CLOUD POINT OF PETROLEUM PRODUCTS: D2500
(Equivalent Test Methods: IP 219, ISO 3015, DIN 51597, JIS K 2269, and AFNOR T60-105)
EXPLANATION
The cloud point of a petroleum oil is an index of the lowest temperature of its utility for certain applications. Cloud point is the temperature at which a cloud of wax crystals first appears in a liquid when it is cooled under conditions prescribed in this test method. This test method covers only petroleum oils which are transparent in layers 38 mm (1 1/2 in.) in thickness, and with a cloud point below 49° C (120° F). The cloud point is usually higher than the pour point (Test Method D97).

TEST SUMMARY
The sample is first heated to a temperature above the expected cloud point and then cooled at a specified rate and examined periodically. The temperature at which haziness is first observed at the bottom of the test jar is recorded as the cloud point.

TEST PRECISION