An insulation system is to be selected for a furnace wall at l000°C using first a layer of mineral wool blocks followed by fiberglass boards. The outside of the insulation is exposed to an environment with h = 15 W/m2 · °C and T8 =40°C. Using the data of Table 2-1, calculate the thickness of each insulating material such that the interface temperature is not greater than 400°C and the outside temperature is not greater than 55°C. Use mean values for the thermal conductivities. What is the heat loss in this wall in watts per square meter?