L04: Glare Control – Above Green

(3 points)

INTENT

Minimize visual discomfort caused by glare from daylight and electric light.

SUMMARY

This WELL feature requires projects to manage glare by using a combination of strategies such as calculating of glare, choosing appropriate light fixtures for the space and using shading techniques.

ISSUE

Glare is defined as excessive brightness of the light-source, excessive brightness-contrasts and excessive quantity of light. Glare management is an integral part of lighting design. Glare has been associated with a host of health issues that range from visual discomfort and eye fatigue to headaches and migraines. Studies have shown that glare can lead to visual impairment and discomfort which can cause accidents in the workplace. Individuals under the age of 50 are more sensitive to glare. Since a substantial section of the workforce falls into this age group it is important to address glare to avoid visual fatigue and glare-induced headaches.

SOLUTIONS

Space planning and lighting design can minimize the amount of glare experienced by individuals in the space. For electric lighting, the light source, type of luminaires used and lighting layout can lead to reduced glare. For daylighting, integrating shading for all windows or conducting a daylighting analysis in the space can help manage solar glare.

IMPACT

Reducing glare improves the visual experience of the occupants in the space. Continued exposure to glare can trigger migraine attacks and headaches in sensitive individuals and eye fatigue in others. Implementing strategies to mitigate glare minimizes distraction and contributes to overall comfort and focus of users.

REQUIREMENTS

Part 1

Control Solar Glare (2 points)

Verified by Policy Document, Modeling Report, Photographic evidence

For All Spaces

Choose between the following:

Option 1. Window shading:

The following requirements are met in regularly occupied spaces:

All exterior envelope glazing has shading. Atria or lobbies may be excluded.
The shading is controllable by the occupants or set to automatically prevent glare. If shading is controlled by occupants, all shades are raised or retracted either manually or automatically at least twice per week.

Option 2. Glare calculation:

The following requirement is met:

Annual sunlight exposure of ASE_1000,250 is achieved for no more than 10% of regularly occupied space.

Part 2

Manage Glare from Electric Lighting (2 points)

Verified by Architect

For All Spaces

Each luminaire meets one of the following requirements for regularly occupied spaces. Wall wash fixtures and task lamps positioned as specified by manufacturer’s data, as well as decorative fixtures, may be excluded from meeting these requirements:

100% of light is emitted above the horizontal plane.
Unified Glare Rating (UGR) values are met as per the below conditions:
1. Luminaires installed at a height of 5 m [16 ft] or lower meet UGR of 19 or lower.
2. Luminaires installed at a height greater than 5 m [16 ft] meet UGR of 22 or lower.

Shielding angles are as described in the below table:

Luminance	Shielding angle, α (α = 90 - cutoff angle)
< 20,000 cd/m² (including reflected sources)	No shielding required
20,000 cd/m² to 50,000 cd/m²	15°
50,000 cd/m² to 500,000 cd/m²	20°
> 500,000 cd/m²	30°

Fixtures have a luminance of less than 10,000 cd/m² between 45 and 90 degrees from nadir, and/or an intensity of less than 1,000 candela between 45 and 90 degrees from nadir.