Hull and structural survey parts volume2 model course3 07

pro-The procedures chosen are limited and must be seen as very special aspects, generally embedded in the wider scope of classi- fication requirements.Applicable and superimposed on thes

PART B INSPECTION AND TESTING PROCEDURES

1 GENERAL REQUIREMENTS

In some trades cargo hoses are carried aboard This gives the vessel

added responsibil ity for safety during cargo handl ing in port The IMO

Codes require that the cargo hoses must be inspected by the officer in

charge before they are taken into use each time and that pressure tests

shall be carried out

The burst pressure for new hoses shall be at least 5 times the working

pressure of the hose

The hose shall be inspected and pressure tested as per National

Regula-tions This nonnally means annual tests It is advisable to have a

representative of the maker inspect the hose during the testing The

procedure includes measuring the lengthwise elongation during pressure

increase from 1 kp/cm2 to working pressure (max pennissible elongation

10%) and resulting elongation when back to 1 kp/cm2 (max 2.5%) Test

pressure shall normally be working pressure + 25% The hose shall lie

straight on flat ground dudng tests and shall be rolled backwards and

forwards to enable it to stretch freely The condition of internal liner

and flange connections to be inspected in particular Check hose wall for

delaminations and flange connections for creep British Standard

BS 1435/54 gives further details Check electrical bond between flanges

(**124)

2 SURVEY INSTRUCTIONS

regu-lations in force, i.e.:

components and equipment, reg 16 "shipboard cargo hoses"

non-metal-lic and metalnon-metal-lic materials.

350

PART D: SECTION 2 STRUCTURAL STRENGTH

Ship structures are subjected to changing static load distribution upon receiving or discharging cargo, during ballast and cargo voyages.

IIIn each static condition the structure will a 1 so be subjected to dynamic forces and fatigue failure of a structure will usually be a combination of low and high cycle fatigue".

(**124, p.24) The capabi 1 ity of steel to withstand cyclic loads is derived by material tests which determine

- endurance strength under a constant load with a stress amplitude under defined cycles (NB) The 1 ifetime expectation before breakage starts is then above 106NB;

- low cycle strength is derived by usi ng the same constant load, but acting with a higher stress amplitude - which signifies lifetime until fracture formation between 102 - 106NB;

- fatigue strength finally is the endurance of materi a 1 or of welded structures to sustain a number of different load changes with variations of stress amplitudes of different stress levels and variations in the cycles.

Note: Sketches/drawingsmarkedwith** and bibliographynumber indicate the

publicationfrom which the materialhas been taken

531

Part D

Section 9: Damage Designations

6 Cracking of Shell Sides and Bulkheads in CP-Propeller Ships

Note: The details in the following pages are attempts to assess defects visually

and to enable a more or less accurate description of various forms of defects

Such determinations, however do not necessarily lead to the actual cause

of the damage

623

Thiscourse on the survey of ship's huil and structural components

and to the Rmish and German Govemments

for contributing to the costs of deveiopment

Printed and published by the

Copyright © (MO 1992

TM 307E

Contents of this Volume

Compendium to the Course

Part B: Inspectionand Testing Procedures 181

Part C: Acceptanceand ToleranceCriteria 371

pro-The procedures chosen are limited and must be seen as very special aspects, generally embedded in the wider scope of classi- fication requirements.

Applicable and superimposed on these procedures are construction rules, material requirements, detailed welding rules for assembly and special components, and the general workmanship performance,

as laid down in the relevant publications of the Society cerned.

con-Interpretation of classification regulations is exclusively the matter of the Society issuing the respective rules.

Numbers marked ** refer to the relevant sources as listed in the bibliography in Part E of this compendium

183

Part B

Inspection and Testing Procedures

01 General

02 Newbuilding Supervision/Modifications

02-02 Newbuilding Supervision - Details of Reporting

02-04 Welding Requirements for Shipbuilders and Workshops 208

02-14 Initial Ship Structure and Equipment Vibration Survey 234

02-35 Doors of Cargo Holds - Tightness and Function Tests 269

02-36 Ramps of Cargo Holds - Tightness and Function Tests 270

03 Condition Assessment/Maintenance/Repairs

03-16 Structural Fitness of Tankers exceeding200 m Length 324

03-24 Control of Ships - Procedures of inspecting Reported Hull

PART B INSPECTION AND TESTING PROCEDURES

- STANDARD PROCEDURES TO BE FOLLOWED BY THE SURVEYOR _ 01 - 01

3 When Surveyor is informed of defects/deficiencies:

ASSESSMENT OF ACT ION REQU IRED INFO TO ADMINISTRATION

1 Defects corrected Endorse certificates, NO by copyi ng

before vessel's issue survey report the report

departure

2 minorDefectsimportanceare of - as under 1 - NO - "

