Glare Control Explained: Why Glare-Free Light Matters
What Does Glare Control Mean?
Glare control refers to all structural and optical measures in a luminaire that ensure light is emitted into the room free of glare or with minimal glare. The aim is to prevent direct sight of the light source or to shield it sufficiently so that no disturbing glare occurs. Glare control is a key quality feature of premium luminaires – particularly at workstations, in screen-based environments and wherever visual comfort is important.
How Is Glare Prevented?
Luminaire manufacturers employ various techniques for glare control:
- Deep-Set Reflectors: The luminaire body is designed so that the light source sits deep within the housing and is only visible at a defined angle. Typical for downlights and recessed luminaires.
- Louvre Grilles and Baffles: Honeycomb louvres or blade louvres direct the light downward and shield it laterally. Frequently used in office and workplace luminaires.
- Diffuse Covers: Opal or satin-finished glass and plastic elements scatter the light and reduce point-source brightness. The light source is not directly visible.
- Lenses and Optics: Precision lenses focus or distribute the light so that the beam angle is controlled and glare is minimised.
- Setback (Recessed Positioning): The light source is positioned well back within the luminaire housing. The deeper the light source is set, the lower the glare effect from lateral viewing angles.
What Is the UGR Value?
The UGR value (Unified Glare Rating) is an internationally standardised measure of the psychological glare caused by a lighting installation as perceived by the observer. The scale ranges from 10 (no perceptible glare) to 30 (severe glare) and is given in increments of three: 10, 13, 16, 19, 22, 25, 28.
The UGR value does not describe the glare from a single luminaire but assesses the entire lighting situation in a room – including the arrangement of luminaires, the room geometry and the reflective properties of the ceiling, walls and floor. This means the same luminaire can produce different UGR values depending on the installation situation.
What UGR Limits Apply?
The European standard DIN EN 12464-1 (Lighting of Indoor Workplaces) defines maximum UGR values for various activities:
- UGR 16: Technical drawing, quality control, precision mechanical work – tasks with high visual performance requirements.
- UGR 19: Office work, screen-based workstations, reading, classrooms, reception areas – the most commonly required limit in practice.
- UGR 22: Industrial manufacturing, workshops, kitchens, retail spaces – moderate glare control requirements.
- UGR 25: Warehouses, stairwells, corridors – low visual demands, short periods of occupancy.
- UGR 28: Circulation areas, passageways – minimal requirements.
How Is the UGR Value Determined?
Luminaire manufacturers provide UGR table data in their datasheets. These show the expected UGR value for standardised room sizes and reflectance values. The calculation takes into account the luminance of the luminaire, the solid angle, the position of the luminaire within the observer's field of view and the background luminance in the room.
For reliable UGR calculations in practice, lighting design software such as DIALux or Relux is used. These programs simulate the specific installation situation and deliver room-specific UGR values.
UGR < 19 – What Should You Look Out For?
The specification "UGR < 19" on a luminaire datasheet means that the luminaire achieves a UGR value below 19 under defined standard conditions. In the actual installation, however, the value may differ – higher or lower – depending on room size, ceiling height, wall colours and luminaire spacing. Professional lighting design ensures that UGR requirements are also met in the specific room.
Where Is Glare Control Particularly Important?
- Offices and Screen-Based Workstations: Glare on the screen leads to visual fatigue and loss of concentration.
- Classrooms and Lecture Halls: Effective glare control improves concentration and reading ability.
- Retail Lighting: Accent light on merchandise must be sufficiently shielded so that customers are not dazzled.
- Residential Spaces: Even in the home, well-considered glare control significantly enhances visual comfort – for example with pendant luminaires above the dining table.
Frequently Asked Questions (FAQ)
What does "glare-controlled" mean for luminaires?
A glare-controlled luminaire is designed so that the light source is not directly visible or the glare effect is reduced to a minimum – for example through reflectors, louvre grilles or diffusers.
What is a good UGR value?
For offices and screen-based workstations, a maximum UGR value of 19 is the standard (DIN EN 12464-1). Values below 16 are considered very well shielded and are suitable for demanding visual tasks. Important: the UGR value always relates to the overall room situation, not to a single luminaire viewed in isolation.
Why is the UGR value particularly relevant for LED luminaires?
LED light sources have a very high luminance concentrated on a small surface area – significantly higher than fluorescent tubes, for example. This point-source brightness can cause greater glare, even when the total luminous flux is lower. This is why targeted glare control measures are especially important for LED luminaires, and the UGR value is a decisive selection criterion.
Are all LED luminaires glare-free?
No. By their nature, LEDs are point light sources with high luminance and can cause significant glare. Premium luminaires compensate for this through targeted glare control measures such as reflectors, lenses or diffusers.
In Summary:
Glare control is an essential factor for visual comfort and light quality. Well-shielded luminaires protect the eyes, reduce fatigue and create a pleasant lighting atmosphere. At Leuchtenland.com you will find glare control and UGR information in the product details to help you select the right luminaire.