CONVERSION FACTORS

Appendix B

CONVERSION FACTORS

377

Table B.l Conversion Factors for Quantity of Radiation per Unit Area Units 1 1 1 1

Jm~2 Whm"2 cal c m - 2 Btuft" 2

Jm"2

Whm"2

calcm" 2 a

Btuft" 2

1 3.60 x 103 4.187 x 104 1.136 x 104

2.778 x 10" 4 1 11.63 3.155

2.39 x 10" 5 0.0860 1 0.271

8.81 x 10" 5 0.317 3.69 1

a

It is useful to note that in the United States, cal cm" 2 is also called Langley, named after Samuel Pierpont Langley (1834-1906) of the Smithsonian Institution, a pioneer of solar radiation studies, astronomer, physicist, inventor and engineer. He built the first steam-driven pilotless airplane.

Table B.2 Conversion Factors for Radiant Flux per Unit Area Units

Wm~2

cal cm" 2 min" 1

Btuft" 2 h"

1 Wm"2 1 cal cm" 2 min"* 1 Btuft" 2 h" 1

1 698 3.155

1.433 x 10" 3 1 4.521 x 1 0 ' 3

0.317 221.2 1