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Appendix Three: Data on Thermal Transmittance

Table A3.1. Values of coefficients of thermal transmittance for different wall materials and combinations in kcal/hm²C°.

 

Wall Thickness (in m)
Type of Masonry 0.30 0.40 0.50 0.60 0.70 0.80 0.90
Limestone masonry:
External wall plastered on exterior 2.40 2.00 1.80 1.60 1.45 1.33 1.22
External wall plastered on both sides 2.30 2.00 1.80 1.60 1.41 1.30 1.19
Internal wall plastered on both sides 1.90 1.70 1.50 1.37 1.25 1.16 1.08
Dense stone, including marble and granite:
External wall plastered on exterior 2.90 2.60 2.40 2.20 2.00 1.90 1.70
External wall plastered on both sides 2.80 2.50 2.30 2.10 1.90 1.80 1.70
Internal wall plastered on both sides 2.20 2.00 1.90 1.80 1.60 1.50 1.45
 

Wall Thickness (in m)
  0.05 0.10 0.15 0.20 0.30 0.40 0.50
Concrete masonry (gravel, cement, and sand):
External wall without plaster 4.20 3.60 3.10 2.70 2.20 1.80 1.60
Internal wall without plaster 3.10 2.70 2.40 2.20 1.80 1.60 1.36
External wall plastered on both sides 3.50 3.00 2.70 2.40 2.00 1.70 1.44
Internal wall plastered on both sides 2.70 2.40 2.20 2.00 1.70 1.44 1.27
 

Wall Thickness (in m)
  0.12 0.25 0.38 0.51 0.64 0.77 0.90
Red brick:
External wall plastered on exterior 2.60 1.80 1.37 1.11 0.93 0.80 0.70
External wall on both sides 2.50 1.70 1.34 1.09 0.91 0.79 0.69
External wall plastered on interior 1.90 1.33 1.04 0.85 0.71 0.62 0.55
Light concrete block:              
External wall plastered on both sides 2.00 1.25 0.93 0.73 0.60 ... ...
Internal wall plastered on both sides 1.70 1.12 0.85 0.68 0.57 ... ...
Sand-lime brick:
External wall plastered on exterior 2.90 2.00 1.60 1.27 1.08 0.93 0.82
External wall plastered on both sides 2.70 1.90 1.50 1.23 1.05 0.91 0.81
Internal wall plastered on both sides 2.10 1.60 1.24 1.03 0.89 0.78 0.69
 

Wall Thickness (in m)
  0.12 0.25 0.38 0.51 0.64 0.77 0.90
Red-brick double wall plastered on both sides with 5-12 cm cavity . . . 1.38 1.11 0.93 0.81 0.70 0.63
Ordinary red-brick wall insulated with cork sheeting on internal wall only for insulation:
2-cm thick insulation 1.11 0.93 0.80 0.70 0.63 0.57 0.52
5-cm thick insulation 0.61 0.55 0.50 0.46 0.43 0.40 0.37
10-cm thick insulation 0.34 0.33 0.31 0.29 0.28 0.27 0.25

Table A3.2. Values of coefficients of thermal transmittance for different wall materials and combinations in Btu/hft²F°.

 

Wall Thickness (in in)
Type of Masonry 4.7 9.8 15 20 25 30 35
Red brick:
External wall plastered on exterior 0.533 0.369 0.281 0.227 0.190 0.164 0.143
External wall on both sides 0.512 0.348 0.274 0.223 0.186 0.162 0.141
External wall plastered on interior 0.389 0.272 0.213 0.174 0.145 0.127 0.113
Light concrete block:
External wall plastered on both sides 0.410 0.256 0.190 0.150 0.123 ... ...
Internal wall plastered on both sides 0.348 0.229 0.174 0.139 0.117 ... ...
Sand-lime brick:
External wall plastered on exterior 0.594 0.410 0.328 0.260 0.221 0.190 0.168
External wall plastered on both sides 0.553 0.389 0.307 0.252 0.215 0.186 0.166
Internal wall plastered on both sides 0.430 0.328 0.254 0.211 0.182 0.160 0.141
 

Wall Thickness (in in)
  12 16 20 24 28 31 35
Limestone masonry:
External wall plastered on exterior 0.492 0.410 0.369 0.328 0.297 0.272 0.250
External wall plastered on both sides 0.471 0.410 0.369 0.328 0.289 0.266 0.244
Internal wall plastered on both sides 0.389 0.348 0.307 0.281 0.256 0.238 0.221
Dense stone, including marble and granite:
External wall plastered on exterior 0.594 0.553 0.492 0.451 0.410 0.389 0.348
External wall plastered on both sides 0.573 0.512 0.471 0.430 0.389 0.369 0.348
Internal wall plastered on both sides 0.451 0.410 0.389 0.369 0.327 0.307 0.297
 

Wall Thickness (in in)
  2 4 6 8 12 16 20
Concrete masonry (gravel, cement, and sand):
External wall without plaster 0.860 0.737 0.635 0.553 0.451 0.369 0.328
Internal wall without plaster 0.635 0.553 0.492 0.451 0.369 0.327 0.279
External wall plastered on both sides 0.717 0.614 0.553 0.492 0.410 0.348 0.295
Internal wall plastered on both sides 0.553 0.492 0.451 0.410 0.348 0.295 0.260
 

Wall Thickness (in in)
  4.7 9.8 15 20 25 30 35
Red-brick double wall plastered on both sides with 13-31 cm cavity . . . 0.283 0.227 0.190 0.166 0.143 0.129
Ordinary red-brick wall insulated with cork sheeting on internal wall only for insulation:
0.8-in thick insulation 0.227 0.190 0.164 0.143 0.129 0.117 0.107
2-in thick insulation 0.125 0.113 0.102 0.094 0.088 0.082 0.076
4-in thick insulation 0.070 0.068 0.063 0.059 0.057 0.055 0.051

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