Field measurement of illuminance

Abstract

A variety of methods have been developed for field measurement of working plane illuminance from interior artificial lighting. The methods recommended by the various national lighting bodies are generally similar to, or derivatives of, the methods set out in the CIBSE Code for Interior Lighting, IES Lighting Handbook or DIN Standard. All the methods require measurement of illuminance at points on a grid at working-plane height, but the grid size and position of the measuring points differ. The IES method, and its derivatives, position the grid relative to the luminaire locations; the CIBSE and DIN methods use a grid which is a function of room size. The techniques of analysis of the field measurement results also differ. This paper reports the results of a series of comparative field measurements taken in typical installations according to the recommendations of the various lighting codes. Modifications to the CIBSE method are suggested.