abs inspection grading criteria

8/10/2019 ABS Inspection Grading Criteria

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NOTICE

This manual and the inspection regime described herein are foruse solely within the ABS Hull Inspection Maintenance Program(HIMP). The grading and actions to be taken on those gradingsare of a suggested nature only. They are not to be construed asrepresentative of ABS class criteria or the actions taken by classupon discovery of the various types of defects noted in this hullinspection grading manual.

Owner inspections carried out utilizing this manual do not replaceor substitute the classification survey requirements as stated inIACS PR-33.

IACS PR-33 Owners Hull Inspection and Maintenance SchemesOwners hull inspection and maintenance schemes are to

be encouraged as means for maintaining compliance withclassification and statutory requirements between surveys.However, these schemes are not to be accepted as an alternativeto, or a substitute for, the performance of required classificationand/or statutory surveys of the hull by the surveyors of the society,or of another duly authorized society. The surveyors may beassisted, where appropriate, by service suppliers as defined inUR Z17.


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INSPECTION GRADING CRITERIA FOR ABS HIMP 1

Table of Contents

Introduction ............................................................... 2

Inspection Criteria..................................................... 4

Coating Condition..................................................... 5

General Corrosion ....................................................15

Pitting & Grooving Corrosion................................. 25

Deformation............................................................. 34

Fracture .................................................................... 43

Cleanliness & Housekeeping................................... 50

Notifying Superintendent & Class Surveyor............ 59

Point Rating System................................................. 60


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2 INSPECTION GRADING CRITERIA FOR ABS HIMP

Introduction

This manual should be utilized in accordance with

the Hull Inspection and Maintenance Program(HIMP) outlined in the ABS Guide for Hull Inspectionand Maintenance Program. Vessels enrolled in theprogram will be eligible for the HIMP class notation.

This hull inspection grading manual details a program

for hull structural inspections to be performed byqualified inspectors in order to comply with theABS HIMP Guide. It outlines the work scope andreporting requirements for this vessel and containsthe information to be collected by the vessel crew orsuperintendents. Staff executing the HIMP inspection

regime are to be formally qualified by successfullycompleting the ABS approved HIMP training.The hull condition is to be assessed and rated inaccordance with a set of six general conditioncriteria coupled with selected targeted inspectionsof identified critical areas for this design series.

This manual draws on the information available fromIMO, IACS and ABS publications. It is intended tosupport the sound judgment of qualified inspectorsand assist owners with the development and appli-cation of a reliable maintenance program based

on inspection and reporting techniques that are inconformance with the ABS HIMP Guide requirements.


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This manual is to be used in conjunction with thefollowing ABS publications:

Guide for Hull Inspection and Maintenance Program

Rules for Building and Classing Steel Vessels, Part7: Surveys after Construction

Guidance Notes for Inspection, Maintenance andApplication of Marine Coatings

Attention should also be paid to the IACS guidelinesfor surveys, assessment and repair of hull structuresfor relevant ship types.

The inspector is required to grade each particularzone on each of the six criteria. The scoring for

a particular zone should not be influenced bythe scoring of other inspection criteria in thatcompartment.


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Inspection Criteria

This manual identifies six different criteria to be

addressed during the inspections. These are to bedocumented based on a traffic light point ratingsystem (0 through 6 scale) on zones for eachcompartment (space or tank). The score assignedto a compartment will denote the compartmentscondition as good, fair or poor and will correspond

to one of three colors, green, yellow or red.

The six inspection criteria cover:

Coating condition

Presence of general corrosion

Presence of pitting or grooving or other localizedlinear corrosion

Presence of deformation

Presence of fractures

Compartment or space cleanliness (housekeepingand fabric maintenance such as anode replace-ment, etc.)

GOOD CONDITION

FAIR CONDITION

POOR CONDITION

Table 1. Traffic Light Condition Scoring


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Coating Condition

The coating condition is defined as per ABS Rule

requirements and the ABS Guide for Inspection,Maintenance and Application of Marine Coatings:

GOOD is a condition with only minor spotrusting. (Score is 0 to 2 inclusive)

FAIR is a condition with local breakdown at

edges of stiffeners and weld connections and/or light rusting over 20 percent or more of areasunder consideration, but less than as defined forPOOR condition. (Score is 3 to 4 inclusive); and

POOR is a condition with general breakdownof coating over 20 percent or more of areas, or

hard scale at 10 percent or more of areas underconsideration. (Score is 5 to 6 inclusive)


