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Glare in sports lighting: how can it be reduced?
Achieving 300, 500 or 750 lux is not enough to guarantee good sports lighting. A player must be able to follow a ball, shuttlecock or other moving object without being disturbed by a light source that is too prominent in their field of vision.
Glare control begins with the geometry of the project: height, layout, optics, aiming and luminaire positions in relation to lines of sight.
Understanding the phenomenon
Why can you have enough lux and still have poor lighting?
Glare occurs when a light source becomes excessively prominent in the field of vision compared with its surroundings.
In sport, this issue is particularly important: the player's gaze is not fixed. Athletes follow a trajectory, an opponent or an area of play and may therefore regularly look close to a luminaire.
Two installations producing exactly the same average lux level can therefore provide very different visual conditions.
Discomfort glare
The light source causes visual discomfort or an unpleasant sensation, even though the player remains able to distinguish their surroundings.
Disability glare
The presence of the light source actually reduces the ability to correctly perceive an object, a player or a trajectory.
Outdoor installations
GR – Glare Rating
For sports installations and large outdoor areas, GR – Glare Rating is an indicator used to assess glare from defined observer positions and viewing directions.
The result depends in particular on the photometric characteristics of the luminaires, their aiming, their number, their layout, their height and the luminance of the illuminated area.
GR is not a single value associated with a floodlight. It depends on the complete configuration of the installation and the observer position being analysed.
An important limitation
When the player looks directly towards a light source
The CIE GR system is designed for viewing directions below eye level. It assumes, in particular, that direct viewing of a floodlight is limited through appropriate positioning.
This limitation becomes particularly important for sports where players regularly look upwards: badminton, volleyball, tennis or padel, for example.
Designing for visual comfort
6 ways to reduce glare
Glare should be addressed from the layout stage. It is rarely corrected effectively by changing only one parameter.
Optimise mounting height
An appropriate height can reduce the presence of light sources in certain lines of sight and help distribute the light more progressively.
Height should always be considered together with optics and layout.Choose the right optics
A suitable light distribution directs the luminous flux towards the required area without excessively tilting the luminaire.
The right optics → more favourable aiming.Review the layout
When an area lacks light, moving or adding a lighting point may be preferable to significantly increasing the aiming angle or power.
Position before power.Limit steep aiming angles
The more a light source is aimed towards the playing area, the more its luminous surface may become visible from certain positions.
Height + setback + optics should be considered together.Control spill light
Depending on the site, shields, louvres or other cut-off devices can limit unwanted light in certain directions.
These accessories must be included in the photometric calculation.Consider the visual background
A light source may appear more aggressive when viewed against a very dark night-time environment.
Contrast is part of the problem.Two different contexts
Indoor and outdoor glare
Sports halls and indoor sports facilities
- clear height of the hall
- luminaire positions within the roof structure
- high trajectories of balls and shuttlecocks
- multiple light sources across the ceiling
- reflections from walls, glazing or floors
- several sports within the same playing area
Pitches and large areas
- pole height and setback
- high-power floodlights
- large aiming angles
- very dark night-time background
- multiple observer positions
- GR and spill light
Trajectories and lines of sight
Some sports are particularly sensitive to glare
The shuttlecock frequently travels very high. The position of the luminaires in relation to its trajectory is therefore particularly important.
Players regularly look towards the ceiling, particularly when serving, setting or blocking.
Serves, lobs and high balls can bring the player's line of sight directly close to the light sources.
Long viewing distances and pole-mounted floodlights require analysis of observer positions and viewing directions.
Two issues that should be distinguished
Glare and spill light are not the same thing
A floodlight can be correctly positioned from a player's point of view while still sending too much light towards neighbouring properties.
Conversely, an installation may perfectly control light outside the playing area while still causing discomfort for players.
- light source positions
- viewing directions
- GR where applicable
- trajectories
- visible luminance
- light outside the playing area
- neighbouring properties
- upward light
- optics and cut-off devices
- operating hours
STADÉLUM method
Glare should influence the study from the outset
A good study does not simply involve calculating GR once the layout has been finalised. Visual comfort should help shape the solution from the beginning.
Dimensions, height, poles, roof structure, surroundings and existing layouts.
Player positions, typical viewing directions and characteristic trajectories.
Adapt the light distribution to the geometry of the playing area before selecting the power.
Determine the number, height and position of the luminaires.
Average lux, uniformity and GR where the method is relevant.
On-site aiming should remain consistent with the settings used in the study.
After the study
Poor aiming can compromise a good calculation
Floodlight aiming is an integral part of the photometric result.
Changing the angles on site to gain a few extra lux can create hot spots, reduce uniformity, increase glare or send more light outside the playing area.
FAQ
Frequently asked questions about glare in sports lighting
What is GR in sports lighting?
GR, or Glare Rating, is an indicator used to assess glare in sports installations and large outdoor areas from defined observer positions and viewing directions.
Does a more powerful floodlight cause more glare?
Not necessarily. The floodlight's photometric characteristics, position, height, aiming and contrast with the surrounding environment also play a decisive role.
Should power be reduced to limit glare?
Not necessarily. Different optics, a different mounting height or a more suitable layout may make it possible to maintain the required lighting level while improving visual comfort.
Can colour temperature eliminate glare?
No. It can influence the perception of the environment, but it does not replace work on geometry, apparent luminance, optics and the aiming of the light sources.
Are GR and UGR the same thing?
No. GR is used in particular for sports installations and large outdoor areas. UGR is a different method of assessing glare, commonly used for certain indoor environments.
Does a photometric study guarantee that no player will ever experience glare?
It helps optimise the installation and assess calculable criteria. Situations where a player looks directly at a light source also require analysis of positions, trajectories and viewing directions.
Learn more
Understand the other criteria involved in sports lighting
YOUR PROJECT STUDY
Good lighting should perform without causing discomfort
Before defining the number or power of the floodlights, STADÉLUM analyses the site configuration: heights, layouts, lux, uniformity, lines of sight, optics and glare.
Request a sports lighting studyThis page is intended for educational purposes. The applicable limit values and methods should be checked against EN 12193, CIE publications and, where applicable, the regulations or specifications relating to the relevant sport and level of competition.