Nace CP 1, Course Manual

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RP0169-2002
NACE International 21
________________________________________________________________________
Section 8: Installation of Cathodic Protection Systems
8.1 Introduction
8.1.1 This section recommends procedures that will
result in the installation of cathodic protection systems
that achieve protection of the structure.
The design
considerations recommended in Sections 4 and 7
should be followed.
8.2 Construction Specifications
8.2.1 All construction work on cathodic protection
systems should be performed in accordance with
construction
drawings and specifications. The
construction specifications should be in accordance
with recommended practices in Sections 4 and 7.
8.3 Construction Supervision
8.3.1 All construction work on cathodic protection
systems should be performed under the surveillance of
trained and qualified personnel to verify that the
installation is in strict accordance with the drawings and
specifications. Exceptions may be made only with the
approval of qualified personnel responsible for external
corrosion control.
8.3.2 All deviations from construction specifications
should be noted on as-built drawings.
8.4 Galvanic Anodes
8.4.1 Inspection, Handling, and Storage
8.4.1.1 Packaged anodes should be inspected
and steps taken to ensure that backfill material
completely surrounds the anode.
The individual
container for the backfill material and anode
should be intact. If individually packaged anodes
are
supplied in waterproof containers, the
containers must be removed before installation.
Packaged anodes should be kept dry during
storage.
8.4.1.2 Lead wire must be securely connected to
the anode.
Lead wire should be inspected for
assurance that it is not damaged.
8.4.1.3 Other galvanic anodes, such as the
unpackaged “bracelet” or ribbon type, should be
inspected to ensure that dimensions conform to
design specifications and that any damage during
handling does not affect application. If a coating is
used on bands and the inner side of bracelet
anode segments, it should be inspected and, if
damaged,
repaired before the anodes are
installed.
8.4.2 Installing Anodes
8.4.2.1 Anodes should be installed according to
construction specifications.
8.4.2.2 Packaged galvanic anodes should be
backfilled with appropriately compacted material.
When anodes and special chemical backfill are
provided separately, anodes should be centered in
special backfill, which should be compacted prior
to backfilling. Care should be exercised during all
operations so that lead wires and connections are
not damaged. Sufficient slack should exist in lead
wires to avoid strain.
8.4.2.3 When anodes in bracelet form are used,
external pipe coating beneath the anode should be
free of holidays. Care should be taken to prevent
damage to the external coating when bracelet
anodes are installed. After application of concrete
(if used) to pipe, all coating and concrete should
be removed from the anode surface. If reinforced
concrete is used, there must be no metallic
contact between the anode and the reinforcing
mesh or between the reinforcing mesh and the
pipe.
8.4.2.4 When a ribbon-type anode is used, it can
be trenched or plowed in, with or without special
chemical backfill as required, generally parallel to
the section of pipeline to be protected.
8.5 Impressed Current Systems
8.5.1 Inspection and Handling
8.5.1.1 The rectifier or other power source should
be inspected to ensure that internal connections
are mechanically secure and that the unit is free of
damage. Rating of the DC power source should
comply with the construction specification. Care
should be exercised in handling and installing the
power source.
8.5.1.2 Impressed current anodes should be
inspected
for conformance to specifications
concerning anode material, size, length of lead
cable, anode lead connection, and integrity of seal.
Care should be exercised to avoid cracking or
damaging anodes during handling and installation.
8.5.1.3 All cables should be carefully inspected to
detect defects in insulation. Care should be taken
to avoid damage to cable insulation. Defects in
the cable insulation must be repaired.