Please upgrade your browser. This site requires a newer version to work correctly. Read more
Our "watch" feature allows you to stay current on all aspects of this specific credit. In your account, you can control what you get updated on and how you receive your notifications. Hide

Daylight

Possible point

Intent

To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

To provide a connection between indoor spaces and the outdoor environment through use of daylight and views in the occupied areas of the building.

Provide the occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the tenant space.

Provide the occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the tenant space.

Provide the occupants with a connection between indoor spaces and the outdoor environment through the introduction of daylight and views into the regularly occupied areas of the tenant space.

Provide a connection between indoor spaces and the outdoor environment through introduction of daylight and views into the occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Provide a connection between indoor spaces and outdoor environments through the introduction of sunlight and views into the occupied areas of the building.

Provide a connection between indoor spaces and outdoor environments through the introduction of sunlight and views into the occupied areas of the building.

Provide a connection between indoor spaces and the outdoor environment through introduction of daylight and views into the occupied areas of the building.

Provide for the building occupants a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

To provide a connection between indoor spaces and the outdoor environment through use of daylight and views in the occupied areas of the building.

To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building.

Requirements

Through 1 of the 4 options, achieve daylighting in at least the following spaces1:

Regularly Occupied Spaces Points
75% 1

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

Use a combination of sidelighting and/or toplighting to achieve a total daylighting zone (the floor area meeting
the following requirements) that is at least 75% of all the regularly occupied spaces.

For sidelighting zones:

  • Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area
    ratio (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).

  • 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.

For toplighting zones:

  • 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.

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.
  • 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).
  • 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.

For toplighting zones:

  • 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.

Project teams must achieve the performance thresholds in either the daylight or views requirements below:

Option 1. Daylight

Through 1 of the 4 paths, achieve daylighting in at least 50% of all regularly occupied spaces.

Path 1. Simulation

Demonstrate through computer simulations 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.

OR

Path 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) 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 in 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 below).
  • 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.

For toplighting zones:

  • 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.
Path 3. Measurement

Demonstrate through records of indoor light measurements that a minimum daylight illumination level of10 fc (108 lux) and a maximum of 500 fc (5,400 lux) has been achieved in applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid and 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.

Path 4. Combination

Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces.

Option 2. For views

Achieve a direct line of sight to the outdoor environment via vision glazing between 30 inches and 90 inches above the finished floor for building occupants in 45% of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

  • In plan view, the area is within sight lines drawn from perimeter vision glazing.
  • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.

The line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has a direct line of sight to perimeter vision glazing. For multioccupant spaces, the actual square footage with a direct line of sight to perimeter vision glazing is counted.

Option 1 — Calculation

Achieve a minimum glazing factor of 2% in a minimum of 75% of all regularly occupied areas. The glazing factor is calculated as follows:
[INSERT FIGURE HERE]

OR

Option 2 — Simulation

Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 footcandles has been achieved in a minimum of 75% of all regularly occupied areas. Modeling must demonstrate 25 horizontal footcandles under clear sky conditions, at noon, on the equinox, at 30 inches above the floor.

OR

Option 3 — Measurement

Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of 25 footcandles has been achieved in at least 75% of all regularly occupied areas. Measurements must be taken on a 10-foot grid for all occupied spaces and must be recorded on building floor plans.

In all cases, only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be applied towards the 75% of total area calculation required to qualify for this credit.

In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

Achieve direct line of sight to the outdoor environment via vision glazing between 2’6” and 7’6” above finish floor for building occupants in 90% of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

  • In plan view, the area is within sight lines drawn from perimeter vision glazing.
  • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.
  • Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. For multi-occupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

    • EQ Credit 2.4 (1 point): Achieve a 2% daylight factor in 50% of all spaces occupied for critical visual tasks.
      OR
      Achieve direct line of sight to vision glazing for building occupants in 45% of regularly occupied spaces.
    • EQ Credit 2.5 (1 point): Achieve a 2% daylight factor in 75% of all spaces occupied for critical visual tasks
      OR
      Achieve direct line of sight to vision glazing for building occupants in 90% of regularly occupied spaces.
    For daylight:

    Achieve a minimum daylight factor of 2% (excluding all direct sunlight penetration) in space occupied for critical visual tasks, not including copy rooms, storage areas, mechanical, laundry and other low-occupancy support areas. Exceptions include those spaces where tasks would be hindered by daylight or enhanced by direct sunlight. Provide glare control for all windows where direct sunlight would interfere with normal activities. Choose one of the following options:

    Option A. Measurement

    Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of
    25 foot-candles has been achieved in at least 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Measurements must be taken on a 10-foot grid for all occupied spaces and must be recorded on building floor plans.

