РОССИЙСКИЙ МОРСКОЙ РЕГИСТР СУДОХОДСТВА ROSSIAN MARITIME REGISTER OF SHIPPING

ПРИЛОЖЕНИЕ К ПРАВИЛАМ И РУКОВОДСТВАМ РОССИЙСКОГО МОРСКОГО РЕГИСТРА СУДОХОДСТВА

ПРОЦЕДУРНЫЕ ТРЕБОВАНИЯ, УНИФИЦИРОВАННЫЕ ИНТЕРПРЕТАЦИИ И РЕКОМЕНДАЦИИ МЕЖДУНАРОДНОЙ АССОЦИАЦИИ КЛАССИФИКАЦИОННЫХ ОБЩЕСТВ

SUPPLEMENT ТО RULES AND GUIDELINES OF RUSSIAN MARITIME REGISTER OF SHIPPING

I ACS PROCEDURAL REQUIREMENTS, UNIFIED INTERPRETATIONS AND RECOMMENDATIONS

НД № 2-020101-109-R-E

2018

Настоящее Приложение к правилам и руководствам Российского морского регистра судоходства содержит обязательные для применения процедурные требования и унифицированные интерпретации Международной ассоциации классификационных обществ (МАКО), а также рекомендации МАКО, ссылки на которые имеются в правилах и других нормативных документах Регистра.

Все материалы публикуются на английском языке.

Данный документ публикуется в электронном виде отдельным изданием и является обязательным Приложением к правилам Регистра.

The present Supplement to rules and guidelines of Russian Maritime Register of Shipping contains IACS Procedural Requirements and IACS Unified Interpretations compulsory for implementation, and IACS recommendations, which are referred to in the rules and other normative documents of the Register.

All materials are published in English.

The present document is published in electronic format as a separate edition and is a compulsory Supplement to the Register rules.

Imperfection surface area Ratio (%) is obtained as influenced area / area under consideration (i.e. plate surface area) x 100%.

For isolated surface discontinuities, influenced area is obtained by drawing a continuous line which follows the circumference of the discontinuity at a distance of 20 mm. (Figure 1)

For surface discontinuities appearing in a cluster, influenced area is obtained by drawing a continuous line which follows the circumference of the cluster at a distance of 20 mm. (Figure 2)

Figure 1 - Determination of the area influenced by an isolated discontinuity (Ref. Nr. EN 10163-1:2004+AC:2007 E)

Figure 2 - Determination of the area influenced by clustered discontinuities (Ref. Nr. EN 10163-1:2004+AC:2007 E)

4.2.3 Remedial of Defects

Defects are to be remedied by grinding and/or welding in accordance with IACS Rec.12.

4.2.4 Further Defects

4.2.4.1 Lamination

Investigation to be carried out at the steelmill into the cause and extent of the detected laminations. Severe lamination is to be remedied by local insert plates. The minimum breadth or length of the plate to be replaced is to be:

•    1600 mm for shell and strength deck plating in way of cruciform or T-joints,

•    800 mm for shell, strength deck plating and other primary members,

•    300 mm for other structural members.

Local limited lamination may be remedied by chipping and/or grinding followed by welding in accordance with sketch (a). In case where the local limited lamination is near the plate surface, the remedial may be carried out as shown in sketch (b). For limitations see paragraph 4.2.2.

(b)

4.2.4.2 Weld Spatters

Loose weld spatters are to be removed by grinding or other measures to clean metal surface (see Table 9.13), as required by the paint system, on:

•    shell plating

•    deck plating on exposed decks

•    in tanks for chemical cargoes

•    in tanks for fresh water and for drinking water

•    in tanks for lubricating oil, hydraulic oil, including service tanks

5. Gas Cutting

The roughness of the cut edges is to meet the following requirements:

Free Edges:

Standard Limit

Strength Members    150 pm    300 pm

Others    500 pm    1000 pm

6.    Fabrication and fairness

6.1    Flanged longitudinals and flanged brackets (see Table 6.1)

6.2    Built-up sections (see Table 6.2)

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6.3    Corrugated bulkheads (see Table 6.3)

6.4    Pillars, brackets and stiffeners (see Table 6.4)

6.5    Maximum heating temperature on surface for line heating (see Table 6.5)

6.6    Block assembly (see Table 6.6)

6.7    Special sub-assembly (see Table 6.7)

6.8    Shape (see Table 6.8 and 6.9)

6.9    Fairness of plating between frames (see Table 6.10)

6.10    Fairness of plating with frames (see Table 6.11)

6.11    Preheating for welding hull steels at low temperature (See Table 6.12)

7.    Alignment

The quality standards for alignment of hull structural components during new construction are shown in Tables 7.1, 7.2 and 7.3. The Classification Society may require a closer construction tolerance in areas requiring special attention, as follows:

•    Regions exposed to high stress concentrations

•    Fatigue prone areas

•    Detail design block erection joints

•    High tensile steel regions

8.    Welding Joint Details

Edge preparation is to be qualified in accordance with URW28 or other recognized standard accepted by the Classification Society.

