The need for a unified approach to interior lighting design parameters

Abstract

The single most used lighting design parameter today is the average illuminance on the horizontal working plane. A number of attempts to introduce other lighting parameters into the design procedure have been made from time to time, but with little success. In most designs only the average illuminance on the horizontal working plane is considered. In a small percentage of designs glare index is also taken into account. Designs to a higher technical specification are rare. This paper investigates why this situation exists and what can be done about it. Considerable thought has been given to what parameters are useful for specifying known requirements, but insufficient thought has, in the Authors' opinion, been given to the problems of understanding what a parameter means, its prediction and its measurement. Any designer who tries to satisfy all of the requirements of the 1977 IES (CIBS) Interior Lighting Code will find that the methods available for doing so are fragmented, confusing and often unpractical. This paper argues the need for a systematic or unified approach to lighting design parameters, and suggests some improvements which could be made to encourage a more cohesive system.