Protecting Nature: Glazing Codes for Birds and Other Animals

By Jordan Scott

Glass plays an important role in architecture and gives people connection to the outside world. While the benefits of glass are plentiful, it can cause unintentional harm to some wildlife, especially birds and turtles. Codes are being put in place to protect them from deadly collisions or unnatural light sources that confuse them.

Bird-Friendly Glazing

Jurisdictions throughout North America are beginning to include bird-friendly glass design considerations into their codes as the danger glass poses to birds becomes increasingly documented. Canada has developed a standard, CSA A460-2019, in compliance with requirements from the Standards Council of Canada for National Standards of Canada. While the U.S. has yet to develop any national codes or standards, cities are taking matters into their own hands.

San Francisco’s Standards for Bird-Safe Buildings

Per San Francisco Planning Code Section 139, “Standards for Bird-Safe Buildings,” there are two types of bird hazards:

Bird-safe building treatments should be applied to 90% of glazing from grade up to 60 feet and applied to 100% of building feature-related hazards. These treatments should follow the 2×4 rule, which requires that patterns smaller than 2 by 4 inches be used.

Glazing Options

• Glass that reflects the ultraviolet light (which birds can see);
• Glass which has photovoltaic cells embedded;
• Dichroic glass;
• Fritted glass;
• Etched Glass;
• Translucent glass; or
• Film.

New York City’s Bird-Friendly Building Legislation – Int. No. 1482-2019-B

For new construction and exterior glazing renovations:

Below 75 feet above grade

• The exterior wall envelope and associated openings must be construction with bird-friendly materials up to 75 feet above grade.
• Materials other than bird-friendly materials are not allowed to exceed a total of 10 square feet within any 10 feet by 10 feet square area of exterior wall.

Glass for Marine Life

Views of the water make large spans of glass a no-brainer for coastal properties. However, light emitting from buildings near the shore can disorient sea turtle hatchlings, causing them to head toward light over the ocean and in the wrong direction. This increases the hatchlings’ risk of dying before reaching the ocean.

Codes that protect sea turtles:
• Federal Endangered Species Act of 1973;
• Florida Endangered and Threatened Species Act of 1977; and
• Florida’s Marine Turtle Protection Act of 1995 (379.2431).

Florida developed a Model Lighting Ordinance for Marine Turtle Protection to prevent light from negatively effecting nesting and hatching turtles. The ordinance requires that tinted glass be used on all doors and windows, including hurricane-resistant systems, in new construction of structures within line-of-sight of the beach.

Tinted glass: Has an inside-to-outside visible light transmittance (VLT) value of 45% or less and limited to the visible spectrum.

For existing buildings, the ordinance lays out a number of measures to reduce or eliminate the negative effects of interior light coming from doors and windows within line-of-sight of the beach, including:
• Updating windows to meet the 45% VLT requirements;
• Applying tint or film that meets these standards; and
• Using window treatments.

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