This International Standard specifies a procedure of test for the amount of water content in DME used as fuel by the Karl Fischer titration method. This procedure is applicable to determine the amount of water up to the value specified in ISO 16861. This test method is intended for use with commercially available coulometric (or volumetric) Karl Fischer reagents and for the determination of water in DME additives, lube oils, base oils, automatic transmission fluids, hydrocarbon solvents, and other petroleum products. By proper choice of the sample size, this test method can be used to determine water from mg/kg (ppm) to percent level concentrations. NOTE The precision of this method has been studied for a limited set of samples and content levels by a limited amount of labs. It allows establishment of a quality specification of DME but cannot be considered as a full precision determination in line with the usual statistical methodology as in ISO 4259.