Entrance canopies found at the main door of many buildings are considered “exterior projections” by NFPA 13 Standard for the Installation of Sprinkler Systems and may require sprinkler protection when exceeding 4 feet in width and/or where storage is located below the canopy. The 2013 edition of NFPA 13 currently applicable in Massachusetts contains two exceptions applicable to entrance canopies exceeding 4 feet in width, which are outlined below. It should be noted that, where storage of combustible materials is located below canopies, sprinkler protection is required when such canopies exceed 2 feet in width regardless of whether one of these exceptions is otherwise applicable (NFPA 13 §18.104.22.168).
The first exception states that sprinklers can be omitted where the canopy is constructed with materials that are noncombustible, limited-combustible, or fire retardant-treated wood (NFPA 13 §22.214.171.124). These types of materials are specifically defined terms in NFPA 13 and NFPA 703 Standard for Fire Retardant-Treated Wood and Fire-Retardant Coatings for Building Materials (2012 edition referenced by NFPA 13-2013), and these definitions are reproduced below for reference. Note that this exception requires that the entire canopy assembly meet these construction requirements, not just the exposed surface.
The second exception states that sprinklers can be omitted from canopies of combustible construction where the exposed finish material is noncombustible, limited-combustible, or fire retardant-treated wood (NFPA 13 §126.96.36.199). To meet this exception, however, the concealed spaces within the combustible canopy must also meet one of the following alternative options:
- Be provided with sprinkler protection within the combustible concealed space (NFPA §188.8.131.52);
- Be filled entirely with noncombustible insulation (NFPA 13 §184.108.40.206(1));
- Meet specific construction requirements to limit enclosed joist spaces to 160 cubic feet or less in volume in accordance with NFPA 13 §220.127.116.11(2); or,
- Be located over canopy areas not exceeding 55 square feet (NFPA 13 §18.104.22.168(3)).
Entrance canopies exceeding 4 feet in width are only permitted to be unsprinklered if they meet one of the exceptions above. For such canopies without sprinkler protection, storage of combustible materials below the canopy is not permitted.
Noncombustible Material – A material that, in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat; materials that are reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C, shall be considered noncombustible materials. (Reference NFPA 13 §3.3.17)
Limited-Combustible Material – Refers to a building construction material not complying with the definition of noncombustible material that, in the form in which it is used, has a potential heat value not exceeding 3500 Btu/lb (8141 kJ/kg), where tested in accordance with NFPA 259 Standard Test Method for Potential Heat of Building Materials, and includes either of the following: (1) materials having a structural base of noncombustible material, with a surfacing not exceeding a thickness of 1⁄8 in. (3.2 mm) that has a flame spread index not greater than 50; or (2) materials, in the form and thickness used, having neither a flame spread index greater than 25 nor evidence of continued progressive combustion, and of such composition that surfaces that would be exposed by cutting through the material on any plane would have neither a flame spread index greater than 25 nor evidence of continued progressive combustion, when tested in accordance with ASTM E 84, Standard Test Method of Surface Burning Characteristics of Building Materials, or ANSI/UL 723, Standard Test Method of Surface Burning Characteristics of Building Materials. (Reference NFPA 13 §3.3.16)
Fire retardant-treated wood – A wood product impregnated with chemical by a pressure process or other means during manufacture, which is tested in accordance with ASTME E 84 or ANSI/UL 723, has a listed flame spread index of 25 or less, and shows no evidence of significant progressive combustible when the test is continued for an additional 20-minute period; nor does the flame front progress more than 10.5 feet beyond the centerline of the burners at any time during the test. (Reference NFPA 703 §3.3.2).