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6

INSPECTIONGRA

DING

CRITERIA

FOR

ABSHIMP

CoatingCondition

Rating Points Condition Comme

Good

Excellent 0Freshly coated, negligible

breakdown

Good 1 Minor spot rusting

Good Fair 2General breakdown of c

over 5%

Fair

Fair 3Local breakdown at ed

stiffeners and weld conn

(uncoated)

Fair Poor 4General breakdown of c

over 10%

Poor

Poor 5General breakdown of c

over 20%

Worst 6General breakdown of c

over 30%


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Coating Assessment Scale Surfaces

Assessment Scale for Breakdown

0.1%

1%

20%

Weld

Weld

Weld

10%

15%

20%

0.5%

10%

50%

0.2%

2%

25%

0.3%

5%

33%

Diagram for Pitting Linear Extent


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Coating

CoatingCondition

Points Condition CommentColorCode

Good 0Freshly coated, negligible

coating breakdown


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CoatingCondition


Good 1 Minor spot rusting


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CoatingCondition


Good 2

General breakdown of

coating over 5%


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CoatingCondition


Fair 3

Local breakdown at edges

of stiffeners and weldconnections (uncoated)


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CoatingCondition


Fair 4

General breakdown of coating

over 10%


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CoatingCondition


Poor 5


over 20%


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CoatingCondition


Poor 6


over 30%


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General Corrosion

General or overall corrosion appears as non-

protective rust which can uniformly occur on tankinternal surfaces that are uncoated, or where coatinghas totally deteriorated. The rust scale continuallybreaks off, exposing fresh metal to corrosive attack.Material thickness loss cannot be judged visuallyuntil excessive loss has occurred.


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16

INSPECTIONGR

ADING

CRITERIA

FOR

ABSHIMP

Corrosion as %of zone

Rating Points Condition Comm

0% Excellent 0 No rusting

< 5% Light rust Good 1 Negligible rusting/cor

< 20% Light rustGood

Fair2 Minor spot rustin

> 20% Light rust> 5% Hard scale

Fair 3Local breakdown at edges of sti

connections and/or light rustor more of zone

> 10% Hard scale Fair Poor 4 Hard scale at 10% or mo

> 30% Hard scale Poor 5Serious/significant corrosion: M

corrosion and active scale is preis loose or has fallen off th

> 70% Hard scale Worst 6

Extensive area of corrosion: corro

or loose scale, including pitting, oof the plating surface in question

evidence of thinni


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INSPECTION GRADING CRITE RIA FOR ABS HIMP 17

Corrosion Extent Diagrams Edges and Welds

Localized Corrosion Extent Diagrams

Linear Extent Diagrams

2% localizedbreakdown

15% scatteredbreakdown





5%

10%

20%

50%

80%


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Corrosion

Corrosion as% of zone


0% 0 No rusting


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< 5% Light

rust 1 Negligible rusting/corrosion


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< 20% Light

rust 2 Minor spot rusting


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INSPECTION GRADING CRITE RIA FOR ABS HIMP 21



> 20% Lightrust

> 5% Hardscale

3

Local breakdown at edges

of stiffeners and weldconnections and/or light

rusting over 20% ormore of zone


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> 10% Hard

scale 4

Hard scale at 10%

or more of zone


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> 30% Hardscale

5

Serious/significant corrosion:

More than 30% corrosion andactive scale is present. Active

scale is loose or has fallenoff the structure.


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> 70% Hardscale

6

Extensive area of corrosion:corrosion of hard and/or

loose scale, including pitting,over 70% or more of the

plating surface in questionaccompanied by evidence of

thinning.


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Pitting & Grooving Corrosion

Localized corrosion can occur on bottom plating,

other horizontal surfaces and at structural detailsthat trap or follow the flow of water and other fluids,particularly in aft bays of tank bottoms and in theregion of suction bell mouths. For coated surfaces,the attack produces deep and relatively smalldiameter pits that can lead to penetration of the steel

member in isolated random places in the tank.

Pitting of uncoated tanks, as it progresses, formsshallow but very wide scabby patches (e.g. 300 mmdiameter). The appearance resembles a conditionof general corrosion. Pitting is usually seen on

horizontal hull parts such as the inner bottom orstringers.

Grooving is a localized, linear corrosion whichoccurs at structural intersections in welds or heataffected zones. This corrosion is sometimes referred

to as in line pitting attack and can also occur onvertical members and flush sides of bulkheads inway of flexing. Grooving or necking is usually seenon the butt/seam welds and weldments of stiffenersto plating. In particular pitting is found below thesuction bell mouths in ballast tanks.


