DAYLIGHT DESIGN RULES OF THUMB

This paper discusses the history and simulation studies conducted to validate simplified daylighting principles or rules of thumb for building. The rules of thumb are gathered from architecture and lighting literatures as well as architectural practices. Incorporated in these day lighting rules are room parameters (such as room depths, floor area, window head heights and widths) related to effective unilateral daylighting. The rules of thumb are tested for a single location (35oS 150oE) close to Sydney, Australia under Standard CIE Overcast and Clear Skies by means of lighting simulations software Lumen Micro 8, which has a limited verification tolerance of ± 8%. The simulation studies indicate that under a strict set of criteria the rules of thumb based upon the ratios of window area to floor area and room depth to window head height for task plane illuminance and daylight factor to be valid. The validation process also contributes to a number of new rules associating average illuminance with window to floor area ratio and a modification to an existing daylighting formula proposed by Littlefair (Littlefair, 1996).