JANUARY 31 2003
system on either (or both) sides of the resistance bond.
Measure the DC ampere current flow through the bond and annotate the
direction of the current flow.
Measure potential of the metallic structures on both sides of the bond.
Evidence of proper functioning may be current output, normal power
consumption, a signal indicating normal operation, or satisfactory cathodic protection
levels on the structures, according to the function or design of the bond.
Compare measurements to measurements previously taken at the same
locations to determine if changes have occurred.
If the potential measurements, current flow, current direction, or other
measurement has changed from the last check, adjust or repair the component as
necessary, and repeat the test of the bond.
LEAK SURVEY. The leak survey is a comprehensive, thorough survey to
identify the cause of all leaks and the action required to prevent future leaks from
occurring, or to reduce the leak rate.
Maintenance Interval. Leak surveys should be conducted after excavation,
before backfilling of any leak on any pipeline or tank.
Measure the pH of the soil where it contacts the pipeline or tank.
4-10.2.2 Measure the "as found" S/E potential of the pipe or tank where it contacts the
soil. "As found" means before any adjustments of existing cathodic protection systems,
addition of any form of cathodic protection, or installation of isolation or bonding
Determine the cause of the leak.
4-10.2.4 Evaluate the condition and determine appropriate repairs to the pipe or tank
4-10.2.5 Measure the "as left" S/E potential of the pipe or tank where it contacts the
soil. "As left" means after all actions are taken to prevent future leaks. If these actions
are taken after backfill operations, surface potentials are acceptable as described in
If the leak survey determines the cause to be corrosion, determine the type