Lighting Properties of Surrounding Development When Calculating the Natural Illumination in Premises of Embedded Buildings with Natural Upper Lighting System
Issues of the definition of lighting effect level of the surrounding development on the levels of natural lightning in below-ground premises of civil buildings, when the upper natural lighting systems are used in them, are highlighted. The character of this effect, which can be either reflecting or shadowing due to different sky conditions, different faзade finishing, different geometric parameters both of premises and surrounding buildings are defined. Due to the shortage of urban territories, the considered problem is very urgent in connection with constant increase in development of underground spaces in large cities (trade centers, underground parking etc.). At that, acting normative documents do not consider the influence of the surrounding development on the levels of natural illumination in these buildings. This seriously influences on the assessment of the light environment in premises, on the calculation and design of illumination. The authors put forward a scientific hypothesis according to which and on the basis of universality of the distribution of natural lighting at the standard diffusion illumination from the completely cloudy sky, the coefficient of natural illumination in the premise can be defined using the formulas which also have the universal character regardless of the system of natural illumination. In this regard, some principles of a daylight factor calculation in the case of a side natural illumination are suggested to use in calculations for upper natural illumination, with due regard for the lighting effect on the surrounding development for example. It is noted that subjects of further scientific research will be the assessment of economic efficiency of above-mentioned suggestions and the lighting effect of the surrounding development under conditions of the clear sky.