Z10.3

Z10.3 Hull Surveys of Chemical Tankers
Z10.3(cont)(1996)(Rev.1
1997)(Rev.2
July 1999)(Rev.3
Sept 2000)(Rev.4
Nov 2000)(Rev.4.1
June 2001)(Rev.5
Mar 2002)(Rev.6
Oct 2002)(Rev.7
June 2005)(Rev.8
Jan 2006)(Corr.1
Sept 2006)(Rev.9Nov 2007)(Rev.10
Dec 2008)(Rev.11
Mar 2009)(Rev.12Mar 2011)(Rev.13
July 2011)(Rev.14
Aug 2012)(Rev.15
May 2013)(Rev.16
Jan 2014)(Rev.17
Feb 2015)(Rev.18
Jan 2018)(Rev.19
May 2019)(Rev.20
May 2022)(Rev.21
Aug 2023)

CONTENTS
1.
1.1
1.2
1.3
1.4
1.5

GeneralApplication
Definitions
Repairs
Thickness measurements and close-up surveys
Remote Inspection Techniques (RIT)

2.
2.1
2.2
2.2.1
2.2.2
2.2.3
2.3
2.4
2.5
2.6

Special Survey
Schedule
Scope
GeneralDry Dock Survey
Tank Protection
Extent of Overall and Close-up Survey
Extent of Thickness Measurement
Extent of Tank Testing
Chemical Tankers over 10 years of Age

3.
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5

Annual Survey
Schedule
Scope
GeneralExamination of the Hull
Examination of Weather decks
Examination of Cargo pump rooms and pipe tunnels, if fitted
Examination of Ballast Tanks

4.
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4

Intermediate Survey
Schedule
Scope
GeneralChemical Tankers 5 - 10 years of Age
Chemical Tankers 10 - 15 years of Age
Chemical Tankers over 15 years of Age

5.
5.1
5.2
5.3
5.4
5.5
5.6
5.7

Preparation for Survey
Survey Programme
Conditions for Survey
Access to Structures
Equipment for Survey
Rescue and emergency response equipment
Survey at Sea or at Anchorage
Survey Planning Meeting

6.
6.1
6.2
6.3
6.4

Documentation On Board
GeneralSurvey Report FileSupporting Documents
Review of Documentation On Board

Page 1 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 7.7.1(cont)

7.2
7.3

Procedures for Thickness Measurements
GeneralCertification of Thickness Measurement Firm
Reporting

8.
8.1
8.2

Reporting and Evaluation of Survey
Evaluation of Survey Report
Reporting

Page 2 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 ENCLOSURES(cont)

Table I.1: Minimum requirements for Close-up Survey at Special Survey of Single Skin
Chemical Tankers
I.2: Minimum requirements for Close-up Survey at Special Survey of Double Skin
Chemical Tankers
Table II:

Minimum requirements for thickness measurements at Special Survey ofChemical Tankers

Table III:

Minimum requirements for tank testing at Special Survey of Chemical Tankers

Table IV:

Requirements for extent of thickness measurements at those areas of substantial
corrosion

Table V:

Procedures for certification of Firms Engaged in Thickness Gauging of Hull
Structures

Table VI:

Survey Reporting Principles

Table VII: Executive Hull Summary

Annex I:

Guidelines for Technical Assessment in conjunction with planning forEnhanced Surveys of Chemical Tankers Special Survey - Hull

Annex II:

Recommended Procedures for Thickness Measurements of Chemical
Tankers

Annex IIIA:

Survey ProgrammeAppendix 1 List of Plans
Appendix 2 Survey Planning Questionnaire
Appendix 3 Other Documentation

Annex IIIB:

Survey Planning Questionnaire

Annex IIIC:

Owner’s Inspection Report

Page 3 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 Notes:(cont)

1.

This UR Z10.3 is applicable from the first Annual, Intermediate or Special Survey
commencing on or after 1 July 1997.

2.

Changes introduced in Rev.2 to UR Z10.3 are to be applied by all Member Societies
and Associates from 1 September 1999.

3.

Changes introduced in Rev.3 to UR Z10.3 are to be applied by all Member Societies
and Associates from 1 July 2001.

4.

Changes introduced in Rev.4 and Rev.4.1 to UR Z10.3 are to be applied by all
Member Societies and Associates from 1 July 2001.

5.

Paragraph 4.2.4.3 is newly introduced in Rev.5 in accordance with Res MSC.105(73)and is to be implemented from 1 July 2002.
The other changes introduced in Rev.5 are to be implemented within one year of the
adoption by Council.

6.

Changes introduced in Rev.7 are to be uniformly implemented from 1 July 2006. The
amendments to paragraphs 2.2.3.1 and 4.2.2.2 related to the protective coating
condition are to apply to the ballast tanks of which the condition will be assessed at
the forthcoming Special Survey and Intermediate Survey on or after 1 July 2006.

7.

Changes introduced in Rev.8 (para. 1.4, 5.5.4, 5.5.6 and 7.1.3) are to be uniformly
applied by IACS Societies on surveys commenced on or after 1 January 2007.

8.

Changes introduced in Rev.9 are to be uniformly applied by IACS Societies forsurveys commenced on or after the 1 January 2009.

9.

Changes introduced in Rev.10 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 January 2010.

10.

Changes introduced in Rev.11 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2010.
As for the requirements regarding semi-hard coatings, these coatings, if alreadyapplied, will not be accepted from the next special or intermediate survey commenced
on or after 1 July 2010, whichever comes first, with respect to waiving the annualinternal examination of the ballast tanks.

11.

Changes introduced in Rev.12 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2012.

12.

Changes introduced in Rev.13 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2012.

13.

Changes introduced in Rev.14 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2013.

14.

Changes introduced in Rev.15 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2014.

15.

Changes introduced in Rev.16 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 January 2015.
Page 4 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 16.

Changes introduced in Rev.17 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2016.

17.

Changes introduced in Rev.18 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 January 2019.

18.

Changes introduced in Rev.19 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2020.

19.

Changes introduced in Rev.20 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 January 2023.

20.

Changes introduced in Rev.21 are to be uniformly applied by IACS Societies forsurveys commenced on or after 1 July 2024.

(cont)

Page 5 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 1.
(cont)

1.1

GENERAL
Application

1.1.1 The requirements apply to all self-propelled Chemical Tankers with integral tanks i.e.
vessels with IMO certificate of fitness for the carriage of dangerous chemicals in bulk. If achemical tanker is constructed with both integral and independent tanks, these requirements
are applicable only to that portion of the cargo length containing integral tanks. Combined gas
carriers/chemical tankers with independent tanks within the hull, are to be surveyed as gas
carriers.
1.1.2 The requirements apply to surveys of hull structure and piping systems in way ofcargo tanks, pump rooms, cofferdams, pipe tunnels, void spaces within the cargo area and all
Ballast Tanks. The requirements are additional to the classification requirements applicable to
the remainder of the ship. The requirements are not applicable for independent tanks on deck.
Refer to Z7.
1.1.3 The requirements contain the minimum extent of examination, thickness
measurements and tank testing. The survey is to be extended when Substantial Corrosion
and/or structural defects are found and include additional Close-up Survey when necessary.
1.2

Definitions

1.2.1 Chemical Tanker
A Chemical Tanker is a ship constructed or adapted and used for the carriage in bulk of any
liquid product listed in Chapter 17 of the International Code For The Construction And
Equipment Of Ships Carrying Dangerous Chemicals In Bulk, IBC Code.
1.2.2 Ballast Tank
A Ballast Tank is a tank which is used primarily for the carriage of salt water ballast.
1.2.2 bis A Combined Cargo/Ballast Tank is a tank which is used for the carriage of cargo orballast water as a routine part of the vessel’s operation and will be treated as a Ballast Tank.
Cargo tanks in which water ballast might be carried only in exceptional cases per MARPOL
I/18.3 are to be treated as cargo tanks.
1.2.3 Overall Survey
An Overall Survey is a survey intended to report on the overall condition of the hull structureand determine the extent of additional Close-up Surveys.
1.2.4 Close-up Survey
A Close-up Survey is a survey where the details of structural components are within the close
visual inspection range of the surveyor, i.e. normally within reach of hand.
1.2.5 Transverse Section
A Transverse Section includes all longitudinal members such as plating, longitudinals andgirders at the deck, sides, bottom, inner bottom and longitudinal bulkheads. For transversely
framed vessels, a transverse section includes adjacent frames and their end connections in
way of transverse sections.
1.2.6 Representative Tank
Representative Tanks are those which are expected to reflect the condition of other tanks ofsimilar type and service and with similar corrosion prevention systems. When selecting
Representative Tanks account is to be taken of the service and repair history onboard andidentifiable Critical Structural Areas and/or Suspect Areas.
Page 6 of 63

IACS Req. 1996/Rev.21 2023

Z10.3
1.2.7 Suspect Area
Z10.3 Suspect
Areas are locations showing Substantial Corrosion and/or are considered by the(cont)

Surveyor to be prone to rapid wastage.

1.2.8 Critical Structural Area
Critical Structural Areas are locations which have been identified from calculations to requiremonitoring or from the service history of the subject ship or from similar or sister ships (ifavailable) to be sensitive to cracking, buckling or corrosion which would impair the structural
integrity of the ship.
1.2.9 Substantial Corrosion
Substantial Corrosion is an extent of corrosion such that assessment of corrosion patternindicate a wastage in excess of 75% of allowable margins, but within acceptable limits.
1.2.10 Corrosion Prevention System
A Corrosion Prevention System is normally considered a full hard protective coating.
Hard Protective Coating is usually to be epoxy coating or equivalent. Other coating systems,
which are neither soft nor semi-hard coatings, may be considered acceptable as alternatives
provided that they are applied and maintained in compliance with the manufacturer’s
specifications.
1.2.11 Coating condition
Coating condition is defined as follows:
GOOD

condition with only minor spot rusting.

