EVALUATION OF THE QUALITY OF THE INDOOR ENVIRONMENT IN COLLEGE CLASSROOMS

ABSTRACT

The topic of increased CO2 concentration is very actual in the Czech Republic, especially in the connection to the current effort for a massive revitalization of buildings, which aims to reduce the energy performance of buildings. Both residential and civil buildings revitalization includes predominantly replacement of windows and insulation by the contact system. Exchange of windows and high-quality contact insulation then result in almost no infiltration at all. So, when the forced ventilation is not compulsory proposed to such revitalised buildings, due to insulated thermal bonds and tight windows, the problem with an increased CO2 concentration in the indoor environment appears. Increased concentration of CO2 means, in less serious eventualities, a concentration disorder. In more serious cases, it may cause headaches, nausea, difficulties in breathing or even loss of consciousness. It is evident that it presents a serious problem that cannot be easily revealed by laymen as he could misinterpret his sleepiness or nausea as a sigh of his poor state of health. The current legislation deals with the problem of increased CO2 concentration in schools, but only taking kindergartens, elementary and secondary schools into consideration. As far as universities are concerned, they are mentioned only marginally in Regulation No. 268/2009 Coll., dealing with technical requirements of buildings, which indicates the CO2 concentration - 1500 ppm as limit. College students spend even longer period of time in classrooms than elementary or secondary school students, and mostly without the possibility of supplying fresh air. That can be strongly reflected in their concentration. The purpose of the article is to measure and evaluate indoor air quality in the classrooms of VŠB-TUO Faculty of Civil Engineering. The analysis of carbon dioxide, temperature and humidity of indoor air was conducted during the lectures. Measurements took place in three different classrooms with different number of people, with different internal gains and with different ventilation modes.

Keywords: building revitalization, infiltration, carbon dioxide, college classrooms, ventilation