AIR QUALITY AND THERMAL COMFORT OF INDOOR BUS INTERCHANGES

Abstract

A study was conducted at Toa Payoh Bus Interchange to analyse air-conditioned bus interchanges' thermal comfort and air quality. It is a challenge to manage the indoor environment due to flow of occupants and weather, without putting a strain on the airconditioning system. Bus interchanges in Singapore serve as a multi-purpose area. This makes specialised standards or guidelines unusable, as the requirements need to be more stringent to cater to different types of occupants. An objective analysis was carried out to test the effectiveness of the air-conditioning system by monitoring the indoor parameters at six different Zones. A comparison was made with the relevant standards or guidelines. In addition, the overall trend is generated and analysed. A subjective analysis was done with shopkeepers on their comments as well as their view on effects of people and weather. Although the air-conditioning system managed to reduce temperatures and humidity to a more comfortable level, the carbon dioxide was at the limits of the standards, which indicates a lack of ventilation. Air quality was better at the naturally ventilated bus parking bay (Zone 1 in the study) than the indoor areas (Zones 2-6). Occupants in a hot weather and high occupancy rate are likely to be less satisfied at the thermal comfort. They are satisfied with the air quality even at hot temperatures and high occupancy. The control of infiltration is a challenging task. The cloudy weather was considered as the best weather conditions in terms of thermal comfort and ventilation. ii The recommendations include individual temperature control systems, the installation and use of air curtains to all doors and increase the ventilation rate.