Sections 1609.1 through 1609.4 are amended to read as follows:
"1609.1 Applications.
Buildings, structures and parts thereof shall be designed to withstand the minimum wind loads prescribed herein. Decreases in wind loads shall not be made for the effect of shielding by other structures.
1609.1.1 Determination of wind loads.
Wind loads on every building or structure shall be determined in accordance with Chapters 26 to 30 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 design wind speed, V, 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:
- Subject to the limitations of Section 1609.1.1.1, the provisions of ICC 600 shall be permitted for applicable Group R-2 and R-3 buildings.
- Subject to the limitations of Section 1609.1.1.1, residential structures using the provisions of AWC WFCM.
- Subject to the limitations of Section 1609.1.1.1, residential structures using the provisions of AISI S230.
- Designs using NAAMM FP 1001.
- Designs using TIA-222 for antenna-supporting structures and antennas, provided the effect of topography is included in accordance with Section 1609.3.3 Topographic effects.
- Wind tunnel tests in accordance with ASCE 49 and Sections 31.4 and 31.5 of ASCE 7.
The wind speeds in Figures 1609.3(1) through 1609.3(8) are basic design wind speeds, V, and shall be converted in accordance with Section 1609.3.1 to allowable stress design wind speeds, Veff-asd, when the provisions of the standards referenced in Exceptions 4 and 5 are used.
1609.1.1.1 Applicability.
The provisions of ICC 600 are applicable only to buildings located within Exposure B or C as defined in Section 1609.4.
The prescriptive provisions of ICC 600, AWC WFCM, or AISI S230 shall not be permitted for either of the following cases:
- Structures which are more than three stories above grade plane in height.
- Structures designed using exception 3 in Section 1609.2 Protection of Openings.
1609.2 Protection of openings.
In windborne debris regions, glazing in buildings shall be impact resistant or protected with an impact-resistant covering meeting the requirements of an approved impact-resistant standard or ASTM E1996 and ASTM E1886 referenced herein as follows:
- Glazed openings located within 30 feet (9144 mm) of grade shall meet the requirements of the large missile test of ASTM E1996.
- Glazed openings located more than 30 feet (9144 mm) above grade shall meet the provisions of the small missile test of ASTM E1996.
- Glazing in Risk Category II, III or IV buildings located over 60 feet (18 288 mm) above the ground and over 30 feet (9144 mm) above aggregate surface roofs located within 1,500 feet (458 m) of the building shall be permitted to be unprotected.
- Glazing in Risk Category IV buildings and structures, and those Risk Category III buildings of the following occupancies shall be provided with windborne debris protection:
- Covered structures whose primary occupancy is public or educational assembly with an occupant load greater than 300.
- Health care facilities with an occupant load of 50 or more resident patients, but not having surgery or emergency treatment facilities.
- Any other public building with an occupant load greater than 5,000.
- Glazing in Risk Category I, II, and other Risk Category III buildings and structures are subject to the following exceptions:
Exceptions:
- Wood structural panels with a minimum thickness of 7/16 inch (11.1 mm) and maximum panel span of 8 feet (2438 mm) shall be permitted for opening protection in buildings with a mean roof height of 33 feet (10 058 mm) or less that are classified as a Group R-3 or R-4 occupancy. 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 predrilled as required for the anchorage method and 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, with corrosion-resistant attachment hardware provided and anchors permanently installed on the building. Attachment in accordance with Table 1609.2 with corrosion-resistant attachment hardware provided and anchors permanently installed on the building is permitted for buildings with a mean roof height of 45 feet (13 716 mm) or less where Veff-asd determined in accordance with Section 1609.3.1 does not exceed 140 mph (63 m/s).
- Glazing in Risk Category I buildings, including greenhouses that are occupied for growing plants on a production or research basis, without public access shall be permitted to be unprotected.