Some typical edge preparations are shown in Table 8.1, 8.2, 8.3, 8.4 and 8.6 for reference.

8.1    Typical butt weld plate edge preparation (manual and semi-automatic welding) for reference - see Table

8.1 and 8.2

8.2    Typical fillet weld plate edge preparation (manual and semi-automatic welding) for reference - see Table

8.3 and 8.4

8.3    Butt and fillet weld profile (manual and semi-automatic welding) - see Table 8.5

8.4    Typical butt weld plate edge preparation (Automatic welding) for reference - see Table 8.6

8.5    Distance between welds - see Table 8.7

9. Remedial

All the major remedial work is subject to reporting by shipbuilder to the Classification Society for approval in accordance with their work instruction for new building.

Some typical remedial works are shown in Tables 9.1 to 9.13.

9.1    Typical misalignment remedial - see Tables 9.1 to 9.3

9.2    Typical butt weld plate edge preparation remedial (manual and semi-automatic welding) - see Table 9.4 and 9.5

9.3    Typical fillet weld plate edge preparation remedial (manual and semi-automatic welding) - see Tables 9.6 to 9.8

9.4    Typical fillet and butt weld profile remedial (manual and semi-automatic welding) - see Table 9.9

9.5    Distance between welds remedial - see Table 9.10

9.6    Erroneous hole remedial - see Table 9.11

9.7    Remedial by insert plate - see Table 9.12

9.8    Weld surface remedial - see Table 9.13

9.9    Weld remedial (short bead) - see Table 9.14

TABLE 6.3 - Corrugated Bulkheads

Detail Standard Limit Remarks Mechanical bending 1* 1 И R > 3t mm R > 4.5t mm for CSR ships Notel 2t mm Nole2 Material to be suitable for cold flanging (forming) and welding in way of radius Depth of corrugati f on ± 3 mm ± 6 mm Breadth of corrugation ± 3 mm ± 6 mm Pitch and depth of corrugated bulkhe with correct value P swedged ad compare >_r 4-► P d h : ± 2.5 mm Where it is not aligned with other bulkheads P:±6 mm Where it is aligned with other bulkheads P:±2 mm h : ± 5 mm Where it is not aligned with other bulkheads P:±9 mm Where it is aligned with other bulkheads P : ± 3 mm

Notes:

1.    For CSR Bulk Carriers built under the “Common Structural Rules for Bulk Carriers” with the effective dates of 1 July 2010 and 1 July 2012, the standard is R>2t mm.

2.    For CSR ships, the allowable inside bending radius of cold formed plating may be reduced provided the following requirements are complied with.

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When the inside bending radius is reduced below 4.5 times the as-built plate thickness, supporting data is to be provided. The bending radius is in no case to be less than 2 times the as-built plate thickness. As a minimum, the following additional requirements are to be complied with: a) For all bent plates:

•    100% visual inspection of the bent area is to be carried out.

•    Random checks by magnetic particle testing are to be carried out.

b) In addition to a), for corrugated bulkheads subject to lateral liquid pressure:

•    The steel is to be of Grade D/DH or higher.

The material is impact tested in the strain-aged condition and satisfies the requirements stated herein. The deformation is to be equal to the maximum deformation to be applied during production, calculated by the formula t_as._buat 1(2r_bdg + tas-ъиад, where t_as._buiU is the as-built thickness of the plate material and r_bdg is the bending radius. One sample is to be plastically strained at the calculated deformation or 5%, whichever is greater and then artificially aged at 250°C for one hour then subject to Charpy V-notch testing. The average impact energy after strain ageing is to meet the impact requirements specified for the grade of steel used.

