A wall is constructed of two layers of 0.6-in-thick sheetrock (k = 0.10 Btu/h·ft·°F), whic...

A wall is constructed of two layers of 0.6-in-thick sheetrock (k = 0.10 Btu/h·ft·°F), which is a plasterboard made of two layers of heavy paper separated by a layer of gypsum, placed 7 in apart. The space between the sheetrocks is filled with fiberglass insulation (k = 0.020 Btu/h·ft·°F). Determine (a) the thermal resistance of the wall and (b) its /?-value of insulation in English units.

FIGURE P3-31E