Monday, January 14, 2008
Also known as hurricane windows or high-impact windows, impact-resistant windows are an excellent alternative to hurricane shutters or storm panels. When struck by flying debris during a storm, they are designed to stay in one piece, protecting the building from the devastating effects of high winds. The main assembly difference between a standard and an impact-resistant window is that the latter is securely fastened to a heavy duty aluminum frame. Unlike the single-glazed design on standard windows, the impact-resistant glazing consists of two layers of annealed or tempered glass bonded to an intermediate layer of a shatter-proof membrane. This membrane is typically made of Polyvinyl Butyral (PVB), a plastic film which varies from .015 to .090 inches in thickness, depending on the design pressures needed. If the outer glass breaks, the shattered pieces will adhere to the PVB film. In contrast, standard-glass windows are made of standard float glass that, when broken, will fracture in large sharp shards.