What is glare?
You can experience glare in different circumstances. If you look directly at the sun, you will have to immediately close your eyes or look away due to the bright rays. This is disability glare. When the light shines directly into your eyes, you are no longer able to see clearly.
But other circumstances can also cause a thing called discomfort glare: you are still able to see objects and texts, but it will be harder to concentrate and you might even get a headache. It is mostly caused by annoying reflections on computer screens and furniture or by lack of contrasts.
Daylight Glare Probability
Not everyone is equally sensitive to this discomfort glare. That is why scientists have developed an index for it based on thorough research and experiments: the Daylight Glare Probability (DGP) described in the European Daylight Standard EN17037. It predicts what the chances are that people in a room will experience glare.
To keep the DGP as low as possible, the scientists recommend solar shading with a certain diffuse and direct light transmittance. The advice they give depends on the location and orientation of the building and the amount of glazing.
Based on this DGP index, a new glare control classification was made in the European Norm EN 14501 for which the publication is expected by the end of 2020.
How is glare classified in the future standard?
This is the current classification:
This is the future - more refined - classification:
So ideal is a fabric with an openness factor of maximum 3% with a low diffuse light transmittance.
For a good glare control we therefore advise you to use dark colours or metallized fabrics like our Panama Chrome+.
The following Helioscreen fabrics will have a class 4 with the new EN14501: