Winter indoor air quality, thermal comfort and acoustic performance of newly built secondary schools in England

Previous studies have found that classrooms are often inadequately ventilated, with the resultant increased risk of negative impacts on the pupils. This paper describes a series of field measurements that investigated the indoor air quality, thermal comfort and acoustic performance of nine recently built secondary schools in England. The most significant conclusion is that the complex interaction between ventilation, thermal comfort and acoustics presents considerable challenges for designers. The study showed that while the acoustic standards are demanding it was possible to achieve natural ventilation designs that met the criteria for indoor ambient noise levels when external noise levels were not excessive. Most classrooms in the sample met the requirement of limiting the daily average CO2 concentration to below 1500 ppm but just a few met the need to readily provide 8 l/s per person of fresh air under the easy control of the occupants. It would seem that the basic requirement of 1500 ppm of CO2 is achieved as a consequence of the window areas being just sufficient to provide the minimum of 3 l/s per person at low and intermittent occupancy. Thermal comfort in the monitored classrooms was mostly acceptable but temperatures tended to be much higher in practice than the design assumed.