A consequence analysis of new Norwegian building regulations on air infiltration.

In 1981 Norwegian building regulations introduced quantitative requirements to air leakages in different types of buildings. The requirements were formed as maximum allowed air changes per hour at 50 Pa pressure difference according to the pressurization method. To evaluate the consequences of these new requirementsimposed to Norwegian building industry a model proposed by the Nordic Committee for Building Regulations (NKB) was used. The average air leakages of residential buildings , built before the new requirements,are known through a research project performed i n 1979. Average air leakages of other buildings are not known. Energy losses due to air infiltration are calculated with the computer program ENCORE. Extra costs for achieving necessary tightness in detached houses are estimated to be NOK 1000,- i n average per house, and the resulting energy saving is estimated to be 1200 kWh/year corresponding to NOK 360,- per year. For block flats the new requirements are supposed to have none or little practical influence. For other buildings the influence is not known. The most evident negative consequence is the possibility of reduced and too low air change rate i n detached one storey houses with natural ventilation systems. In some of these houses it may be necessary to introduce mechanical ventilation systems to achieve air quality control.