ASTM D156 – Standard Test Method for Saybolt Color of Petroleum Products (Saybolt Chromometer Method)
Description:
Significance and Use
5.1 Determination of the color of petroleum products is used mainly for manufacturing control purposes and is an important quality characteristic since color is readily observed by the user of the product. In some cases the color may serve as an indication of the degree of refinement of the material. When the color range of a particular product is known, a variation outside the established range can indicate possible contamination with another product. However, color is not always a reliable guide to product quality and should not be used indiscriminately in product specifications.
Scope
1.1 This test method covers the determination of the color of refined oils such as undyed motor and aviation gasoline, jet propulsion fuels, naphthas and kerosine, and, in addition, petroleum waxes and pharmaceutical white oils.
NOTE 1: For determining the color of petroleum products darker than Saybolt Color − 16, see Test Method D1500.
1.2 This test method reports results specific to this test method and recorded as, “Saybolt Color units.”
1.3 The values stated in inch-pound units or in SI units and which are not in parentheses are to be regarded as the standard. The values given in parentheses are for information only.
NOTE 2: Oil tubes and apparatus used in this test method have traditionally been marked in inches, (the tube is required to be etched with 1/8 in. divisions.) The Saybolt Color Numbers are aligned with inch, 1/2 in., 1/4 in., and 1/8 in. changes in the depth of oil. These fractional inch changes do not readily correspond to SI equivalents and in view of the preponderance of apparatus already in use and marked in inches, the inch/pound unit is regarded as the standard. However the test method does use SI units of length when the length is not directly related to divisions on the oil tube and Saybolt Color Numbers. The test method uses SI units for temperature.
ASTM D1557