-Request master's and temporari ly fication upon completion

noti-dea It with of permanent repairs

3 A Major defectstemporarily corr- Issue Recommendations YES - "

-for repair includingrected, but not time 1imit and

affecting opera- resurvey

tion of vessel

- - - - - - - - - - - I- - -

B Affectingoperation safeof vsl - As under 3 A - YES - "

-Limitation of operationuntil next repair faci-lity or suitable port

4 Major defectsnot corrected, Withdraw one or all cer- YES - "

-tificates concerned Report natureaffecting safe SAFCON, LL, IOPP or of defects,

operation of SAFEQ as the case may be necessary

cir-cumstances infull

5 Major defectsas under 4 not - As under 4 - YES - "

-Discuss means of safe Obtain possible to procedure to next poss- mation for

confir-repair in the ible place(s) for repair "Technical

and arrive safely

Issue certificate fortechnical fitness

3/3

189

PART 8 INSPECTI(~,J AND TESTING PROCEDURES

- PRECAUTIONS BEFORE ENTERING ENCLOSED COMPARTMENTS - 01 - 02

AND SIMILAR ENCLOSED COMPARTMENTS

This also applies to tanks which have been inerted.

The master or a responsible officer MUST ensure that it is safe to enter an enclosed space by:

.1 ensuring that the space has been thoroughly ventilated by natural or mechanical means;

deficiency and harmful vapour where suitable instruments are available;

and 3 requiring breathing apparatus to be worn by all persons entering the space where there is any doubt as to the adequacy of ventilation or testing before entry.

WARNING

Where it is known that the atmosphere in an enclosed space is unsafe, it should

only be entered when it is essential or in an emergency All the safety checks

overleaf should be carried out before entry and breathing apparatus must be

worn.

Protective equipment and clothing

It is important that all those entering an enclosed space wear suitable clothing

and that they make use of protective equipment which may be provided on

board for their safety Access ladders and surfaces within the space may be

slippery and suitable footwear should be worn Safety helmets protect against

falling objects and, in a confined space, against bumps Loose clothing, which

are necessary where there is a risk of contact with harmful chemicals Safety

harnesses, belts and lifelines should be worn and used where there is any danger

of falling from a height.

There may be additional safety instructions on board the ship - make sure that

they are made known to all concerned.

190

PART B INSPECTION AND TESTING PROCEDURES

KEEL-LAYING DATE, YEAR OF BUILD, PERIOD OF CLASS

1 KEEL-LAYING DATE

1.1 The tenn "keel-laying date or at a similar stage of construction" means

the stage at which:

a) construction identifiable with a specific ship begins; and

b) for that ship assembly has commenced, comprising not less than 50

tons or 1 per cent of the estimated mass of all structural material,whichever is less

The structural members must be clearly marked

The above definition is a decision by the IMO Maritime Safety Committee

2 YEAR OF BUILD

2.1 The date (month and year) of completion constitutes a vessel's year of

construction It shou 1d be noted tha t in many instances underwri ters

consider the year of launching as the year of construction Amendments to

the year of construction as a result of any later comprehensive

conver-sions will neither be made nor granted, as underwriters do not recognize

this

2.2 A shipowner can, however, apply to Head Office for a certificate covering

the extent of the conversion; furthermore, on application from the

ship-owner an appropriate entry additional to the year of build can be made

into the ship's certificate and the Register Book if at least 60% of the

strength members of the ship concerned have been renewed Proof of the

"percentage" renewal is to be furnished by the shipowner or the shipyard,

as the case may be The Surveyor supervising the conversion is to examine

this carefully and forward it to Head Office

3 PERIOD OF CLASS

3.1 All ships built under the supervision of GL are assigned a Period of

Class commencing from the month in which they enter service

Where the dates of completion and entry into service differ, Head Office

will decide on the Period of Class

3.2 The ship's hull, the machinery installation and, where applicable, the

refrigerating installation always have the same Period of Class

For the conditions governing the Validity of Class, see the appropriate

section of the Rules of Classification and Surveys

I

I

193

PART B INSPECTION AND TESTING PROCEDURES

3.3 The duration of a Period of Class, i.e the interval between two

consecu-tive Class Renewal Surveys, is 4 years in the case of the character of

class "100 A 4"

