In addition to the aesthetic requirements, planners of lighting systems must above all deal with the normative requirements for indoor and outdoor areas.
For outdoor areas in Europe this is often the EN-12464-2 "Light and lighting - Lighting of workplaces - Part 2: Outdoor workplaces" and the underlying CIE150. Together with the desired lighting requirements, it also describes those components of light that should be avoided as far as possible in order to prevent errors or even accidents, such as glare and disturbing light.
Unlike to the desired lighting with its minimum target values, glare and obtrusive lighting has to deal with absolute limits. A well-known glare limit value is the Rg value (formerly GR value).
In future there will be, next to the Rg value, the glare value ks. It takes not only the light intensity, but also the size of the visible glare source and the distance.
Other values to be complied with in accordance with CIE 150/EN 12464-2 are
Ev vertical illuminance at the point of immission
I luminous intensity at the point of immission
Lb,Ls mean luminance on façades and signs
Rul/Ulr upward light ratio
Rulo/Ulor upward light output ratio
Rdlo/Dlor downward light output ratio
Ruf upward flux ratio( luminous flux reflected from the surroundings into the sky in relation to the ideally utilized luminous flux on the surface to be illuminated)
The limit values depend on the ambient zone of our lighting system, from rather dark areas (ambient zone E1) to areas with high brightness (ambient zone E4). A further ambient zone E0 for particularly sensitive areas, as already described in CIE150, is also planned for the forthcoming new version of the EN 12464-2.
To minimize the negative effects of lighting on people and the environment, these limit values should be observed in outdoor areas.
Your opinion on this topic is important to us. What do you think about outdoor lighting, glare and obtrusive light? What values are you planning with, how close are you to the standards?