JANUARY 31 2003
SCOPE. This handbook provides guidance for inspection and maintenance of
cathodic protection (CP) systems. It should be used by field personnel to perform
scheduled inspections and preventive maintenance, and to troubleshoot and repair
defects. Information on non-routine field measurements is also included to enable
technical assistance personnel to troubleshoot problems beyond the capability of field
personnel to isolate or correct. For Army facilities use Public Works Bulletin 420-49-29,
Operation and Maintenance of Cathodic Protection Systems, 2 December 1999.
CATHODIC PROTECTION SYSTEMS. Cathodic protection is an
electrochemical method used to prevent or control corrosion of buried or submerged
metallic structures. CP systems are active systems that rely on the application of
electric current to control corrosion. If current is interrupted, corrosion will progress at a
normal rate for the material/environment combination; if supplied current is inadequate
for complete protection, corrosion will progress at a reduced rate. After a CP system is
installed and adjusted to provide adequate protection, currents and potentials should
remain relatively stable; changes in currents or potentials indicate a problem.
Application. Facilities that may employ cathodic protection in a corrosion
control program include:
Underground fuel storage tanks and ground level tank bottoms.
Fuel distribution systems.
Elevated and ground level water storage tank interiors.
Potable water distribution systems.
Natural gas distribution systems.
Compressed air distribution systems.
Sewage lift stations.
Steel sheet pile seawalls, pier support/fender piles, and other submerged
Concrete reinforcing steel.