The Development of the IES Glare Index System: Contributed by the Luminance Study Panel of the IES Technical Committee

The Luminance Study Panel was set up by the Technical Committee at the end of 1958 to study ways and means of introducing luminance concepts into the forthcoming revision of the IES Code. This report of the Panel describes the basis of the acceptance of the BRS glare formula, together with some amendments to the glare criterion scales. Details are given of the work of Glare Index calculation using a digital computer, the adoption of the British Zonal Classification for fittings, the evaluation of background luminance, together with the conception of conversion terms for downward flux, luminous areas and height of fittings. Full details are given of the numerous field surveys undertaken, leading to the construction of the Glare Index tables and the setting of the closed system of limiting Glare Indices.