OXIDATION STABILITY OF GASOLINE: D525
(Equivalent Test Methods: IP 40, ISO 7536, DIN 51780, and AFNOR M07-012)
EXPLANATION
The induction period may be used as an indication of the tendency of motor gasoline to form gum in storage. However, its correlation with the formation of gum in storage may vary markedly under different storage conditions and with different gasolines.
This test method is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as they may cause explosive conditions within the apparatus.
TEST SUMMARY
The sample is oxidized in a pressure vessel initially filled at 15 to 25° C with oxygen pressure at 680 to 703 kPa and heated at a temperature between 98 and 102° C. The pressure is recorded continuously at stated intervals until the breakpoint is reached. The time required for the sample to reach this point is the observed induction period at the temperature of the test from which the induction period at 100° C can be calculated.
TEST PRECISION
Repeatability: 5%
Reproducibility: 10 %
The bias for this test method has not been determined.
