TEXAS · COLLIN

Corporate-campus wind design on the Collin County blackland prairie

Plano is a North Dallas suburb of glass headquarters and master-planned subdivisions, built on flat prairie with no coast and no hills. Its design wind speed is set by North Texas severe-storm season, not the Gulf.

100–115MPH DESIGN GUST · RISK II
BEXPOSURE · SUBURBAN DEFAULT
7-22ASCE EDITION · VIA IBC
CollinCOUNTY JURISDICTION

NORTH TEXAS CLIMATE

What a flat Collin County prairie does to the design gust

Plano has no relief and no coast — its 100–115 mph map value comes from supercell and squall-line season sweeping unobstructed across the blackland plain.

Squall-line straight winds

Spring fronts drive damaging gusts straight across the open prairie with little to slow them.

CONVECTIVE

Collin County tornado exposure

The county sits in North Texas tornado country and logs storms most years; the base speed reflects it.

SEVERE

Hail-and-uplift roof demand

Campus and subdivision roofs across Plano resist storm uplift and severe hail in the same event.

ROOF SYSTEMS

No coastal certification

Far inland from the Gulf — no wind-borne debris zone, no windstorm certificate, no HVHZ rules apply.

INLAND

ASCE 7-22 tornado note: The 2022 edition added Chapter 32 tornado-load provisions, but for Plano these are a qualitative trigger only — they apply chiefly to higher-risk-category buildings. Standard Plano occupancies are still governed by the synoptic basic wind speed map; the prairie tornado climate is what keeps that mapped value at 100–115 mph rather than a lower inland figure.

TERRAIN CALL

Exposure in a master-planned suburb

Plano is almost entirely built-out and tree-lined, so Exposure B is the routine call — but corporate sites fronting wide arterials and open parking can read as something rougher.

Exposure B — the Plano default

Established subdivisions, mature canopy, and dense Legacy-area build-out shelter most sites. This is the baseline for the typical Plano permit.

SUBURBAN

Exposure C — open campus frontage

Large corporate-campus lots, wide tollway frontage and expansive surface parking can present open terrain, lifting pressures above the sheltered case.

OPEN FRONTAGE

Where the line moves: Plano's headquarters campuses sit on big setbacks with parking seas and broad roads upwind. Even inside a built-out suburb, an isolated campus tower can warrant the more conservative Exposure C on its exposed faces — verify the upwind terrain per ASCE 7-22 rather than defaulting to B.

RISK & RETURN PERIOD

How occupancy lifts Plano's mapped wind speed

ASCE 7-22 dropped the wind importance factor. A higher risk category instead reads a longer-return-period map, so essential and assembly Plano buildings design to a higher gust than homes do.

Risk CategoryPlano Mapped GustRepresentative Buildings
I · 300-yr map~95–110 mphMinor agricultural, temporary and storage structures
II · 700-yr map100–115 mphHomes, retail, hotels, offices and most standard occupancies
III · 1,700-yr map~110–125 mphSchools, large assembly, corporate-headquarters occupancies
IV · 3,000-yr map~115–130 mphHospitals, fire stations, shelters and emergency centers

PERMIT PATHWAY

Clearing a wind-load review with City of Plano

Texas has no statewide residential code mandate, so Plano builds on the IBC with local amendments. These are the six pieces a Collin County submittal turns on.

IBC + Plano amendments

City of Plano adopts the International Building Code with local amendments referencing ASCE 7-22.

CODE BASIS

Mapped basic wind speed

Pull V from the ASCE 7-22 map for the site: 100–115 mph for ordinary Plano occupancies.

V = 100–115

Exposure determination

Justify B for sheltered subdivisions or C for open campus frontage based on upwind terrain.

B OR C

Risk category check

Confirm occupancy — campus assembly and essential uses read a higher return-period map and gust.

TABLE 1.5-1

Flat-terrain topographic factor

Plano's level prairie carries no speed-up, so Kzt is 1.0 — no escarpment or hill correction applies.

Kzt = 1.0

PE-sealed calculations

Commercial and campus Plano projects need calcs sealed by a Texas-licensed Professional Engineer.

TEXAS PE

INLAND VS GULF

Why a Plano campus is not a Texas coast structure

Same state, two different design problems. Suburban North Texas trades hurricane debris rules for tornado-grade base winds on flat ground.

RequirementPlano (Inland Suburb)Texas Coast HVHZ
Design wind speed100–115 mph140–160 mph
Exposure categoryMostly B, some C on campus frontageC required
Topographic factorKzt = 1.0 (flat prairie)Kzt = 1.0 (flat coast)
TDI product evaluationNot requiredRequired for TWIA
Wind-borne debrisNot requiredImpact protection required
Primary hazardTornadoes, severe thunderstormsHurricanes, tropical storms

ACROSS THE METROPLEX

Carry these loads to the rest of North Texas

Wind speeds run consistent across the DFW suburbs, but exposure shifts where campuses and tracts meet open prairie. Branch out from Plano to the wider state map.

FINISH THE PLANO CALC

Turn the North Texas wind map into a sealed permit set

Enter a Plano address and the calculator applies the 100–115 mph gust, sorts Exposure B or C, runs the risk category, and returns MWFRS and C&C pressures ready for review.