Example:

Start of 1st Period of Class: August 1976 (8.76)

End of 1st Period of Class: (31) August 1980 (8.80)

Start of 2nd Period of Class: August 1980 (8.80)

(after Class Renewal Survey)

End of 2nd Period of Class: (31) August 1984 (8.84)

3.4 By Class Extension Surveys, the duration of the Period of Class can be

extended up to a maximum of 5 years

No extension of class is possible beyond this limit

3.5 The actual start of the new Period of Class is determined by the date of

completion of the Class Renewal Survey

3.6 Where the Continuous Class Renewal system has been agreed for the hull

and the machinery/electrical installation jointly, the Period of Clas-s-i s

5 years This perlod must under no clrcumstances be exceeded

3.7 Where the Continuous Class Renewal system is applied to only one of the

two sectors, paras 3.1-3.3 above are applicable This means that a Class

Extension Survey is needed for the sector not covered by the Continuous

Class Renewal system if an extension of class beyond the 4-year Period of

Class is required

For the other sector, entry of the Extension of Class is a formal act

3.8 On the occasion of major conversions such as lengthening the ship,

in-stallation of new machinery etc., a proposal may be made to the shipowner

to renew the Class at the same time The new Period of Class is

calcu-lated from the month in which the conversions are completed Where such

conversions are completed less than six months before expi ry of the

regular class, the new Period of Class commences on completion of the

previous one

3.9 Where ships are laid up when the Class expires, the new Period of Class

sha11 in principle run from the expiry of the previous Period of Class

notwithstanding any temporary suspension of Class Exceptions in the

event of prolonged laying-up periods are at the sole discretion of Head

Office A Class Renewal Survey is required before the ship is

recommis-sioned

3.10 In special cases, or where there is doubt concerning the Period of Class

applicable, the Surveyor shall reach agreement with Head Office

I

194

PART8 INSPECTIONANDTESTINGPROCEDURES

GENERAL PROCEDURES FOR SUPERVISION OF NEWBUIlOING CLASSIFICATION

1 Head Office will provide the surveyor with copy of the Application for

Classification, copies of the approved drawings and copies of the

rele-vant correspondence to assist him in supervising construction

As these drawings are subject to copyright, they are to be treated

confidentially

The surveyor is to make sure whether the latest drawings required for

supervision of construction have been duly approved If the surveyor does

not receive the drawings in time, he will have to advise the Head Office

immediately

Drawings of substructures for load support or transmission of the forces

arising during opening and closing of hatch covers etc are also required

to be submitted Surveyors are requested to take an active part in

requiring, where applicable, additional special drawings and

documenta-tion, since it may in individual cases be difficult for Head Office to

assess such special conditions which may only be identified locally

during construction

2 The surveyor in whose inspection district the vessel is completed is to

make sure with the shipyard that Head Office has been informed about any

subcontracts for hull components, deckhouses, etc placed with other

firms Class requirements apply for these subcontractors as well

3 Surveys during construction comprise:

- random checks of current fabrication

- inspection of completed blocks and flat panels

- supervision of assembly of the sections on the sl ipway or in the

dock

- final inspection of the individual areas

4 In all construction phases mentioned the surveyor will have to satisfy

himself that

- the materials and components employed meet the requirements of the

Construction Rules and Rules for Materials

- assembly, seam preparation and we1dings comply with the Gl

re-quirements For details see

+ Construction Rules, Chapter 2, Section 20

+ Rules for Welding of Hull Structures, Section 8

+ Production Standard of the German Shipbuilding Industry

where applicable

- exclusively welding procedures approved by a Gl workshop approval or

upon procedure tests are employed

- exclusively approved welding consumab1es of adequate grades are

employed (see list of "Approved welding consumab1es and auxiliary

materials for ship construction")

I

:

195

PART 8 INSPECTION AND TESTING PROCEDURES

of the character of class and possible class notations This cludes, for instance the testing of container stowage and lashingdevices, where the relevant class notation has been assigned

in all testings stipulated in the Construction Rules and other tions that may be applicable such as checkings of we1dings tight-ness tests and operational tests are duly performed

regula-5 In the following circumstances detailed information is to be given onspecific survey items:

5.1 In case of grave deficiencies of materials or of conspicuous lations of deficiencies suggesting faulty manufacture of the materialconcerned Head Office will have to be advised immediately

accumu-5.2 The assessment and elimination of surface defects in plates employed innaval construction are to be based on the lACS Recommendation

