Wind design rules for new buildings in Hawaii County

Construction. Appendix W is added to read as follows: “APPENDIX W HAWAI‘I WIND DESIGN PROVISIONS FOR NEW CONSTRUCTIONS W101 Revisions to Chapter 16. When Appendix W is adopted, wind design shall be in accordance with Chapter 16 as amended by Sections W101.1 through W101.10. W101.1 Revisions to section 1603.1. Section 1603.1 is amended to read as follows: “1603.1 General. Construction documents shall show the size, section, and relative locations of structural members with floor levels, column centers and offsets dimensioned. The design loads and other information pertinent to the structural design required by Sections 1603.1.1 through 1603.1.8 shall be indicated on the construction documents. Exception: Construction documents for buildings constructed in accordance with the conventional light-frame construction provisions of Section 2308 shall indicate the following structural design information: (1) Floor and roof live loads. (2) Ground snow load, Pg. (3) Basic wind speed (3-second gust) and Effective wind speed Veff (3-second gust), miles per hour (mph)(km/hr) and wind exposure. (4) Seismic design category and site class. (5) Flood design data, if located in flood hazard areas established in Section 1612.3.” 5A-47 SUPP. 9 (1-2021) W101.2 Revisions to section 1603.1.4. Section 1603.1.4 is amended to read as follows: “1603.1.4 Wind design data. The following information related to wind loads shall be shown, regardless of whether wind loads govern the design of the lateral-force-resisting system of the building: (1) Basic wind speed (3-second gust), miles per hour (km/hr), V, and effective windspeed Veff. (2) Wind importance factor I, and building category. (3) Wind exposure, if more than one wind exposure is utilized, the wind exposure for each applicable wind direction shall be indicated. (4) The applicable internal pressure coefficient. (5) Components and cladding. The design wind pressures in terms of psf (kN/m²) used for the design of exterior components, and cladding not specifically designed by the registered design professional.” W101.3 Revisions to section 1609.1.1. Section 1609.1.1 is amended to read as follows: “1609.1.1 Determination of wind loads. Wind loads on every building or structure shall be determined in accordance with Chapter 6 of ASCE 7. Minimum values for Directionality Factor, Kd, Velocity Pressure Exposure Coefficient, Kz, and Topographic Factor, Kzt, shall be determined in accordance with Section 1609. The type of opening protection required, the basic wind speed and the exposure category for a site is permitted to be determined in accordance with Section 1609 or ASCE 7. Wind shall be assumed to come from any horizontal direction and wind pressures shall be assumed to act normal to the surface considered. Exceptions: (1) Subject to the limitations of Section 1609.1.1.1, the provisions of SBCCI SSTD 10 shall be permitted for applicable Group R-2 and R-3 buildings. (2) Subject to the limitations of Section 1609.1.1.1, residential structures using the provisions of the AF & PA WFCM. (3) Designs using NAAMM FP 1001. (4) Designs using TIA/EIA-222 for antenna-supporting structures and antennas.” SUPP. 9 (1-2021) 5A-48 BUILDING CODE § 5A-3-25 W101.4 Revisions to section 1609.1.2. Section 1609.1.2 is amended to read as follows: “1609.1.2 Protection of openings. In wind-borne debris regions, glazing in building shall be impact-resistant or protected with an impact-resistant covering meeting the requirements of an approved impact-resisting standard or ASTM E 1996 and of ASTM E 1886 referenced therein as follows: (1) Glazed openings located within 30 feet (9144 mm) of grade shall meet the requirements of the Large Missile Test of ASTM E 1996. (2) Glazed openings located more than 30 feet (9144 mm) above grade shall meet the provisions of the Small Missile Test of ASTM E 1996. Exceptions: (1) Wood structural panels with a minimum thickness of 7/16 inch (11.1 mm) and a maximum panel span of 8 feet (2438 mm) shall be permitted for opening protection in one- and two-story buildings. Panels shall be precut so that they