Bird friendly glazing is here to stay.  With codes changing and the bird deterrence topic in glass industry news, it is becoming very clear that the health and welfare of birds is a clear priority when architects are designing structures with glass.  So, without question, when a world-famous Aviary building was undergoing remodeling, the availability of glass that could meet the diverse needs of the design team was crucial. 


The Project

The project is the National Aviary located in Pittsburgh, Pennsylvania.  Specifically, an upgrade and remodel of the greenhouse that opened in 1952.  The renovation was sorely needed and the safety of the birds inside and outside was a key driver.  

The team at Walker Glass in Montreal, QC, Canada has been pioneering and perfecting the development of bird friendly glass and glazing products for many years.  Their industry-leading bird friendly glass would be put to the test on the Aviary project with the goal of protecting the birds inside the aviary while providing an energy performance allowing the plant life inside the structure to thrive.

Cheryl Tracy, the Executive Director of the National Aviary, noted that aspect in a public statement about the project. “The unique bird-friendly glass selection played a key role in transforming the space, both because it protects birds inside and outside the habitat and because the UV light penetration is so beneficial in supporting plant and animal life.” The glass products chosen for this significant remodel included everything that Tracy noted in her statement. Collaboration between Walker Glass and two other players on the supply and manufacturing side made it work. 


The Design

But first there was the inspiring design from the prominent architectural firm Montgomery Smith- Inc.  Their focus on historic structures, greenhouses and conservatories is extremely well known, and these specific project goals were very clear to James Smith AIA, Principal, Glasshouse Design and Preservation Consultant for Montgomery Smith-Inc. “We needed a glass surface that was proven to be “Bird Friendly” something that birds can “see” rather than “see through” and recognize that there is a physical barrier ahead.  Also, in this special facility this needed to happen from both the interior and from the exterior – we have birds on both sides of the glass. The change in glass has been good for reducing bird strikes and has also been good in diffusing the sunlight entering the conservatory which is better for the plants.”

The etched glass is applied to the exterior face for specific reasons.  Walker’s Velour finish provides as much as 79% diffused transmittance and up to 90% wide angle scattering commonly referred to as “haze.”  As a result, acid etched glass in exterior glazing units spreads natural light over a much larger area of the interior space thereby reducing the need for artificial light providing a positive benefit for the plants and other inhabitants at the conservatory.  Visible Light Transmittance (VLT) is a key factor here and the etched glass checks in at 92%.  That is an incredible data point and extremely important to the performance of the conservatory.



bird safe glass


The Glass 

With the design set the glass was in the spotlight.  The raw glass was manufactured by Vitro Architectural Glass (formerly known as PPG Glass) with a majority of the iron removed from it.  This glass is commonly known as “low iron” glass and is sold under the brand name Starphire Ultra-Clear™ glass.  The decrease in iron significantly lowers the greenish appearance of the glass and allows more light into the space.

Walker Glass then fabricated the low iron glass with a bird friendly etched finish known as AviProtek Velour.  This smooth aesthetically pleasing finish allows light to come through in a highly diffused manner.  This product met both the bird friendly design goals as well as the team’s interests related to light dispersion and transmittance.


The Final Process

The final process of the manufacturing and fabrication of the glass was provided by Dlubak Specialty Glass.  They added a specialty laminated interlayer from Trosifol® by the name of SentryGlas® Natural UV.  This specific laminated product increases transmittance of natural ultraviolet (UV) light unlike most safety glass interlayer technologies.  It was developed for specific applications including zoos, greenhouses, conservatories, and other areas where full-spectrum light is beneficial. 

Smith summed up the end result of the design choices and execution perfectly. “It was a wise decision and a unique opportunity to select this special glass because the existing glazing was in dire need of replacement so with a minimal increase in cost they also solved a long term problem.”

With the marked increase in awareness of the dire need to stop the deaths of a billion birds every year due to clear glass collisions, the movement to bird friendly glazing will continue its aggressive market growth. National Aviary is a great example of how a project having an excellent design and strong industry collaboration can achieve superior results.

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