Masonry Magazine July 2011 Page. 26
Nonresidential
Energy CodeFFF
Compliance with
Concrete
Masonry Walls
BY TOM YOUNG
Thermal mass is the energy saver in masonry buildings.
THE CONCEPT THAT MASSIVE WALLS ABSORB AND RETAIN HEAT, TO BE LATER RELEASED, HAS BEEN UNDERSTOOD SINCE THE TIME OF THE WORLD'S EARLIEST STRUCTURES, many of which were built to benefit from the delaying effect of mass on the transfer of heat. This physical property, combined with the dynamic temperature cycles a building is subjected to, allows masonry materials to be utilized effectively in the design of energy-efficient buildings. The benefits of thermal mass have been incorporated into modern energy code requirements, permitting concrete masonry assemblies to have less insulation than lightweight frame systems.
It is important to note that R-values, alone, do not fully describe the thermal performance of a concrete masonry wall. Masonry's thermal performance depends upon its steady-state thermal char-
Temperature
Time Lag
Damping
Building
Operation
4AM
SAM Noon 4PM BPM
Time of Day
Temp.on
Inside of
mass wall
Outdoor
Temperature
Building
Operation
Mac 4 AM 8 AM Noon 4 PM 8PM M
Figure 1-The Benefits of Thermal Mass on Building Energy Efficiency
24 MASONRY
July 2011 www.masoncontractors.org
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