Describes the influence on heat resistance of an insulated wall of workmanship and forced convection. Compares experimental investigations on cross-bar walls with calculated values. Examples show the influence on heat resistance of insulation installation, air-flow along the insulation and air-flow through the insulation. Concludes that air-tightness of the vapour barrier and partly of the inside board are of great importance. If there are holes and defects in these layers the permeability of the wind protection can be of importance to the overall air-flow through and the heat resistance of the wall. An insulated wall structure with such defects will normally show a considerable reduction in its thermal resistance due to forced convective air-flow.
ASTM Symposium on Advances in heat Transmission measurement on thermal insulation material systems, September 19-20 1977, Swedish National Authority for Testing, Inspection and Metrology report no 19.