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26

INSPECTIONGR

ADING

CRITERIA

FOR

ABSHIMP

Pitting/Grooving

TypeRating Points Pitting & Grooving Depth

No Pits/Grooves Excellent 0

Shallow Pits/Grooves

Good 1 Less than 1/3 of original thickness


Good Fair 2 Less than 1/3 of original thickness


Fair 3 Less than 1/3 of original thickness

Deep Pits/Grooves

Fair Poor 4 More than 1/3 of original thickness

Deep Pits/Grooves

Poor 5 More than 1/3 of original thickness

Deep Pits/Grooves

Worst 6Less than 6 mm of original thickness

remaining


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Pitting & Grooving

Pitting/

GroovingType Points

Pitting &

Grooving Depth

Intensity

(% of Zone)

Color

Code

No Pits/Grooves

0


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Pitting/Grooving

TypePoints

Pitting &Grooving Depth

Intensity(% ofZone)

ColorCode

ShallowPits/

Grooves1

Less than 1/3 oforiginal thickness

< 5%


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Pitting/Grooving

TypePoints


Intensity(% ofZone)

ColorCode

ShallowPits/

Grooves2

Less than 1/3of originalthickness

< 15%


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Pitting/Grooving

TypePoints


Intensity(% ofZone)

ColorCode

ShallowPits/

Grooves3

Less than 1/3 oforiginal thickness

> 15%


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Pitting/Grooving

TypePoints


Intensity(% ofZone)

ColorCode

DeepPits/

Grooves4

More than 1/3 oforiginal thickness

< 15%


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Pitting/Grooving

TypePoints


Intensity(% ofZone)

ColorCode

DeepPits/

Grooves5

More than1/3 of original

thickness> 15%


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Pitting/Grooving

TypePoints


Intensity(% ofZone)

ColorCode

DeepPits/

Grooves6

Less than 6 mmof originalthicknessremaining


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Deformation

Deformation is caused by impact loads, contact or

overloading. Deformation may be local (deformationof panel or stiffener) or global (deformation of abeam, frame, girder or floor including associatedplating). Permanent buckling is easily identified andmay result from overloading, reduction of thicknessdue to corrosion or contact damage. Elastic buckling

may be identified from coating damage, stress linesand/or shedding of scale.

The panel is defined as the area between adjacenttransverse frames and adjacent longitudinal stiffeners.A bay is the area between adjacent transverse frames

from longitudinal bulkhead to longitudinal bulkhead(or side shell).


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INSPECTIONGRADING

CRITE

RIA

FOR

ABSHIMP

35

Set-in Area Set-in Depth Rating Points Cond

No Deformation Excellent 0 No

Within Panel < 75 mm (3 in) Good 1 Gr

Within Panel > 75 mm (3 in)Good

Fair2 Gr

Within Bay (multiplepanels)

< 75 mm (3 in) Fair 3 Set-ininte

Brackets and Internals Tripped Fair Poor 4Trippinter

Within Bay > 75 mm (3 in) Poor 5

Buck

trip

Multiple Bays Worst 6Bucinde


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Deformation

Set-in Area

Set-in

Depth Points

Condition

Comment

Color

Code

NoDeformation

0No

deformation


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Set-in AreaSet-inDepth

PointsConditionComment

ColorCode

Within Panel> 75 mm

(3 in)2

Gradualset-in


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ColorCode

Within Bay(multiplepanels)

< 75 mm(3 in)

3

Set-in withassociatedinternalstripped


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ColorCode

Brackets &Internals

Tripped 4

Tripped andbuckled

internals &brackets


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ColorCode

Within Bay> 75 mm

(3 in)5

Buckled,indented,tripped

internals


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ColorCode

Multiple Bays 6

Buckled,heavily

indented,tripped

internals


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Fracture

Location Points

Condition

Comment

Risk

Level

Color

Code

NoFractures

0 No fracturesVeryLow

Welds 3Weld fractures insupport brackets,

internals, detachments

Low Medium

Flanges 3Flanges of brackets,internals, stiffeners

Medium

Webs 4Webs of frames,floors, brackets,

stiffeners, internals

Medium High

Bulkheads 5Transverse &longitudinal

bulkheads, primarystructure members

High

HullEnvelope

(Shell)6

Sideshell, bottom& deck

VeryHigh

Fracture

Fractures are categorized by a different point system

based on the location of the fracture and that localstructures contribution to overall hull integrity. Afracture of the toe welds of brackets and flanges ofbrackets, stiffeners or webs is given 3 points. Thefractures to the web plating of frames, floors andstiffeners are given 4 points. Fractures to transverse

bulkheads and longitudinal bulkheads are given5 points. Any fracture to the external hull envelopeis treated as the worst case and given 6 points.