shall be attached to the framing surrounding the opening containing the product with the glazed opening. Panels shall be secured with the attachment hardware provided. Attachments shall be designed to resist the components and cladding loads determined in accordance with the provisions of ASCE 7. Attachment in accordance with Table 1609.1.2 is permitted for buildings with a mean roof height of 33 feet (10,058 mm) or less where wind speeds do not exceed 130 mph (57.2 m/s). (2) Glazing in Occupancy Category I buildings as defined in Section 1604.5, including greenhouses that are occupied for growing plants on a production or research basis, without public access shall be permitted to be unprotected. (3) Glazing in Occupancy Category II, III or IV buildings located over 60 feet (18,288 mm) above the ground and over 30 feet (9,144 mm) above aggregate surface roofs located within 1,500 feet (458 m) of the building shall be permitted to be unprotected. (4) Glazing in Occupancy Category II and III buildings that can receive positive external pressure in the lower 60 feet (18,288 mm) shall be assumed to be openings unless such glazing is impact-resistant or protected with an impact- resistant system. 5A-49 SUPP. 9 (1-2021) Exception: Glazing in Occupancy Category III buildings defined by Table 1604.5 of the following occupancies shall be provided with windborne debris protection: (a) Covered structures whose primary occupancy is public assembly with an occupant load greater than 300. (b) Health care facilities with an occupant load of 50 or more resident patients, but not having surgery or emergency treatment facilities. (c) Any other public building with an occupant load greater than 5,000. 1609.1.2.1 Building with openings. Where glazing is assumed to be an opening in accordance with Section 1609.1.2, the building shall be evaluated to determine if the openings are of sufficient area to constitute an open or partially enclosed building as defined in ASCE 7. Open and partially enclosed buildings shall be designed in accordance with the applicable provisions of ASCE 7. Partially enclosed Occupancy R-3 buildings shall also include a residential safe room in accordance with Section 422, Hawai‘i Residential Safe Room. 1609.1.2.2 Louvers. Louvers protecting intake and exhaust ventilation ducts not assumed to be open that are located within 30 ft (9,144 mm) of grade shall meet requirements of an approved impact-resisting standard or the Large Missile Test of ASTM E 1996. TABLE 1609.1.2 WIND-BORNE DEBRIS PROTECTION FASTENING SCHEDULE FOR WOOD STRUCTURAL PANELS a,b,c FASTENER SPACING 4 feet 6 feet Panel span < Panel span < Panel span FASTENER TYPE ≤ 4 feet ≤ 6 feet ≤ 8 feet No. 6 screws 16" 12" 9" No. 8 screws 16" 16" 12" For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 0.454 kg, 1 mile per hour = 1.609 km/h. a. This table is based on a maximum wind speed (3-second gust) of 130 mph and mean roof height of 33 feet or less. b. Fasteners shall be installed at opposing ends of the wood structural panel. Fasteners shall be located a minimum of 1 inch from the edge of the panel. SUPP. 9 (1-2021) 5A-50 BUILDING CODE § 5A-3-25 c. Fasteners shall be long enough to penetrate through the exterior wall covering a minimum of 1.75 inches into wood wall framing; a minimum of 1.25 inches into concrete block or concrete; or into steel framing by at least three threads. Fasteners shall be located a minimum of 2.5 inches from the edge of concrete block or concrete. d. Where screws are attached to masonry or masonry/stucco, they shall be attached utilizing vibration-resistant anchors having a minimum withdrawal capacity of 490 pounds.” W101.4.1 Revisions to section 1609.2. Section 1609.2 is amended to read as follows: “1609.2 Definitions. The following words and terms shall, for the purposes of Section 1609, have the meanings shown herein. HURRICANE-PRONE REGIONS. Areas vulnerable to hurricanes defined as: (1) The U.S. Atlantic Ocean and Gulf of Mexico coasts where the basic wind speed is greater than 90 mph (40 m/s) and (2) Hawai‘i, Puerto Rico, Guam, Virgin Islands and American Samoa. WIND-BORNE DEBRIS REGION. Portions