Test Method for the Determination of Total Acidity in Polyol Ester and Diester Gas Turbine Lubricants by Automatic Potentiometric Titration
ARP5088
The test method describes the procedure for determination of the total acid number of new and degraded polyol ester and diester based gas turbine lubricants by potentiometric titration technique. The method was validated to cover an acidity range 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 lubricant.
Rationale: Method is overdue for 5-year review, and furthermore the committee has approved some changes such as defining the ASTM grade of water, insertion of annex to include electrode maintenance. It is also planned to allow a smaller solvent size to improve HSE credentials, subject to round robin data being acceptable
