States that preventing surface sweating (moisture from humid air condensing on any surface) is an important function of foam insulation. States that no specific efforts have been made to understand the relationship between heat transfer from a surface exposed to humid air and the mechanism of surface sweating. Notes that for the effective application of any insulation product used for cold temperature applications, knowledge of this mechanism is essential. Describes an experimental apparatus consisting of a cold plate covered with a sheet of foam insulation built to address this objective. Describes studies carried out and states that the understanding of surface sweating developed during the study can be applied to any kind of cold pipe/sheet insulation product.

KEYWORDS: Thermal insulation, condensation, foams, experiment, research, pipes, heat flow, humidity.