Concern for biodiversity is prompting glass manufacturers to produce coatings visible to birds, in order to prevent collisions. NSG Group, one of the three largest glass manufacturers in the world, also offers such a coating. Pilkington AviSafe™ glass was recently installed at a new leisure centre attached to the Les Cygnes kindergarten in the municipality of Enghien-les-Bains, France. The building is located in an area inhabited by over 70 species of birds, which led architect Olivier Bratigny and ecologist Aurélien Huguet to seek a glazing solution that would be safe for wildlife – and they chose Pilkington AviSafe™.
This glass has a special patterned coating visible to birds in the ultraviolet spectrum, which they can perceive. For humans, it appears as faint vertical stripes, almost invisible under normal daylight conditions. This approach reduces the risk of bird strikes without affecting the amount of natural light entering the building.
The Pilkington AviSafe™ coating follows the so-called “2×4 rule”: no more than 5 cm (2 inches) between horizontal elements and 10 cm (4 inches) between vertical ones. These gaps correspond to the size of an average songbird, which discourages them from attempting to fly through. The glass has been tested by the American Bird Conservancy (ABC) and received a “threat factor” of 12 when installed on the exterior side of a window. This means birds are 12 times less likely to collide with it than with conventional glass.
A German company has also developed a mobile laser device called BIRDfriend Mobile, which can apply a bird-safe pattern to existing glass without requiring removal.