If you are located in a 120 mph wind zone or above, you are most likely required to have some form of impact protection.* Typically, if your windows or doors are between ground level and 30 feet in height, you will be required to use products that have passed the large missile requirements for wind-borne debris. Anything over 30 feet in height will require products that have passed small missile requirements.
 
A product that meets the tougher large missile standard can be used where the lesser small missile standard is required, but a small missile product cannot be used where a large missile product is required.

* The wind zone map is developed by the American Society of Civil Engineers.