We offer these Color Rating Charts in accordance with ASTM D2276/IP216. The limits of acceptable fuel quality are set by such organizations as A4A and EI. There ratings are for testing aviation turbine fuels.

The three color scales are identified as the A, B, and G scales. The A scale is a reddish shade, indicative of a red oxide (or rust) contamination. The B scale is tan, and is representative of dust/dirt/soil, oxidation products, or silica. It can even be an indication of diesel contamination. A reading on the grey colored G scale may indicate either black iron oxide or black sulfides for example. When evaluating a Membrane for color, if the shade is between two ratings, report the lower number.

The color rating method is an important means of communication throughout the industry. But this test method has as its primary objective the means for telling you that something is wrong.

ATA Spec 103 (A4A) sets the recommended limits for acceptable ratings here in the USA. Currently those parameters are as follows; A, B or G 2 – DRY -or- A, B or G3 – WET. Anything observed outside of these limits may indicate a contamination problem and should be reported immediately. (Wet ratings should be reserved for experienced QC personnel.)

See also:

• GamGram 13: The Mystery of the Color Rating
• GamGram 25: Filter Membrane Testing and Rating
• GamGram 4: Anatomy of a Jet Fuel Pipe
• GamGram 6: Anatomy of a Sampling Connection
• GamGram 42
• GamGram 67