- Risk Category II buildings shall be permitted to be designed with unprotected openings subject to the following requirements:
- For each direction of wind, determination of enclosure classification shall be based on the assumption that all unprotected glazing on windward walls are openings while glazing on the remaining walls and roof are intact and are not assumed to be openings.
- Partially enclosed and open occupancy R-3 buildings without wind-borne debris protection shall also include a residential safe room in accordance with Section 425, Hawaii residential safe room, or alternatively provide an equivalently sized room structurally protected by construction complying with Section 429.5.
1609.2.1 Louvers.
Louvers protecting intake and exhaust ventilation ducts not assumed to be open that are located within 30 feet (9144 mm) of grade shall meet the requirements of AMCA 540.
1609.2.2 Application of ASTM E1996.
The text of Section 6.2.2 of ASTM E1996 shall be substituted as follows:
6.2.2 Unless otherwise specified, select the wind zone based on the basic design wind speed, V, as follows:
6.2.2.1 Wind Zone 1—130 mph ≤ basic design wind speed, V < 140 mph.
6.2.2.2 Wind Zone 2—140 mph ≤ basic design wind speed, V < 150 mph at greater than one mile (1.6 km) from the coastline. The coastline shall be measured from the mean high water mark.
6.2.2.3 Wind Zone 3—150 mph (58 m/s) ≤ basic design wind speed, V < 160 mph (63 m/s), or 140 mph (54 m/s) ≤ basic design wind speed, V ≤ 160 mph (63 m/s) and within one mile (1.6 km) of the coastline. The coastline shall be measured from the mean high water mark.
6.2.2.4 Wind Zone 4— basic design wind speed, V > 160 mph (63 m/s).
| Fastener Type | Fastener Spacing | ||
| Panel Span ≤ 4 feet | Panel span > 4 feet and ≤ 6 feet | Panel span > 6 feet and ≤ 8 feet | |
| No. 8 Wood screw based anchor with 2 inch embedment length | 16" | 10" | 8" |
| No. 10 Wood screw based anchor with 2-inch embedment length | 16" | 12" | 9" |
| 1/4-inch lag screw based anchor with 2-inch embedment length | 16" | 16" | 16" |
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.
- This table is based on a 175 mph ultimate design wind speed and a mean roof height of 45 feet.
- 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.
- Anchors shall penetrate through the exterior wall covering with an embedment length of 2 inches minimum into the building frame. Fasteners shall be located a minimum of 2-1/2 inches from the edge of concrete block or concrete.
- Where panels are attached to masonry or masonry/stucco, they shall be attached utilizing vibration-resistant anchors having a minimum withdrawal capacity of 1,500 pounds.
1609.2.3 Garage doors.
Garage door glazed opening protection for windborne debris shall meet the requirements of an approved impact-resisting standard of ANSI/DASMA 115.
1609.3 Basic design wind speed.
The basic design wind speed, V, in mph, for the determination of the wind loads shall be determined by Figures 26.5-2A through 26.5-2D of
ASCE 7. The basic design wind speed, V, for use in the design of Risk Category II buildings and structures shall be obtained from Figure 26.5-2B of ASCE 7. The basic design wind speed, V, for use in the design of Risk Category III buildings and structures shall be obtained from Figure 26.5-2C of ASCE 7). The basic design wind speed, V, for use in the design of Risk Category IV buildings and structures shall be obtained from Figure 26.5-2D of ASCE 7. The basic design wind speed, V, for use in the design of Risk Category I buildings and structures shall be obtained from Figure 26.5-2A of ASCE 7. The basic design wind speed, V, shown for Hawaii in Figures 26.5-2A through 26.5-2D of ASCE 7 include topographic effects near mountainous terrain and near gorges, and shall be used with a topographic factor Kzt of 1.0 and the directionality factors given in Table 26.6-1 of ASCE 7.
