Enhancing visual comfort in staircases: A comprehensive analysis and design recommendations

People should be walking towards the inside of the dwelling through an appropriate visual environment in transitional space; this environment is the staircase in the collective housing. The proper understanding of visual adaptation parameters in the staircase helps architects provide a suitable environment for inhabitants. This paper aims to specify design elements of the staircase in collective housing, to achieve a visual comfort in this transitional space. The work involved two approaches: field measurements and a visual comfort survey using a questionnaire; 144 questionnaires are collected, in four residential buildings with different staircases treatment in the city of Arris, Algeria, to examine the illuminance levels in different staircase positions along the path from outside the building to inside, in summer and winter where illuminance ratios were calculated and compared with CIBSE Code. The discomfort sensations ranged from "subtle” to "dramatic”. The results show that a staircase with the percentage of opening of 88% indicated "strong" and "dramatic" visual shock in many points and as this staircase is open, it is exposed to light conditions and so it does not ensure the necessary transition. This leads to advising against the open staircase. In the case of a staircase treated with transoms of clear glass with the percentage of opening of 11%, these transoms direct the light to specific areas creating "strong" visual shock in many points of the stair landings and hence it leads to advise against that. The staircases treated with vertical bays throughout the façade presenting a percentage of opening between 19% and 22%, these treatments allow the penetration of daylight in a diffused way which ensures a balanced distribution of daylight inside the staircases. The existence of a solid overhang at the entrance; the façade treated with vertical bays, where the percentage of opening of the façade is about 19% and 22%, provided adequate transition leading to reasonable visual comfort.