Provide access to natural daylight

Rationale: Implementing design strategies, such as high-visible light transmittance and optimal window-to-wall ratios, increases access to natural daylight, which supports circadian rhythm regulation — contributing to wide-ranging health benefits including improved sleep quality, a strengthened immune system, and lower stress levels.

Requirements

Demonstrate compliance with one of the options below:

Option 1 - Window-to-Wall Ratio (Full Credit):

To achieve full credit, demonstrate compliance with all of the following requirements:

1. Ensure that all windows within all regularly occupied spaces in the building(s) can exceed a Visible Light Transmittance (VLT) of 40%.

Qualifying regularly occupied spaces must include but are not limited to the following:

• Workspaces: which include workstations, flexible workspaces, individual offices, and circulation between workstations. Note that hallways, corridors, and elevator banks are not considered regularly occupied spaces.
• Common spaces: which include spaces where occupants can gather to work, eat, take breaks, or meet — such as meeting rooms, lactation rooms, quiet rooms, and reception areas.
• Common building amenities: which include resource centers, fitness facilities, and exercise rooms.

2. Provide a minimum window-to-wall ratio of 35% on each floor of the building(s).

3. Provide educational materials specifying the health benefits of access to daylight to all full- and part-time employees through a minimum of one of the following methods:

• a digital platform, such as a website, digital application, or display screen in common areas
• communication material, such as notification emails or newsletters

Option 2 - Natural Daylight Simulation Score (Full Credit):

The project may achieve full credit by demonstrating compliance with all of the following requirements:

1. Ensure an average sDA300,50% is achieved for a minimum of 60% of the floor area of each regularly occupied space within the building(s).

2. Provide educational materials specifying the health benefits of access to daylight to all full- and part-time employees through a minimum of one of the following methods:

• a digital platform, such as a website, digital application, or display screen in common areas
• communication material, such as notification emails or newsletters

Option 3 - Natural Daylight Calculation (Full Credit):

The project may achieve full credit by demonstrating compliance with all of the following requirements:

1. Ensure that all windows within all regularly occupied spaces in the building(s) can exceed a Visible Light Transmittance (VLT) of 40%.

2. Ensure that 51% of each regularly occupied space within the building(s) includes access to natural daylight.

Qualifying regularly occupied spaces must include but are not limited to the following:

• Workspaces: which include workstations, flexible workspaces, individual offices, and circulation between workstations. Note that hallways, corridors, and elevator banks are not considered regularly occupied spaces.
• Common spaces: which include spaces where occupants can gather to work, eat, take breaks, or meet — such as meeting rooms, lactation rooms, quiet rooms, and reception areas.
• Common building amenities: which include resource centers, fitness facilities, and exercise rooms.

Qualifying Calculation:

To calculate the total percentage of access to daylight within each regularly occupied common space(s) follow the steps below and input the required values in the tables on the calculation tab to apply the following formula [((A + B) / C) x 100)]:

Step 1, determine C: establish the total area of the regularly occupied common space.

Step 2, determine A and B: establish the area with access to daylight, using the windows located in the regularly occupied common space identified for C in Step 1 by applying the following:

– (i) to determine A, identify each window with access to daylight for north and south façades and input the required values in the table for each identical window with access to daylight to apply the following formula: North and South façades Area with Access to Daylight = [(Window(s) Head Height x 1.5) x (Window(s) Width + 2 feet from the right side of the window(s) + 2 feet from the left side of the window(s))].

– (ii) to determine B, identify each window with access to daylight for east and west façades and input the required values in the table for each identical window with access to daylight to apply the following formula: East and West façades Area with Access to Daylight = [(Window(s) Head Height) x (Window(s) Width)].

– (iii) repeat steps (i) and (ii) on each unique window type within the space.

– (iv) determine A and B by adding the results calculated from Step (i) and (ii).

Step 3, determine the percentage: to determine the percentage of the regularly occupied common space(s) with access to natural daylight, apply the formula [((A + B) / C) x 100)].

Step 4, repeat steps 1 through 3 for each regularly occupied common space within the project.

Permanent furniture partitions or other permanent features that measure above 42 inches or 106 centimeters are considered obstructions of natural daylight. Areas behind these obstructions should not to be included in the daylit area. Window head height is the height of the window measured from the finished floor level to the top of the window frame.

If there are spaces behind walls and obstructions: Subtract those areas behind obstructions from the total area with access to daylight (A+B). These obstructed areas include spaces behind partitions 42 inches or higher as well as enclosed rooms. The final formula would appear like this: ((A+B) - area behind obstructions) / C.

Option 4 - Equivalent Standard (Full Credit):

The project may achieve partial credit by demonstrating compliance with all of the following requirements:

1. LEED 2009 IEQ Credit 8.1: Daylight and Views – Daylight.

2. LEED v4 BD+C: Daylight, Option 2 OR Option 3.

3. LEED v4.1 BD+C EQ Credit: Daylight, Option 2 OR Option 3.

Compliance Documentation

Types of compliance documentation required:

• Annotated design drawings
• Annotated plans
• Certified statements
• Calculations
• Annotated photographs