Basic principles
What is the EN 12464-1 norm?

The EN 12464-1 norm contains guidelines for the visual comfort of light in workplaces. In addition to a minimum illuminance (expressed in Lux) and a minimum colour rendering index (expressed in Ra), the maximum glare rating is given an important place in the standard (expressed in UGR from 10 to 28).

What is the difference between Lux and Lumen?

Lux and lumen are both units related to the intensity of light. Lux is the amount of light that you experience in a particular place, while Lumen refers to the total amount of light that a particular light source emits. The European Union has set minimum standards for lux values in various interior lighting environments:
  • Offices, meeting rooms and lecture hall | Lux > 500
  • Practice rooms and drawing rooms | Lux > 750
  • Reception area, classrooms and sport centers | Lux > 300
  • Canteens and archives | Lux > 200
  • Corridors, toilets, stairs, storage rooms and elevators | Lux > 100

What is the CRI or color rendering index?
The CRI or Coloring Rendering Index is an index that shows how well a light source is able to faithfully reproduce the colors of illuminated objects. A high value stands for better color rendering. A lamp with a low value (<70) will cause the visible colour to deviate from the natural colour. A lamp with a value of 100 will reproduce the colors as in daylight.

What is UGR?
UGR or Unified Glare Rating is a rating that indicates the degree of glare. It is an internationally unified index, developed by the CIE (Commission Internationale de l'Éclairage), for evaluating direct glare according to the position of the luminaires, the characteristics of the room and the observation position of the users. The lower the value, the less light interference a person will experience.
Applying the right lighting, with a sufficiently low UGR value, is essential because it has a major impact on people's productivity and performance. The light must be bright enough to be able to carry out work properly, but must not cause glare or blinding. A precise UGR level is calculated for a specific position of the observer in a specific room. For the sake of convenience, lighting manufacturers calculate the UGR value for each individual luminaire based on a reference room with an average reflectance value of the ceiling (0.70), walls (0.50) and floor (0.20). In this way, you quickly gain a good insight into whether certain luminaires are suitable for a specific application.
The EN 12464-1 standard specifies what the maximum UGR value may be for various types of rooms:
  • Offices, meeting rooms and classrooms | UGR ≤ 19
  • Spaces where detailed work is carried out (e.g. operating theatre, drawing office) | UGR ≤ 16
  • Reception rooms | UGR ≤ 22
  • Storage rooms, stairs and elevators | UGR ≤ 25
  • Corridors | UGR ≤ 28

What is the color temperature of a lamp?
Color temperature refers to the color a light source emits and is measured in degrees Kelvin (K). The lower the color temperature, the "warmer" the light is perceived to be. The higher the color temperature, the higher the degrees Kelvin and the bluer or "colder" the color is. Light sources with a (relatively) low temperature have a redder color. For places where lots and lots of bright light is needed, it's best to choose lamps with a high color temperature. After all, if you have to perform functional tasks, your concentration is optimal at color temperatures around daylight. For places where coziness is paramount, a low color temperature gives the best results. It is softer on the eyes and has a calming effect.

  • Candlelight | 1200 K
  • Incandescent, sunrise and sunset | 2700 K
  • Modern warm white, ideal in offices and showrooms | 3000 K
  • Natural white, ideal in warehouses, workshops and sports halls | 4000 K
  • Standard daylight | 5600 K

What is the SDCM of a lamp?
SDCM stands for "Standard Deviation of Color Matching." It illustrates the deviation in color quality/temperature. A high SDCM (>3) can result in luminaires with the same color temperature, yet perceived differently. This deviation is required to be displayed in the EU and is indicated in 1-, 2-, 3- or >4 SDCM. When the SDCM is between 0 and 3, the color difference will not be noticed. A higher color difference may be perceived as annoying. We therefore recommend that only fixtures with an SDCM of up to 3 be used in indoor environments.

What is the IP value of a luminaire?
The IP value or Ingress Protection indicates the extent to which electrical devices are protected against external conditions and/or objects. The first digit indicates the extent to which the electronics are protected against the penetration of materials, objects and dust. The second digit indicates the degree to which the electronics are protected against moisture. Moisture resistance tests are usually performed with regular tap water. Seawater or pool water are often not covered by the warranty because of this, unless otherwise stated.
The first digit indicates the extent to which the fixture is protected against the ingress of objects and/or dust:
0 - not protected
1 - protected against ingress of solid objects larger than 50 mm
2 - protected against ingress of solid objects larger than 12 mm
3 - protected against the penetration of solid objects larger than 2.5 mm
4 - protected against the penetration of solid objects larger than 1 mm
5 - protected against objects, closed armature, sufficiently protected against dust
6 - protected from objects, closed armature, well protected from dust
The second digit indicates the extent to which the fixture is protected from moisture ingress:
0 - not protected
1 - protected against dripping water
2 - protected against dripping water, up to a maximum angle of 15 degrees.
3 - protected against spraying water (10 l/min), angle of -60° - 60°
4 - protected against spraying water (10 l/min)
5 - protected against spraying water (12.5 l/min)
6 - water resistant (100 l/min)
7 - protected against immersion (max. 1m deep, max. 30 min.)
8 - suitable for permanent submersion (pressure watertight)
9 - water resistant when sprayed under high pressure or humidity degree of >90%
What is a "flicker-free" driver?
Modern light fixtures flicker quite often, even though we don't always see it with the naked eye. Try holding a camera, from your phone for example, pointed at an LED lamp. In many cases, the image will then flicker slightly.
That flicker is simply explained by the constant fluctuations of the power grid. Drivers with a single circuit do not fully succeed in filtering out this fluctuation. A so-called flicker-free driver, which contains a dual circuit, is a bit more expensive to buy, but provides many advantages.
After all, the invisible flicker adversely affects our health and general comfort. In spaces where people spend several hours a day, such as in offices, hospitals or classrooms, flickering and dazzling lighting is pernicious. It significantly reduces concentration levels and working comfort. Moreover, prolonged exposure to imperceptible flicker can lead to headaches, fatigue, visual impairment or even seizures. Flicker-free ballasts are also essential for good camera work in areas where photographs are often taken, such as banquet halls.

What is lighting uniformity?

Illumination uniformity is defined as the ratio between minimum and average lux, or minimum to maximum lux. Lux, as you already know, is the unit of illuminance, which indicates the actual brightness received on the ground. High uniformity is valuable, as research shows that it improves the visibility of workers or road users at night. This can be an important parameter, especially in areas where people work at night.

Lighting uniformity standards:

  • Airport | 0.2 - 0.3
  • Seaport | 0.3 - 0.4
  • Warehouse, offices | 0.4 - 0.6
  • Highway, parking lot | 0.4 - 0.6