The heat loss from a boiler is to be held at a maximum of 900btu/h ft2 of wall area. what thickness of asbestos (k= 0.10 btu/h ft ℉) is required if the inner and outer surfaces of the insulation are to be 1600 and 500℉, respectively? now if a 3-in.-thick layer of kaolin brick (k= 0.07 btu/h ft ℉) is added to the outside of the asbestos, what heat flux will be result if the outside surface of the kaolin is 250℉? what will be the temperature at the interface between the asbestos and kaolin for this condition?