Measurements and Comparisons of Sunlighted and North-Lighted Atriums on Two Office Buildings in Dallas, Texas

Abstract

The use of natural light (daylighting) in the atriums of office buildings is often done to supplement or eliminate the artificial lighting otherwise required. To the extent that the daylight can be effectively admitted and then distributed, the dependence on artificial light is reduced, and energy is conserved. This study involves two major Dallas Texas office buildings: Dallas City Hall (I. M. Pei and Partners) and Diamond Shamrock Corp. (Harwood K. Smith and Partners), both with linear type atriums. The fenestration type used at City Hall is a north-facing barrel vault system for indirect light, while Diamond Shamrock uses a north-south pyramidal system which permits direct solar gain. This paper compares the illumination levels of these two systems and the relative merits of each, as well as indicating the effectiveness of daylight distribution in both buildings. Also included in this study are data indicating some brightness ratios for each building and subjective responses to an informal survey.