How Do Garage Doors Fail?
- They are destroyed by flying debris.
- The door is blown inwards, twist or buckle and are pushed away from their tracks. (Known as positive pressure)
- The garage door is sucked outwards, twist or buckle and are pulled away from their tracks. (Known as negative pressure)
Once the damage begins, it usually gets worse with the result that anything in the property – both people and possessions – also suffer damage. The pressure-changes in the building result in windows and doors being smashed and the roof lifting which can then lead to total destruction.
What Are Impact Resistant Garage Doors?
Hurricane-rated doors (aka impact-resistant and wind-resistant) are designed, built, and installed to standards which enable them to maintain their integrity in winds of up to 200 mph (above Category 5 hurricane strength.)
Such winds blow debris into doors. Hurricane-rated doors can withstand powerful impacts. They are tested by having a piece of two-by-four wood blasted out of a pressure cannon. The door is struck three times after which it must not have any holes in it greater than three feet and must still remain operable.
What are the Standards?
The standards are based on Wind Code and they differ depending on several things. The six factors listed below are used to determine which rating the door must have.
- Where the property is located.
- The average roof height of the building.
- The length and width of the property from corner to corner.
- The garage door size (single or double door for example.)
- The distance from the garage door jamb to the building's corner.
- The building's orientation (north, south, east or west-facing.)
Do I Live in an Exposure Zone?
The property location also determines which wind-rating meets current building code. Palm Beach, Broward, and Miami-Dade fall into "Exposure B" "C" or "Exposure D" zones. To keep it simple, most Broward and Miami-Dade residential buildings require a garage door rated between W5 and W8.
- Exposure B covers all urban and suburban areas with "numerous closely spaced obstructions."
- Exposure C covers "open terrain with scattered constructions" and affects most of Broward and Miami-Dade.
- Exposure D covers any building "located within 600 feet of oceanfront or other large body of water measuring at least 5000 feet across."