air leakages

Problem analysis

The aim of improving air tightness of structures is to prevent the uncontrolled air leakages through structures. Built environments contain microbes, particulate and gaseous impurities but removing them is not always necessary. For example, an ageing building envelope commonly contains microbial impurities even when there is no obvious moisture damage. Air leaks convey impurities to indoors where they can lead to poor indoor air quality and associated health problems. Air leaks have also negative impact to energy efficiency and living comfort.

The efficiency of air-to-air heat recovery ventilation units is of great importance for EP calculations (energy performance of buildings) throughout Europe. Efficiencies compared on a reliable basis are also crucial for contractors and installers of such systems.

This work presents a field measurement study, investigating the airtightness of 64 French dwellings less than ten year old. Buildings have been classified according to the type of construction (masonry or timber frame) and of occupancy mode (multi- or single- family). Using a fan-depressurization technique, we assessed the air leakage rate of each dwelling, based on a theoretical flow model that relates the infiltration airflow rate to the differential pressure .