Evaluation of assumptions in building-energy standards: A method for assessing the lighting provision

Building-energy standards and guidelines have been instrumental in raising awareness of energy and environmental concerns within architectural practice. As energy and environmental concerns take hold as an important consideration in the practice of architecture, the provisions that define building-energy standards and guidelines are having greater impacts on the methods and approaches adopted by the profession to address issues of energy and environment. But some of the provisions in current building-energy standards are founded on potentially outdated methods and assumptions that were initially developed and adopted in urgent response to the energy crisis of the 1970's.; This thesis evaluates the method and assumption in one provision---the lighting energy provision---in a widely adopted building-energy standard developed by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard (ASHRAE). The lighting energy provision in the ASHRAE Standard is founded on the zonal cavity method (ZCM), a simplified lighting calculation method developed initially in 1916 to evaluate light levels in a space. But a fundamental assumption of the ZCM---that light is uniformly distributed on an imaginary horizontal plane that extends across the entire extent of the evaluated space---is at odds with the goal of reducing lighting energy use; a single uniform illuminance level at task light levels would require excessive energy use, or a single uniform illuminance level at general light levels may be inadequate for the intended task. Despite the incorporation of a fix to address this fundamental limitation, the method used to develop the lighting energy provisions still does not effectively assess non-uniform light distribution on lighting energy and quality in a space.; This thesis revisits, via computer simulation, the original 1916 experiment that established the ZCM, and presents an experiment and evaluation method that directly assesses the fundamental assumption in the ZCM of uniform light distribution. The evaluation method presented in this thesis expands the assessment criteria of the ZCM so that the method is capable of assessing the effects of non-uniform light distribution on both light levels and overall lighting quality. The evaluation demonstrates the potential of non-uniform light distribution for substantial reductions in lighting energy use.