DIN ISO 6618:2015-07

This document contains the German translation of the International Standard ISO 6618:1997 which has been prepared by Technical Committee ISO/TC 28 "Petroleum products and lubricants". The responsible national committee is Working Committee NA 062-06-84 AA "Gemeinschaftsausschuss NA 062-06-42 AA/NA 062-06-61 AA" ("Joint working group NA 062-06-42 AA/NA 062-06-61 AA") of the Petroleum, Fuels, Lubricants and Related Products Standardization Committee (FAM) at the Materials Testing Standards Committee (NMP). This International Standard specifies a colour-indicator titration method for the determination of acidic or basic constituents in petroleum products and lubricants soluble in mixtures of toluene and propan-2-ol. The method is applicable for the determination of acids or bases whose dissociation constants in water are greater than 10^-9. The method is not suitable for measuring the basic constituents of many basic additive-type lubricating oils. They can be determined according to ISO 3771. This International Standard indicates relative changes that occur in an oil during use under oxidizing conditions. Although the titration is made under definite equilibrium conditions, the method does not measure an absolute acidic or basic property that can be used to predict performance of an oil under service conditions.