Commercial Overhead Door Learning Center

Clopay has developed a unique WindCode® ID program to help you select the right garage door for your area based on factors like local building code, MPH requirements and mean roof height.

Clopay WindCode® doors are identified by "W" designations on a rating scale from W1 to W9. The higher the "W" rating, the stronger the door.

The International Building Code includes a wind speed map based on data compiled by the National Weather Service (NWS). Wind speed is converted to design pressure and measured in pounds per square foot (PSF) to develop a product rating. On the table below exposure B is used in most situations (urban, suburban, and wooded areas) and Exposure C is generally used in open land with few obstructions or within 1500 feet of the coastline.

Notes:
1. Values are nominal design 3-second gust wind speeds in miles per hour (m/s) at 33 ft (10 m) above ground for Exposure C category.
2. Linear interpolation between wind contours is permitted.
3. Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area.
4. Mountainous terrain, gorges, ocean promontories, and special wind regions shall be examined for unusual wind conditions.

Map

Location V mph (m/s)
Hawaii 105 (47)
Puerto Rico 145 (65)
Guam 170 (76)
Virgin Islands 145 (65)
American Samoa 125 (56)

FLORIDA BUILDING CODE (ASCE7) - (EXPOSURE B**)
Mean Roof
Height
90
MPH
100
MPH
110
MPH
120
MPH
130
MPH
140
MPH
150
MPH
15' One-Story W1 W2/W3 W3/W4 W4 W5 W6 W7
25' Two- Story W1 W2/W3 W3 W4 W5 W6 W7

FLORIDA BUILDING CODE (ASCE7) - (EXPOSURE C***)
Mean Roof
Height
90
MPH
100
MPH
110
MPH
120
MPH
130
MPH
140
MPH*
146
MPH*
150
MPH
15' One-Story W3/W4 W3/W4 W4 W5 W6 W7 W7 W8
25' Two- Story W4 W4 W5 W6 W7 W7 W8/W9 W8/W9

* Broward County, Florida is 140 MPH and Miami-Dade County, Florida is 146 MPH, Exposure C only.
** Exposure B is defined as urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions. Exposure B is assumed unless building site meets the definition of another exposure.
*** Exposure C is defined as open terrain with scattered obstructions including flat open ground, grasslands and shorelines in hurricane prone regions, and all of Miami-Dade and Broward County is Exposure C.

This grid is to be used as a guideline only. Contact your local building official for code details and building permit information. The final authority on building code interpretation is the "authority having jurisdiction" (AHJ). The AHJ could be the state building official, county building official or city building official in which a building resides. Building code changes are not automatic but must be approved by the AHJ through an approved resolution or bill.

WindCode Related Terms:

ASTM E330 The testing standard used in the garage door industry. Also known as uniform static air pressure testing. This standard was developed by the American Society for Testing and Materials (ASTM) to allow products to be measured in air pressure chambers. ASCE7 Design standard developed by the American Society of Civil Engineers titled "Minimum Design Loads for Buildings and Other Structures". Section 6 of this standard deals with wind loads.

ASCE7 is the basis for wind load calculations used in most building codes.

International Building Code Model building code developed by the International Code Council. Most of the U.S. has adopted this building code (sometimes with slight, locally adopted variations). The wind load provisions in this code specifically call out ASCE7 to be using in wind load calculations.

Design Pressure The measurement of resistance in both positive and negative directions that a door system must withstand. Design pressures are usually expressed in both positive (PSF+) and negative (PSF-) values. Also known as design load.

Test Pressure The actual tested wind pressure resistance that a door system will withstand during laboratory testing. Most building officials usually require that the test pressure be equal to 150% of the design pressure. Also known as test load.

3-Second Gust How wind is measured by the National Weather Service. This data is then compiled into wind maps incorporated into ASCE7 and the International Building Code. The wind speed maps are based on a yearly 2% probability of occurrence (50-year average peak wind).

Mean Roof Height The height above grade level of the midpoint of the roof. Mean roof height is calculated by averaging the eave and ridge heights, and is used as part of design pressure calculations in both ASCE7 and the International Building Code.

Wind Velocity The actual measured speed of airflow during a wind event; usually expressed in MPH. Wind velocity is typically measured at 33 feet (10 meters) above ground level at airports and similar open country locations.

WindCode® The registered name for all Clopay Building Products garage door products designed and tested to comply with wind resistance requirements of local, state, and national building codes. The WindCode® program includes engineering, marketing and sales efforts designed to assist Clopay's customers understand code issues and to offer the best products for their market.