are at least two feet wide.
c On the street floor of one-story buildings in construction group II, ceilings, beams, trusses, etc. that are twenty feet or more in height from the floor to their lowest part, may have a class C finish.
d Class C interior finish may be used in offices, or groups of offices, whose use is accessory to an occupancy, provided such offices are separated from the occupancy, by construction having at least a two hour fire-resistance rating.
e Class C interior finish may be used in the residential rooms of one- and two-story motels when there is a direct exit from each room to the exterior.
f Interior finish when used in the following spaces shall be at least class B:
(1) Kitchens, cooking spaces, and pantries in buildings classified in occupancy groups other than J-2 and J-3.
(2) Repair and maintenance rooms.
(3) Boiler rooms and incinerator combustion rooms.
Coatings applied in the field by brush or spray shall not be used as flame-spread retardants except on existing surfaces of buildings existing on December sixth, nineteen hundred sixty-eight, and then only with the express permission of, and in a manner directed by, the commissioner.
Ceilings that are to be suspended below floor or roof construction by means of a framing system shall consist of supporting hangers, carrying channels and a supporting grid complying with reference standard RS 5-16 or shall have supporting hangers and carrying channels and a supporting grid that can be demonstrated to the satisfaction of the commissioner to be of strength adequate to support the ceiling material. The hangers and supporting grid shall be of noncombustible materials. In buildings of construction group II, every other hanger supported from wood members shall be attached by a through bolt or clinched through nail. Where, in table 3-4, floor or roof construction is required to have a fire-resistance rating, a ceiling having no fire-resistance rating may be suspended below the fire-resistance construction.
(a) Luminous ceilings. For the purpose of this section, a luminous ceiling shall be defined as a ceiling consisting of translucent, louvered, egg-crated, mesh, or similar light-diffusing material suspended from the ceiling or structural framework. A suspended ceiling containing less than twenty square feet of translucent, louvered, egg-crated, mesh, or similar material in any one hundred square feet of ceiling area shall not be considered a luminous ceiling, and shall be constructed and installed in accordance with department of buildings requirements for lighting fixtures. Luminous ceilings shall, in addition to the requirements of this section, conform to all of the requirements of section 27-348 of this article for interior finish.
(1) LUMINOUS CEILINGS OF NONCOMBUSTIBLE MATERIAL. Luminous ceilings constructed of glass and/or metal or other noncombustible materials may be used in any location.
a. Glass used in luminous ceilings, unless it is wire glass or heat-resistant glass as specified below, shall not weigh more than two psf, nor shall any pane be larger than eight square feet in area. If glass used in luminous ceilings is wire glass, or is heat resistant by reason of having a maximum coefficient of expansion of 36 x 10-7 in. per in. per degree C, the glass may be of any weight and any size, limited only by considerations of structural safety.
b. Luminous ceilings installed below sprinkler heads shall be constructed of a type of noncombustible louver, mesh, or other open material that will not impede the flow of water from the sprinkler heads over the intended area of coverage. The luminous ceiling shall be constructed so as to provide access to all heads and valves.
(2) LUMINOUS CEILINGS OF COMBUSTIBLE MATERIAL. Luminous ceilings constructed of combustible materials shall not be installed in:
a. Any exit or corridor.
b. Any room classified in occupancy group H, or any room leading therefrom as defined in note b of table 5-4.
c. Any room in which the net floor area per occupant is twenty square feet or less, or any room leading therefrom as defined in note b of table 5-4.
d. Luminous ceilings constructed elsewhere than in the spaces listed in subparagraphs a, b, and c above shall be exempt from the provisions of section 27-348 of this article, provided that:
1. The panels of such ceilings are of slow-burning plastic;
2. The panels are installed above or below sprinklers that are constructed in accordance with the provisions of subchapter seventeen of this chapter;
3. No individual plastic panel exceeds ten feet in maximum dimension. Where installed below sprinkler heads, the plastic shall be a material that will fall from its mounting at a temperature at least fifteen degrees lower than the temperature at which the sprinkler heads are designed to operate or are constructed of open material which will not impede the flow of water from the sprinkler heads. Luminous ceilings shall be installed so as to provide ready access to all heads and valves.
(b) Suspension of new ceilings below existing suspended ceilings. In construction group I a new ceiling may be suspended below not more than one existing suspended ceiling and shall be supported directly from the ceiling carrying channels adjacent to the hangers. In construction group II, an existing suspended ceiling shall be completely removed before a new ceiling may be suspended.
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 1996/059.
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