Abstract
A protected and an unprotected length of aluminum gas line pipe were buried at the same time and put into use. The longer length was protected by coating with a grease type sealant followed by a wrap of dielectric material; the shorter length was put into the ground unprotected. One month after the wrapped aluminum was installed a cathodic protection survey was performed. By means of a field test it was determined that a current requirement of only 97 milli-amperes polarized the aluminum line from a potential of —0.85 volt to —1.00 volt referred to a saturated copper sulfate electrode.
The two lines were dug up at the end of five years and examined for corrosion. The insulating gaskets of the unprotected pipe line were found to be in good condition; the unprotected line was superficially stained over its entire length but the stain was of no significant depth. In spite of these findings the author thought it necessary in future operations to adequately coat aluminum lines and to supply the modest requirements for cathodic protection in order to eliminate the hazards of soil corrosion and electrolytic corrosion. 2.2.6
