ABSTRACT
Controlled airflows, having adequate flow rate and passing at the appropriate locations are essential for good indoor air quality. Leakage, allowing the uncontrolled air to follow inappropriate paths, should therefore be reduced as much as possible. This requires an airtight building envelope and airtight ductwork: building and ductwork airtightness is a prerequisite for efficient natural or mechanical ventilation. Envelope leakage is not an appropriate way for airing buildings.
