Large Missile Impact Testing
Testing is comprised of two main components and is expressed as Zone Number, Missile Type and design pressure. The intent of this testing is to simulate debris hitting a window during a storm. During a hurricane, the atmospheric pressures inside and outside the home can vary greatly. Since nature wants all pressures to be equal, if a large window is impacted and the entire piece of glass is removed from the opening, a very rapid pressure equalization can occur which can cause major structural damage to the building envelope, sometimes to the point of failure.
The two main components of Hurricane Impact testing are:
- Impact: A “missile”, which could be a 2x4 or steel ball bearings, is sent toward a window at varying speeds. Multiple “missiles” impact various parts of the window. The zone number and missile type typical for the geographic location and building type dictates the type of missile used for testing and where it impacts the product.
- Cycling: After being impacted, the window or door is then cycled thousands of times in both the inward and outward directions. During this cycling certain breakdowns, such as deglazing and tearing, must only occur within a specific range.
Images from Architectural Testing, Inc.