"Guidelines for Surface Finish of Hot Rolled Steel Platesand Wide Flats" (see PART C 02 - 05)

In general admissible limit values are in line with EURONORM 163-83 (see

"Production Standard of the German Shipbuilding Industry (FS )" • tion 1) (see PART C 01 - 01/10)

Sec-5.3 Where higher-strength structural steels stainless steels clad plates orother special materials are employed the surveyor is to insist that allmeasures required to be taken by the shipyard such as marking acquain-ting the staff with processing regulations additional checks etc aretaken This is particularly important at shipyards and workshops starting

to use such materials If the surveyor is not sufficiently experienced inthe respective work he is to obtain advice from an experienced colleague

or Head Office (e.g • in case of joint performance of the welding dure test)

proce-5.4 Ou ring checking of construction for compliance with the approveddrawings particular attention wi 11 have to be paid to observation ofthe entries in red in the workshop drawings and due observance to these.Any deviations from the approved drawings are admissible only with theconsent of Head Office Where necessary corrected drawings are to besubmitted to Head Office for examination

5.5 All abutting or detached main structural members in particular allcontinuous girders are to be checked for perfect alignment, possibly bydownhead welding, as per GL Rules Chapter lA Section 8.0

5.6 Especially it will have to be checked whether the location and size ofopenings and cutouts in the strength deck and the sheer strake complywith the approved drawings

196

PART B INSPECTION AND TESTING PROCEDURES

5.7 long, continuous hatchcoamings form part of the upper flange of the hull

exposed to maximum stresses It will have to be ensured that

- butts in the longitudinal hatch coamings are to be welded and tested

in the same way as butts in the sheer strake,

- in particular the upper part of the longitudinal hatch coaming is to

be kept free from irregularities and notches due to improperly

welded-on auxiliary structures,

- transitions of cross sections are gradual and notch-free

5.8 Watertight bulkheads are to be carefully checked upon installation of all

penetrations For performance of this check Head Office will provide the

surveyor with a general arrangement plan showing the watertight

bulk-heads

6 The surveyor must not confine himself to performing final checks of the

finished parts and sections -By systematic checks also during manufacture

he wi11 have to satisfy himself that e.g. welding seams are properly

prepared and that prior to welding of back sealing runs or of the 2nd

side of full penetration single or double bevel welds are properly

grooved out, that instructions for preheating and weather protection are

observed, etc (see also Rules for Welding)

7 The Surveyor is to insist on responsible and effective control on the

part of the shipyard, without being forced into the role of a "shipyard

contro11er" alone See Construction Rules, Chapter 2, Section 20, A.2

"Quality Control" and Chapter 7A, Section I, F "Welding Shop

Respon-sibil ity" and 2, D "Welding Supervisors" Subject thereto the shipyards

are in particular obliged to themselves perform prechecking of sections

and part structures and to ensure proper workmanship prior to calling for

final inspection by the surveyor

The said Rules do not relieve the surveyor of this obligation to himself

carry out checkings to the extent requi red However, where reasonably

applied, they may considerably facilitate and supplement the surveyor's

activities

8 The surveyor will have to check whether the structural fire protection

arrangements have been constructed in accordance with the fi re control

plan and the insulation and/or divi sions plan See Construction Rules,

Chapter 2, Section 22

In particular, it will have to be made sure that

- insulation materials and setup of the A-IS, A-30 and A-60 Class

divisions are in compliance with the above plans

- the B-Class corri dor bulkheads and all other B-class bulkheads

extend from steel deck to steel deck, unless continuous B-O-Class

linings and/or ceilings are fitted on both sides of the bulkhead

- doors of stair casings and accesses to engine rooms are of

PART B INSPECTION AND TESTING PROCEDURES

9 Information concerning technical details and testings to be performed iscontained in Newbuilding Report FlO This form is to be used as "CheckList" from the very beginning of supervision of construction and shouldnot be filled on completion only

(See "Newbuilding Report" PART B 02 - 02)

10 In all surveys the experience gained during GL investigations on previousdamages is to be considered Head Office continuously provides relevantinformation to all surveyors supervising newbuildings

II. The acting surveyor will have to attend the vessel's launching and watchthe launching process In the event of damages caused to the hull struc-tural elements, rudder or propeller or assumed damages a thorough inspec-tion will have to be performed

