5.1 It has long been the practice to include in fuel specifications a requirement that the fuel be clear and bright and free of visible particulate matter (see Note 1). However, there has been no standard method for making this determination so that practices have differed. This test method provides standard procedures for the test.

Note 1: Clean and bright is sometimes used in place of clear and bright. The meaning is identical.

5.2 Procedure 1 provides a rapid pass/fail method for contamination in a distillate fuel. Procedure 2 provides a gross numerical rating of haze appearance, primarily as a communication tool. Other test methods, including Test Methods D1744, D2276, D2709, and D4860, permit quantitative determinations of contaminants. No relationship has been established between Procedure 2 and various quantitative methods.

5.3 Limited laboratory evaluations of samples that have failed this clear and bright test indicate that an experienced tester can detect as little as 40 ppm of free water in the fuel.

1.1 This test method covers two procedures for estimating the presence of suspended free water and solid particulate contamination in distillate fuels having distillation end points below 400°C and an ASTM color of 5 or less.

1.1.1 Both procedures can be used as field tests at storage temperatures, or as laboratory tests at controlled temperatures.

1.1.2 Procedure 1 provides a rapid pass/fail method for contamination. Procedure 2 provides a gross numerical rating of haze appearance.

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.