The regulation is: UNI EN 12210.

The resistance wind load is the capacity of a window, subjected to strong pressures, like that caused by wind, to maintain an acceptable deformation and to preserve its property.

Window is subjected to abrupt and strong pressures, and later it is verified that it has maintained its functional and performance characteristics. Window is classified in five classes for wind pressure (from 1 to 5) and three classes for frontal face (A, B, C) and then they supply window estimation.

If a window passes the test, it means that window guarantees strength, low deformations, even if it is under strong pressure. There aren’t any breaking of closing points, any unexpected and uncontrolled window opening and first of all consumer’s security.

Impact resistance performance - I Nobili