Mountain View Municipal Code Div. 18 Bird-Safe Glass Requirements (appendix A5)

Add Section A5.107 (Bird-Friendly Building Design) of Appendix A5 of the 2025 California Green Building Standards Code as mandatory measures, inclusive of amendments in Sec. 8.96.10.

(Ord. No. 9.2025, § 6(Exh. B), 9/9/25.)

Subsections AS.107.1 and AS.107.2 of Appendix A5 of the 2025 California Green Building Standards Code are amended to read as follows:

A5.107.1 Required elevation treatment. Building elevation treatment shall incorporate bird-friendly mitigation strategies. No less than 90 percent of a building elevation, measured from grade to a height of 40 feet (12 m) above grade, or from grade to the height of an adjacent mature tree canopy (whichever is greater), shall incorporate bird-friendly mitigation strategies. No less than 60 percent of building elevation, 40 feet (12 m) above grade to the top of the building elevation, shall incorporate bird-friendly mitigation strategies.

Strategies to minimize the risk of birds colliding with buildings:

1. Glazing. Glazing with visual markers shall include, but is not limited to, the following:

a. Etched or fritted glass with patterns of elements on the exterior having minimum dimensions of 1/4" (0.64 cm) diameter for dots or 1/8" (0.32 cm) width for stripes in a density of 2 inches (5.1 cm) maximum horizontally and vertically (the "2 x 2 Rule"). Note: If the visual markers are on glass surface 2, they can be effective if visible behind an exterior surface with reflectivity of 15 percent or less.

b. Exterior glazing film with 2 x 2 visual markers.

c. Laminated glass with 2 x 2 visual markers, patterned ultraviolet (UV) coating or use of contrasting patterned UV-absorbing and UV-reflecting films. Note: Low-e coatings shall be behind the visual markers.

d. Glass block or channel glass.

e. Developed glazing technologies documented to reduce bird strikes, as tested by an independent third party and approved by the authority having jurisdiction; or

2. Slats, Screens, Netting, Louvers. Glazing protected by exterior features that create a visible barrier in front of the glazing, may include, but not be limited to:

a. Horizontal or vertical slats of 1/8" (0.32 cm) minimum face width with minimum 2" (5.1 cm) spacing that obscure 85 percent or more of glass when viewed from all feasible angles.

b. Grilles, screens or 1/8" (0.32 cm) dia. welded wire mesh with openings no more than 2" (5.1 cm) maximum horizontally and vertically installed parallel to and no more than 3 ¼ ft (1 m) from the first surface of glass (glass surface 1).

c. Sunshades or louvers 9" (22.5 cm) deep vertically spaced a maximum 9" (22.5 cm) or 6" (15 cm) deep horizontally at maximum 6" (15 cm) spacing and parallel or angled to the glass surfaces.

A5.107.2 Special conditions. The following special conditions shall comply with the provisions in Section A5.107.1, as amended (as appropriate):

1. Glass facades adjacent to vegetated roof.

2. Three floors of glass façade(s) adjacent to any green roof or partial green roof.

3. Glass railings and guardrails.

4. Transparent corners that extend 5.5 feet (1.68 m) on either side of a building.

5. Glass passageways, skyways, skywalks, or other building connectors.

6. Glass around an open or enclosed atrium.

7. Auxiliary glass buildings such as a glass pavilion or atrium exposed to the sky.

8. Auxiliary glass building such as a glass pavilion or atrium exposed to a courtyard with a water feature or plants.

9. Any stand-alone auxiliary or accessory structure, such as, but not limited to, gazebo, bus shelter, ticket booth, or any free-standing structure or installation with a clear, transparent or highly reflective surface.

10. Any glass adjacent to a courtyard.

11. Stained glass windows insulated on the exterior with clear glazing.

(Ord. No. 9.2025, § 6(Exh. B), 9/9/25.)