... 2-1/5 2, heat-resistant than the cement pressure plate, gypsum board high 400-600 °C, the thermal ... conductivity of cement pressure plate is only 1 / 3 3, small volume change ... 2-1/5 2, heat-resistant than the cement pressure plate, gypsum board high 400-600 °C, the thermal ... conductivity of cement pressure plate is only 1 / 3 3, small volume change ...