5.1 This test method provides a measurement of the presence of surfactants in aviation turbine fuels. Like previous obsolete Test Methods D2550 and D3602 and current Test Method D3948, this test method can detect trace amounts of refinery treating chemicals in fuel. The test methods can also detect surface active substances added to fuel in the form of additives or picked up by the fuel during handling from point of production to point of use. Some of these substances degrade the ability of filter separators to separate free water from the fuel.

5.2 This test method yields approximately the same (low) MSEP ratings as Test Method D3948 for fuels that contain strong surfactants.

5.2.1 This test method will give approximately the same MSEP ratings for Jet A, Jet A-1, JP-5, JP-7, and JP-8 fuels as Test Method D3948 when testing reference fluids.

5.3 The MSEP ratings obtained by this test method are less affected by weak surfactants than Test Method D3948. Somewhat higher MSEP ratings for Jet A, Jet A-1, JP-5, JP-7, and JP-8 fuels are obtained by this test method than those obtained by Test Method D3948 when additives such as static dissipater additives (SDA) and corrosion inhibitors are present in the fuel. This correlates with the satisfactory performance of filter separators for such fuels, when wet. However, these same additives adversely affect the MSEP ratings obtained by Test Method D3948 by erroneously indicating that such additized fuels would significantly degrade the ability of filter separators to separate free water from the fuel in actual service.

5.4 The Micro-Separometer instrument has an effective measurement range from 50 to 100. Values obtained outside of those limits are undefined and invalid.

Note 1: In the event a value greater than 100 is obtained, there is a good probability that light transmittance was reduced by material, typically water, contained in the fuel that was used to set the 100 reference level. During the coalescing portion of the test, the contaminating material as well as the 50 µL ± 1 µL of distilled water was subsequently removed during this portion of the test. Thus, the processed fuel had a higher light transmittance than the fuel sample used to obtain the 100 reference level resulting in the final rating measuring in excess of 100.

1.1 This test method covers a rapid portable means for field and laboratory use to rate the ability of kerosine-type aviation turbine fuels, both neat and those containing additives, to release entrained or emulsified water when passed through fiberglass coalescing material.

1.1.1 This test method is applicable to kerosine-type aviation turbine fuels including: Jet A and Jet A-1 (as described in Specification D1655); JP-5, JP-7, JP-8, and JP-8+100. (See Section 6.)

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.3 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 warning statements, see 8.2 – 8.5.