Abstract
This report describes factors that affect the thermal performance of roof systems and a technique for field measuring thermal resistance. This measurement technique utilizes a combination of infrared thermographic imaging, surface heat-flow meters and surface thermopiles. The thermal resistance of the roof system is computed from temperature differences across the roof and the measured heat flow through the roof. A field test of the measurement procedure is detailed, along with an examination of the time period required to perform a roof thermal resistance measurement, as related to the thermal time lag for heat flow through the roof due to the effect of the thermal mass of the roof. Roof thermal resistance determined via this measurement procedure is very accurate if the measurements are performed over a sufficient time interval, the minimum interval depending upon the thermal mass of the roof system.
This report describes factors that affect the thermal performance of roof systems and a technique for field measuring thermal resistance. This measurement technique utilizes a combination of infrared thermographic imaging, surface heat-flow meters and surface thermopiles. The thermal resistance of the roof system is computed from temperature differences across the roof and the measured heat flow through the roof. A field test of the measurement procedure is detailed, along with an examination of the time period required to perform a roof thermal resistance measurement, as related to the thermal time lag for heat flow through the roof due to the effect of the thermal mass of the roof. Roof thermal resistance determined via this measurement procedure is very accurate if the measurements are performed over a sufficient time interval, the minimum interval depending upon the thermal mass of the roof system.
Date
0/1981
0/1981
Author(s)
S Treado
S Treado
Page(s)
50-57
50-57
Keyword(s)
thermal resistance; infrared thermography; heat flow meter; thermopiles; temperature difference; moisture accumulation
thermal resistance; infrared thermography; heat flow meter; thermopiles; temperature difference; moisture accumulation