ASSESSING THE STRENGTH OF SOME KEY NUMERIC METRICS USED FOR GLARE EVALUATIONS IN DAYLIGHTING

Abstract

Both natural and artificial lightings can cause glare in poorly-lit indoor spaces. Many metrics have been developed to solve glare from artificial lighting. Until recently, many scholars have used artificial lighting indices to evaluate glare from natural lighting. Recently, some numeric metrics have been developed for predicting discomfort from glare as a result of daylighting. The two most used indices are Daylight Glare Index (DGI) and Daylight Glare Probability (DGP). Each of the two has it strengths and weaknesses. This research set out to assess the two metrics. Rubrics for the assessment were developed using criteria like relevance, accuracy, interpretability, robustness, Contextual Validity and practicability. The outcomes from the evaluations show that DGI scored 15 out of 24 while DGP got 18 out of 24. This result indicates that Daylight Glare probability metric performed better than Daylight Glare index. Despite the good performance, DGP has its weaknesses as it requires large amount of computational resources for the evaluations.