HAWAII · 2018 HI BUILDING CODE · ASCE 7-16 APPENDIX W
Hawaii Wind Load Requirements
Every Hawaiian island is high-wind, hurricane-exposed terrain. Design here runs on ASCE 7-16 with the mandatory Appendix W Hawaii Wind Design Provisions.
ADOPTED CODE
The code in force
Hawaii adopted the 2018 Hawaii Building Code (based on the 2018 IBC), effective April 2021, incorporating ASCE 7-16 plus Appendix W.
2018 HI Building Code
Based on the 2018 IBC, effective April 2021.
2018 IBCASCE 7-16 + Appendix W
Appendix W supersedes standard 7-16 wind provisions statewide.
APPENDIX WCounty AHJs
Hawaii, Honolulu, Maui & Kauai county building departments enforce.
4 COUNTIESPE Seal Required
A Hawaii-licensed PE must seal registered design professional work.
PE SEALAppendix W is mandatory. Using standard ASCE 7-16 wind maps instead of Appendix W for a Hawaii project produces a non-compliant design. Basic wind speeds are read from the ASCE Wind Design Geodatabase by latitude/longitude or address.
DESIGN WIND SPEEDS · RANGES
Wind speeds by island
All islands are hurricane-exposed; speeds rise sharply with elevation, exposed headlands and topographic amplification. Values are typical ranges — the geodatabase governs each site.
| County / Island | Locale | Typical range (mph) |
|---|---|---|
| Honolulu (Oahu) | Honolulu urban | 100–115 |
| Honolulu (Oahu) | North Shore | 115–130 |
| Honolulu (Oahu) | Elevated ridges | 125–140+ |
| Maui County | Coastal Maui / Molokai / Lanai | 110–130 |
| Maui County | Haleakala slopes | 130–150+ |
| Hawaii County (Big Island) | Kona / Hilo | 100–125 |
| Hawaii County (Big Island) | Mauna Kea/Loa slopes, South Point | 125–150+ |
| Kauai County | Coastal & North Shore | 115–140 |
| Kauai County | Waimea Canyon area | 125–145 |
Wind-borne debris regions: any site with a design wind speed of 130+ mph requires protected glazed openings — impact-resistant glazing (ASTM E1996), impact-rated assemblies, approved shutters, or PE-sealed protection systems.
CITY & COUNTY GUIDES
Major island markets
Each county building department is its own AHJ. Explore the city-level guide, with more island guides on the way.
Honolulu (Oahu)
City wind loads, code & local enforcement.
130–150 MPH GUIDEMaui County
Maui, Molokai & Lanai — Haleakala-driven uplift.
110–150+ MPHHawaii County
Big Island — Kona, Hilo, Mauna Kea/Loa slopes.
100–150+ MPHKauai County
Kauai & Niihau — Waimea Canyon amplification.
115–145 MPHWHAT THE CODE REQUIRES
Island-specific requirements
Beyond wind speed, Hawaii's marine climate and volcanic terrain drive hardware, envelope and topographic provisions.
Corrosion-Resistant Hardware
Type 316 SS within 3,000 ft of high water; Type 304 SS or hot-dip galvanized (ASTM A153) inland.
TYPE 316 SSTopographic Kzt
Exposed ridges & escarpments raise speeds 30–60% over flat terrain — Appendix W Kzt is essential.
KZTImpact Protection
Glazed openings in 130+ mph regions need impact-rated glazing, assemblies or shutters.
130+ MPHContinuous Load Path
Roof-to-foundation tie-down with stainless straps, screws & anchor bolts.
LOAD PATHRISK CATEGORY
Higher risk, higher map
Risk category selects which basic wind speed map you read — a longer return period, not a fixed multiplier. PE sealing scales up with the category.
Category I
Low hazard — minor agricultural / storage. 300-yr map.
300-YR MRICategory II
Standard occupancy — homes, offices, most buildings. 700-yr map.
700-YR MRICategory III
Substantial hazard — assembly, schools. 1,700-yr map.
1,700-YR MRICategory IV
Essential facilities — hospitals, fire/police, shelters. 3,000-yr map.
3,000-YR MRICOASTAL WIND SPECIALISTS SINCE 2002
Run Hawaii loads with Appendix W built in
Instant ZIP results with Appendix W treatment, topographic Kzt, and Type 316 SS hardware callouts — for every county and risk category.