In the last few years energy regulations have been introduced in many Swiss Cantons. The main goal of these regulations, relative to the building envelope, is to improve the insulation value. Consequently, typical current construction for new buildings is characterized by exterior wall and roof insulation U-values under 0.5 W/m2.K and windows with triple glazing or its thermal equivalent.
In Finland, there are three main topics in the field of air infiltration research: * simulation and measurement of air-leakage rates in building components and in buildings as a whole * airtightness and indoor air quality (thermal comfort) * thermal effects of air flow in building components. Goes on todiscuss aspects of air infiltration research in Finland.
There are several methods by which the airtightness of a building can be measured. One method involves the use of a fan to pressurize or depressurize the building. This creates a known pressure difference across the building envelope. Thecorresponding air flow through the fan is measured and this is an indication of the airtightness of the building. This air flow rate can be expressed as the number of building air changes per hour, a useful unit when comparing buildings of different volumes. So far only simple methods have been employed to analyse this condition.
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