ASTM D2440-13

This test method determines the resistance of mineral transformer oils to oxidation under prescribed accelerated aging conditions. Oxidation stability is measured by the propensity of oils to form sludge and acid products during oxidation. This test method is applicable to new oils, both uninhibited and inhibited, but is not well defined for used or reclaimed oils.

Note 1- A shorter duration oxidation test for evaluation of inhibited oils is available in Test Method D2112.

Note 2 - For those interested in the measurement of volatile acidity, reference is made to IEC Method 61125.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.