Classification of environmental zones in the Czech Republic

Abstract

Nowadays obtrusive light is discussed quite often and so this term has become well-known not only to professionals in the field of lighting but also to the public, designers and administrators. Quantification of obtrusive light depends on many factors. The biggest factor is the amount of the luminous flux directly emitted into the upper hemisphere. Other factors include the reflection qualities of illuminated surfaces and finally conditions in the atmosphere. Based on knowledge of the amount of luminous flux directly emitted into the upper hemisphere, depending on the surroundings (size of the agglomeration, protected landscape areas – national preserves, observatory, etc.), we can classify obtrusive light into several classes according to the standards EN 12464-2 and EN 12 193. These standards use only four environmental zones. For any outdoor lighting system it is possible to calculate the amount of luminous flux emitted into the upper hemisphere and determine if this potential source of obtrusive light is appropriate for the environmental zone. These calculations can also show if the lighting system is a significant contributor to the amount of obtrusive light. This paper tries to describe problems over larger areas where different environmental zones can exist side by side. Adjacent environmental zones should not differ by more than one level (for example E1 to E2 only). The aim of this paper is to establish methodologies for classifying environmental zones. A specific example of classification relates to a 420 kV outdoor electricity distribution substation, which is located in a selected area of the Czech Republic.