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Detail Standard Limit Remarks Pillar (between decks) 4 mm 6 mm 1 / L Cylindrical structure diameter (pillars, masts, posts, etc.) / D \ ± D/200 mm max. + 5 mm ± D/l 50 mm max. 7.5 mm Tripping bracket and small stiffener, distortion at the part of free edge a < t/2 mm t Ovality of cy indrical structure dmin \ dmax - d1T1in ^ x dmax \ X \ я \т§

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Item		Standard	Limit	Remarks
Conventional	Water cooling just	Under 650°C
Process	after heating
AH32-EH32 &
AH36-EH36
	Air cooling after	Under 900°C
TMCP type	heating
AH36-EH36
(Ceq>0.38%)
	Air cooling and	Under 900°C (starting
	subsequent water	temperature of water
	cooling after	cooling to be under
	heating	500°C)
TMCP type	Water cooling just	Under 1000°C
AH32-DH32 &	after heating or air
AH36-DH36	cooling
(Ceq. < 0.38%)
TMCP type	Water cooling just	Under 900°C
EH32 & EH36	after heating or air
(Ceq. < 0.38%)	cooling
NOTE:
Mn Cr + Mo + V Ni + Си , ч
Ceq = C +-+-	-+-(%
6 5	15

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TABLE 6.6 - Block Assembly

Item Standard Limit Remarks Flat Plate Assembly Length and Breadth ± 4 mm ± 6 mm Distortion ± 10 mm ±20mm Squareness ± 5 mm ±10mm Deviation of interior members from plate 5 mm 10mm Curved plate assembly Length and Breadth ± 4 mm ± 8 mm measured along the girth Distortion ± 10 mm ± 20 mm Squareness ± 10 mm ± 15 mm Deviation of interior members from plate 5 mm 10 mm Flat cubic assembly Length and Breadth ± 4 mm ± 6 mm Distortion ± 10 mm ± 20 mm Squareness ± 5 mm ± 10 mm Deviation of interior members from plate 5 mm 10 mm Twist ± 10 mm ± 20 mm Deviation between upper and lower plate ± 5 mm ± 10 mm Curved cubic assembly Length and Breadth ± 4 mm ± 8 mm measured along with girth Distortion ± 10 mm ± 20 mm Squareness ± 10 mm ± 15 mm Deviation of interior members from plate ± 5 mm ± 10 mm Twist ± 15 mm ± 25 mm Deviation between upper and lower plate ± 7 mm ± 15 mm

TABLE 6.7 - Special Sub-Assembly

Item Standard Limit Remarks Distance between upper/lower gudgeon ± 5 mm ± 10 mm Distance between aft edge of boss and aft peak bulkhead ± 5 mm ± 10 mm Twist of sub-assembly of stem frame 5 mm 10 mm Deviation of mdder from shaft center line 4 mm 8 mm Twist of mdder plate 6 mm 10 mm Flatness of top plate of main engine bed 5 mm 10 mm Breadth and length of top plate of main engine bed ± 4 mm ± 6 mm NOTE: Dimensions and tolerances have to fulfill engine and equipment manufacturers’ requirements, if any.

6. MPC6 (Rev. 1 Aug 2015)    Calculation of aggregate capacity of SBT    Document    is

applied from 1 July 2016

Применение: Руководство по применению положений международной конвенции МАРПОЛ 73/78, часть II, пункт 3.5.1.1.

Application: Guidelines on the Application of Provisions of the International Convention MARPOL 73/78, part VI, para 3.5.1.1.

7. MODU 1 (Rev.1 Oct 2015)    IACS Unified Interpretations for the application    Document    is

of MODU Code Chapter 2 paragraphs 2.1,2.2,    applied    from

2.3, 2.4 and revised technical provisions for means 1 January 2017 of access for inspections (resolution MSC. 158(78))

Применение: Правила классификации, постройки и оборудования плавучих буровых установок и морских стационарных платформ (2014), часть III, пункт 9.3.1.1.

Application: Rules for the Classification, Construction and Equipment of Mobile Offshore Drilling Units and Fixed Offshore Platforms (2014), Part III, para 9.3.1.1.

Рекомендации MAKO IACS Recommendations

Номер документа    Название    документа

Document number    Document name

1.    Rec. No. 47 (Rev.7 June 2013)    Shipbuilding    and    Repair Quality Standard

Применение: Правила классификационных освидетельствований судов в эксплуатации (2017), часть I (пункт 5.13), приложение 2 (пункт 5.1.12), приложение 3 (пункт 7).

