Chapter 14. LIGHT POLLUTION
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• Permanent illuminations with low brightness during all night. are equally acceptable. In the case of a porch in a house, a compact fluorescent lamp of 9 W. (600 lm.) is adequate for most cases. - For motor traffic lighting, flux emitted above the horizontal plane must be reduced and close light must be restricted.
14.12. Apendix: "Recommended orientative values for limiting bothering light coming from exterior lighting installations" Division 5 of the C.I.E. elaborated a roughdraft of a technical report "Guide on the limitation of the effects of bothering light coming from exterior lighting installations" through its Technical Committee TC 5-12, at the end of 1995 . Given its empirical nature and subject to modifications resulting from observing parameters included in the mentioned Guide, the most adequate attitude seems to be including such parameters as a way of orientation and not as obligatory values to be applied. This way, their incorporation has been performed by means of limitation charts like an appendix and not as part of the present chapter. The intention being that consignated valued will be compared with our own experience in our country. Five types of specific effects produced by bothering lighting coming from exterior lighting installations may be considered. These are the following: Effects on astronomical observations Lighting engineering parameters implied are: - Night- time lighting of the sky by dispersion of light coming from exterior lighting installations (night- time luminous glow). It depends on the (FHSinst) installed upper hemisphere flux as well as on the reflected flux. - Spectral characteristics of night- time luminous glow. It is equivalent to speaking about wavelengths coming from luminous emissions (types of lamps). - Direct light on the astronomical observatory itself. Effects on residents Lighting engineering parameters to be considered are the following: - Vertical illuminance (EV) on face surfaces, for example, bedroom windows. -Luminance (L) of luminaires, given the fact that their direct vision may be disturbing. Due to the difficulty in predetermining such luminance, this parameter is substituted by luminous intensity (Ι) of the source of light in the potential direction of the bothering source of light. Effects on citizens Lighting engineering parameters to bear in mind when talking about the effects of lighting on citizens in general (passers-by, tourists, etc.) are the following: - Average luminance (Lm) of surfaces of vertical faces in edifices. Sometimes, as a consequence of excessive lighting, they may be bothering instead of highlighting decorative or ornamental aspects. Effects on users of transportation systems Significative lighting engineering parameters are the following: - Increase of threshold contrast (TI) which expresses limitation of disturbing glare in the lighting of motor roads. This also constitutes the measurement through which a loss of sight caused by such glare is quantified. - Visual caos originated by signalling observation against bright backgrounds produced by intense luminous sources. Effects on transportation signalling systems Significative lighting engineering parameters are the following: - Disturbing glare represented by an increase in the threshold area (ΤΙ), defined as the amount of extra contrast, with regards to the original contrast, necessary to see the object again when there is glare. - In case transportation systems work near lighting installations, as in the case of maritime transport, aviation, etc., relevant authorities will establish adequate norms. According to the classification of zones established in Chart 1, recommendations as a way of orientation for limiting bothering or discomforting light coming from exterior lighting installations, are expressed as maximum values in the following chart:
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LIGHTING ENGINEERING 2002