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What is Bird-Friendly Glass? 

Glass facades deliver many benefits including daylight, views and dynamic aesthetics. A counterpoint is that birds do not perceive traditional clear glass as an obstacle to their flight path. It is possible to balance glass benefits with the adverse impact on birds by selecting glass that can take advantage of its many benefits while also minimizing the potential for bird to glass collisions.

Research has shown that adding a pattern can increase a bird’s ability to perceive glass, thus reducing the likelihood of a collision. This awareness has lead organizations, cities and states to develop bird-safe building guidelines, laws and official standards.

Viracon's Involvement

As a glass fabricator, Viracon has been actively involved in the ongoing research, focusing specifically on finding practical solutions using conventional glass products with applied patterns. Additional information about the research and testing is available in the Tech Talk.

Tested Products and Threat Factors

Scores from the American Bird Conservancy (ABC) tunnel test are utilized by ABC and the U.S. Green Building Council® (USGBC) to assign a threat factor for each tested material. A lower threat factor means that the product deterred more birds in the tunnel test than a product with a higher threat factor. Viracon has six products that have been tested by ABC.

Threat Factor 6

Color: V901 Dark Gray Viraspan
Pattern: 1/8” horizontal lines alternating with 1/2” spaces (screen 2256); 20% coverage

 

Threat Factor 24

Color: V175 High Opacity White
Pattern: 1/8” dots (screen 5006); 40% coverage

Threat Factor 10

Color: V948 Medium Gray Viraspan
Pattern: 1/8” horizontal lines alternating with 1/2” spaces (screen 2256); 20% coverage

 

Threat Factor 17

Color: Digital White and Digital Etch (every other line switches between the colors)
Pattern: 1/8” horizontal lines 2” on center (screen 2824); 6% coverage

Threat Factor 41

Color: V175 High Opacity White
Pattern: 1/8” dots, 1/4” on center (screen 5065); 20% coverage

 

Threat Factor 29

Color: Digital White and Digital Etch (1/8” etch lines and 1/16” white white)
Pattern: alternating 1/8” and 1/16” horizontal lines all 2” on center; 5% coverage

2x4 Rule

Researchers acknowledge it isn’t practical to test every pattern. To address this practicality, researchers have used existing research to develop a guideline commonly referred to as the 2x4 Rule. The 2x4 Rule is referred to in multiple bird friendly design guidelines and indicates that developing patterns with horizontal lines spaced no more than 2” apart or vertical lines spaced no more than 4” apart can deter collisions.

Project Examples

Viracon has participated in numerous projects that utilized printing to reduce the likelihood of bird collisions. These projects utilized patterns, many of them customized, to meet the needs of the specific guideline, standard or law required by the project owner or design team.

Bell Museum of Natural History

Jacob K Javits Convention Center

Newhouse III, Syracuse University

The Cathedral of Christ the Light

Intuit Marine Way

Market Street Place

Springbrook Nature Center

Product Resources