Relative brightness of facades in the L-shaped urban buildings

Abstract

Day lighting of premises under conditions of compacted urban development is depended of brightness of the finishing material of the facades of buildings of the surrounding buildings. Measure of influence of opposing buildings on the light regime of the premises is determined by relative brightness coefficient of facade, which is the ratio of the brightness of the facade to the average brightness of the sky. Derivation of the formula for coefficient of relative brightness of the facade in L-shaped urban buildings is presented. The derivation of the formula is based on the some components. The first component is the light transmission rate component on the facade of the designed building, which takes into account the reflection of daylight from an area of the earth’s surface. The second component is a coefficient, which takes into account the increase in the light transmission rate component on the facade of the projected building. This is due to the exchange of reflected light fluxes between the facades of the buildings and the land surface, which is adjoined to the buildings. Relative brightness coefficient values are calculated depending on the building geometry and the reflective properties of the facade finishing material.