Test Method for the Determination of Total Acidity in Polyol Ester and Diester Gas Turbine Lubricants by Automatic Potentiometric Titration ARP5088C

The test method describes the procedure for determination of the total acid number (TAN) of new and degraded polyol ester and diester-based gas turbine lubricants by the potentiometric titration technique. The method was validated to cover an acidity range of 0.05 to 6.0 mg KOH g^-1. The method may also be suitable for the determination of acidities outside of this range and for other classes of lubricants.