Table 6. Fracture Inspection Criteria Point Scoring


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Fracture

FractureLocation


NoFractures

0 No fractures


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FractureLocation


Welds 3

Weld fractures in support

brackets, internals,detachments


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FractureLocation


Flanges 3

Flanges of brackets,

internals, stiffeners


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FractureLocation


Webs 4

Webs of frames, floors, brackets,

stiffeners, internals


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FractureLocation


Bulkheads 5

Transverse & longitudinal

bulkheads, primary structuremembers


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FractureLocation


Hull

Envelope(Shell)

6 Sideshell, bottom & deck


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Cleanliness & Housekeeping

This criteria is used to evaluate the general condition

of the compartment for cleanliness and housekeeping.This should be judged based on the following:

Amount of the sediments and dredge/sludgeremaining in the tank

Wastage of the anodes and their perceived

effectiveness General cleanliness of the space

Condition of the piping and its supports

Condition of access hatches, manholes, entryspaces, ladders and other means of access

Loose scale and plugged drainage openings in thestructure (e.g., rat holes/scallops)


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INSPECTIONGRADING

CRITE

RIA

FOR

ABSHIMP

51

Cleanliness & Housekeeping Rating Points Condition

Clean and excellent condition Excellent 0 Similar to newl

Very light, negligible layer ofresidue and sediments

Good 1Anodes in good co

90% re

Light layer of residue, sedimentsinspections

Good Fair

2Anodes 75% rema

required fo

Spaces sufficiently clean and free

from water, scale, dirt, containerresidues etc. to reveal corrosion,

deformation, fractures, damages or

other structural deterioration

Fair 3Anodes 50% rem

examinatioand may require s

Spaces with surfaces containingloose accumulated corrosion scale

Fair Poor

4Anodes 30% rema

dirt, container residexaminati

Spaces with residue and sedimentswhich do not give access to surfaces

Poor 5Anodes not effe

examination not poss

In addition to above, spaceswith means of access and

entry not safeWorst 6

Cathodic protectionCompartment nee

for e


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Cleanliness & Housekeeping

Cleanliness &Housekeeping


Clean andexcellentcondition

0 Similar to newly built condition


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Very light, negligible

layer of residue andsediments

1Anodes in good condition,more than 90% remaining


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Light layer ofresidue, sediments 2

Anodes 75% remaining. Cleaningnot required for close-up.


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Cleanliness & Housekeeping Points Condition CommentColorCode

Spaces with surfaces

containing looseaccumulated corrosion

scale

4

Anodes 30% remaining.

Water, scale dirt, containerresidues, etc. which make

examination difficult.


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Spaces with residue andsediments which do notgive access to surfaces

5

Anodes not effective,

Meaningful examinationnot possible with

cleaning.


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In addition to all other

conditions, spaces withmeans of access and

entry not safe

6

Cathodic protection

systems ineffective.Compartment needs to be

made safe for entry.


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Notifying Superintendent

and Class Surveyor

All deformation or fractures discovered duringinspection should be brought to the attention ofthe superintendent (owners representative) andthe attending class surveyor at the first opportunity.

When a compartment transitions from good to faircondition, the class surveyor should be alerted atthe next survey. When a compartment transitions topoor condition, class surveyor attendance should berequested at the next port of call.

Having a comparison of the normalized total scores

enables the owner to rank like compartments interms of the overall condition. Such a ranking mayfurther enable a class surveyor to focus surveys incompartments where anomalies and higher scoreshave been identified.

Table 8. Suggested Notification Thresholds

Inspection CriteriaNotify

Superintendent

Coating Condition > 3 points

General Corrosion > 3 points

Pitting & Grooving Corrosion > 3 points

Deformation > 0 points

Fracture > 0 points

Cleanliness & Housekeeping > 3 points


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ABS WORLD HEADQUARTERS

Tel: 1-281-877-5800 Fax: 1-281-877-5803

Email: [email protected]

ABS EUROPE DIVISION

Tel: 44-20-7247-3255 Fax: 44-20-7377-2453


ABS PACIFIC DIVISION

Tel: 65-6276-8700 Fax: 65-6276-8711Email: [email protected]

ABS AMERICAS DIVISION

Tel: 1-281-877-6000 Fax: 1-281-877-6001


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