A Systematic Procedure for Calculating the Average Illuminance on a Work Plane from Skylights Located in a Pitched Roof.

Abstract : A systematic design procedure has been developed to calculate the average horizontal illuminance upon a work plane due to skylights in a pitched roof. The calculation procedure allows for pitched roofs with slopes up to 30 degrees from horizontal, and for both clear and overcast sky conditions. The procedure is divided into two basic steps: (1) the calculation of total external daylight illuminance upon the sloped skylight surface, and (2) the calculation of average horizontal illuminances upon an interior workplane due to the sloped skylights. Worksheets are used to systemically step through the procedures. All necessary tables and equations are included. (Author)