4.1.1 The condition of the coating in crude oil
cargo tanks is assigned and categorized as "GOOD", "FAIR" or "POOR",
based on visual inspection and estimated percentage of areas with
coating failure and rusty or blistered surfaces.
4.1.2 The definitions of coating conditions "GOOD",
"FAIR" and "POOR" in the Guidelines on the enhanced programme of inspections
during surveys of oil tankers (resolution
A.744(18)) are as follows:
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Good
Condition with only minor spot
rusting.
-
Fair
Condition with local breakdown
of coating at edges of stiffeners and weld connections or light rusting
over 20% or more of areas under consideration, but less than as defined
for POOR condition.
-
Poor
Condition with general breakdown
of coating over 20% or more of areas or hard scale at 10% or more
of areas under consideration.
4.1.3 These Guidelines clarify the above definitions
in order to achieve unified assessment of cargo tank coating conditions
as follows, see also table 1 below:
-
Good
Condition with spot breakdown
on less than 5% of the area under consideration without visible failure
of the coating, or non perforated blistering. Breakdown at edges or
welds should be less than 20% of edges or weld lines in the area under
consideration.
-
Fair
Condition with breakdown of
coating or penetration on less than 20% of the area under consideration.
Total paint failure should be less than 10% of the area under consideration.
Breakdown at edges or welds should be less than 50% of edges or weld
lines in the area under consideration.
-
Poor
Condition with breakdown of
coating or penetration on more than 20% or on total paint failure
more than 10% of the area under consideration or local breakdown concentrated
at edges or welds on more than 50% of edges or weld lines in the area
under consideration.
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Table 1 – "GOOD", "FAIR" and "POOR" coating conditions
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GOOD (3)
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FAIR
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POOR
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| Breakdown of coating (spot breakdown)
(1)(3)
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< 5%
|
5 – 20%
|
> 20%
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| Area of complete breakdown
(1)
|
—
|
< 10%
|
≥ 10%
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| Local breakdown of coating on edges or
weld lines (2)
|
< 20%
|
20 – 50%
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> 50%
|
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Notes:
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1 % is the percentage calculated on basis of the area
under consideration or of the "critical structural area".
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2 % is the percentage calculated on basis of edges or
weld lines in the area under consideration or of the "critical structural
area".
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3 Spot breakdown, i.e. rusting in spots without
visible failure of coating.
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