Dallas County, TX | 105-115 mph Design Wind Speed | IBC with Texas Amendments | Tornado Alley Edge | Exposure B/C
Calculate Dallas Wind Loads Now →Dallas, located in Dallas County, Texas, has moderate wind load requirements that account for its position on the edge of Tornado Alley and exposure to severe thunderstorm systems. Texas does not have a statewide building code—Dallas uses the International Building Code (IBC) with state amendments adopted by the Texas Department of Licensing and Regulation (TDLR). Design wind speeds for Risk Category II structures typically range from 105-115 mph (3-second gust) based on ASCE 7-22 wind speed maps.
These requirements exist because Dallas experiences frequent severe weather including tornadoes, severe thunderstorms with straight-line winds, hail events, and occasional tropical system remnants. While Dallas is located far inland and NOT subject to hurricane wind loads, the DFW metroplex sits on the southern edge of Tornado Alley and experiences significant convective wind events throughout spring and summer months.
Design Wind Speed (Risk Category II): 105-115 mph (3-second gust, varies by location)
Design Wind Speed (Risk Category III): ~120-130 mph
Design Wind Speed (Risk Category IV): ~130-140 mph
Exposure Category: B (urban/suburban), C (open areas)
Building Code: International Building Code (IBC) with Texas state amendments
Wind Load Standard: ASCE 7-22 (current edition)
County: Dallas County
Weather Risks: Tornadoes, severe thunderstorms, hail, straight-line winds
Dallas's design wind speed of 105-115 mph for Risk Category II structures reflects the city's location on the edge of Tornado Alley and exposure to severe convective weather systems. While not as extreme as coastal hurricane zones or the core of Tornado Alley in Oklahoma, Dallas wind speed requirements account for:
Recent severe weather events include the 2019 Dallas tornado outbreak (October 20-21) when an EF3 tornado struck north Dallas and Richardson causing $2+ billion in damage. The 2015 Dallas EF4 tornado in Rowlett caused catastrophic damage. Severe thunderstorm derechos regularly produce wind gusts exceeding 80 mph across the metroplex.
Calculating wind loads for Dallas projects requires following ASCE 7-22 methodology as adopted by the IBC and Texas state amendments. The fundamental velocity pressure equation is:
qz = 0.00256 Kz Kzt Kd Ke V²
For Dallas with V = 110 mph (typical central Dallas) and standard conditions, the resulting pressures are moderate. A Dallas project with:
Results in a velocity pressure of approximately qz = 22.4 psf—moderate compared to coastal hurricane zones but higher than many non-severe-weather regions.
For open suburban areas using Exposure C (northern Dallas suburbs with new development), the pressures increase due to the higher velocity pressure coefficient for open terrain exposure.
Texas does not have a statewide building code. Dallas has adopted the International Building Code (IBC) with state amendments promulgated by the Texas Department of Licensing and Regulation (TDLR). The City of Dallas also adds local amendments specific to Dallas conditions.
Key Dallas building code considerations:
You can access Dallas building permits and requirements through the City of Dallas Development Services Department.
Dallas projects must be classified into Risk Categories per ASCE 7-22 Table 1.5-1. Higher risk categories require increased design wind speeds:
| Risk Category | Dallas Design Wind Speed | Building Types |
|---|---|---|
| Risk Category I | ~100-105 mph | Agricultural facilities, temporary structures, minor storage |
| Risk Category II | 105-115 mph | Residential, commercial, most standard occupancies |
| Risk Category III | ~120-130 mph | Schools, assembly >300, substantial hazardous materials |
| Risk Category IV | ~130-140 mph | Hospitals, fire stations, emergency shelters, EOCs |
Dallas projects require careful Exposure Category determination based on surrounding terrain and development density:
Exposure Category B (Urban/Suburban): Most of Dallas qualifies as Exposure B due to dense urban and suburban development with numerous buildings, trees, and other obstructions. Exposure B assumes urban and suburban areas with buildings having heights generally less than 30 feet extending more than 800 feet upwind. This applies to most established Dallas neighborhoods, downtown, Uptown, and mature suburbs.
