Feature 53 Visual Lighting Design

• Maximum Size of Ambient Lighting Zone:  Whichever is larger:
  • 500 sq. ft. (46.5 sq. m.)
  • 20 % of the space

Feature 54 Circadian Lighting Design

• If light models/calcs are used, need to provide:
  • Measured in vertical plane, 4 ft. high (seated gaze height)
  • 250 EML (Equivalent Melanopic Lux) minimum
  • 4 hours / day, minimum, every day
  • At 75% of workstations

• Feature 54 Circadian Lighting Design, Table L1 Melanopic Ratio

  • Equivalent Melanopic Lux (EML) = Visual Lux (L) x Melanopic Ratio (R)

Feature 59 Surface Design

• Minimum areas of interior surfaces required to have minimum Light Reflectance Values:
  • Ceilings: Min. 80 % area: Min. LRV = 0.8 (80%)
  • Walls: Min. 50% area: Min. LRV = 0.7 (70%)
  • Furnture: Min. 50% area: Min LRV 0.5 (50%)

Feature 61 Right to Light

• Guidelines for regularly occupied spaces and seats:
  • Spaces: 75% (by area) needs to be within 25 ft. (7.5 m) of a view window
  • Seats:
    • 75% need to be within 25 ft. (7.5 m) of a view window or atrium
    • 95% need to be within 41 ft (12.5 m) or a view window or atrium

Feature 62 Daylight Modeling

• Minimums:
  • At least 55% of regularly occupied spaces
  • Receive at least 300 lux (28 fc)
  • For at least 50% of the year (business hours)
• Maximums:
  • No more than 10% of regularly occupied spaces
  • Receive not more than 1000 lux (93 fc)
  • For more than 250 hours / year

Feature 63 Daylighting Fenestration

• 3 guidelines for window size, shading and placement:
  1. Size:  20% – 60% of exterior wall area should be glazed.
  2. Shading:  If window area is > 40%: prevent glare and heat gain with exterior shading or electrochromic glass.
  3. Daylight effectiveness:  40% to 60% of the window area should be above 7 ft (2.1 m)