198

- IDENTIFICATION OF MATERIALS & COMPONENTS USED - 02 - 03

1 The surveyor wi 11 obtain infonnation on the shipyard's system of

i-dentification of plates and sections based on their markings and reliablecorrelation to the pertinent test certificates, in the plate and sectionyard as well as during the handling of the material up to assembling

At many shipyards surveyors will be able to accept the existing system ofidentification and correlation Where this is not the case, they willhave to demand improvements and check whether these are actually intro-duced

2 In general, for nonnal-strength hull structural steels of grades A and B

in conjunction with random checks during processing this verification ofthe shipyard's control system will suffice

3 However, where nonna1-strength hull structural steels of grades D or E or

higher-strength hull steels are employed, the stampings are to be cribed piecewise during processing and noted down in a steel plan, such

as-as to ensure the correct materials being installed at the place envisaged

by the designer

In special cases, e.g where high strength fine-grained structural steelsare employed in structures consisting of different steels, beyond thisre-stamping of each individual component is to be stipulated

4 In general, surveyors will delegate the above check of stampings and/or

re-stamping and relevant entries to the work's quality control ment, or in smaller finns, to a reliable person

depart-The surveyor will satisfy himself by random checks of the efficiency and

correct handl ing of the qua 1ity control department and/or correct

per-formance by the reliable person

5 • In connection with castings and forgings~ such as the rudder stock, and

equipment, such as anchors and anchor chain cables, hatch covers, boat

davits, boat winches, etc., the surveyor is to personally ascertain and

note down the stampings at an appropriate moment

6 Generally all test certificates for materi a 1s and components wi 11 be

collected either at the design office or at the work's quality assurance

department

7 Prior to del ivery of the ship a list of test certificates is to be

prepared and submitted to the su rveyor, possibly together with other

records, such as the steel plan referred to above wi th notes on the

materials employed

The surveyor wi 11 then check the certificates against the list, the

existing documentation and his notes

I

,

PART B INSPECTION AND TESTING PROCEDURES

- IDENTIFICATION OF MATERIALS & COMPONENTS USED - 02 - 03

8 The "List of Components and Materials Employed" will have to be prepared

All individual items subject to testing or inspection as per the

Classi-fication, Survey and Construction Rules, as well as any technical rules

and regulations of relevance on account of the character of

classifi-cation and any possible notations affixed thereto, will have to be listed

therein

All regularly employed components, with the exception of roll ing

mate-rial, are alre~dy indicated in this list

These also relate to structural fire protection, with due regard to the

latest edition of the relevant Rules

The 1istis to be supplemented by deta ils on ro11ing ma teria 1 (plates,

sections, tubes) and possibly any other items not indicated

In connection with the components given - should the space provided not

be sufficient - supplementation will also be required

_No_t_e_:have to be included in the NewbuildingDetails on the equipment with anchors and anchor chain cables willReport I

9 For subdivisions and other materials relating to structural fire

protec-tion a GL Approval Certificate must be available

New approvals will be granted upon application by manufacturers following

submission of the fire test protocols

10 Where in individual cases test certificates of other classification

societies and/or other institutions are accepted, copies of such test

certificates will always have to be attached to the relevant list

II. The list of test certificates is to be forwarded to GL Head Offi ce,

together wi th the Newbuilding Report, and wi 11 form part of the

do-cumentation on the newbuilding concerned

207

- WELDING REQUIREMENTS FOR SHIPBUILDERS AND WORKSHOPS - 02 - 04

GENERAL CONDITIONS FOR ACCEPTANCE OF WELDING WORK

l. Workshops must have at thei r disposal appropri ate manufacturi ng

faci-1ities and qualified staff, enabling them to construct newbuildings (or

parts thereof) in accordance with current engineering practice and to

meet the requirements of classification

2 A shipyard or welding shop must obtain admittance before carrying out

welding at hull structures

In general, the (basic) authorization by the classification society

implies approval on the basis of valid welders' tests for

- manual arc welding and, if applied,

- semi-mechanized gas shielded metal arc welding

of normal strength hull structural steels A to D

3 Also the usual

- single wire submerged-arc welding

of butt-joints in normal-strength hull structural of steels A - 0 may be

covered by the approval provided that unobjectionable workmanship is

proved by sample welds and non-destructive tests in accordance with the

instructions (root fusion, resistance to porosity) of the attending

surveyor

4 The workshops must have at their disposal a sufficient number of tested

welders (at least two) and a trained welding supervisor

5 Before welding procedures other than those 1isted in 2 and 3 and/or

higher grade material s are used, procedure tests in accordance wi th a

test programme are required by Head Office

Procedure tests previously carried out under the supervision by some

other institution may be recognized To this effect complete test

pro-tocols should be submitted to the Head Office

6 The quality cont ro1 department and/or the institutions and/or persons

dealing with quality control of weldings (testing of welds) should not be

involved in the fabrication process and have sufficient scope for

ob-jective decisions (including the rejection of objectionable components)

