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Title: Observation and analysis of protected membrane roofing systems
Authors: Schaefer, David.
Larsen, E. T.
Aamot, H. W. C. (Haldor W. C.)
Keywords: Cold regions
Protected membrane roofs
Thermal properties
Heat losses
Test methods
Thermal insulation
New Hampshire
Publisher: Cold Regions Research and Engineering Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: CRREL report ; 77-11.
Description: Technical report
Abstract: Two performance indicators, effectiveness and thermal efficiency, are defined and used to evaluate the year-round performance of three protected membrane roofs in Alaska and New Hampshire. Effectiveness is a measure of the deviations of ceiling temperatures from a yearly average, with large deviations indicating erratic performance in the roofing-insulation system and small departures indicating a thermally stable system. Thermal efficiency, the ratio of calculated heat loss to measured heat loss, is affected by climatic conditions such as rain, snow, solar radiation and wind. Thermal efficiency values of 100% or greater are possible since the calculated heat loss is based only on the inside and outside air temperature differences and the thermal properties of the roof components. Results of the year-round evaluation indicate that the three protected membrane roofs generally have high values of both effectiveness and thermal efficiency.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:CRREL Report

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