ASTM D 664 Total Acid Number - ASTM D 2896 Total Base Number

Testing Total Acid Number (Total Acid Number) is a measurement of the acidity of a lubricating oil which is determined by the number of milligrams of potassium hydroxide (KOH) needed to neutralize free fatty acids in one gram of lubricating oil. High acid numbers will affect the acidity and corrosiveness of the oil, if the corrosion rate increases it will accelerate the corrosion of metal materials.

The Total Acid Number test can use the ASTM D 664 method. The TAN value is expressed in mgKOH/g.

Total Base Number is a measurement of the basicity of a lubricating oil which is determined by the number of milligrams of potassium hydroxide (KOH) in one gram of oil. The higher the Total Base Number value in the oil, the better its ability to neutralize contaminants such as combustion by-products and acids formed during engine operation.

The Total Base Number test can use the ASTM D 2896 method. The TBN value is expressed in mgKOH/g.