Describes an investigation of the performance of polyurethane pipe insulation used in district heating and cooling subjected to underground water attack. Measures the effective thermal conductivity and moisture absorption rate under conditions similar to those found in operating system that have failed. Determines the drying rate and to what extent the insulation can be dried out once the source of moisture is removed.

KEYWORDS: year 1997, District heating, pipelines, thermal insulation, polyurethane, performance, water, underground, ground water, thermal conductivity