ASTM D7224 Standard Test Method for Determining Water Separation Characteristics of Kerosine-Type Aviation Turbine Fuels Containing Additives by Portable Separometer
1. Scope
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.

2. Referenced Documents
2.1 ASTM Standards:
D1655 Specification for Aviation Turbine Fuels
D2550 Method of Test for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1989)
D3602 Test Method for Water Separation Characteristics of Aviation Turbine Fuels (Withdrawn 1994)
D3948 Test Method for Determining Water Separation Characteristics ofAviation Turbine Fuels by Portable Separometer
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D7261 Test Method for Determining Water Separation Characteristics of Diesel Fuels by Portable Separometer

2.2 Military Standards:
MIL-DTL-5624 Turbine Fuel, Aviation Grades JP-4, JP-5, and JP-5/JP- 8 ST
MIL-DTL-25524 Turbine Fuel, Aviation, Thermally Stable
MIL-DTL-38219 Turbine Fuels, Low Volatility, JP-7
MIL-DTL-83133 Turbine Fuel, Aviation, Kerosene Types, NATO F-34 (JP-8), NATO F-35, and JP-8+100

3. Terminology
3.1 For definitions of the terms used in this test method that are not shown below, refer to Test Methods D3948 and D7261.

3.2 Definitions:
3.2.1 Micro-Separometer rating (MSEP rating), n - in the aviation fuel industry, a numerical value indicating the ease of separating emulsified water from aviation (jet) fuel by coalescence as affected by the presence of surface active materials (also known as surface active agents or surfactants).
3.2.1.1 Discussion - MSEP ratings are only valid within the range of 50 to 100, with ratings at the upper end of the range indicating a clean fuel with little or no contamination by surfactants, which is expected to show good water-separating properties when passed through a filter-separator (coalescing type filter) in actual service.

3.2.2 reference fluid, n - in MSEP and DSEP, [diesel separability] water separability tests, a reference fluid base to which a prescribed quantity of a known surface active agent has been added.
3.2.2.1 Discussion - The known surface active agent is typically bis-2-ethylhexyl sodium sulfosuccinate, commonly referred to as AOT, dissolved in toluene.

3.2.3 reference fluid base, n - in aviation MSEP water separability tests, jet fuel that has been cleaned in a prescribed manner to remove all surface-active contaminants (agents), and having a minimum MSEP rating of 97.

3.2.4 surfactant, n - in petroleum fuels, surface active material (or surface active agent) that could disarm (deactivate) filter separator (coalescing) elements so that free water is not removed from the fuel in actual service.
3.2.4.1 Discussion - Technically, surfactants affect the interfacial tension between water and fuel which affects the tendency of water to coalesce into droplets.

3.2.5 strong surfactant, n - in petroleum fuels, surface active material that disarms filter separator elements, allowing water to pass.
3.2.5.1 Discussion - Strong surfactants can be refinery process chemicals left in the fuel or contaminants introduced during transportation of the fuel.

3.2.6 weak surfactant, n - in petroleum fuels, surface active material, typically certain types of additives such as static dissipator additive, that does not adversely affect the performance of filter separator elements in actual service.

3.3 Definitions of Terms Specific to This Standard:
3.3.1 MCell Coalescer, n - referring to a particular coalescing filter element specifically designed for this test method.

3.4 Abbreviations:
3.4.1 AOT - aerosol OT (see 8.1).

3.4.2 DSEP - diesel separability.

3.4.3 MSEP - micro-separometer.

3.4.4 SDA - static dissipator additive.