Daylight prediction algorithms are empirically developed for three-sided generic atrium types (Saxon 1983 ) under various sky conditions with a series of scale model studies in university sky simulator. Algorithms are developed for the prediction of light levels normal to the vertical wall surfaces at the middle floors of high rise atriums with opaque and transparent roof systems. These algorithms are then compared to the actual measured performance of two buildings for noontime conditions at the equinox periods of the year.

Actual measurements were conducted at two existing buildings in Houston and San Antonio to produce full-scale building tests. In the actual building measurements, horizontal (on floor) and vertical (normal to wal surface) illumination levels were measured. Basically, horizontal light levels were measured on the atrium floor, while illumination levels were measured normal to the vertical wall surfaces as well.

Units: Dual