§ 27-335.1 Acoustical and thermal insulation; use in noncombustible construction.
AC § 27-335.1
(a)Notwithstanding any provision of this code to the contrary, acoustical or thermal insulation which is not noncombustible may be used where noncombustible construction is required if: (1) it satisfactorily passes a test for determining noncombustibility of elementary materials, based on the test procedures of ASTM E 136-65, and, upon exposure to fire will not produce products of decomposition or combustion that are more toxic in point of concentration that those given off by wood or paper when decomposing or burning under comparable conditions; or (2) it has a flame-spread rating not greater than twenty-five, a smoke developed rating not greater than fifty, is without evidence of continued progressive combustion when tested in accordance with the test procedure of reference standard RS 5-5, and upon exposure to fire will not 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.
(b)Notwithstanding any provision of subdivision a of this section or any other provision of this code to the contrary, acoustical or thermal insulation, which is not noncombustible and which does not meet the requirements of subdivision a of this section, may be used where noncombustible construction is required subject to the approval of the commissioner, and provided it is installed in a composite method of construction, with a minimum of three inches of unpierced masonry or concrete on all sides.
(c)Notwithstanding any provision of subdivision a or b of this section or any other provision of this code to the contrary, thermal insulation, which is not noncombustible and which does not meet the requirements of subdivisions a and b of this section, may be installed in an exterior wall system in any noncombustible construction group, provided that: (1) such insulation is of a thickness no greater than four inches; provided, additional thickness used exclusively for decorative or leveling purposes shall be permissible, where the area of such additional thickness does not exceed fifteen percent of the wall area on any single story; (2) such insulation has a heat value not in excess of six thousand BTU per square foot; (3) such insulation is installed in a composite method of construction and is separated from interior spaces by a thermal barrier having at least a one-hour fire resistance rating; (4) such insulation has a flame spread rating not greater than twenty-five and a smoke developed rating not greater than four hundred fifty, and is covered with, and sealed or joined by, material having a flame spread rating not greater than twenty-five and a smoke developed rating not greater than fifty, when tested in accordance with the procedures of reference standard RS 5-5; (5) such insulation is installed in a manner which meets the requirements for firestopping set forth in section 27-345; (6) upon exposure to fire, the exterior wall system and each of its components will not 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; (7) the structure on which the exterior wall system is installed meets the requirements of section 27-331 pertaining to minimum horizontal and vertical separation distances; provided, however, that such insulation shall not be used on the exterior surface of a wall of a court or shaft if the horizontal or vertical separation distance between such wall and another wall of such court or shaft is less than twenty feet; (8) the use of such insulation on soffits or other horizontal areas shall not extend more than three feet beyond the outside face of the building enclosure; (9) the use of such insulation on buildings having party walls meets the requirements of section 27-332; (10) such insulation meets the acceptance requirements of section 27-131; (11) the results of a fire test of a representative portion of the exterior wall system meet the requirements of reference standard RS5-21; (12) the edge or face of the assembly containing such insulation is labeled with the following information: a. the name of a nationally recognized testing laboratory acceptable to the commissioner which has inspected such insulation; b. the model of the exterior wall assembly for which such insulation is listed by a nationally recognized testing laboratory acceptable to the commissioner; c. the identity of the manufacturer of such insulation; d. the flame spread and smoke developed ratings; and (13) the installation of such insulation shall be subject to controlled inspection to ensure that the installation is fully consistent with the terms of the listing by a nationally recognized testing laboratory acceptable to the commissioner, acceptance requirements of section 27-131 and the manufacturer's installation recommendations.
(d)The commissioner may, with regard to thermal insulation, the use of which is authorized by this subdivision, establish by regulation training criteria for persons installing such insulation, and prohibit the installation of such insulation by persons not adequately trained. Any person installing such insulation shall certify to the commissioner that the installation is fully consistent with the terms of the listing by a nationally recognized testing laboratory acceptable to the commissioner, acceptance requirements of section 27-131 and the manufacturer's installation recommendations.
(e)Definitions. As used in this section: (1) "Composite method of construction" shall mean a method of construction in which diverse materials are combined to form an assembly, whether the assembly is prefabricated or fabricated at the site of installation.
(2)"Exterior wall system" shall include the exterior walls of a building and the appurtenances thereof.
