In the weathering test for propane, add 0.3°C (0.6°F) to
the corrected temperature for each 1.3 kPa (10 mm Hg) that the
test is conducted below 101 kPa (760 mm) pressure, or subtract
0.3°C (0.6°F) from the observed temperature for each 1.3 kPa
(10 mm Hg) that the test is conducted above 101 kPa (760
mm).