Bird friendly glass refers to glass that has been treated to make it more visible to birds in order to prevent bird collisions. One way this is achieved is through the application of UV coatings on the glass surface. UV coatings reflect ultraviolet light, which birds can see but humans cannot, effectively alerting birds to the presence of glass.
Why do birds collide with glass?
Birds have excellent vision and are able to see into the ultraviolet spectrum. However, standard clear and reflective glass does not reflect UV light. As a result, birds are unable to distinguish glass from the surrounding habitat and will accidentally fly directly into glass, often with fatal results.
It is estimated that up to 1 billion birds die each year in the United States from striking glass on buildings and homes. This makes glass collisions one of the leading causes of bird mortality worldwide.
How do UV coatings work to prevent bird strikes?
UV coatings contain ultraviolet absorbing and reflecting compounds that allow the glass to be visible in the UV spectrum. For birds, this turns clear or reflective glass into a glowing barrier that they can clearly identify and avoid.
There are two main types of bird friendly UV coatings:
- UV absorbent coatings – These coatings absorb UV light and re-emit it as longer, visible wavelengths. This creates a bright glow from 330-400 nm that birds can see.
- UV reflective coatings – These coatings reflect UV light directly, creating a strong UV signal on the glass surface.
Both types of UV coatings provide the cue needed for birds to discern and avoid the glass without obstructing visibility or aesthetics for humans.
What materials are used in UV coatings?
The active ingredients in most UV coatings for bird friendly glass include:
- Cerium oxide – A rare earth metal oxide that absorbs UV radiation.
- Titanium dioxide – A bright white pigment that reflects and scatters UV light.
- Zinc oxide – An inorganic compound and semiconductor that absorbs UV light.
These UV-reactive compounds are suspended in a silica or acrylic binding agent that adheres the coating securely to the glass surface. The coating is usually applied via spray or roller in multiple thin layers and then cured under UV lamps.
How is the effectiveness of UV coatings measured?
The effectiveness of bird friendly UV glass coatings is determined by its UV reflection, transparency, and visibility. Key metrics include:
- UV reflection from 300-400 nm – Measures the percentage of UV light reflected by the coated glass. A minimum of 20% UV reflection is recommended.
- Visible light transmission – Assesses how much visible light passes through the coated glass. At least 70% visibility is ideal.
- UV brightness – Evaluates the perceived glow or visibility of the coating to birds. A brighter response is better.
Field testing is also critical to assess the coating’s ability to prevent bird collisions. Collision rates, avoidance behavior, and flight patterns are monitored at buildings before and after the application of UV coatings.
How durable are UV coatings on glass?
UV coatings are designed to be highly durable and long-lasting to maintain their effectiveness over time. Important durability factors include:
- Abrasion resistance – The coating adheres tightly to the glass and resists wear from weathering or cleaning.
- UV stability – The UV-reflecting compounds maintain their optical performance when exposed to sunlight.
- Heat tolerance – Withstands high temperatures without cracking, peeling or degrading.
Quality UV coatings can last 5-10 years or more before needing reapplication. Periodic reapplication helps renew the coating and its bird strike prevention capabilities.
Are there any limitations to UV coatings on glass?
UV coatings have some potential limitations to be aware of:
- Effectiveness varies by species – Smaller birds like hummingbirds or sparrows may not see the UV cues as well as larger birds.
- Not effective at night – UV coatings rely on daylight to generate the visual glow.
- Can wear off over time – Periodic reapplication is needed to maintain optimal UV reflectance.
- Visible haze or color – May impart a faint purple/blue tint if applied too thickly.
Proper application by an experienced vendor helps ensure the UV coating has maximum impact while minimizing any downsides.
Are there any health or safety concerns with UV coatings?
UV coatings must meet stringent eco-friendly regulations and manufacturing standards to be approved for architectural use. Potential health and environmental impacts are minimized by:
- Using non-toxic ingredients like titanium and cerium oxides.
- No heavy metals, solvents or VOC compounds.
- Curing and drying the coatings fully to inert hardness.
- Low biopersistence materials that do not accumulate in the body.
When properly formulated and applied, UV coatings present negligible health hazards for installation workers or the general public.
What are some examples of UV glass coating products?
Some popular options for bird friendly UV glass coatings include:
Product | Manufacturer | Features |
---|---|---|
Ornilux Mikado | Arnold Glass | Durable exterior coating with high UV reflectance |
CollidEscape | Walker Glass | Interior or exterior use with light UV tint |
BirdGuard | Guardian Glass | Low maintenance and abrasion resistant |
Feather Friendly | Viracon | Customizable UV reflectance and visible transmission |
Various aftermarket UV glass coatings are also available from window film installers and specialty coating contractors.
How much does UV coated bird friendly glass cost?
The cost to apply UV coatings to glass can vary depending on:
- Coating product selected
- Amount of glass to be treated
- Accessibility of the glass panels
- Specialized equipment or staging needed
- Labor and installation fees
As a rough estimate, UV coatings add between $1.00 – $3.00 per square foot in material and installation costs. High-performance coatings for large-scale projects can run higher.
Specifying bird friendly glazing at the start of new construction is the most economical option. Retrofitting existing buildings is more labor intensive and therefore more expensive.
Are there any rebates or tax credits for bird friendly glass?
There are a few programs that offer financial incentives for installing bird friendly glazing such as:
- LEED credits – Projects seeking LEED green building certification can earn innovation credits for using bird collision deterrent techniques like UV coated glass.
- Energy utility rebates – Some energy providers offer rebates for bird friendly glass installed along with energy efficient windows.
- Avian-specific programs – Organizations like American Bird Conservancy partner with green building councils to provide subsidies for qualifying UV window retrofit projects.
Tax credits may also be available for certain non-profit and community development projects utilizing bird friendly building materials.
Conclusion
UV coatings provide an effective and scientifically-proven method of reducing bird collisions with glass. The specialized coatings reflect ultraviolet light as a visual signal to birds while remaining aesthetically subtle and practically invisible to humans. Proper product selection, application, and maintenance of UV coatings allows glass facades to be transformed into bird-safe barriers without compromising design or visibility. Continued innovation and advocacy efforts are still needed to drive broader adoption of bird friendly solutions as standard practice for future construction.