Acid Number

Definition

Acid Number is the amount of acid present. Values higher than that of the new lubricant is an indication of oxidation or contamination.

Standard Test Method Used

mod. ASTM D664

Reporting Measurement

mg KOH/g (milligrams potassium hydroxide per gram of sample)

Amount of Sample Needed

4g

Test Limitation

Does not determine type of acid, only amount of acid present. Does not distinguish between strong or weak acids.

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