    Only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be counted in the calculations.

    In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by daylight will be considered on their merits.

    Option B. Calculation

    Achieve a minimum glazing factor of 2% in a minimum of 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Calculate the glazing factor as follows:
    [INSERT FIGURE HERE]

    Option C. Simulation

    Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 foot-candles has been achieved in a minimum of 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Modeling must demonstrate 25 horizontal foot-candles under clear sky conditions, at noon on the equinox, at 30 inches above the floor.

    For views:

    Achieve direct line of sight to the outdoor environment via vision glazing between 2’6” and 7’6” above the finished floor for building occupants in 45% (Credit 2.4) or 90% (Credit 2.5) of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

    • In plan view, the area is within sight lines drawn from perimeter vision glazing.
    • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.

    Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. For multioccupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

    For at least 75% of all regularly occupied areas:

    • Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetrations)
      OR
    • Using a computer simulation model, achieve at least 25 footcandles.

    AND

    • Provide daylight redirection and/or glare control devices to ensure daylight effectiveness.

    Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

    For at least 90% of all regularly occupied areas:

    • Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetrations)
      OR
    • Using a computer simulation model, achieve at least 25 footcandles.

    AND

    • Provide daylight redirection and/or glare control devices to ensure daylight effectiveness.

    Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

    Achieve direct line of sight to the outdoor environment (vision glazing between 2’-6” and 7’-6”) for building occupants in 90% of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

    • In plan view, the area is within sight lines drawn from perimeter vision glazing.
    • In section view, a direct sight line can be drawn from a point 42 in. above the floor to perimeter vision glazing.

    Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. If less than 75% of the area has direct line of sight then only the area with the direct line of sight will be counted towards meeting the credit requirement not the whole office area. For multi-occupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

    Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in space occupied for critical visual tasks, not including copy rooms, storage areas, mechanical, laundry and other low-occupancy support areas. Exceptions include those spaces where tasks would be hindered by the use of daylight or where accomplishing the specific tasks within a space would be enhanced by the direct penetration of sunlight. Provide glare control for all windows where direct penetration of sunlight would interfere with normal occupant activities.
    Achievement of a 2% daylight factor in:

    • IEQ Credit 8.1: 50% of all spaces occupied for critical visual tasks. (1 point)
    • IEQ Credit 8.2: 75% of all spaces occupied for critical visual tasks. (1 point)

    Through one of the three optional methodologies, achieve daylighting through one of the three options below in at least the following spaces:

    • 75% of all classroom spaces (1 point), or
    • 90% of all classroom spaces (2 points), or
    • 75% of all other regularly occupied spaces (1 additional point). Project teams can only achieve a point for these other spaces if they have also achieved at least one point for classroom spaces.
    Option 1 — Calculation

    Achieve a minimum glazing factor of 2%. The glazing factor is calculated as follows:

    Glazing Factor Window Area [SF] Window Geometry Factor Actual T vis Window Height Factor
    = x x x
    Floor Area [SF] Minimum T vis

    Option 2 — Simulation

    Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 footcandles has been achieved. Modeling must demonstrate 25 horizontal footcandles under clear sky conditions, at noon, on the equinox, at 30 inches above the floor.

    Option 3 — Measurement

    Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of 25 footcandles has been achieved. Measurements must be taken on a 10-foot grid for all occupied spaces and must be recorded on building floor plans.

    In all cases, only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be applied towards the calculation required to qualify for this credit.

    In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

    Achieve direct line of sight to the outdoor environment via vision glazing between 2’6” and 7’6” above finish floor for building occupants in 90% of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

    • In plan view, the area is within sight lines drawn from perimeter vision glazing.
    • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.
    • Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. For classrooms and other multi-occupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

      Option 1 — Calculation

      Achieve a minimum glazing factor of 2% in a minimum of 75% of all regularly occupied areas. The glazing factor is calculated as follows:
      [INSERT FIGURE HERE]

      OR

      Option 2 — Simulation

      Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 footcandles has been achieved in a minimum of 75% of all regularly occupied areas. Modeling must demonstrate 25 horizontal footcandles under clear sky conditions, at noon, on the equinox, at 30 inches above the floor.

      OR

      Option 3 — Measurement

      Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of 25 footcandles has been achieved in at least 75% of all regularly occupied areas. Measurements must be taken on a 10-foot grid for all occupied spaces and must be recorded on building floor plans.

      OR

      Option 4 – Prescriptive

      Use a combination of side-lighting and top-lighting to achieve a total Daylighting Zone (that floor area meeting the following requirements) that is at least 75% of all the regularly occupied spaces.

