ENERGY CODE ALLOWANCES
A “mass wall” includes walls weighing not less than 35 psf of wall surface area; or 25 psf if the material weight is not more than 120 pcf. The majority of masonry wall systems qualify as mass walls.
The WS IECC contains three options for prescriptive path compliance with mass walls for non-residential buildings. They include:
- Meeting a wall assembly u-factor requirement of 0.104 (0.078 for Ferry, Okanogan, Pend Oreille and Stevens counties), or
- Using continuous insulation, or
- Using the concrete masonry exception for certain building uses. This exception allows an integral insulated, partial-grouted concrete masonry wall to comply.
Masonry walls can also comply with the energy code via the component performance (trade-off) option or the total building performance path where the benefits of mass walls are fully accounted for.
Note: U-factors for mass walls can be found in table a 18.104.22.168(1) in the WS IECC.
For further information on this subject contact the Northwest Concrete Masonry Association at www.nwcma.org or 425-697-5298; or the Masonry Institute of Washington at (425) 214-7476.