Formicary Corrosion of Copper Tubing in a Buried Application

Natural gas and propane supply lines made from copper leaked in buried underground service conditions. Formicary corrosion was identified as the failure mechanism after a detailed failure analysis. A complete chemical analysis of the unused copper tubing and at in areas surrounding leak sites identified the source of the contamination that resulted in formicary corrosion. While copper piping and tubing have been known to suffer from formicary corrosion in automotive and HVAC applications for example, the key factors that resulted in this type of corrosion in a buried application will be discussed.