Driving rain tightness

Driving rain tightness describes the tightness of a closed and locked window element or an external door with regard to water penetrating from a rain event with a defined wind force and duration of stress. Depending on the test method and the test pressure, the driving rain tightness according to DIN EN 12208 is classified as follows:

• Test method A, for unprotected windows/external doors: 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A, 9A and E[n]
• test method B, for windows/external doors that are partially protected in the upper area, e.g. by a balcony,  a canopy, a roof overhang or a larger building overhang: 1B, 2B, 3B, 4B, 5B, 6B and 7B.

The numbers distinguish the test pressure in pascals (Pa):

1=0 Pa, 2=50 Pa, 3=100 Pa, 4=150 Pa, 5=200 Pa, 6=250 Pa, 7=300 Pa, 8=450 Pa and 9=600 Pa.

For a test pressure >600 Pa, the driving rain tightness is denoted by E[n], where [n] is the respective test pressure in pascals, which increases in steps of 150 pascals, e.g. E750, E1050.

Example: Driving rain tightness 4A: the driving rain tightness of the unprotected window/exterior door element must be achieved at a maximum test pressure difference of 150 Pa.

The choice of the required driving rain tightness depends in particular on the wind load zone and the installation height of the window centre above ground (>10 m, 10 - 18 m or 18 - 25 m).

A clear decision-making aid for the selection of the right driving rain tightness is provided by Tables 2 and 3 of the guideline FE-05/2, Application recommendations for windows and exterior doors – Part 1, of the ift-Rosenheim. There, a tabular classification must be made depending on the wind load zone, the installation height and the terrain category.

Source: bauwion