Masonry Magazine March 1969 Page. 44
TABLE 2-CONDUCTANCE (C OR k) AND RESISTANCE (R) OF VARIOUS BUILDING MATERIALS OTHER THAN HOLLOW CONCRETE MASONRY
Material | Density p.c.f. | Conductivity or Conductance (k) | (C) | Resistance (1/k) | (1/C)
---|---|---|---|---|---
Poured Concrete, Mortar, and 100% Solid Concrete Masonry Units | 60 80 100 120 140 | 1.7 2.5 3.6 5.2 9.0 | | 0.59 0.40 0.28 0.19 0.11 |
Surface Conductance fo-for outside wall, 15 mile/hr. wind (winter) fo-for outside wall, 7½ mile/hr. wind (summer) fi-for inside wall | | | 6.00 4.00 1.46 | | 0.17 0.25 0.68
Air Space Conductance Vertical air space %"-4" Winter Summer Reflective lining one side | | | 1.03 1.16 0.33 | | 0.97 0.86 3.00
Plaster Cement, sand aggregate Gypsum, perlite aggregate Gypsum, vermiculite aggregate Gypsum, sand aggregate | | 5.00 1.50 1.70 5.60 | | 0.20 0.67 0.59 0.18 |
Lath and Plaster Metal lath, %-in, plaster Sand aggregate Lightweight aggregate %-in, gypsum lath, ½-in, plaster Sand aggregate Lightweight aggregate -in, insulation board lath and ½-in, sand aggregate plaster Wood lath and ½-in, sand aggregate plaster | | 7.69 2.12 2.43 1.56 0.66 2.50 | | 0.13 0.47 0.41 0.640 1.52 0.40 |
Insulating Materials Mineral wool, fibrous form Loose fill 01 Rigid fiber boards, typical | | 0.27 0.50 0.33 | | 3,70 2.00 3.03 |
Wood Maple, cak, similar hard woods Fir, pine, similar soft wood | | 1.10 0.80 | | 0.91 1.25 |
Sample Calculation
10° Cavity Wall
4" Concrete Brick Unit Weight = 140 lb/cf
2ª Air Space
4" Hollow Concrete Block Unit Weight = 60 lb/cf
Referring to Tables 1 and 2
1/f. Outside Surface 0.17
1/C Concrete Brick 4 x 0.11 = 0.44
1/a Air Space 0.97
1/C Concrete Block 2.07
1/fi Inside Surface 0.68
Rt Total Resistance = 4.33
U=1/Rt1/4.33 = 0.23
TIONAL CONCRETE MASONRY ASSOCIATION