Determining the required proportions of light-wells in residential buildings based on the Code Four of the National Building Regulations of Iran

The proportions of light-wells that are specified in the Code four of the National Building Regulations of Iran are determined only for one-floor to four-floor buildings. These proportions are based on land area and number of floors. Furthermore, the determination of the proportions of buildings with more than four floors up to 23 meters is dedicated to the decision of the architectural designer. The purpose of this study is to determine the light-well's proportion for a five-floor residential building so as to have the required lighting in close spaces next to the light-wells. First, the performance of the given proportions in the Code Four for four-floor buildings was studied. Second, various proportions of light-well were examined for a four-floor and a five-floor building. In every stage, the results were compared with the standards of lighting. The lighting process was carried out by using Grasshopper, Honeybee, and Ladybug plugins. These plugins use Radiance and Daysim engines for calculation. Also, this study was carried out using the Spatial Daylight Autonomy and under real sky conditions. The results show that the given proportion in Code Four does not meet the lighting's requirement. The required proportion of the light-well for a four-floor building is 5.5 × 6.5 m. Besides, the required proportion of the light-well for a five-floor building is 6 × 7 m.