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Requirements
Option 1. Simulation
Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles (fc) (108 lux) and a maximum of 500 fc (5,400 lux) in a clear sky condition on September 21 at 9 a.m. and 3 p.m. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.Option 2. Prescriptive
For sidelighting zones:- Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) between 0.150 and 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).
- Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 0.150 value.
|
0.150 |
|
VLT |
x |
|
0.180 |
- The toplighting zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of (see diagram below):
- 70% of the ceiling height
- 1/2 the distance to the edge of the nearest skylight
- The distance to any permanent partition that is closer than 70% of the distance between the top of the partition and the ceiling.
- Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area.
- The skylight must have a minimum 0.5 VLT.
- A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003.
Option 3. Measurement
Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and shall be recorded on building floor plans. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.Option 4. Combination
Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces. See all forum discussions about this credit »What does it cost?
Cost estimates for this credit
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Learn more about The Cost of LEED v4 »Frequently asked questions
When should daylight measurements be taken?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Do I need to have glare control devices?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Where can I find the Supplemental Views and Daylight Calculator?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Do I need to submit the Supplemental Views and Daylight Calculator?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Can I average the compliant square footage between 9 a.m. and 3 p.m. for a space and use the average as the compliant square footage?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
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Can I use Option 2: Prescriptive method if I have: windows with different Tvis values within the same wall width, windows with different head heights within the same wall width, windows with different sill heights (and above 30”) within the same wall width, windows with permanent shading devices, skylights with different Tvis values within the same ceiling area, clear skylights, light that is transferred between one room to the next through an interior wall opening—glazed or unglazed, a Tvis/WFR value above 0.180, rooms that borrow light from an atrium, roof monitors, tubular daylighting devices such as Solatube, roof overhangs, or shared daylighting scenarios? The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Option 1. Simulation
Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 10 footcandles (fc) (108 lux) and a maximum of 500 fc (5,400 lux) in a clear sky condition on September 21 at 9 a.m. and 3 p.m. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.Option 2. Prescriptive
For sidelighting zones:- Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) between 0.150 and 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).
- Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 0.150 value.
|
0.150 |
|
VLT |
x |
|
0.180 |
- The toplighting zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of (see diagram below):
- 70% of the ceiling height
- 1/2 the distance to the edge of the nearest skylight
- The distance to any permanent partition that is closer than 70% of the distance between the top of the partition and the ceiling.
- Achieve skylight coverage for the applicable space (containing the toplighting zone) between 3% and 6% of the total floor area.
- The skylight must have a minimum 0.5 VLT.
- A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003.
Option 3. Measurement
Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and shall be recorded on building floor plans. Provide glare control devices to avoid high-contrast situations that could impede visual tasks. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 10 fc (108 lux) illuminance level.Option 4. Combination
Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces.XX%
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- Examples of actual submissions from certified LEED projects.
When should daylight measurements be taken?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Do I need to have glare control devices?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Where can I find the Supplemental Views and Daylight Calculator?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Do I need to submit the Supplemental Views and Daylight Calculator?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
Can I average the compliant square footage between 9 a.m. and 3 p.m. for a space and use the average as the compliant square footage?The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
|
Can I use Option 2: Prescriptive method if I have: windows with different Tvis values within the same wall width, windows with different head heights within the same wall width, windows with different sill heights (and above 30”) within the same wall width, windows with permanent shading devices, skylights with different Tvis values within the same ceiling area, clear skylights, light that is transferred between one room to the next through an interior wall opening—glazed or unglazed, a Tvis/WFR value above 0.180, rooms that borrow light from an atrium, roof monitors, tubular daylighting devices such as Solatube, roof overhangs, or shared daylighting scenarios? The answer to this question is available to LEEDuser premium members. Start a free trial » (If you're already a premium member, log in here.) |
