building leakage

A new low pressure ‘quasi-steady’ pulse technique for determining the airtightness of buildings has been developed further and compared with the standard blower-door technique for field-testing a range of typical UK homes. The reported low pressure air pulse unit (APU) has gone through several development stages related to optimizing the algorithm, pressure reference and system construction. The technique, which is compact, portable and easy to use, has been tested alongside the standard blower-door technique to measure the airtightness of a range of typical UK home types.

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.