1.1 This test method describes a procedure for determining the filter blocking tendency (FBT) of distillate fuel oils where the end use demands an exceptional degree of cleanliness. This test method is applicable to fuels within the viscosity range of 1.50 to 6.00 mm2/s (cSt) at 40°C.

Note 1-ASTM specification fuels falling within the scope of this test method are Specification D396 Grade Numbers 1 and 2, Specification D975 Grades 1-D and 2-D, and Specification D2880 Grades 1-GT and 2-GT.

1.2 This test method is thus not applicable to fuels that are found to contain undissolved water, because such water interferes with the measurement of filter blockage (see 9.3).

1.3 Annex A1 describes a standard procedure for preparing a test fluid for use in calibrating the apparatus used in this test method.

1.4 The values stated in acceptable SI units shall be considered standard.

1.5 This standard does not purport to address all of the safety problems 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.> Specific precautionary statements are given in Notes 2 and 3.