Wind load on curtain walls, windows and doors
Windows, doors and facades have to be able to withstand the force of the wind, even in stormy weather. The wind load that can be expected depends first and foremost on the location of the building – experience has shown that it is stormier near the coast than inland. However, wind load is also a factor that needs to be considered when designing especially tall buildings. The resistance of curtain walls to wind load (wind pressure and wind suction) is therefore specified and requirements laid down for both fixed-glazed and opening sections of curtain walls. The resistance of windows and doors to wind load is tested to the appropriate DIN EN standard and designated into classes 1 (light load) to 5 (high resistance).
Resistance to water/driving rain
Windows, doors and facades using steel profile systems must be watertight – no matter whether it is light drizzle or a storm driving the rain at full force against the facade. Tests of each of the rainproofing classifications for curtain walls using steel profile systems, and for windows and doors, are specified in the relevant DIN EN standards. There are two different methods for the test: Method A is used for doors and windows that are fully exposed to the weather, while Method B is used for building elements that are protected from the rain by canopies or balconies.
Air permeability: steel profile systems produce the best results
Gaps around windows and doors produce draughts not only when it is windy but even, during the colder months, when the air is calm, due to the natural exchange of cold and warm air. Powerful draughts are inextricably linked with the loss of precious heat, which escapes through the gaps. Only tightly closing windows and doors ensure consistent heat insulation, which makes the Q-value described in DIN EN 12207 an important thermal insulation value. As with the U value described previously, the lower the Q value, the better.
The air permeability of curtain walls is classified according to the relevant DIN EN standard. The thermally insulated facade systems for mullion-transom structures – Jansen VISS, VISS Basic and VISS SG – achieve the best possible level, ‘AE’. The thermally insulating door and window systems for external applications have been rated in the top class – class 4.
At our test centre in Oberriet, Switzerland, we test steel profile system windows, doors and facades with regard to wind load, tightness against water/driving rain and air permeability (the ‘WWA’ test). This functional test enables us to ensure that the planned construction reliably satisfies the requirements imposed on it. By means of WWA tests not only on all of our system solutions but also when developing building-specific special solutions, we offer customers a high degree of design security, whilst at the same time cutting down the planning time for safe and compliant facades, windows and doors with steel profile systems. You will find detailed information on the standards and product characteristics on our website.
