Masonry Magazine June 1981 Page. 15
TABLE 1
Typical Material Properties of Brick
| Material | Face Brick, ASTM C 216 | Building Brick ASTM C 62 | Paving Brick, ASTM C 902 | Hollow Brick, ASTM C 652 | Mortar or Grout |
|---|---|---|---|---|---|
| Specific Heat' c Btu/lb°F | 0.24 | 0.22 | 0.24 | 0.22 | 0.20 |
| Density ρ lb/cu ft | 130 | 120 | 135 | 126 | 120 |
| Thermal Conductivity k Btu/hr/°F/ft² per inch | 9.00 | 5.00 | 9.00 | 10.00 | 12.00 |
| Thermal Resistivity r (hr°F ft²)/Btu per inch | 0.11 | 0.20 | 0.11 | 0.10 | 0.08 |
| Thermal Conductance C (Btu/hr/°F/ft²)/ft | 0.758 | 0.417 | 0.758 | 0.833 | 1.042 |
| Heat Capacity β Btu/cu ft/°F | 31.2 | 26.4 | 32.4 | 27.7 | 24.0 |
| Thermal Diffusivity δ ft²/hr | 0.024 | 0.016 | 0.023 | 0.030 | 0.043 |
| Emissivity e | 0.93 | 0.93 | 0.93 | 0.93 | - |
These values are representative of the information available to the Brick Institute of America, and are typical for brick being manufactured today. These values may vary by plus or minus 10% depending on the specific brick being considered. Hollow brick are assumed to be 60% solid and the core space fully grouted. Source is Reference 3. The thermal conductivity of grouted hollow brick should be determined by dual path analysis. Typically grouted hollow brick, 60% solid, fully grouted will have a thermal conductivity of approximately 10 Btu/hr" F/ft² per inch.
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C = Specific heat of the brick in the interior brick masonry wythe, in Btu/lb/°F. t = Nominal thickness of the grout, in inches. C = Specific heat of the grout, in Btu/lb/°F.
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Consider a 14-in. thick brick thermal storage wall constructed of 4-in. face brick, a 4-in. grouted space and a 6-in. grouted hollow brick wythe. Although this example is not representative of typical brick masonry thermal storage components, it is offered to include the available combinations of brick masonry construction. The specific heat of the wall assembly components may be determined by using Table 1 where:
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t = 4 in., C = 0.24 Btu/lb/°F
t = 6 in., C = 0.22 Btu/lb/°F
t = 4 in., C = 0.20 Btu/lb/°F
The approximate average specific heat of the wall assembly is found by substituting these values into Equation 1:
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C = [(4 × 0.24) + (6 × 0.22) + (4 × 0.20)]/(4 + 6 + 4)
C = 0.22 Btu/lb/°F
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Density. The density, p, of brick varies with the type of clay, the additives used in manufacturing and with