(Equivalent Test Method: IP 435)
This is an automated phase transition method used in the temperature range -80 to 20° C. Results by this test method have a resolution of 0.1° C, and have a precision better than that of Test Method ASTM D2386. It also eliminates most of the operator time and judgment required in Test Method ASTM D2386. In this test, a specimen is cooled at a rate of 15 +/- 5 ° C/min by a Peltier device while continuously being illuminated by a light source. The specimen is continuously monitored by an array of optical detectors for the first formation of solid hydrocarbon crystals. After that the specimen is warmed at the rate of 10 +/- 0.5° C/min until all crystals return to the liquid phase, and that temperature is also recorded.
TEST PRECISION
Bias of any of these three methods is not known. However, all three give equivalent results.