In the North American building codes, there’s an acknowledgement of the benefits of high-mass walls, but there’s still no official test standard for determining the effect of thermal mass in a wall. The testing done to meet U.S. and Canadian codes concentrates solely on the thermal resistance (R-value) of a wall based on steady-state evaluations of materials and assemblies.
To get a more complete picture of thermal mass performance, the Insulating Concrete Forms Manufacturers Association recently commissioned a study by CLEB Laboratories (now known as UL-CLEB) in accordance with test procedure ASTM C1363-11. The study revealed that insulating concrete form walls can achieve up to 60 percent greater annual energy savings and 58 percent higher R-Value/RSI than can be attained by standard batt insulated 2x6 wood-framed walls.