ASTM D4176 method for free water and particulate contamination in distillate fuel
ASTM D4176 standard test method for free water and particulate contamination in distillate fuels (visual inspection procedures)
4. Summary of Test Method
4.1 In Procedure 1 approximately 900 mL of fuel is placed into a clear, glass, 1-L jar and is examined visually for clarity. The sample is then swirled and examined for visual sediment or water drops below the vortex.
4.2 In Procedure 2 approximately 900 mL of fuel is placed into a clear, glass, 1-L jar and is examined visually for clarity. Fuel clarity is rated by placing a standard bar chart behind the sample and comparing its visual appearance with the standard haze rating photos. The sample is then swirled and examined for visual sediment or water drops below the vortex.
4.3 When field testing, both Procedures 1 and 2 are performed immediately after sampling and at storage temperature conditions.
4.4 When lab testing, both Procedures 1 and 2 are performed after the sample has equilibrated at the test temperature of interest.
5. Significance and Use
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.
6. Interferences
6.1 When a fuel is tested at low temperatures at or below the cloud point temperature of the fuel, small amounts of solid wax particles may be confused with a water-induced haze or cloudiness.
6.2 If an attempt is made to use the test with fuels darker than a color rating of 5 in Test Method D1500, the presence of free water or particulate could be obscured and missed by the viewer.
