DISTRIBUTION OF REFLECTANCE ON WALLS AND CEILINGS AND THEIR INFLUENCE ON LIGHTING PARAMETERS (PP21, 611-621)

The paper deals with reflectances of main surfaces in interiors and their influence on lighting parameters. Reflectance of various common furniture finishes and paints has been measured. Focus of the paper is in distribution of reflectances on walls and how this distribution affects the calculated lighting parameters. While ceiling has usually quite uniform reflectance and impact of floor is almost neglectable, walls are the critical surfaces for lighting calculations. In many common rooms in administrative, educational and similar buildings, walls can be free of objects, or fully or partly obstructed by furniture. Experience with lighting designs showed that it is practical to divide the walls to three zones, each with its own reflectance. This approach keeps the lighting design and calculation still simple enough but it can bring better precision of resulting lighting parameters, assuming to gain higher illuminance under certain conditions. Model calculations with different set-ups and the benefit from the proposed zoning of walls is presented in this paper.