Calculated by the Series-Parallel Method 
(Required by the Minnesota Energy Code)


Light Weight Concrete Units
(95 pounds per cubic foot density)


Details of Construction

(1) No Insulated or Grout 2.6 2.8 2.8
(2) Grouted Cores Without Insulation n/a n/a n/a
(3) Cores Filled With Perlite Loose Fill 6.7 7.9 9.2
(4) Cores Filled With Urea-Formaldehyde or Plastic Form 7.1 8.4 9.7
(5) Added R-Value To Any of the Above Walls:      
  1. 2″ x 2″ wood furring (24″ o.c.) with 1 1/2″ think molded polystyrene and 1/2″ gypsum board
5.5 5.5 5.5
  1. 2″ x 2″ wood furring (24″ o.c.) with 1 1/2″ think extruded polystyrene and 1/2″ gypsum board
6.5 6.5 6.5
  1. 2″ x 2″ wood furring (24″ o.c.) with 1 1/2″ thick cellular polyisocynanurate, gas permeable face, and 1/2″ gypsum board.
7.6 7.6 7.6
1. For intergrally insulated masonry, Series-Parallel calculations are the method mandated by the U.S. Department of Energy, most State Energy Codes (including Minnesota and Wisconsin), the American Society of Heating, Refrigeration and Air-conditioning Engineers ASHRAE STANDARD 90.1 and the National Concrete Masonry Association (NCMA). The only acceptable alternative is testing according to the ASTM C-236 “Guarded Hot-Box” by an independent accredited laboratory at specific densities & properties.

2. Concrete thermal resistivity values (R per inch) are from NCMA TEK 6-2A, resistivity high range (protected from moisture). Perlite loose fill thermal resistivity (R per inch) is taken from NCMA TEK 6-2A = 3.13; polystyrene loose fill is assumed the same as it is processed form various unknown scrap sources. Foam thermal resistivity value R = 4.46 (average from literature of three companies.)

3. R-value include inside air film (.68) and outside air film (.17) coefficient totaling R = .85.

4. All R-values are steady-state values to be used in the “ENVSTD”, “COMcheck” and “MNcheck” computer programs which allow for mass of walls; for other applications, a mass adjustment is allowed according to the 1989 Model Energy Code, Table No, 502.1.2c.