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| v3 - LEED 2008

Occupant comfort - daylight and views

EQc2.4 | Possible 1 point

Intent

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

Requirements

  • 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.

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