determining the thermal resistance of {HEAD ~ the insulation} from the known cavity depth and {TAIL ~ insulation density} 
determining the thermal resistance of { HEAD ~ the insulation } from the known cavity depth and { TAIL ~ insulation density }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL