Acids and sulfur-containing compounds have the potential to cause corrosion in an engine system. The Copper Strip Corrosion test, performed in accordance with ASTM D130, indicates the potential of the biodiesel to affect copper and brass fuel system parts. Polished copper strips are immersed in the biodiesel sample and placed in a sample tube in a heated bath for several hours. The sample test strip is then compared to a standard test strip to determine the effect of the biodiesel on the copper.
ASTM D6751 Requirement: a maximum copper strip corrosion Number 3.