Targo Kalamees, Alan Väli, Urve Kallavus, Lembit Kurik, Üllar Alev
Bibliographic info:
The International Journal of Ventilation, Vol. 14 N°2, September 2015

Indoor temperature and humidity conditions as well as CO2 and airborne mould concentrations were measured in four manor schools in the Estonian cold climate. Based on these measurements, the influence of the indoor climate on the performance of schoolwork was assessed. The indoor environmental quality in manor schools turned out to be quite poor due to the inadequate performance of ventilation and heating systems. Intermittent stove heating was found to secure the minimum temperature in general but in winter thermal comfort was not always guaranteed. In addition, temporary overheating resulting in a significant temperature rise in the morning was intended to maintain room temperatures until the afternoon. Overheating in the summer period was not a problem in these schools. Ventilation airflow and indoor air quality were significantly lower in classrooms equipped with natural ventilation, resulting in higher CO2 and airborne mould concentrations and higher humidity loads for the building envelope. Original natural passive stack ventilation and window airing were not suitable solutions for providing the required indoor environmental conditions in cold climate conditions due to the type and efficiency of ventilation, inadequate duct size and air speed in ducts. Using previously published models, the level of schoolwork performance was estimated to be lower (75%...95%) in classrooms with natural ventilation and stove-heating. Air change was significantly higher in classrooms with mechanical exhaust ventilation; however, according to current standards for classrooms, the airflow was too low with both ventilation systems. Occupation density influences the indoor air quality significantly. To fulfil the requirements of indoor climate, pupil density in classrooms must be 2-3 times lower than the current requirement. In order to maintain schools in old manors in a cold climate, special attention should be paid to ensuring indoor environmental conditions. In addition to heritage values, other values, such as schoolwork performance and energy efficiency, should also be used as parameters in the improvement of indoor conditions and building service systems in old manor schools.