Nace CP 1, Course Manual

Page: 282 / 535

RP0169-2002
NACE International 11
Table 4 Continued
Design and Construction Factor Recommended Test Methods
(A)
Suitability of Joint Coatings and Field Repairs
Peabody’s Control of Pipeline Corrosion
15
ANSI/AWWA C 213
16
API RP 5L7
17
CSA Z245.20M
18
NACE Standard RP0190
19
ASTM G 8
25
ASTM G 19
26
ASTM G 42
27
ASTM G 95
28
ASTM G 9
29
ASTM G 18
42
ASTM G 55
43
(A)
No specific criteria are available. Comparative tests are recommended for use and evaluation as supplementary information only.
TABLE 5
Methods for Evaluating In-Service Field Performance of External Coatings
Title or Subject of Method Reference Basis for Rating
(1) Rate of Change in Current
Required for Cathodic
Protection Underground Corrosion
34
Comparison of initial current requirement with
subsequent periodic determination of current
requirement
(2) Inspection of Pipeline
Coating NACE Standard RP0274
12
(a) With cathodic protection: no active corrosion
found
(b) Without cathodic protection: no new holidays
showing active corrosion
(3) Cathodic Disbondment ASTM G 8
25
ASTM G 19
26
ASTM G 42
27
ASTM G 95
28
Purpose is to obtain data relative to specific
conditions for comparison with laboratory data
5.2.2 Inspection
5.2.2.1 Qualified personnel should keep every
phase
of the coating operation and piping
installation under surveillance.
5.2.2.2 Surface preparation, primer application,
coating thickness, temperature, bonding, and
other specific requirements should be checked
periodically, using suitable test procedures, for
conformance to specifications.
5.2.2.3 The use of holiday detectors is
recommended to detect coating flaws that would
not be observed visually.
The holiday detector
should be operated in accordance with the
manufacturer’s instructions and at a voltage level
appropriate to the electrical characteristics of the
coating system.
5.2.3 Installation
5.2.3.1 Joints, fittings, and tie-ins must be coated
with a material compatible with the existing
coating.
5.2.3.2 Coating defects should be repaired.
5.2.3.3 Materials used to repair coatings must be
compatible with the existing pipe coating.
5.2.3.4 The ditch bottom should be graded and
free of rock or other foreign matter that could
damage the external coating or cause electrical
shielding. Under difficult conditions, consideration
should be given to padding the pipe or the ditch
bottom.
5.2.3.5 Pipe should be lowered carefully into the
ditch to avoid external coating damage.
5.2.3.6 Care should be taken during backfilling so
that rocks and debris do not strike and damage
the pipe coating.