7 If independent and self-responsible ultrasonic testings are to be

per-formed at weld connections, testing institution and tester alike have to

be authorized by the Head Office

8 Weldable shop primers:

For details on testing, approval application checks and workmanship tests

see GL Rules for Welding, Chapter 7A, Section 6

(**2)

I

PART B INSPECTION AND TESTING PROCEDURES

GENERAL REQUIREMENTS

1 Weldings wi 11 be tested in accordance with classification rules for

welding The shipyard has to submit to the surveyor and in particular

cases to Head Office an examination plan for approval and agreement

It should be noted that, when determining the individual poi nts to be

examined, all main structural elements are to be considered, e.g also

butts of deck longitudinals and butts in continuous longitudinal hatch

coamings

Beyond this, a sufficient number of checkpoints is to be provided outside

the main structural elements such as to ensure proper welding throughout,

even at those points, which are not subject to obligatory examination

2 For some we1dings, such as the corner connection between deck stringer

and sheer strake, ultrasonic testing is compulsory Owing to the fact

that in X-ray testings with increasing plate thicknesses details

areincreasingly difficult to see, it should preferab 1y be

employed intestings of plates exceeding 30 mm in thickness Apart from this, part of

the prescribed X-ray testings may be replaced by ultrasonic testing

At any rate approva 1 of the testers for ultrasonic testing has to be

granted by Head Office

3 Where a defect shown in an X-ray photograph or appearing at the end of

the film or section ultrasonically tested must be supposed to extend

beyond the picture or section examined, the adjacent areas will have to

be examined as well The same is true if, in view of the test results,

recurring defects, such as inadequate weld penetration due to false

welding data, have to be suspected in the further course of the welding

Requirements, Evaluation Groups"

An extract from this Standard is given in the Appendix to the "Production

Standard of the German Shipbuilding Industry (FS)" (See PART C 01 - 10)

Apart from this, the

DVS Evaluation Catalogue DIN 8563 Part 3 (Collection of trated examples simi lar to the Ca ta1ogue of IIW X-Ray Photo-graphs)

illus-may assist in properly assessing the quality of welding seams. This

catalogue can ~e referred to at the shipyard (if available)

GL-INSTRUCTIONS TO SURVEYORS, PART 3

1/2

209

PART B INSPECTION AND TESTING PROCEDURES

5 The evaluation groups (required weld quality grades) should be determined

by the shipyard's design office in accordance with stressing In building generally Evaluation Groups B, C and 0 are applied

ship-Accordingly,

Evaluation Group BS can be correlated to Weld Quality Grade 1Group CS to Weld Quality Grade 2, and

Group OS to Weld Quality Grade 3

Details on weld quality grades required for the respective components

and/or weld connections, their location and stressing are given inSection 3.1 "Production Standard of the German Shipbuilding Industry{FS)" These requirements supplement those contained in GL Rules forWelding of Hull Structures (Section 9, including Table 9.1)

They have been agreed with GL and recognized in principle

7 For correct assessment of seam grades in connection with ultrasonic

testings the DVS Memorandum 0704 "Recommendations for Evaluation ofResults of Ultrasonic Testings Performed at Fusion Welds in Accordance

with DIN 8563 Part 3" can be referred to (See PART C 01 - 10)

210

PART 8 INSPECTION AND TESTING PROCEDURES

No.20 Guide for inspection of ship hull welds

(1988)

I SCOPE The purpos<: of Ihis document is to give guidelines for quality control of ship hull welds during newhuilding The document contains general guidance for the application of non- destructive examinalion (NDE) methods extent of examinations and recommended qual.

ily level for satisfactory workmanship.

The ~uldehnes wnramed herem are intended for welds in structural members where malerials class III and IV arc used according to UR 56 Ihat is the bulk of the welds within OAL amidships.

As a general principle regardless of the application of the recommendations in this ment by the individual Societv a plan of the areas to be examined and the methods to be employed should he suhmllted for approval.

docu-Z BASIC CONDITIONS

The guide 1:'\ hased on the cOfHtilioliS mcntioned hctow.

l.1 Type of material Normal and high strength structural steels according 10 UR W II.

