This test method is intended for use in the laboratory or in the field for evaluating the cleanliness of distillate fuels, and liquid bio fuels. It is not applicable to on or in-line applications.

This test method offers advantage over traditional filtration methods in that it is a precise rapid test, and advantage over visual methods as it is not subjective.

An increase in particle counts can indicate a change in the fuel condition caused by storage or transfer for example.

High levels of particles can cause filter blockages and have a serious impact on the life of pumps, injectors, pistons and other moving parts. Knowledge of particle size in relation to the metallurgy can provide vital information especially if the hardness of particles is also known from other sources.

This test method specifies a minimum requirement for reporting measurements in particle size bands (see A1.1.2). Some specific applications may require measurements in other particle size bands.

Obtaining a representative sample and following the recommended sample and test specimen preparation procedures and timescales is particularly important with particle counting methods. (See Sections 8, 10, 14.1.4 and Note 8.)

1.1 This test method uses a specific automatic particle counter (APC) to count and measure the size of dispersed dirt particles, water droplets and other particles, in light and middle distillate fuel, and bio fuels such as biodiesel and biodiesel blends, in the overall range from 4 µm(c) to 100 µm(c) and in the size bands ≥4 µm(c), ≥6 µm(c), and ≥14 µm(c).

Note 1—ASTM specification fuels falling within the scope of this test method include Specifications: D975 grades 1D and 2D, D1655, D3699, D4814 (see 14.1.1.1), D6751, D6985, D7467 and distillate grades of D396 and D2880.

Note 2—For the purposes of this test method, water droplets are counted as particles, and agglomerated particles are detected and counted as a single larger particle. Dirt includes biological particles. Although the projected area of a particle is measured, this is expressed as the diameter of a sphere for the purposes of this test method.

Note 3—The notation (c), used with particle sizes, is used to denote that the apparatus has been calibrated in accordance with ISO 11171. Strictly this only applies to particles up to 50 µm.

Note 4—This test method may be used for particle sizes bands up to 100 µm(c), however the precision has only been determined for the size bands ≥4 µm(c), ≥6 µm(c), and ≥14 µm(c). All measurements are per mL.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

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.