In this research the gas permeabilities of different materials and cellulose-insulated wall structures without a vapour barrier were determined with material tests and modelling, and carbon dioxide balance of bedroom air was modelled. Test equipment was developed for the study, consisting of a test chamber and measuring apparatus.
The carbon dioxide resistance values determined with the test equipment correlate closely with the water vapour transmission values presented in other studies. Moisture seems to clearly lower the carbon dioxide permeability of wood. The test results do not allow the determining of how moisture affects the carbon dioxide flow through a structure composed of other materials. To sum up the modeling, it may be said that the need of ventilation is not reduced by the use of gas permeable structures, but their use can alleviate the harmful effects of temporarily raised carbon dioxide contents.
Research report was published in the publication series of TUT’s Department of Civil Engineering (Publication 104).
The research was financed by National Technology Agency of Finland TEKES and four companies.