The regulation is: UNI EN 12208.

The classification is characterized by 9 classes: from 1A to 9A (the highest). When a window exceeds the highest value, performance is represented by the E letter, associated to pressure value.

With the water holding test, it is verified the window capacity to avoid water infiltrations. The test consists in wetting a window surface with a great quantity of water, initially with a pressure of 0 Pascal (1 class) later with a pressure of 600 Pascal (9 class).

The test overcoming guarantees absence of water infiltration, even if there is a strong shower. We avoid damages on windowsills and on wood floors or on other delicate materials, as carpeting or rug.

Water holding perfomarnce examples - I Nobili
Water holding performance - I Nobili