Survey on the Empirical Method to Evaluate the Thermal Performance of Roof Assembly

Roof constitutes as one of the largest surfaces in a building that receives high amount of heat through radiation, conduction and convection. The amount of heat received by a roof depends greatly on climate condition and roof design configurations. In a hot climate, roof is designed as a barrier to the hot sun, while in cold climate, roof is an amplifier that magnifies the amount of heat gains into building envelope. As Malaysia is in tropical climate, roofs in Malaysia must be able to curb heat from the sun. Latest insertion of Malaysia Standard MS1525 requirement to the Universal Building By Law (UBBL) mandate for authority approval on the achievable thermal transmittance (U-value) not greater than 0.4W/m²K for light weight roof and 0.6W/m²K for heavy weight roof. The lower the U-value, the better the roof as a barrier to the external heat. Based on a survey study done in Malaysia, only 43.18% of building practitioners are aware on the requirement, and the current implementation of the regulation involves submission of U-value numerical calculation for total roof assembly during Building Plan (BP) submission. The result of this study suggests a need for an empirical method to measure roof performance. Computer Controlled Solar Simulator (CCSS) is suggested as a platform to ensure effective implementation of MS1525 and certify that housing design in Malaysia complies with the thermal comfort requirement. (paper)