Hygrothermal Performance of a New Light Gauge Steel-Framed Envelope System

Hygrothermal performance of a new light gauge steel-framed building envelope system has been analyzed using three-dimensional thermal simu lations, two-dimensional combined heat, air, and moisture transfer simulations, labo ratory testing in a calibrated and guarded hot box (ISO 8990), weather resistance tests for full-sized structures, and corrosion tests and field measurements at experimental buildings in Ylojarvi, central Finland. The results show that a modern steel wall structure based on perforated steel studs performs satisfactorily in the cold climate at Finland. The perforations significantly reduce heat loss along the web of the profile. The field measurements show that no condensation has occurred in the frame sys tem. Temperature measurements and infrared surveys in demonstration buildings show that temperatures on the inner surface of the wall are sufficiently high to pre vent surface condensation or even increased surface humidity that could cause mold growth on the surface. According to the calculations, there are no corrosion risks in the steel frames during their estimated service life in the Finnish climate The cli mate, however, has an important effect on performance, and the structures should be designed with regard to climatic conditions.