of hurricane- prone regions that are within 1 mile (1.61 km) of the coastal mean high water line where the basic wind speed is 110 mph (48 m/s) or greater; or portions of hurricane-prone regions where the basic wind speed is 120 mph (53 m/s) or greater.” W101.5 Revisions to section 1609.3. Section 1609.3 is amended to read as follows: “1609.3 Basic wind speed and topographic and directionality factors. The basic wind speed, in mph, for the determination of the wind loads shall be determined by Figure 1609. Special wind regions near mountainous terrain and valleys are accounted within the Topographic Factor defined in Section 1609.3.3. Wind speeds derived from simulation techniques shall only be used in lieu of the basic wind speeds given in Figure 1609 when, (1) approved simulation or extreme-value statistical- analysis procedures are used (the use of regional wind speed data obtained from anemometers is not permitted to define the hurricane wind speed risk in Hawai‘i) and (2) the design wind speeds resulting from the study shall not be less than the resulting 700-year return period wind speed divided by √1.6.” 5A-51 SUPP. 9 (1-2021) W101.6 Addition of section 1609.3.2. Section 1609.3.2 is added to read as follows: “1609.3.2 Effective basic wind speed conversion. For Section 2308.10.1, the provisions of ASCE Section 6.4, and the exceptions permitted under Section 16099.1.1, the basic wind speed value used for determination of the wind loads, shall be the Effective Basic Wind Speed, Veff, determined by Figure 1609.1.1.1, which adjusts the basic wind speed for special topographic wind regions.” SUPP. 9 (1-2021) 5A-52 BUILDING CODE § 5A-3-25 W101.7 Addition of effective wind speed contour maps. Figure 1609.1.1.1(a) is added as follows: Figure 1609.1.1.1(a) County of Hawai‘i Effective Basic Wind Speed, Veff , for Components and Cladding for Buildings less than 100 ft. tall 5A-53 SUPP. 9 (1-2021) W101.8 Addition of section 1609.3.3. Section 1609.3.3 is added to read as follows: “1609.3.3 Topographic effects. Wind speed-up effects caused by topography shall be included in the calculation of wind loads by using the factor Kzt, where Kzt is given in Figure 1609.3.3(a). Exception: Site-specific probabilistic analysis of directional Kzt based on wind-tunnel testing of topographic speed-up shall be permitted to be submitted for approval by the Building Official.” SUPP. 9 (1-2021) 5A-54 BUILDING CODE § 5A-3-25 Figure 1609.3.3(a) County of Hawai‘i Peak Gust Topographic Factor Kzt 5A-55 SUPP. 9 (1-2021) W101.9 Directionality factor. Section 1609.3.4 is added to read as follows: “1609.3.4 Directionality factor. The wind directionality factor, Kd, shall be determined from Tables 1609.3.4(a) and 1609.3.4(b). TABLE 1609.3.4(a)(1) Kd VALUES FOR MAIN WIND FORCE RESISTING SYSTEMS SITED IN HAWAI‘I COUNTY a,b Main Wind Force Resisting Systems with totally Main Wind Force independent Resisting Systems systems in each Biaxially orthogonal Symmetric and Topographic direction Axisymmetric Location on the Mean Mean Mean Mean Structures of any Island of Hawai‘i Roof Roof Roof Roof Height and Arched Height Height Height Height Roof Structures less greater less greater than or than 100 than or than 100 equal to ft. equal to ft. 100 ft. 100 ft. Sites in North Kohala, South Kohala, South Kona, South Hilo, 0.65 0.70 0.70 0.75 0.85 and Puna Districts at an elevation not greater than 3000 ft. All other sites 0.70 0.80 0.75 0.80 0.95 a. The values of Kd for other non-building structures indicated in ASCE-7 Table 6-4 shall be permitted. b. Site-specific probabilistic analysis of Kd based on wind-tunnel testing of topography and peak gust velocity profile shall be permitted to be submitted for approval by the Building Official, but Kd shall have a value not less than 0.65. SUPP. 9 (1-2021) 5A-56 BUILDING CODE § 5A-3-25 TABLE 1609.3.4(b)(1) Kd VALUES FOR COMPONENTS AND CLADDING OF BUILDINGS SITED IN HAWAI‘I COUNTY a,b Components and Cladding Mean Roof Mean Roof Occupancy Topographic Location on Height less Height Category IV the Island of Hawai‘i than or equal greater Buildings and to 100 ft. than 100 ft. Structures