AN INNOVATIVE TECHNIQUE FOR MEASUREMENT OF BUILDING LEAKAGE AT LOW PRESSURES

Conventional techniques for the measurement of adventitious leakage of building envelopes are basedon steady pressurisation at high pressures (e.g. 50 Pa) that are not normally encountered with naturalor mechanical ventilation. It is the leakage at low pressures (e.g. 4 Pa) that is of interest and it is shownthat the conventional technique leads to large uncertainty in the low-pressure leakage. Ideally apressurisation of 4 Pa should be used, but with the conventional technique the uncertainty due to windeffects is unacceptably large. The paper describes a new pulse pressurisation technique that allowsaccurate measurement of the leakage at low pressures, even in the presence of wind effects. Thetechnique makes use of pulse pressurisation. The three key features that have led to a successfultechnique are described. Examples of measurements are presented and a comparison between thenew technique, the conventional steady technique and a theoretical model is shown.