Natural ventilation. Ofrivillig ventilation.

Reports investigation of airtightness of two types of industrial wall when subjected to a differential pressure across the wall construction. Laboratory tests were performed on wall units, overlap joints in vapour barriers of plastic sheet,on steel stud wall with metal sheeting and joints in the light- weight concrete element wall being studied. Shows that methods of construction employed so far can be retained if modifications are made concerning junctions and the sealing of joints. In sheet metal walls, the contact pressure onto the plastic foil must be guaranteed. It should be possible to comply with recommendations in swedish building regulations 1975 concerning permitted air leakage.