Stack Effect Ventilation of an Infant's School.

This paper presents the results of monitoring the ventilation in Netley Infants School in Hampshire. The study was carried out on behalf of the Department of Trade and Industry as part of the Energy Performance Assessment Project, as managed by the Energy Technology Support Unit. The school was designed so that during the summer the solar heating of a south facing conservatory would enhance the stack effect and induce ventilation in the adjacent classrooms. It was expected that ventilation rates would be adequate to maintain comfort conditions and air quality. The monitoring was carried out over a period of two months in 1991 and incorporated oneoff measures of ventilation rates, short term tests of the ventilation strategy and long term monitoring of carbon dioxide to assess air quality. The measurements were carried out using an automated NDIR analyser sampling from points throughout the school, and a weather station erected in the school grounds. The results show a general background infiltration rate of 0.4 ach with ventilation rates of about 1.5 ach when the building was operated as designed. The more normal operation, which involved opening the doors between the classrooms and conservatory, raised the ventilation rate to approximately 2 to 4 ach. This still fell short of the recommended fresh air rate of 30m³/person/h. Over periods of high ambient temperatures and solar radiation the external fire doors of the classrooms were opened to augment the vents: satisfactory ventilation was then achieved.