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