Sites in North Kohala, South Kohala, South Kona, South Hilo, and Puna 0.65 0.70 0.75 Districts at an elevation not greater than 3000 ft. All other sites 0.75 0.80 0.85 a. The values of Kd for other non-building structures indicated in ASCE-7 Table 6-4 shall be permitted. b. Site-specific probabilistic analysis of Kd based on wind-tunnel testing of topography and peak gust velocity profile shall be permitted to be submitted for approval by the Building Official, but in any case subject to a minimum value of 0.65.” W101.10 Addition of exposure category maps. Section 1609.4.4 is added to read as follows: “1609.4.4 Exposure category maps. Exposure categories are permitted to be determined using Figure 1609.4.4(a). 5A-57 SUPP. 9 (1-2021) Figure 1609.4.4(a) Exposure Category Zones for Hawai‘i County SUPP. 9 (1-2021) 5A-58 BUILDING CODE § 5A-3-25 W102 Revisions to chapter 23. When Appendix W is adopted, wood construction shall be in accordance with Chapter 23 as amended by Sections W102.1 and W102.2. W102.1 Revisions to section 2308.2.1. Section 2308.2.1 is amended to read as follows: “2308.2.1 Basic wind speed greater than 100 mph. Where the Effective Basic Wind Speed exceeds 100 mph, the provisions of the AF&PA WFCM, or the SBCCI SSTD 10 are permitted to be used.” W102.2 Revisions to table 2308.10.1. Table 2308.10.1 is amended to read: TABLE 2308.10.1 REQUIRED RATING OF APPROVED UPLIFT CONNECTORS (pounds)a,b,c,d,e,f,g,h,i Effective Basic Wind Roof Span (feet) Overhangs Speed (pounds/ft)d Veff, 3-sec gust 12 20 24 28 32 36 40 85 -72 -120 -144 -168 -192 -216 -240 -38.55 90 -91 -152 -182 -213 -243 -274 -304 -43.22 100 -131 -218 -262 -305 -349 -392 -436 -53.36 110 -175 -292 -350 -409 -467 -526 -584 -64.56 120 -240 -400 -480 -560 -640 -720 -800 -76.83 130 -304 -506 -607 -708 -810 -911 -1012 -90.17 For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 1.61 km/hr, 1 pound = 0.454 Kg, 1 pound/foot = 14.5939 N/m. a. The uplift connection requirements are based on a 30-foot mean roof height located in Exposure B. For Exposure C and for other mean roof heights, multiply the above loads by the adjustment coefficients below. EXPOSURE Mean Roof Height (feet) 15 20 25 30 35 40 45 50 55 60 B 1.00 1.00 1.00 1.00 1.05 1.09 1.12 1.16 1.19 1.22 C 1.21 1.29 1.35 1.40 1.45 1.49 1.53 1.56 1.59 1.62 For SI: 1 inch – 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 1.61 km/hr, 1 pound = 0.454 Kg, 1 pound/foot = 14.5939 N/m. b. The uplift connection requirements are based on the framing being spaced 24 inches on center. Multiply by 0.67 for framing spaced 16 inches on center and multiply by 0.5 for framing spaced 12 inches on center. c. The uplift connection requirements include an allowance for 10 pounds of dead load. 5A-59 SUPP. 9 (1-2021) d. The uplift connection requirements do not account for the effects of overhangs. The magnitude of the above loads shall be increased by adding the overhang loads found in the table. The overhang loads are also based on framing spaced 24 inches on center. The overhang loads given shall be multiplied by the overhang projection and added to the roof uplift value in the table. e. The uplift connection requirements are based upon wind loading on end zones as defined in Figure 6-2 of ASCE 7. Connection loads for connections located a distance of 20 percent of the least horizontal dimensions of the building from the corner of the building are permitted to be reduced by multiplying the table connection value by 0.7 and multiplying the overhang load by 0.8. f. For wall-to-wall and wall-to-foundation connections, the capacity of the uplift connector is permitted to be reduced by 100 pounds for each full wall above. (For example, if a 500- pound rated connector is used on the roof framing, a 400-pound rated connector is permitted at the next floor level down.) g. Interpolation is permitted for intermediate values of basic wind speeds and roof spans. h. The rated capacity of approved tie-down devices is permitted to include up to a 60-percent increase for wind effects where allowed by material specifications. i. Veff is given by Figure 1609.1.1.1.” (2020, ord 20-61, sec 3.) 5A-3-25