The Required Amount of Ventilation Air for the Classroom and the Possibility of Air Infiltration through the Windows

Abstract

The majority of education buildings in Poland are equipped with natural (gravity) ventilation, where the air inflow depends on the level of window airtightness. A complete statistical urban population of 50 school buildings in Czestochowa have been examined. The main issue to be clarified is the answer to the following questions: Is it theoretically possible to supply enough air to meet the ventilation requirements with gravity ventilation? What is the airtightness of the windows at which it will be possible? The average technical conditions of windows in the analysed buildings were bad. However, only in the case in which high external air leakage coefficient a = 7.0 m3/(h m daPa2/3) (q100KL = 32.4912 m3/(h m) is the amount of air passing through the leaks similar to the quantitative ventilation requirements for classrooms. The quantity of air flowing from the outside through modernized windows that meet the technical requirements (a = 0.6 to 1.0 m3/(m h daPa2/3)) covers on average only about 12% and about 21% of the ventilation needs. Without installing additional vents in the rooms, or better yet, installing mechanical ventilation with heat recovery, meeting the ventilation norm requirements will be impossible.

Active Soil Filter System for Indoor Air Purification in School Classrooms

“…The ventilation rate in the classroom was determined by the number of students and the dimensions of the classroom. The amount of outdoor air required according to the number of students was determined by Equation (1) [ 29 ]. where Q SN , q p , and N sc are the required air volume, the outdoor air volume per student in the classroom, and the number of students in the classroom, respectively.…”