1.1 This test method describes a technique for measuring the concentration of Ethylene Glycol Monomethyl Ether (EGME) and Diethylene Glycol Monomethyl Ether (DiEGME) in aviation fuels. The HB and Brix scale refractometers are specified to determine the concentration of these fuel system icing inhibitors (FSII) by measuring the refractive index of a water extract. Precision estimates have been determined for the EGME and DiEGME additives using specific extraction ratios with a wide variety of fuel types. The extraction ratios are high enough that portable hand-held refractometers can be used, but not so high as to sacrifice accuracy or linearity, or both, in the 0.01 to 0.25 vol % range of interest.

1.2 This test method does not identify which FSII additive is present. The analyst must know which additive is to be measured prior to performing the test. Consult the appropriate fuel specification to determine which additive is to be measured.

1.3 The values stated in SI units are to be regarded as the standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 4.1, 8.2, 9.2.1.1, 9.3.1.1, 9.3.2, and 9.3.10