The effect of building height and facade area ratio on pedestrian wind comfort of London

The evaluation of wind environment has been receiving increasing attention as it has been associated with issues related to the quality of the urban climate, such as heat island intensity and air pollution, affecting health and wellbeing in large metropolitan areas. Focusing on the context of London, this study aims to associate pedestrian level wind comfort with the characteristics of urban morphology that incorporate information about the height variability and the vertical dimensions of buildings. More than 20 case studies of different configurations and dimensions 500 x 500 m were examined through CFD simulations. For each case study, eight wind directions were tested and the BRE wind comfort criteria were implemented for the different outdoor human activities. The results reveal a strong connection between the ground level mean wind speed ratio and the development of acceptable or tolerable wind conditions for pedestrians. From the morphological indicators examined, facade area ratio was the most dominant on mean wind speed ratio and on the percentage of outdoor space which is comfortable for certain activities, especially for increasing values of plan area ratio. The results of the study indicate that facade area ratio should be taken into consideration for assessing pedestrian level wind environment.