Hurricanes are a fact of life in South Florida, which is why doors and windows here must measure up to county- and state-wide codes that ensure some protection against storm-borne winds and debris. One such code — and in fact one of the most well-known and often used codes — is Miami-Dade County hurricane missile impact test. It is implemented by Miami-Dade County’s Building Code and Compliance Office, which issues a notice of approval (NOA) signifying which doors and windows in its jurisdiction are impact resistant.
How the Missile Impact Test Works
The test for South Florida hurricane protection products is divided into two “missile impact tests”. These tests measure a product’s ability to withstand the impact of an object flying through the air (i.e. a “missile”), such as hurricane debris. If your door, window, shutter, etc. cannot withstand the impact, the material will crack and your home will flood with extra air. The resultant change in air pressure will then cause your roof to collapse from within.
Since hurricane protection products are key to the overall protection of every house, each exterior – whether it’s residential or commercial – must pass and be rated according to the missile impact tests. Depending on the type of building, the test will be:
- Large missile test – windows and doors are impacted two times with 2” x 4” pieces of wood, weighing about 9 lbs and about 6-8 feet tall, at speeds of 34 mph.
- Small missile test – windows and doors are impacted three times with 10 ball bearings at speeds of 50 mph.
What the Missile Impact Test Means
After the initial impact, products are exposed to 9,000 wind cycles, both positive (pushing) and negative (pulling). To pass the test, the impacts of wind cycles cannot create a hole any larger than 0.3125 square inches (1/16” x 5”).
Windows and doors higher than 30 feet can be either large or small missile rated. Those lower than 30 feet must be large missile rated. The Building Code and Compliance Office NOA has been so effective that it is now considered the “gold standard” for verifying impact resistance.