A portion of the sample is titrated with an acid solution to a certain end point. The greater the amount of acid needed to reach the endpoint, the higher the base number.
Certain oils such as engine oils have an alkaline reserve additive. This test measures the amount of reserve remaining and a recommendation on lubricant health can be made. Base number is highest when the oil is new and decreases with time.
Diesel and gasoline engine oils are most commonly subject to this type of testing.
|BASE NUMBER (mg KOH / g)|
Applications. Diesel engines.