1994 Volume 78 Issue 10 Pages 516-525
In the CIE TC3-13 meeting in 1993, the unified glare rating (UGR) proposed by K. S φresen was approved for adoption in the TC report. In Japan, the “G-Classification” which classifies luminaires based on the CIE Glare Safeguard System, has been used. Therefore, it is important to clarify the relationship between the “G-Classification” and UGR. This paper analyzes the relationship between them using calculations for nine typical luminaires and establishes that there is a clear relationship between them.
However, UGR has a significant problem. It was developed based not on observations, but on calculations that merely simplify and make more consistent the previous glare evaluation methods. Thus there is no observation data to proveits accuracy. The second part of this paper presents studies done to clarify the relationship between the subjective appraisals of discomfort glare and UGR. Using a full-scale office model where various lighting conditions could be presented, the degree of discomfort glare was evaluated by many observers, and the relationship between the evaluations and the calculated UGR was analyzed. The results show that although there is a certain relationship between them, the degree of discomfort glare obtained by the subjective appraisal is lower than the value calculated for UGR.