To connect building occupants with the outdoors, reinforce circadian rhythms, and reduce the use of electrical lighting by introducing daylight and views into the space.
Option 1. Daylight Measurement (2 points)
Achieve illuminance levels between 300 lux and 3,000 lux for at least 50% of the regularly occupied floor area.
With furniture, fixtures, and equipment in place, measure illuminance levels as follows:
- Measure at appropriate work plane height during any hour between 9 a.m. and 3 p.m.
- Take one measurement in any regularly occupied month, and take a second as indicated in Table 1.
- For spaces larger than 150 square feet (14 square meters), take measurements on a maximum 10-foot (3-meter) square grid.
- For spaces 150 square feet (14 square meters) or smaller, take measurements on a maximum 3-foot (900-millimeter) square grid.
- multiple lines of sight to vision glazing in different directions at least 90 degrees apart;
- views that include at least two of the following: (1) flora, fauna, or sky; (2) movement; and (3) objects at least 25 feet (7.5 meters) from the exterior of the glazing;
- unobstructed views located within the distance of three times the head height of the vision glazing; and
- views with a view factor of 3 or greater, as defined in “Windows and Offices; A Study of Office Worker Performance and the Indoor Environment.”
Table 1. Timing of measurements for illuminance
|If first measurement is taken in …||take second measurement in …|
Option 2. Quality Views (2 points)
Achieve a direct line of sight to the outdoors via vision glazing for 50% of all regularly occupied floor area. View glazing in the contributing area must provide a clear image of the exterior, not obstructed by frits, fibers, patterned glazing, or added tints that distort color balance.
Additionally, 50% of all regularly occupied floor area must have at least two of the following four kinds of views:
Include in the calculations any permanent interior obstructions (e.g., lab hoods, fixed partitions, demountable opaque full- or partial-height partitions). Movable furniture and partitions may be excluded.
Views into interior atria may be used to meet up to 30% of the required area.