Hull forgings according to UR W 7.

Hull castings according to UR W 8.

l.2 Welding processes Gas metal are, gas IUngsten arc !lux cored arc shielded melal arc submerged arc clec.

troslag and eleclrogas welding.

Consumables according to UR WI7, 2.3 Weld joint types

Bun weld joints, T corner and cruciform joints with and wilhout full penetration fillet weld joints.

2.4 Types of discontinuities The main types of discontinuities mentioned in this document arc listed below Reference

is given to ISO 11520-1<)~2 (ElF) which use the IIW/IIS classification numbers given in brackets.

Pomsilv (2(KI) slag inclusions (.1(KI) undercut (SOl 1.5(12) underfill (509 511 606) cessive weld reinforcement ('\02-504), overlap ('\06), cracks (IOI-Ion), lack of fusion

ex-(401) innunplete penetration (402) lamellar rears.

l.5 Examination methods For detection of

surface discontinuities: Visual examination

(VE) Magnetic panicle examination (ME) l.iquid penetrant examination (PE) For deteclion of

embedded discontinultics: Uhrasonic examination (UE)

Radiographic examination (RE)

J. STRUCTURAL ELEMENTS AND WELDMENTSReference is given 10 U R S6 for the definition of hull structural elements and material classes I to V.

This document is intended for weldments in structural elements where materials class III and IV arc used thai is rhe hulk of the welds within OAL amidships.

Welds in structural members requiring material classes I or II may be subject to less Slringent requirements For welds in material class V in specially high stressed areas more slringent requirements should he applied It is left to each Society 10 define the specific

PART B INSPECTION AND TESTING PROCEDURES

NO.20 Relaxationleft to the discretion of each Society.of requirements for low stressed welds within the scope of the document is(cont'd)

4 DEFINITION OF WELD JOINT CONFIGURATION GROUPS WITH RESPECT TO SUITABLE NDE-METHODS

4.1 General The different types of weldments are divided into four groups of weld joint configurations with respect to the applicability of methods for detection of embedded discontinuities (UE and RE) as defined in 4.2 - 4.5 Tvpes of wc\dments normally helon~ing to thc four

groups arc given for guidance see also Tahle t.

4.2 Weld joint confi~uration J:roup A Weldments for which both UE and RE arc applieahle.

Normally this group includes hull weld joints (of full penetration) in plates of minimum IOmm platc thickness.

·u Weld joint configuration group B Weldments for which only RE is applicable.

Normally this group includes bUll welded joints in plates of thickness less than IOmm (or partly penetrated butt welds).

4.4 Weld joint configuration ~roup C Wcldments for which only UE is applieahle.

Normally this group includes T-joints corner-joints and cruciform joints of full penctra·

tion in plates of minimum IOmm thickness.

4.5 Weld joint configuration group D Weldments for which neither UE nor RE is applicable.

Normally this group includes T corncr and cruciform joints of partly penetration or plate thickness less than !Omm and fillet welded joints.

4.6 Types of weld discontinuities capabilit~· ror detection The general eapahility of different Icst methods to detect weld discontinuities arc shown

in Table ( for each group of weld joint configuration:-t.

5 QUALIFICATION OF PF.RSONNt:1.

The sluphuildcr is n:sponsihk h)r ,upplyil1g propc.:rly (raincd operators n:rtlfit.:atcJ 111

acconJancc with an acccptahic international or natIOnal schemc RcconJs llf \Jpcrators and their current certificates arc to he kept anu mauc i.I\-~l1lahlc to th~ surn:yors ft)r 111-

spection.

6 EXAMINATION TECHNIQUES

6.1 General h,l.l Procedure

In general a NDE-proccdure specification should he worked out for each spcClfic NDE-mcthod.

'Ice 6.1.2 6.3.2 6.4.2 6.5.2 anti 6.6.2 In adtlition tht: pr<H.:cdurc spccifiGltion ~hollid l:l1n(ain

Ihese general items:

Surface requirements cleaning and preparation Location reference identification and marking Evaluating of findings and indications - Reporting

The procedure should in addition cover ilems specific to the NDE teehni<juc in <juestion These items arc depending on NDE technique listed below.

0.1.2 Sensitivity Each applied NDE techni<jue should meet with certain re4u,remcnts in order to assurc examina- tion at a required sensitivity level.

