Wind Resistance for External Blinds

External shading systems such as blinds can reduce heat gain almost to zero, and can result in savings of 65% on air conditioning costs. They remove the internal clutter of boxes or rollers around windows, and can even provide insulation in winter.

However, for external systems to perform well, they must withstand precipitation, extreme temperatures and, most crucially, strong winds.

In recent years, there has been a confusion of sales messages about wind resistance and increasingly bold statements about wind speeds and product thresholds. As a result, at European level, a number of interrelated and complex standards have been introduced or updated to regulate this area.

The wind is a powerful force. Even modern wind turbines are designed to be switched off at 100 km/h. In fact, during high winds, wind farms are evacuated and nearby footpaths and roads are closed.

It is for good reasons therefore that external shading systems are regulated by European Norms under the Construction Products Regulations (CPR), with mandatory CE marking introduced in June 2013.

Whilst it is crucial for architects and design teams to have an awareness of the key points when specifying shading solutions, the plethora of interrelated standards that regulate shading systems does not make for light bedtime reading.

In Europe, product manufacturers must:

CE mark external blinds to these classifications, or specify that they are not classified.
Define a windspeed over which blinds must be retracted.
Verify that non-retractable parts of their products can withstand 800 N/m2 without deformation.

By --Guthrie Douglas Group Limited