Правила технического наблюдения за постройкой судов и изготовлением материалов и изделий для судов, часть I, приложение 3 (пункт 7.4)

Application: Rules for the Classification Surveys of Ships in Service (2017), Part I (para 5.13), Appendix 2 (para

5.1.12) , Appendix 3 (para 7).

Rules for Technical Supervision during Construction of Ships and Manufacture of Materials and Products for Ships, Part I, Appendix 3 (para 7.4)

2.    Rec. No. 55 (Rev.1 June 2016)    General    Cargo    Ships - Guidance for Surveys, Assessment

and Repair of Hull Structure Применение: Правила классификационных освидетельствований судов в эксплуатации (2017), часть I (пункт 5.13), приложение 2 (пункт 5.1.12), приложение 3 (пункт 6).

Методические рекомендации по техническому наблюдению за ремонтом морских судов с Приложениями (2016), Приложение 1.

Application: Rules for the Classification Surveys of Ships in Service (2017), Part I (para 5.13), Appendix 2 (para

5.1.12) , Appendix 3 (para 6).

3.    Rec. No. 76 (Corr.1 Sept 2007)    IACS    Guidelines    for Surveys, Assessment and

Repair of Hull Structure - Bulk Carriers Применение: Правила классификационных освидетельствований судов в эксплуатации (2017), часть I (пункт 5.13), приложение 2 (пункт 5.1.12), приложение 3 (пункт 2).

Методические рекомендации по техническому наблюдению за ремонтом морских судов с Приложениями (2016), Приложение 1.

Application: Rules for the Classification Surveys of Ships in Service (2017), Part I (para 5.13), Appendix 2 (para

5.1.12) , Appendix 3 (para 2).

4.    Rec. No. 96 (April 2007)    Double    Hull    Oil    Tankers - Guidelines for Surveys,

Assessment and Repair of Hull Structures Применение: Правила классификационных освидетельствований судов в эксплуатации (2017), часть I (пункт 5.13), приложение 2 (пункт 5.1.12), приложение 3 (пункт 10).

Методические рекомендации по техническому наблюдению за ремонтом морских судов с Приложениями (2016), Приложение 1.

Application: Rules for the Classification Surveys of Ships in Service (2017), Part I (para 5.13), Appendix 2 (para

5.1.12) , Appendix 3 (para 10).

5.    Rec. No. 132 (Dec 2013)    Human    Element    Recommendations    for structural design of lighting,

ventilation, vibration, noise, access & egress arrangements

Применение: Руководство по освидетельствованию условий труда и отдыха моряков на соответствие

требованиям Конвенции 2006 года о труде в морском судоходстве (2016), пункты 2.1.22, 4.7.3. Руководство по освидетельствованию жилых помещений экипажа (2015), пункты 2.1.16,

4.1.2.8.

Application: Guidelines on On-board Maritime Labour Convention, 2006 (MLC) Inspection (2016), paras 2.1.22, 4.7.3.

Guidelines on On-board Inspection for Crew Accomodation (2015), paras 2.1.16, 4.1.2.8.

6.    Rec. No. 142 (June 2016)    LNG    Bunkering    Guidelines

Применение: Правила классификации и постройки морских судов (2017), часть XVII, пункт 11.2.2.

Application: Rules for the Classification and Construction of Sea-Going Ships (2017), Part XVII, para 11.2.2.

7.    Rec. No. 146 (Aug 2016)    Risk    assessment    as    required    by the IGF Code

Применение: Правила классификации и постройки морских судов (2017), часть XVII, пункт 9.1.4.19.

Application: Rules for the Classification and Construction of Sea-Going Ships (2017), Part XVII, para 9.1.4.19.

8.    Rec. No.149 (May 2017)    Guidance    for    applying    the    requirements    of    15.4.1.2 and 15.4.1.3 of

the IGC Code (on ships constructed on or after 1 July 2016)

Применение: Правила классификации и постройки судов для перевозки сжижженных газов наливом (2018), часть VI, пункт 3.20.2.

Application:    Rules    for    the Classification and Construction of Ships Carrying Liquefied Gases in Bulk. Rules for the

Classification and Construction of Ships Carrying Compressed Natural Gas (2018), Part VI, para 3.20.2.

9.    Rec. No. 150 (May 2017)    Vapour    pockets    not    in    communication    with    cargo    tank vapour / liquid

domes on liquefied gas carriers

Применение: Правила классификации и постройки судов для перевозки сжижженных газов наливом (2018), часть VI, пункт 3.16.11.

