Rules for thatch roofs and walls to prevent fire spread

Protection Against Exposure Fires. Appendix M is added to read as follows: “APPENDIX M THATCH MATERIAL ON EXTERIOR OF BUILDINGS; PROTECTION AGAINST EXPOSURE FIRES SECTION M101 GENERAL M101.1 General. Thatched materials used on the roof on a building shall be protected by manually operated sprinkler heads, with adequate water supply, pipe size, and sprinkler head spacing in accordance with sprinkler system requirements set forth in this section. Thatched materials used on the wall of a building shall be protected by manually operated outside sprinklers. Size and spacing of sprinklers and pipe size shall be in accordance with Chapter 7, “Outside Sprinklers and Protection Against Exposure Fires,” of the National Fire Codes of the National Fire Protection Association. Controls shall be set forth in this section. 5A-33 SUPP. 11 (1-2022) SECTION M102 APPLICABILITY M102.1 Applicability. Thatched material on the exterior of buildings shall be permitted only upon buildings located in areas zone for resort (V Resort-Hotel by the Planning Department) uses which primarily service the tourist trade when approved by the building official. The thatched material permitted in this section shall be used for decorative purposes on the roof or wall of buildings. The building, independent of the thatched material, shall comply with all applicable provisions of this appendix. When thatched material is used as permitted in this section, and an appropriate permit is obtained therefore, outside sprinklers for protection against exposure fires shall be required as hereinafter provided. SECTION M103 SPRINKLER M103.1 General. Sprinklers shall be located at the high point of the roof. Upright or pendant sprinklers shall be used for gable roofs. Sidewall sprinklers shall be used for shed roofs. M103.2 Spacing of sprinklers. The maximum width of roof with one row of sprinklers shall be as follows: Orifice Size Roof Slope Width of Roof (In inches) 1:3 or greater 3/8 15' 1:3 or greater 1/2 20' 1:3 or greater 17/32 25' Less than 1:3 3/8 10' Less than 1:3 1/2 15' Less than 1:3 17/32 20' Maximum spacing of sprinklers on branch lines (along ridge) shall be as follows: 3/8- inch orifice – 6 feet;1/2-inch orifice – 8 feet; 17/32-inch orifice – 10 feet. SUPP. 9 (1-2021) 5A-34 BUILDING CODE § 5A-3-23 Conical roofs may be protected with one sprinkler at the apex if the diameter of the roof does not exceed the width of roof referred to in this section. Where the width of a roof exceeds the width allowed for one row of sprinklers, as provided in the table in this section, two or more rows of sprinklers shall be required. The rows of sprinklers shall be placed such that the entire roof area is protected. M103.3 Areas protected. Each area (zone) of thatched material that is separated from another thatched area by an open space of 20 feet or more or by incombustible construction of 20 feet or more shall be considered a separate area (zone). Risers to each separate zone shall not be less than that shown in subsection M103.5, Riser and pipe size, except as modified as follows: (1) More than one zone may be protected by one valve, if the supply is adequate. (2) If one area (zone) is larger than can be protected with the existing supply, the zones can be subdivided into subzones if the following criteria are met: An area of at least 800 square feet is protected by the subzone control valve; there is at least a 10 percent overlap in coverage of adjoining subzones; and operation of the manual control valves will automatically transmit an alarm to the fire department. M103.4 Water supply. The sprinkling system shall have a separate connection to the water main in the street, to an approved automatic fire-extinguishing system supply line, to a wet standpipe supply line, or to a domestic supply of adequate size. The water supply required shall be determined from either of the following: (1) Flow per sprinkler for the largest zone, with residual pressure at the highest sprinkler at 15 pounds per square in with all heads operating, shall be as follows: Orifice Size Gallons Per Minute (In inches) 3/8 15 1/2 20 17/32 25 5A-35 SUPP. 9 (1-2021) (2) The flow shall be hydraulically calculated so as to discharge at least 0.11 gallons per minute per square foot of surface area to be sprinkled. M103.5 Riser and pipe size. Pipe sizes shall be determined from the flow as calculated in subsection M103.4, Water supply. However, no pipe less than one inch in size shall be used. The following table may be used in conjunction with this flow calculated for the selection of pipe or riser sizes. Orifice Pipe or Riser Size (In inches) Size (In inches) 1 1-1/4 1-1/2 2 2-1/2 3 3-1/2 4 No. of Sprinklers 3/8 3 4 7 11 21 37 40 40 1/2 2 3 5 8 15 27 40 40 17/32 1 2 4 6 11 19 30 38 M103.6 Number of sprinklers served. The number of sprinklers on a branch line shall not exceed six. Center feet shall be used for six or more sprinklers. The number of sprinklers under control of each control valve shall not exceed forty. At the location of each valve, there shall be a drain connection and a 1/4-inch valve test connection to accommodate pressure gauge. M103.7 Material installed above grade. Piping shall be galvanized steel schedule 40 with galvanized malleable iron fittings or hard drawn copper with silver solder fittings. Pipes shall be securely fastened to the structure. Valves shall be manual type approved and listed by the Underwriters’ Laboratories or by other approved testing agencies. Valves shall be installed outdoors and so located as to be readily accessible in case of fire. Signs indicating the use of valves shall be conspicuously posted. M103.8 Local alarm. Any one system with 20 or more sprinklers under control of one valve shall be complemented with a local fire alarm, either electrically or mechanically operated.” (2020, ord 20-61, sec 3.) 5A-3-23 SUPP. 9 (1-2021) 5A-36 BUILDING CODE § 5A-3-24