Electric light glare control
- 53 Visual lighting design
- 54 Circadian lighting design
- 55 Electric light glare control
- 56 Solar glare control
- 57 Low-glare workstation design
- 58 Color quality
- 59 Surface design
- 60 Automated shading and dimming controls
- 61 Right to light
- 62 Daylight modeling
- 63 Daylighting fenestration
- P2 Light at night
- P3 Circadian emulation
Electric light glare control
To minimize direct and overhead glare by setting limits on the luminous intensity of luminaires.
The easiest way to assess compliance with Part 2 is to use the Equivalency available for this feature part referencing Unified Glare Rating (UGR) values. UGR values can generally be found in luminaire specifications or calculated in lighting design software. For Part 2, workstations should have a UGR of 19 (or less).
Our project team noticed that the allowable luminance levels is higher than standard U.S. lighting specifications. What is the reason for this higher luminance requirement?
This feature part is based off the best practice lighting requirements and to ensure optimal visual comfort of the occupant (see citation - the European Standard licht.wissen 04: Office Lighting: Motivating and Efficient). The higher levels are regulated as glare caused by excessively high luminance may result in less than optimal visual performance due to fatigue and loss of concentration.
For Part 1, what type of lights need to meet these requirements? Do most office lights meet these requirements?
Most light fixtures manufactured for office environments will meet these requirements already, either because they’re shielded adequately and/or because they do not have the high luminance levels that require additional shielding. Shielding is based on the angle from the horizontal plane of the bottom of the actual light source. WELL requires different levels (angles) of shielding depending on the luminance of the light source (cd/m²).
My project team is evaluating our lighting fixtures for glare minimization. How should we be measuring the 53° angle to determine if our fixtures are meeting the requirement?
For Part 2, the angle is measured from the point of view of the seated occupant. In other words, luminaires that are located above 53 degrees, when measured as an angle from a seated occupant's point of view at a workstation, desk or other seating area, must have luminances that are less than 8,000 cd/m².
Note that this does not necessarily preclude a fixture with over 8,000 cd/m² from being used, but strategies may be required to ensure that the surface that is directly emitting light (the bare lamp or the luminaire surface) is not contributing to direct or overhead glare. Project teams can obtain photometric data from the lamp manufacturer to confirm compliance.
Light fixtures in regularly occupied spaces are required to meet the glare control measures prescribed by the feature. Lighting in transient spaces do not need to comply with the feature requirement.
For our Core and Shell development project, we do not plan on providing any lighting at workstations or desks. How should we confirm compliance with this feature?
If the scope of the Core and Shell buildout includes a space that will have workstations or desks, for example a building reception desk, tenant space being fit out by the developer, and/or a building management office, then the light glare control requirements would need to be met for all light within those spaces.
If lighting is not being provided within tenant areas, and no workstations or desks are included within the owner controlled spaces, then this precondition can be considered met by providing documentation confirming that no spaces within the project fall within the scope of the requirement.