L05: Enhanced Daylight Access

(3 pointS)

INTENT

Support circadian and psychological health through indoor daylight exposure and outdoor views.

SUMMARY

This WELL feature requires projects to design spaces to integrate daylight into indoor environments so that daylight may be used for visual tasks along with electric lighting. It also provides individuals with a connection to outdoor spaces through view windows.

ISSUE

Humans spend approximately 90% of their time indoors. The way buildings are designed has an enormous impact on occupant exposure to daylight. Exposure to daylight has been proven to have a substantial impact on mood, circadian health and productivity. For example, studies have associated lack of exposure to daylight with a disruption in the circadian rhythms of humans and a decrease in quality of sleep. Rooms with large windows reduce recovery time for patients suffering from severe depression and those recuperating after heart attacks, compared to similarly afflicted patients in rooms with windows facing buildings or other obstructions. Exposure to daylight for at least three hours a day was found to reduce stress and increase satisfaction at work for nurses working in a hospital. Window characteristics have also been found to have an impact on students' performance in schools. Students have been shown to perform better when they have access to windows that can be opened. Studies also show strong links between quality of views in office environments and performance of employees.

SOLUTIONS

Building design and interior layout have a substantial impact on the amount of daylight in an indoor space. Indoor daylight access should be accounted for at all stages of building planning from architectural and façade design to interior design and layout. Calculation of daylight ingress accounting for seasonal variances and interior design of indoor spaces is required to ensure that users have adequate access to daylight exposure. 

IMPACT

Providing users with daylight in a space provides visual, emotional and physiological benefits. Daylight contributes to light levels, thus helping with the performance of visual tasks in a space, while exposure to daylight has been proven to have positive impacts on mood and is an integral requirement for circadian rhythm alignment.

REQUIREMENTS

Part 1

Implement Enhanced Daylight Plan (1 point)

Verified by Architectural Drawing

For All Spaces except Dwelling Units

Projects meet at least one of the following requirements on each floor:

1. 70% of all workstations are within 7.5 m [25 ft] of transparent envelope glazing or atria. Visible light transmittance (VLT) of transparent glazing is greater than 40%.

2. Window area is no less than 10% of the floor area. Visible light transmittance (VLT) of transparent glazing is greater than 40%.

For Dwelling Units

The following requirement is met in each dwelling unit:

1. Window area is no less than 10% of the floor area. Visible light transmittance (VLT) of transparent glazing is greater than 40%.

Part 2

Implement Enhanced Daylight Simulation (Max: 2 points)

Verified by Modeling Report

For All Spaces except Dwelling Units

The following requirement is met:

1. Projects demonstrate through computer simulations that sDA _300,50% is achieved for the area on each floor as shown in the table below:

   sDA 300,50%	Points
   Achieved for > 55% of regularly occupied floor area	1
   Achieved for > 75% of regularly occupied floor area	2

For Dwelling Units

The following requirement is met:

1. Project demonstrate through computer simulations that sDA _300,50% is achieved for the area in each dwelling unit as shown in the table below:

   sDA300,50%	Points
   Achieved for > 55% of regularly occupied floor area	1
   Achieved for > 75% of regularly occupied floor area	2

Part 3

Ensure Views (1 point)

Verified by Architectural Drawing

For All Spaces

Transparent envelope glazing provides access to views for at least 50% of regular building occupants. Views meet at least two of the following requirements:

1. If at ground floor, distance from fenestration to roadway is at least 7.5 m [25 ft] from the exterior of the glazing.

2. View factor of 3 or greater.

3. Views with a vertical view angle of at least 30 degrees from occupant facing forward or sideways provide a direct line of sight to the ground or sky.

 

Note: While considering views, permanent interior obstructions are included.

View factors may be calculated using the process outlined in Windows and Offices: A Study of Office Worker Performance and the Indoor Environment.

© International WELL Building Institute