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Purpose of the work
Poor air quality in classrooms is a well-known problem. Achieving good air quality with window ventilation during the cold season requires a great deal of attention and time to the detriment of school lessons. Delivering appropriate air exchange rates for classrooms is only possible by sacrificing some thermal comfort. When replacing school windows, one should take a critical look at the typical window ventilation strategy and come up with better solutions.
Method of approach
The insights of Max von Pettenkofer on ventilation strategies in hospitals and schools lead to ordinances and decrees as early as in the 18th century requiring "vent chimneys" in school rooms. The vent chimney had the purpose to remove stale air from the classroom, while adjustable skylights provided for fresh air. These structures still exist in historical school buildings and are excellent ventilation systems when combining them with modern ventilation technology.
Content of the contribution
Such a ventilation system was revitalized while replacing the windows of a school building in Central Hesse (built in 1904). The ventilation system - which had been shut down but was still installed in the building - was analyzed in depth prior to implementation. Actual carbon dioxide concentrations were captured that had built up during occupancy. Airtightness of the classrooms was measured before and after renovation with a special focus on quantifying indoor leaks. The presentation will discuss the test results as well as the design and practical execution of the entire retrofit.
Results and assessment of their significance
A modern ventilation system was incorporated into the historical ventilation ducts and is now used as a very efficient and well-functioning system which delivers the air volume that is actually required in the classrooms.
Conclusions
Window ventilation in school rooms disrupts school lessens and reduces thermal comfort significantly. More efficient solutions had been implemented as early as in the mid-18th century and should be standard practice nowadays when erecting and renovating school buildings.
For further information please contact Thomas Runzheimer at: e-haus@gmx.net