Xinaps Daylight Ratio Evaluator currently supports LEED 2009 EQc8.1, OPTION 2. Prescriptive, to receive 1 (one) optional credit.
Use a combination of side-lighting and/or top-lighting to achieve a total day-lighting zone (the floor area meeting the following requirements) that is at least 75% of all the regularly occupied spaces.
For side-lighting zones:
- Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor arearatio (WFR) of daylight zone between 0.150 and 0.180.
0.150 < VLT x WFR < 0.180 - The window area included in the calculation must be at least 30 inches (0.8 meters) above the floor.
- In section, the ceiling must not obstruct a line that extends from the window-head to a point on the floor that is located twice the height of the window-head from the exterior wall as measured perpendicular to the glass (see diagram on the next page).
Use the following daylight settings:
- Set the minimum height above floor to 800 mm.
- Disable "include interior glazing"
- Enable "include transparency"
- Set the transparency for the "glass" materials to your appropriate "visual light transmittance value".