Alternatively, when determining wind loads using both the explicit topographic factors given in section 1609.3.2 and the explicit directionality factors of section 1609.3.3, the ultimate design wind speed, Vunt, in mph, without topographic effects shall be as follows:
- Risk Category I buildings and structures: 115 mph
- Risk Category II buildings and structures: 130 mph
- Risk Category III buildings and structures: 145 mph
- Risk Category IV buildings and structures: 153 mph
1609.3.1 Wind Speed Conversion.
Where required, the basic design wind speeds of Figures 26.5-2A through 26.5-2D of ASCE 7, shall be converted to effective allowable stress design wind speeds, Veff-asd, using Table 1609.3.1 or Equation 16-33.
(Equation 16-33)
where:
Veff-asd = Effective Allowable stress design wind speed applicable to methods specified in Exceptions 4 and 5 of Section 1609.1.1
and for Section 2308.10.1.
V = Basic design wind speeds determined from Figures 26.5-2A through 26.5-2D of ASCE 7.
| V | 100 | 110 | 120 | 130 | 140 | 150 | 160 | 170 | 180 | 190 | 200 |
| Veff-asd | 78 | 85 | 93 | 101 | 108 | 116 | 124 | 132 | 139 | 147 | 155 |
For SI: 1 mile per hour = 0.44 m/s.
- Linear interpolation is permitted.
- Veff-asd = Allowable stress design wind speed applicable to methods specified in Exceptions 4 through 5 of Section 1609.1.1.
- V = basic design wind speeds determined from Figures 26.5-2A through 26.5-2D of ASCE 7.
1609.3.2 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
Figures 1609.3.2(a) through 1609.3.2(f).
Exception: Site-specific probabilistic analysis of directional Kzt based on windtunnel testing of topographic speed-up shall be permitted to be
submitted for approval by the building official.
Basic design wind speed, V, is determined per Figures 26.5-2A through 26.5-2D of ASCE 7 that already include topographic effects near mountainous terrain and near gorges, which shall be used with a topographic factor Kzt of 1.0 and the directionality factors given in Table 26.6-1 of ASCE 7.
- 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. For buildings taller than 160 feet, this submittal shall include peak gust velocity profiles for all wind direction sectors.
- At Exposure B sites with ground elevations less than 500 feet, Kzt values ≥ 1.2 shall be permitted to be reduced for building heights greater than 100 feet by multiplying Kzt mapped in Figure 1609.3.2(e) by the height adjustments given in the Table 1609.3.2(e).
Interpolation is permitted.
| Building roof height above ground (ft) | ≤100 | 120 | 140 | 160 | 180 | 200 | 220 | ≥240 |
| Adjustment factor to Kzt ≥1.2 | 100% | 98% | 96% | 94% | 92% | 90% | 92% | 94% |
1609.3.3 Directionality factor.
The wind directionality factor, Kd, shall be determined from Tables 1609.3.3(a)(1) through 1609.3.3(a)(3) and 1609.3.3(b)(1) through 1609.3.3(b)(3), and Figures 1609.3.3(a)(4) and 1609.3.3(b)(4).
Exception: Basic design wind speed, V, is determined per Figures 1609.3(5) through 1609.3(8) that already include topographic effects near mountainous terrain and near gorges, which shall be used with a topographic factor Kzt of 1.0 and the directionality factors given in Table 26.6-1 of ASCE 7.
| Topographic Location on the Island of Hawaii | Main Wind Force Resisting Systems | Main Wind Force Resisting Systems with totally independent systems in each orthogonal direction | Biaxially Symmetric and Axisymmetric Structures of any Height and Arched Roof Structures | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | ||
| Sites in North Kohala, South Kohala, South Kona, South Hilo, and Puna Districts at an elevation not greater than 3000 ft. | 0.65 | 0.70 | 0.70 | 0.75 | 0.85 |
| All other sites | 0.70 | 0.80 | 0.75 | 0.80 | 0.95 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
| Topographic Location in the County of Maui | Main Wind Force Resisting Systems | Main Wind Force Resisting Systems with totally independent systems in each orthogonal direction | Biaxially Symmetric and Axisymmetric Structures of any Height and Arched Roof Structures | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | ||
| Sites on the Island of Maui at an elevation not greater than 1000 ft. | 0.60 | 0.65 | 0.70 | 0.75 | 0.85 |
| Sites on the Island of Maui at an elevation greater than 1000 ft. | 0.65 | .70 | 0.75 | 0.80 | 0.90 |
| All other sites on the Islands of Molokai and Lanai | 0.80 | 0.85 | 0.80 | 0.85 | 0.95 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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 0.60.