Application:    Rules    for    the Classification and Construction of Ships Carrying Liquefied Gases in Bulk. Rules for the

Classification and Construction of Ships Carrying Compressed Natural Gas (2018), Part VI, para 3.16.11.

10.    Rec. No. 151 (July 2017)    Recommendation    for    petroleum    fuel    treatment    systems for marine

diesel engines

Применение: Правила классификации и постройки морских судов (2019), часть VIII, пункт 13.8.1.

Application: Rules for the Classification and Construction of Sea-Going Ships (2019), Part VIII, para 13.8.1.

РЕКОМЕНДАЦИИ МАКО IACS

RECOMMENDATIONS

No.47 Shipbuilding and Repair Quality Standard

(1996)

(Rev. 1, 1999)

(Rev.2, Dec. 2004)

(Rev.3, Nov. 2006)

(Rev.4, Aug. 2008)

(Rev.5, Oct. 2010)

(Rev.6, May 2012)

(Rev.7, June 2013)

Part A Shipbuilding and Remedial Quality Standard for New Construction Part В Repair Quality Standard for Existing Ships PART A - SHIPBUILDING AND REMEDIAL QUALITY STANDARDS FOR NEW CONSTRUCTION

1.    Scope

2.    General requirements for new construction

3.    Qualification of personnel and procedures

3.1    Qualification of welders

3.2    Qualification of welding procedures

3.3    Qualification of NDE operators

4.    Materials

4.1    Materials for structural members

4.2    Surface conditions

5.    Gas Cutting

6.    Fabrication and fairness

6.1    Flanged longitudinals and flanged brackets

6.2    Built-up sections

6.3    Corrugated bulkheads

6.4    Pillars, brackets and stiffeners

6.5    Maximum heating temperature on surface for line heating

6.6    Block assembly

6.7    Special sub-assembly

6.8    Shape

6.9    Fairness of plating between frames

6.10    Fairness of plating with frames

6.11    Preheating for welding hull steels at low temperature

7.    Alignment

8.    Welding Joint Details

8.1    Typical butt weld plate edge preparation (manual welding and semi-automatic welding)

8.2    Typical fillet weld plate edge preparation (manual welding and semi-automatic welding)

8.3    Butt and fillet weld profile (manual welding and semi-automatic welding)

8.4    Typical butt weld edge preparation (Automatic welding)

8.5    Distance between welds

9.    Remedial

9.1    Typical misalignment remedial

9.2    Typical butt weld plate edge preparation remedial (manual welding and semi-automatic welding)

9.3    Typical fillet weld plate edge preparation remedial (manual welding and semi-automatic welding)

9.4    Typical fillet and butt weld profile remedial (manual welding and semi-automatic welding)

9.5    Distance between welds remedial

9.6    Erroneous hole remedial

9.7    Remedial by insert plate

9.8    Weld surface remedial

9.9    Weld remedial (short bead)

REFERENCES

1.    IACS “Bulk Carriers - Guidelines for Surveys, Assessment and Repair of Hull Structure”

2.    TSCF “Guidelines for the inspection and maintenance of double hull tanker structures”

3.    TSCF “Guidance manual for the inspection and condition assessment of tanker structures”

4.    IACS UR W7 “Hull and machinery steel forgings”

5.    IACS UR W8 “Hull and machinery steel castings”

6.    IACS UR Wll “Normal and higher strength hull structural steel”

7.    IACS UR W13 “Thickness tolerances of steel plates and wide flats”

8.    IACS UR W14 “Steel plates and wide flats with specified minimum through thickness properties (“Z” quality)”

9.    IACS UR W17 “Approval of consumables for welding normal and higher strength hull structural steels”

10.    IACS UR W28 “Welding procedure qualification tests of steels for hull construction and marine structures”

11.    IACS URZ10.1 “Hull surveys of oil tankers” and Z10.2 “Hull surveys of bulk carriers” Annex I

12.    IACS UR Z23 “Hull survey for new construction”

13.    IACS Recommendation No. 12 “Guidelines for surface finish of hot rolled plates and wide flats”

14.    IACS Recommendation No. 20 “Non-destructive testing of ship hull steel welds”

Scope

It is intended that these standards provide guidance where established and recognized shipbuilding or national standards accepted by the Classification Society do not exist.

1.1    This standard provides guidance on shipbuilding quality standards for the hull structure during new construction and the remedial standard where the quality standard is not met.

