How UGR values influence lighting quality and comfort at the workplace

Affected by direct and indirect glare

Direct glare arising from non-glare-free lighting and unobstructed sunlight strain vision and lead to fatigue. As a result, concentration lapses and the risk of making mistakes Increase. For physical work, this leads to increased risk of accidents. For this reason, we must use lights with appropriate glare ratio, install sunshades on windows, and redesign the workspace arrangement appropriately.

Supports UGR-optimised lighting

Indirect lighting, matt fixtures with low light reflection, workspace division adapted to light sources, and the elimination of specular surfaces avoid burdensome reflected glare. Thus, concentration is maintained for longer periods, which leads to higher productivity.

To reduce glare, luminaires with a low glare factor should be used and sun protection measures taken. Indirect lighting and matt surfaces also help to minimize reflected glare.

Panels with UGR <19 at 2H and opal surface

Features

• UGR <19 at 2H:
  These panels still achieve a glare rating of less than 19 when the light source is removed further away from the viewer.
• Opal surface:
  Provides uniform light distribution, but can cause more glare when viewed directly.

Evaluation for open-plan offices

• Advantages:
  Uniform light distribution that provides pleasant illumination for workstations.
• Disadvantages:
  The opal surface can lead to higher glare when viewed directly, which is less ideal for VDU workstations.
• Recommendations:
  These panels are acceptable if the light sources are not directly in the employees' field of vision. For optimum working conditions, the direct view of the light-emitting surface should be minimized.

Evaluation for classrooms

• Advantages:
  Uniform light distribution, good for general illumination of the room and visibility on blackboards and work materials.
• Disadvantages:
  Can cause more glare when viewed directly, but less critical than for VDU workstations.
• Recommendations:
  These panels are well suited for classrooms as the even light distribution is important for visibility in the entire room. Direct glare can be minimized by placing the light sources outside the students' direct field of vision.

Panels with UGR <19 at 8H and prismatic surface

Properties

• UGR <19 at 8H:
  These panels also achieve a glare rating below 19 when the light source is positioned closer to the observer.
• Prismatic surface:
  Reduces glare when viewed directly and provides better light distribution.

Evaluation for open-plan offices

• Advantages:
  Reduced glare when viewed directly, which improves visual comfort at VDU workstations.
• Disadvantages:
  No significant disadvantages, particularly when direct glare needs to be avoided.
• Recommendations:
  These panels are ideal for open plan offices with VDU workstations as they increase visual comfort and reduce eye strain from glare.

Evaluation for classrooms

• Advantages:
  Reduced glare when viewed directly, improving concentration and visual comfort for students.
• Disadvantages:
  No significant disadvantages.
• Recommendations:
  These panels are also very suitable for classrooms as they improve visual comfort and reduce direct glare, making for a pleasant learning environment.

Summary and recommendation:

For open-plan offices

Prismatic panels with UGR <19 at 8H are the better choice as they minimize glare when viewed directly, significantly improving visual comfort for VDU workstations.

For classrooms

Prismatic panels with UGR <19 at 8H are preferable as they improve visual comfort and reduce glare, creating a pleasant learning environment.
Opal panels with UGR <19 at 2H are also suitable, particularly if the light sources can be placed outside the students' direct field of vision.

The UGR value takes into account both direct and indirect glare from light sources and reflective surfaces, enabling a comprehensive assessment of the quality of light at the workplace. The EN 12464 standard defines specific UGR limit values for different working environments, such as technical drawings (≤16) or working at a PC (≤19).