Nace CP 1, Course Manual

Page: 318 / 535

RP0285-2002
14 NACE International
8.1.2 Conditions that affect protection are subject to
change with time.
Corresponding changes may be
required in the CP system to maintain protection.
8.1.3 Periodic measurements and inspections are
necessary to detect changes in the CP system.
Conditions in which operating experience indicates
testing and inspections should be conducted more
frequently than recommended in this standard may
exist.
8.1.4 Care shall be exercised in selecting the location,
number, and type of electrical measurements used to
determine the adequacy of CP.
8.2 Maintenance Surveys
8.2.1 A survey shall be conducted after each CP
system is energized to determine whether it satisfies
applicable criteria (see Section 5) and operates
efficiently (see Paragraph 7.4).
8.2.2 Monitoring
8.2.2.1 All corrosion control systems shall be
monitored in accordance with NACE Standard
TM0101
18
to assure effective operation as
designed. The system shall be tested to verify its
effectiveness
after installation and whenever
construction or maintenance in the area of the
structure occurs.
8.2.2.2 Field-installed galvanic and impressed
current CP systems shall be tested annually.
8.2.2.3 A factory-installed CP system shall be
tested at an interval not to exceed three years if
manufactured in accordance with a nationally
recognized standard or code.
8.2.3 Inspection, surveys, and tests of CP systems
shall be made to ensure their effectiveness and proper
operation and maintenance as follows:
8.2.3.1 All sources of impressed current shall be
checked at intervals not exceeding two months.
Evidence of proper functioning may be current
output, normal power consumption, or a signal
indicating normal operation.
8.2.3.2 All impressed current CP facilities shall be
inspected annually as
part of a preventive
maintenance program to minimize in-service
failure. Inspections should include a check for
electrical shorts, ground connections, meter
accuracy, efficiency, and circuit resistance. The
effectiveness of isolating devices and continuity
bonds should be evaluated during the periodic
surveys.
This can be accomplished by on-site
inspection or by evaluating corrosion test data.
8.2.4 Test equipment used for obtaining each
electrical value shall be of an appropriate type (See
Paragraph 4.4.4). Instruments and related equipment
shall be maintained in good operating condition and
checked annually for accuracy.
8.3 Visual Inspection: If the UST or any part of the system
is uncovered, visual inspection for evidence of corrosion
and coating deterioration should be made. The necessary
repairs should be implemented to ensure continued
corrosion protection of the UST.
8.4 Remedial measures shall be taken when periodic tests
and inspections indicate that protection is no longer
adequate according to applicable criteria (see Section 5).
These measures may include the following:
8.4.1 Repair, replacement, or adjustment of CP
system components.
8.4.2 Providing supplementary facilities when
additional protection is necessary.
8.4.3 Repair, replacement, or adjustment of continuity
and interference bonds.
8.4.4 Elimination of accidental metallic contact.
8.4.5 Repair of defective isolating devices.
8.5 Records
8.5.1 All records of the CP system including the
following shall be maintained by the owner for the life of
the system.
8.5.2 A record of surveys, inspections, and tests shall
be maintained to demonstrate that applicable criteria
for CP have been satisfied (see Section 5).
8.5.3 Relative to the maintenance of corrosion control
facilities, the following information shall be recorded:
8.5.3.1 Maintenance of CP facilities.
8.5.3.1.1 Repair of rectifiers and other DC
power sources.
8.5.3.1.2 Repair or replacement of anodes,
connections, and cable.
8.5.3.2 Maintenance, repair, and replacement of
coating, isolating devices, test leads, and other
test facilities.
8.5.4 Records sufficient to demonstrate the evaluation
of the need for and the effectiveness of corrosion
control measures should be retained as long as the
facility involved remains in service.
Other related
corrosion control records should be retained for a
period that satisfies individual company needs.