DASMA TDS 194 - PSF versus MPH in Garage Door Wind Specifications

A homeowner sees their local wind speed listed as 115 mph and asks: "Do I need a door rated for 115 mph?" The question is reasonable, but it mixes two different units. DASMA TDS 194 explains why doors are rated in psf and how to connect a wind speed map number to a door specification.

What this data sheet says

DASMA TDS 194 explains that garage doors are tested and rated in pounds per square foot (psf), which is a measure of pressure, not wind speed. Wind speed in miles per hour (mph) is a measure of how fast the air is moving. Converting one to the other requires additional information: the exposure category, the height of the opening above grade, the zone within the building envelope, and the size of the opening itself.

"Door wind load ratings are expressed in pounds per square force (psf). Wind speed values in miles per hour (mph) cannot be directly compared to door ratings without performing an engineering calculation."

The relationship between wind speed and pressure follows a squared function: doubling the wind speed roughly quadruples the pressure. So a jump from 90 mph to 115 mph produces a much larger pressure increase than the raw numbers suggest.

The ASCE 7-22 calculation process also distinguishes between basic wind speed (Vult) and nominal design wind speed (Vasd), two different values sometimes published for the same location. Mixing them up produces incorrect psf values. TDS 194 explains the distinction and how it applies to door specifications.

When it applies

This confusion comes up whenever a homeowner or contractor reads a wind speed map and tries to match it to a door's rated pressure. It also comes up in permit submittals where the plan reviewer needs both the design wind speed and the design pressure documented separately.

In Denver, the 2025 Denver Building Code establishes Vult at 115 mph, Exposure C. Running the ASCE 7-22 components-and-cladding calculation for a typical 9x7 garage door opening at 10 feet above grade in Exposure C produces a design pressure somewhere in the range of 24 to 30 psf (exact value depends on zone and calculation method). That is the number that must appear on the door's pressure label and match the permit documentation.

A door marketed as "rated for 115 mph" without a psf value is using non-standard marketing language. Ask for the psf rating and the test standard.

What this means for you

Always ask for the psf rating, not an mph claim. When comparing doors, psf is the number that tells you what the door was physically tested to handle in the test chamber. A psf rating tied to an ANSI/DASMA 108 test is specific and verifiable.

The correct design pressure for your door depends on your site, not just the wind speed map. Exposure category, opening size, and height above grade all shift the required psf. Your door contractor or a design professional can run the ASCE 7-22 calculation for your specific address and opening.

In Colorado, get the calculation done at the local Vult value, not a national average. ASCE 7-22 wind speed values for any U.S. address are available through the ASCE Hazard Tool at https://hazards.atcouncil.org/. Enter your address, note the Vult for your location, then apply the components-and-cladding method for the opening.

G Brothers uses ASCE 7-22 design pressures for all wind-rated door specifications in the Denver metro area and can provide permit-ready documentation showing the site psf calculation and matched door rating.

Full text and source

Download DASMA TDS 194 from the official TDS index at https://www.dasma.com/technical-data-sheets/.

This entry explains the PSF versus MPH distinction for residential and commercial garage door wind load specifications. The engineering calculation method referenced here follows ASCE 7-22 as adopted by the 2024 IBC and IRC.

Want to put numbers to this? Use the interactive wind load psf / mph converter below, or open the full wind load psf / mph converter with examples and notes.