306.5—Automotive fuel rating.
If you are a refiner, importer, or producer, you must determine the automotive fuel rating of all automotive fuel before you transfer it. You can do that yourself or through a testing lab.
(a)
To determine the automotive fuel rating of gasoline, add the research octane number and the motor octane number and divide by two, as explained by the American Society for Testing and Materials (“ASTM”) in ASTM D4814-92c, entitled “Standard Specifications for Automotive Spark-Ignition Engine Fuel.” To determine the research octane number, use ASTM standard test method D2699-92, and to determine the motor octane number, use ASTM standard test method D2700-92.
(b)
To determine automotive fuel ratings for alternative liquid automotive fuels other than biodiesel blends and biomass-based diesel blends, you must possess a reasonable basis, consisting of competent and reliable evidence, for the percentage by volume of the principal component of the alternative liquid automotive fuel that you must disclose. In the case of biodiesel blends, you must possess a reasonable basis, consisting of competent and reliable evidence, for the percentage of biodiesel contained in the fuel, and in the case of biomass-based diesel blends, you must possess a reasonable basis, consisting of competent and reliable evidence, for the percentage of biomass-based diesel contained in the fuel. You also must have a reasonable basis, consisting of competent and reliable evidence, for the minimum percentages by volume of other components that you choose to disclose.