Airtightness and underpressures measurements in French apartments.

Dwellings airtigthness is not well known in practice, in France.When dwellings are equipped with mechanical ventilation systems (which represents about 95% of the new dwellings in France) the airtigthness can strongly influence the performance ofventilation.In the frame of the European Joule Project TIP-VENT (Towards Improved MechanicalVentilation Systems) [1], measurements of airtightness and underpressures were made onthree multifamily buildings. It was the first step of a site testing procedure for the evaluationof a new ventilation component which was developed in this project.This paper presents the methodology and the results of the measurements.Airtightness and underpressures were characterised in about thirty apartments, equipped witha mechanical exhaust ventilation system, including air inlets in faades and exhaust terminaldevices in wet rooms.Airtigthness was measured in two configurations :- air inlets closed up : it gives the permeability of the dwelling, excluding air inlets ; itshows the importance of infiltrations ;- air inlets self regulating : it gives the permeability of the dwelling, including air inlets ;or global permeability of the dwelling.Underpressure was measured in the second configuration, and when boosted air flow wasactivated.The measurements were made without additional specific fan unit, but only by using theexisting mechanical exhaust ventilation system.