| Topographic Location on Oahu, Hawaii | Main Wind Force Resisting Systems | Main Wind Force Resisting Systems with totally independent systems in each orthogonal direction | Biaxially Symmetric and Axisymmetric Structures of any Height and Arched Roof Structures | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | ||
| Sites within valleys at an elevation of at least 50 ft. but not greater than 500 ft. | 0.65 | 0.70 | 0.70 | 0.75 | 0.85 |
| Central Oahu above an elevation of 500 ft, the Ewa and Kapolei plains, and coastal areas with Kzt (10m) not greater than 1.2 | 0.75 | 0.80 | 0.75 | 0.80 | 0.95 |
| All other areas, including Hills, Hillsides, Ridges, Bluffs, and Escarpments at any elevation or height; coastal and inland areas with Kzt (10m) greater than 1.2 | 0.70 | 0.75 | 0.75 | 0.80 | 0.90 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
| Topographic Location on the Island of Hawaii | Components and Cladding | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Risk Category IV Buildings and Structures | |
| Sites in North Kohala, South Kohala, South Kona, South Hilo, and Puna Districts at an elevation not greater than 3000 ft. | 0.65 | 0.70 | 0.75 |
| All other sites | 0.75 | 0.80 | 0.85 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
| Topographic Location on the County of Maui | Components and Cladding | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Risk Category IV Buildings and Structures | |
| Sites on the Island of Maui at an elevation not greater than 1000 ft | 0.65 | 0.70 | 0.75 |
| Sites on the Island of Maui at an elevation greater than 1000 ft. | 0.70 | 0.75 | 0.85 |
| All other sites on the Islands of Molokai and Lanai | 0.80 | 0.85 | 0.85 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
| Topographic Location on Oahu | Components and Cladding | ||
| Mean Roof Height less than or equal to 100 ft. | Mean Roof Height greater than 100 ft. | Risk Category IV Buildings and Structures | |
| Sites within valleys at an elevation of at least 50 ft. but not greater than 500 ft. | 0.65 | 0.70 | 0.75 |
| Central Oahu above an elevation of 500 ft, the Ewa and Kapolei plains, and coastal areas with Kzt (10m) not greater than 1.2 | 0.75 | 0.80 | 0.85 |
| All other areas, including Hills, Hillsides, Ridges, Bluffs, and Escarpments at any elevation or height; coastal and inland areas with Kzt (10m) greater than 1.2 | 0.70 | 0.75 | 0.80 |
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
- The values of Kd for other non-building structures indicated in ASCE-7 Table 26.6-1 shall be permitted.
- 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.
1609.4 Exposure Category.
For each wind direction considered, an exposure category that adequately reflects the characteristics of ground surface irregularities shall be determined for the site at which the building or structure is to be constructed. Account shall be taken of variations in ground surface roughness that arise from natural topography and vegetation as well as from constructed features.
1609.4.1 Wind directions and sectors.
For each selected wind direction considered, at which the wind loads are to be evaluated, the exposure of the building or structure shall be determined for the two upwind sectors extending 45 degrees (0.79 rad) either side of the selected wind direction. The exposures in these two sectors shall be determined in accordance with Sections 1609.4.2 and 1609.4.3 and the exposure resulting in the highest wind loads shall be used to represent winds from that direction.
Exception: Exposure categories shall be permitted to be determined using Figures 1609.4(a) through 1609.4(e).