Exposure Category C (Open/Developing Areas): Newer development areas in far north Dallas, Frisco, McKinney, and other outer suburbs may qualify as Exposure C during construction phases before surrounding development is complete. This includes open terrain with scattered obstructions having heights generally less than 30 feet. Exposure C produces significantly higher wind pressures than Exposure B.
Engineering Judgment Required: The transition between Exposure B and C in Dallas's rapidly developing northern suburbs requires professional engineering judgment. When in doubt, the more conservative Exposure C should be used.
Dallas's wind load requirements are influenced by the city's position on the southern edge of Tornado Alley and exposure to severe convective weather:
Tornado Risk: Dallas County averages 2-4 tornadoes annually, with violent tornadoes occurring periodically. The October 2019 tornado outbreak produced an EF3 tornado through north Dallas and Richardson causing $2+ billion in damage. The December 2015 Rowlett EF4 tornado devastated eastern Dallas suburbs. While ASCE 7 wind loads are based on synoptic (large-scale) wind events rather than tornadoes, the elevated base wind speed accounts for Dallas's severe weather exposure.
Severe Thunderstorm Straight-Line Winds: Dallas experiences frequent severe thunderstorms producing damaging straight-line winds. Derecho events (organized lines of severe thunderstorms) can produce wind gusts exceeding 80-100 mph across the DFW metroplex. These widespread high-wind events cause extensive roof damage, siding failure, broken windows, and downed power lines.
Hail Damage Considerations: Dallas is consistently ranked among the top hail-prone cities in the United States. While hail is not a direct wind load consideration, roof systems must be designed to resist both wind uplift and hail impact, requiring coordinated design approaches for Dallas projects.
Dallas zip codes span a large geographic area with relatively consistent wind speed requirements. Common Dallas zip codes include:
The WindLoadCalc.com wind load calculator automatically applies the appropriate Dallas wind speed based on your specific zip code or street address, accounting for local terrain conditions and exposure.
Wind load calculations for Dallas building permits have varying PE requirements depending on building type and complexity:
Texas Professional Engineers must be licensed through the Texas Board of Professional Engineers and Land Surveyors (PELS).
Engineers, architects, and contractors should reference these official resources for Dallas wind load compliance:
The wind load calculator at WindLoadCalc.com automatically applies all Dallas-specific requirements:
WindLoadCalc.com automatically handles all Dallas-specific requirements including the 105-115 mph design velocity, appropriate Exposure Category selection, Risk Category adjustments, and component pressure coefficients. Simply enter your Dallas project address or zip code for instant, accurate calculations.
Calculate Dallas Wind Loads Now →Dallas's wind load requirements differ significantly from Texas coastal hurricane zones:
| Requirement | Dallas (Inland) | Texas Coast HVHZ |
|---|---|---|
| Design Wind Speed | 105-115 mph | 140-160 mph |
| Exposure Category | Primarily B, some C in new areas | C required |
| TDI Product Evaluation | Not required | Required for TWIA |
| WPI-8 Certification | Not required | Required for TWIA |
| Wind-Borne Debris | Not required | Impact protection required |
| Primary Risk | Tornadoes, severe thunderstorms | Hurricanes, tropical storms |
While Dallas does not face hurricane wind loads, the city's tornado and severe thunderstorm risk means engineers must still apply rigorous wind load standards appropriate for the DFW metroplex severe weather environment.
Dallas is the anchor of the Dallas-Fort Worth metroplex, the largest metropolitan area in Texas. Wind load requirements for the broader DFW region are generally consistent with Dallas proper:
Engineers working across the DFW metroplex should verify specific wind speeds and exposure categories for each project location, as rapid suburban development can change exposure conditions over time.
WindLoadCalc.com provides instant, accurate wind load calculations for Dallas projects. Our software automatically handles the 105-115 mph velocity range, Exposure B/C determination, and generates PE-ready reports for building permit submission.
Try Dallas Wind Load Calculator →