Building with earth - Gernot MINKE (1)

Measures
Physical values
R- and U-values
In this book, all measures as regards lengths
and areas as well as physical values are based on
the metric system. The Anglo-Saxon equivalent
of the U-value (describing thermal conductivity in
Central Europe) is the R-value, which has been
added in brackets. In this context, it must be
noted that the R-values are based on the metric
system.
To enable readers to convert values into the
imperial system that is most commonly used
in North America we have listed the most important
conversion factors as follows:
Temperature
Centigrade (Celsius) – Fahrenheit
Multiply by 9/5 and add 32
°C °F
–10 14
0 32
10 50
20 68
30 86
All R- and U-values in this book have been stated
according to the metric system. For the conversion
of the metric system (USI, RSI) into the
respective imperial system (U, R), the use of factors
is required:
R x 0.1761= RSI
RSI x 5.6783 = R
U-values are the reciprocals of the respective
R-values and vice versa.
Lengths and areas
1 mm = 0.03937 inches
1 cm = 0.3937 inches
1 m = 39.37 inches
1 m 2 = 10.764 square feet
1 ha = 2.471 acres
USI (W/m 2 K) RSI (m 2 K/W) U (BTU/hr * sq. ft. * °F) R (hr * sq. ft. * °F/BTU)
0.1 10 0.018 56.78
0.15 6.667 0.026 37.86
0.2 5 0.035 20.39
0.3 3.333 0.053 18.93
0.5 2 0.080 11.36
1.0 1 0.176 5.68
1 inch = 2.54 cm
1 foot = 30.48 cm
1 square foot = 0.093 m 2
1 acre = 0.4047 ha
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Appendices