      Sidelighting Daylight Zone:

      • Achieve a product of the visible light transmittance (VLT) and window to floor area ratio (WFR) of daylight zone between the values of 0.150 and 0.180. Window area included in the calculation must be of the portion of the window at least 2’-6” above the floor.
      • 0.150 < VLT x WFR < 0.180
      • Ceiling should not obstruct a line in section that joins the window-head to a line on the floor that is parallel to the plane of the window and is, in distance from the plane of the glass as measured perpendicular to the plane of the glass, two times the height of the window head above the floor. See diagram below.
      • Provide sunlight redirection and/or glare control devices to ensure daylight effectiveness.

      [INSERT DIAGRAM HERE]

      Toplighting Daylight Zone:

      • The daylit zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of: 70% of the ceiling height, one half of the distance to the edge of the nearest skylight, or the distance to any permanent opaque partition (if transparent show VLT) which is farther away than 70% of the distance between the top of the partition and the ceiling. See diagram below.
      • Achieve a skylight roof coverage that is between 3% and 6% of the roof area with a minimum 0.5 visible light transmittance (VLT) for the skylights.
      • The distance between the skylights shall not be more than 1.4 times the ceiling height
      • Skylight diffuser with a measured haze value of greater than 90% when tested according to ASTM D1003. Avoid direct line of sight to skylight diffuser.

      Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

      [INSERT DIAGRAM HERE]

      In all cases, only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be applied towards the 75% of total area calculation required to qualify for this credit.

      In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

      Achieve direct line of sight to the outdoor environment via vision glazing between 2’6” and 7’6” above finish floor for building occupants in 90% of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

      • In plan view, the area is within sight lines drawn from perimeter vision glazing.
      • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.
      • Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. For multi-occupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

        The core and shell design needs to develop a feasible tenant layout(s) per the default occupancy counts (or some other justifiable occupancy count) that can be used in the analysis of this credit.

        Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in 75% of all space occupied for critical visual tasks. Spaces excluded from this requirement include copy rooms, storage areas, mechanical plant rooms, laundry and other low occupancy support areas. Other exceptions for spaces where tasks would be hindered by the use of daylight will be considered on their merits.

        Direct line of sight to vision glazing from 90% of all regularly occupied spaces, not including copy rooms, storage areas, mechanical, laundry, and other low occupancy support areas.

        Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in 75% of all space occupied for critical visual tasks, not including copy rooms, storage areas, mechanical, laundry, and other low occupancy support areas. Exceptions include those spaces where tasks would be hindered by the use of daylight or where accomplishing the specific tasks within a space would be enhanced by the direct penetration of sunlight.

        Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration) in space occupied for critical visual tasks, not including copy rooms, storage areas, mechanical, laundry and other low-occupancy support areas. Exceptions include those spaces where tasks would be hindered by the use of daylight or where accomplishing the specific tasks within a space would be enhanced by the direct penetration of sunlight. Provide glare control for all windows where direct penetration of sunlight would interfere with normal occupant activities.
        Achievement of a 2% daylight factor in:

        • IEQ Credit 8.1: 50% of all spaces occupied for critical visual tasks. (1 point)
        • IEQ Credit 8.2: 75% of all spaces occupied for critical visual tasks. (1 point)

        Achieve direct line of sight to vision glazing for building occupants in 90% of all regularly occupied spaces. Examples of exceptions include copy rooms, storage areas, mechanical, laundry and other low occupancy support areas. Other exceptions will be considered on their merits.

        • EQ Credit 2.4 (1 point): Achieve a 2% daylight factor in 50% of all spaces occupied for critical visual tasks.
          OR
          Achieve direct line of sight to vision glazing for building occupants in 45% of regularly occupied spaces.
        • EQ Credit 2.5 (1 point): Achieve a 2% daylight factor in 75% of all spaces occupied for critical visual tasks
          OR
          Achieve direct line of sight to vision glazing for building occupants in 90% of regularly occupied spaces.
        For daylight:

        Achieve a minimum daylight factor of 2% (excluding all direct sunlight penetration) in space occupied for critical visual tasks, not including copy rooms, storage areas, mechanical, laundry and other low-occupancy support areas. Exceptions include those spaces where tasks would be hindered by daylight or enhanced by direct sunlight. Provide glare control for all windows where direct sunlight would interfere with normal activities. Choose one of the following options:

        Option A. Measurement

        Demonstrate, through records of indoor light measurements, that a minimum daylight illumination level of
        25 foot-candles has been achieved in at least 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Measurements must be taken on a 10-foot grid for all occupied spaces and must be recorded on building floor plans.

        Only the square footage associated with the portions of rooms or spaces meeting the minimum illumination requirements can be counted in the calculations.

