Germany

More than 64 million pupils spend more time in school than in any other place except home in Europe (European Commission, 2014). The indoor air quality is often a challenge in existing school buildings and the lack of proper ventilation often leads to negative effects like increased absenteeism and sick building syndrome symptoms as well as lowered performance amongst students compared to new buildings.

Wind pressure and thermal forces are driving forces for pressure difference on the building envelope. In European and German standards infiltration is calculated using wind speed, temperature difference and wind pressure coefficients result-ing from upstream and downstream flow on the building envelope. This long term measurements shall present measured pressure differences on the building envelope in comparison to those calculations.

Today one out of six Europeans (84 million Europeans, or the equivalent of Germany’s population), report deficiencies regarding the building status. In some countries, that number is as high as one out of three. This puts these buildings in the ‘Unhealthy Buildings’ category, which is defined as buildings that have damp (leaking roof or damp floor, walls or foundation), a lack of daylight, inadequate heating during the winter or overheating problems.

An airtight building envelope ensures not only the energy-efficiency of a building, but also a damage free construction. Important to achieve optimal airtightness are the planning, implementation and materials. Long-term airtightness requires efforts in all three aspects. Airtightness products are being tested under lab conditions but these results cannot be transferred one-on-one onto buildings.