Ability of daylight Indicators in estimating adequate lighting in space based on user assessments Case study: Architecture design studios in Tehran

Presence of adequate amount of light with an appropriate uniformity, results in a good environment visibility avoiding eye fatigue caused by frequent eye adaptations from over-lit to under-lit areas. With the help of simulation tools and lighting indices that are achieved from experts’ field studies, it is now feasible to estimate lighting quality for a whole year and assess occupants’ visual comfort. However, further studies are needed to ensure that these analyses lead to visually comfortable environments from the perspective of building occupants.This article aims at rating the daylight metrics in terms of their predictive ability and also determining the most accurate metric by comparing the outcomes of indicators recommended for measuring quantity of light with occupant subjective responses. To achieve this, the daylit area predicted by E, DF, UDI and sDA were compared to daylit area drawings prepared in the twenty design studios by 386 architecture students in Tehran. The results show that students consider 125 lux as a threshold between non daylit and partially daylit areas, and 350 lux for differentiating partially and fully daylit areas. Among static metrics, DF>2% performed better than horizontal illuminance (E). With regard to CBDM metrics, sDA150lux,50% and sDA 300lx,50% correctly determined partially and fully daylit areas in the studied spaces except for bright, fully daylit ones.