Testing the Copper Corrosion Properties of Fuel

Hydrogen sulfide, mercaptans, active elemental sulfur, inorganic acids, and ammonia can all attack and corrode copper. The presence of these compounds in fuel can lead to destruction of copper heating lines, cooling coils, and nonferrous metal fittings. Also, hydrogen sulfide and mercaptans can contribute to fuel odor problems. 

Although there is no ASTM specification for gasoline mercaptan or hydrogen sulfide levels, a copper corrosion specification does exist. Since mercaptans and hydrogen sulfide attack copper and copper-containing alloys such as brass and bronze, it is important to minimize fuel mercaptans and hydrogen sulfide concentrations. 

Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test 

A polished copper strip is immersed in a given quantity of sample and heated at a temperature specified for the fuel or oil being tested. 

At the end of the test period, the copper strip is removed, washed, and compared with the ASTM copper strip standards. 

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