Air leakage is the rate of air movement around a window, door, or skylight in the presence of a specific pressure difference across it. A product with a low air leakage rating is tighter than one with a high air leakage rating.
The ability of a window or door to prevent water gets into the house. It requires not only a tight seal of the glazing, but also a proper drain system that weep out water gets into the chamber of profile.
Structural testing measures a window’s ability to resist the intense pressure caused by wind velocity.
To simulate real-life conditions, the window is tested with both positive and negative pressure. There are preload, design-pressure load and over-load that must be performed to the unit. In order to pass the test, the window deflection must less than L/175, where L is the span of the test unit.
Industry practice dictates the use of ASTM test methods which are consolidated into the current AAMA 101 (AAMA/WDMA/CSA 101/I.S.2/A440) document. This standard presents performance requirements based on the type of window and its size.
In our cases, the first priority is ensuring that selected products/options match with the requirements specified by the customer or corresponding building codes.
Above performance are only for corresponding unit in specific sizes, in real practice it will varies based on sizes and options. Smaller size units are tending to have better performance than larger ones. Some options will also impact the performance, for example, the trickle vents and Low-profile thresholds will reduce the water performance.