Direct or indirect scnsitivity requirements for the individual NOE techniques arc given below •

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PART 8 INSPECTION AND TESTING PROCEDURES

NO.20 6.1.3 Reference documents

The examination should in order to assure examination quality and fulfil sensitivity (cont'd) ments. be performed according to nationally or internationally recognized NDE standards. re-

require-commendations or other documents accepted hy the Society Such reference documents should meet the minimum requirements given in this Guide.

The reference documents may be replaced hv equivalent or similar documents issued hy the Society.

6.2 Visual examination 6.2.1 General The technique makes use of visual observation to reveal weld surface discontinuities and irregu- larities like undercut surface porosity and excess weld reinforcement If necessary mechanical aids (gauges and rulers) should be used to assess and size discontinuities.

6.2.2 Procedure Items to he covered by the procedure arc:

Viewing conditions Aids to enhance visibilitv Rulers and gauges to be' used 6.2.3 Sensitivity requirements Direct visual examination requires an illumination at the pOint of ohservation which makes it possible to reveal and describe un;occeptable surface disconllnuities The welds should be pre- sented clean and without paint.

Reporting should consist of acceptance or not for each weld section and if relevant or wise give the type and size of the discontinuity causing non-aeceptance.

other-6.3 Magnetic particle examination 6.3.1 General

The technique to be used is detcction of magnetic leakage fluxes from surface discontinuities.

and to a certain extent also suhsurfacc discontinuities in ferromagnetic materials hv means 01 ferromagnetic particles during application of a magnetic field - 6.3.2 Procedure

Items to be covered by the procedure arc:

Magnetizing procedure and equipment Detcetion media

Field strength measurement/verification Detection media application Viewing conditions Demagnetization Prccau(lons against arcing 6.3.3 Scnsitivity requirements The examination should provide search for weld surface discnntinuitcs of any oricnt~Hion.

The surface to he examined m;IY he as \\'ddcd hut should h,," dL'al) ~IIH.I drv and if nuticcahk' irrcgularitic:-; exist :-;1I1()(J(hcd hy -grinding

The peak value of the tangential magnetic field slrcngth in the ~trca heing 1• 'xamincd should he between 2.4 and 4.0 kA/m.

Magnetization hy AC of 1-IWnC •hould he us • d Fluorescent or non-fluore:)ccnt magnetic inks may ht ' applicu.

The preparation and illumination (by visible or ultra viole I light depcnding on Iype of dctcction media) of the surface under examination should he sufficient to reveal and describe any un-

NO.20 6.4 Penetrant examination (cont"d) 6.4.1 General

The technique applies a low surface tension liquid which penetrates into surface open tinuities By use of a suitable developer the penetrated liquid can be make visible and thus a discontinuity indicated.

discon-6.4.2 Procedure Items to be covered by the procedure are:

Referencclcalihrationlverifieation specimens Surface cleaning and preparation

Object temperature Penetrant and developer type Penetrant application and removal

Penetration timc

Developer aprlication

Development time

6.4.3 Sensitivity requirements '111C slIrfacc.0he n;lIlIill<·d may hc as welded hut should be clean and dry and without notice- able irregularities In order to avoid masking of discontinuities grinding should be applied with considerable care.

Fluorescent or visible water -washable solvent removeable or post emulsified penetrants may be applied Developers may be aqueous non-aqueous wet or dry powders.

Outside the temperature range 5-50" reference comparator hlocks should be used.

Penetration timcs should typically he between 20 and 60 minutes and development times mum 15 minutes When the temperature is below 15"C the development times should be mini- mum 30 minutes During the first 2 minutes of development the building up of indications should be carefully watched.

mini-The illumination (by visible or ultraviolet light depending on type of detection media) of the surface under examination should be sufficient to reveal and describe any unacceptable surface discontinuity.

6.S Ultrasonic examination 0.5.1 General

The technique to be used is the ultrasonic pulse echo technique spplying normal and angle

prob-es The examination may be performed manually or by mechanized or automated equipment.

0.5.2 Proced ure

Items tn he c.,.·ovcn:dhy the procedure arc:

Equipment type Probe types frequencies and angles Calibration hlock(s)

Reference hlock(s) Couplant Equipment calibration and checks (linearity resolution wear) Sensitivity setting and transfer corrections

Examination of parent material Scanning techniques

Sizing techniques 6.5.3 Sensitivity requirements The weld examination should cover search for longitudinal and transverse weld discontinuites using at least une angle probe from each side of the weld The weld geometry may require also normal probes to be used to reveal weld discontinuities.

The weld examination should be done using the echo from a 3mm diameter side drilled hole as reference (defining the Reference Level). ~

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