        In all cases, provide daylight redirection and/or glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by daylight will be considered on their merits.

        Option B. Calculation

        Achieve a minimum glazing factor of 2% in a minimum of 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Calculate the glazing factor as follows:
        [INSERT FIGURE HERE]

        Option C. Simulation

        Demonstrate, through computer simulation, that a minimum daylight illumination level of 25 foot-candles has been achieved in a minimum of 50% (Credit 2.4) or 75% (Credit 2.5) of all regularly occupied areas. Modeling must demonstrate 25 horizontal foot-candles under clear sky conditions, at noon on the equinox, at 30 inches above the floor.

        For views:

        Achieve direct line of sight to the outdoor environment via vision glazing between 2’6” and 7’6” above the finished floor for building occupants in 45% (Credit 2.4) or 90% (Credit 2.5) of all regularly occupied areas. Determine the area with direct line of sight by totaling the regularly occupied square footage that meets the following criteria:

        • In plan view, the area is within sight lines drawn from perimeter vision glazing.
        • In section view, a direct sight line can be drawn from the area to perimeter vision glazing.

        Line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office can be counted if 75% or more of the area has direct line of sight to perimeter vision glazing. For multioccupant spaces, the actual square footage with direct line of sight to perimeter vision glazing is counted.

        Through 1 of the 4 options, achieve daylighting in at least the following spaces:

        Regularly Occupied Spaces Points
        75% 1

        OPTION 1. Simulation

        Demonstrate through computer simulation that the applicable spaces achieve daylight illuminance levels of a minimum of 25 footcandles (fc) (270 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. Areas with illuminance levels below or above the range do not comply. However, designs that incorporate view-preserving automated shades for glare control may demonstrate compliance for only the minimum 25 fc (270 lux) illuminance level.

        OR

        OPTION 2. Prescriptive

        Use a combination of side-lighting and/or top-lighting to achieve a total daylighting zone (the floor area meeting the following requirements) that is at least 75% of all the regularly occupied spaces.

        For the Side-lighting Daylight Zone (see diagram on the next page):

        • Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to- floor area ratio (WFR) of daylight zone between 0.150 and 0.180. The window area included in the calculation must be at least 30 inches (.8 meters) above the floor.
        • 0.150 < VLT x WFR < 0.180

        • The ceiling must not obstruct a line in section that joins the window-head to a line on the floor that is parallel to the plane of the window; is twice the height of the window-head above the floor in, distance from the plane of the glass as measured perpendicular to the plane of the glass.
        • Provide sunlight redirection and/or glare control devices to ensure daylight effectiveness.

        For Top-lighting Daylight Zone (see the diagram below):

        • The daylight zone under a skylight is the outline of the opening beneath the skylight, plus in each direction the lesser of:

          • 70% of the ceiling height
          • OR

          • 1/2 the distance to the edge of the nearest skylight
          • OR

          • The distance to any permanent opaque partition (if transparent show VLT) farther than 70% of the distance between the top of the partition and the ceiling.
        • Achieve skylight roof coverage between 3% and 6% of the roof area with a minimum 0.5 VLT.
        • The distance between the skylights must not be more than 1.4 times the ceiling height.
        • A skylight diffuser, if used, must have a measured haze value of greater than 90% when tested according to ASTM D1003. Avoid direct line of sight to the skylight diffuser.
        • Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

        OR

        OPTION 3. Measurement

        Demonstrate through records of indoor light measurements that a minimum daylight illumination level of 25 fc (270 lux) has been achieved in the applicable spaces. Measurements must be taken on a 10-foot (3-meter) grid for all occupied spaces and recorded on building floor plans. Only the floor area associated with the portions of rooms or spaces meeting the minimum illumination requirements may be counted in the calculations.

        For all projects pursuing this option, provide daylight redirection and/or glare control devices to avoid high- contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by daylight will be considered on their merits.

        OR

        OPTION 4. Combination

        Any of the above calculation methods may be combined to document the minimum daylight illumination in the applicable spaces. The different methods used in each space must be clearly recorded on all building plans.

        In all cases, only the floor area associated with the portions of rooms or spaces meeting the requirements may be applied toward the 75% of total area calculation required to qualify for this credit.

        In all cases, provide glare control devices to avoid high-contrast situations that could impede visual tasks. Exceptions for areas where tasks would be hindered by the use of daylight will be considered on their merits.

Join LEEDuser

Ask questions, share tips, and get notified of new forum posts by joining LEEDuser, a tool developed by BuildingGreen and supported by USGBC!

  • Share on Twitter
  • Share on Facebook
  • Share on LinkedIn
  • Print to PDF
Sample forms
View sample forms