Whereas the standard generally applies to

conventional merchant ship types,

parts of hull covered by the rules of the Classification Society, hull structures constructed from normal and higher strength hull structural steel, the applicability of the standard is in each case to be agreed upon by the Classification Society.

The standard does generally not apply to the new construction of special types of ships as e.g. gas tankers

structures fabricated from stainless steel or other, special types or grades of steel

1.2    In this standard, both a "Standard" range and a "Limit" range are listed. The "Standard" range represents the target range expected to be met in regular work under normal circumstances. The "Limit" range represents the maximum allowable deviation from the "Standard" range. Work beyond the "Standard" range but within the "Limit" range is acceptable. In cases where no ‘limit’ value is specified, the value beyond the ‘standard’ range may be accepted subject to the consideration of the Classification Society.

1.3    The standard covers typical construction methods and gives guidance on quality standards for the most important aspects of such construction. Unless explicitly stated elsewhere in the standard, the level of workmanship reflected herein will in principle be acceptable for primary and secondary structure of conventional designs. A more stringent standard may however be required for critical and highly stressed areas of the hull, and this is to be agreed with the Classification Society in each case. In assessing the criticality of hull structure and structural components, reference is made to ref. 1, 2 and 3.

1.4    Details relevant to structures or fabrication procedures not covered by this standard are to be approved by the Classification Society on the basis of procedure qualifications and/or recognized national standards.

1.5    For use of this standard, fabrication fit-ups, deflections and similar quality attributes are intended to be uniformly distributed about the nominal values. The shipyard is to take corrective action to improve work processes that produce measurements where a skew distribution is evident. Relying upon remedial steps that truncate a skewed distribution of the quality attribute is unacceptable.

2. General requirements for new construction

2.1    In general, the work is to be carried out in accordance with the Classification Society rules and under the supervision of the Surveyor to the Classification Society

2.2    Welding operations are to be carried out in accordance with work instructions accepted by the Classification Society.

2.3    Welding of hull structures is to be carried out by qualified welders, according to approved and qualified welding procedures and with welding consumables approved by the Classification Society, see Section 3. Welding operations are to be carried out under proper supervision by the shipbuilder. The working conditions for welding are to be monitored by the Classification Society in accordance with UR Z23.

3.    Qualification    of personnel and procedures

3.1    Qualification of welders

3.1.1    Welders are to be qualified in accordance with the procedures of the Classification Society or to a recognized national or international standard. Recognition of other standards is subject to submission to the

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Classification Society for evaluation. Subcontractors are to keep records of welders qualification and, when required, furnish valid approval test certificates.

3.1.2    Welding operators using fully mechanized or fully automatic processes need generally not pass approval testing provided that the production welds made by the operators are of the required quality. However, operators are to receive adequate training in setting or programming and operating the equipment. Records of training and operation experience shall be maintained on individual operator’s files and records, and be made available to the Classification Society for inspection when requested.

3.2    Qualification of welding procedures

Welding procedures are to be qualified in accordance with URW28 or other recognized standard accepted by the Classification Society.

3.3    Qualification of NDE operators

Personnel performing non-destructive examination for the purpose of assessing quality of welds in connection with new construction covered by this standard, are to be qualified in accordance with Classification Society rules or to a recognized international or national qualification scheme. Records of operators and their current certificates are to be kept and made available to the Surveyor for inspection.

4.    Materials

4.1    Materials for Structural    Members

All materials, including weld consumables, to be used for the structural members are to be approved by the Classification Society as per the approved construction drawings and meet the respective IACS Unified Requirements. Additional recommendations are contained in the following paragraphs.

All materials used should be manufactured at a works approved by the Classification Society for the type and grade supplied.

4.2    Surface Conditions

4.2.1    Definitions

Minor Imperfections:

Defects:

Depth of Imperfections or defects

4.2.2    Acceptance without    remedies

Minor imperfections, in accordance with the nominal thickness (t) of the product and the limits described in Table 1, are permissible and may be left as they are.

Imperfection surface area Ratio(%) 15—20% 5—15% 0-5% t < 20 mm 0.2 mm 0.4 mm 0.5 mm 20 mm < t < 50 mm 0.2 mm 0.6 mm 0.7 mm 50 mm < t 0.2 mm 0.7 mm 0 9 mm

Table 1 Limits for depth of minor imperfection, for acceptance without remedies