THE VENTILATION RATE OF 344 OSLO RESIDENCES

The ventilation in Norwegian residences was studied with respect to th e effect of new standards, construction techniques adopted, and energy conservation measures implemented. This was compared to residential v entilation performance in other countries with a similar climate. The effective total air change rate (h(-1)) in 344 residences was measured with a passive tracer gas method known as the perfluorocarbon tracer gas method (PFT-method). The measurements were performed over a 14-day integrated sampling period. Overall, 36% of all residences had lower air change rates than the national building code requirement of 0.5 h( -1). In spite of similar construction techniques and building codes in the Nordic countries, Norwegian residences seem to be better ventilat ed in general than residences in other Nordic countries. However, the common belief of a gradual reduction of ventilation rates in Norwegian buildings as the date of construction becomes more recent is supporte d by our findings which show a linear reduction (slope beta=-0.002, P< 0.05) of ventilation until the revision of the national building codes in 1987. Consequently, our results provide evidence supporting the hy pothesis that the introduction of new building standards and construct ion techniques, and the implementation of energy conservation measures , have decreased the effective total air change rates in Norwegian res idences until 1987.