Thermal conductivity of fibrous glass board by guarded hot plates and heat flow meters: An iInternational round-robin

In the early 1980s, an iInternational round-robin was held in which the apparent thermal conductivity of specimens of fibrous glass insulation board was measured by users of guarded hot plates [GHPsl and heat-flow meters I HFMsL The round-robin was performed over a period of several years by laboratories in Europe, North America, Australia, and the Far East. Participants in this round-robin were organized into 12 "loops," 8 for participants with GHPs and 4 for those with HFMs. Each !oop included laboratories located in the same region of the world and sharing the same set of specimens. In an attempt to obtain insight into the accuracy of the measurements, participants were also asked to measure the thermal conductivity of a layer of air. The data submitted in this round-robin are exhibited and analyzed. The overall agreement of individual measurements with a least-squares fitted curve, as measured by one standard deviation or, was a= 2.4% for GHPs and oʹ= 2.7% for HFMs. Suggestions are made fur conducting future round-robins of this type.