FAIR

condition with local breakdown at edges of stiffeners and weld
connections and/or light rusting over 20% or more of areas underconsideration, but less than as defined for POOR condition.

POOR

condition with general breakdown of coating over 20% or more, or hardscale at 10% or more, of areas under consideration.

Reference is made to IACS Recommendation No.87 “Guidelines for Coating Maintenance &Repairs for Ballast Tanks and Combined Cargo/Ballast Tanks on Oil Tankers”.
1.2.12 Cargo Area
Cargo Area is that part of the ship which contains cargo tanks, slop tanks and cargo/ballast
pump-rooms, cofferdams, ballast tanks and void spaces adjacent to cargo tanks and also
deck areas throughout the entire length and breadth of the part of the ship over the above
mentioned spaces.
1.2.13 Special consideration
Special consideration or specially considered (in connection with close-up surveys andthickness measurements) means sufficient close-up inspection and thickness measurements
are to be taken to confirm the actual average condition of the structure under the coating.
1.2.14 Prompt and Thorough Repair
A Prompt and Thorough repair is a permanent repair completed at the time of survey to thesatisfaction of the Surveyor, therein removing the need for the imposition of any associatedcondition of class.

Page 7 of 63

IACS Req. 1996/Rev.21 2023

Z10.31.2.15 Remote Inspection Techniques(RIT)
Z10.3 Remote
Inspection Technique is a means of survey that enables examination of any part of(cont)

the structure without the need for direct physical access of the surveyor(refer to Rec.42).

1.3

Repairs

1.3.1 Any damage in association with wastage over the allowable limits (including buckling,
grooving, detachment or fracture), or extensive areas of wastage over the allowable limits,which affects or, in the opinion of the Surveyor, will affect the vessel’s structural, watertight orweathertight integrity, is to be promptly and thoroughly (see 1.2.14) repaired. Areas to beconsidered include:-

bottom structure and bottom plating;side structure and side plating;deck structure and deck plating;watertight or oiltight bulkheads;
hatch covers or hatch coamings, where fitted.

For locations where adequate repair facilities are not available, consideration may be given to
allow the vessel to proceed directly to a repair facility. This may require discharging the cargo
and/or temporary repairs for the intended voyage.
1.3.2 Additionally, when a survey results in the identification of structural defects or corrosion,
either of which, in the opinion of the Surveyor, will impair the vessel’s fitness for continued
service, remedial measures are to be implemented before the ship continues in service.
1.3.3 Where the damage found on structure mentioned in Para. 1.3.1 is isolated and of a
localised nature which does not affect the ship's structural integrity, consideration may be
given by the surveyor to allow an appropriate temporary repair to restore watertight orweather tight integrity and impose a condition of class in accordance with IACS PR 35, with a
specific time limit.
1.4

Thickness measurements and close-up surveys

1.4.1 In any kind of survey, i.e. special, intermediate, annual or other surveys having thescope of the foregoing ones, thickness measurements, when required by Table II, of
structures in areas where close-up surveys are required shall be carried out simultaneouslywith close-up surveys.
1.4.2 Consideration may be given by the attending Surveyor to allow use of Remote
Inspection Techniques (RIT) as an alternative to close-up survey. Surveys conducted using a
RIT are to be completed to the satisfaction of the attending Surveyor.
1.5

Remote Inspection Techniques (RIT)

1.5.1 The RIT is to provide the information normally obtained from a close-up survey. RIT
surveys are to be carried out in accordance with the requirements given here-in and therequirements of IACS Recommendation 42 ‘Guidelines for Use of Remote Inspection
Techniques for surveys’. These considerations are to be included in the proposals for use of
a RIT which are to be submitted in advance of the survey so that satisfactory arrangements
can be agreed with the Classification Society.
1.5.2 The equipment and procedure for observing and reporting the survey using a RIT are to
be discussed and agreed with the parties involved prior to the RIT survey, and suitable time is
to be allowed to set-up, calibrate and test all equipment beforehand.
Page 8 of 63

IACS Req. 1996/Rev.21 2023

Z10.3
1.5.3 When using a RIT as an alternative to close-up survey, if not carried out by the Society
Z10.3 itself,
it is to be conducted by a firm approved as a service supplier according to UR Z17 and(cont)

is to be witnessed by an attending surveyor of the Society.

1.5.4 The structure to be examined using a RIT is to be sufficiently clean to permit meaningful
examination. Visibility is to be sufficient to allow for a meaningful examination. The
Classification Society is to be satisfied with the methods of orientation on the structure.
1.5.5 The Surveyor is to be satisfied with the method of data presentation including pictorial
representation, and a good two-way communication between the Surveyor and RIT operator
is to be provided.
1.5.6 If the RIT reveals damage or deterioration that requires attention, the Surveyor may
require traditional survey to be undertaken without the use of a RIT.

Page 9 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 2.
(cont)

2.1

SPECIAL SURVEY 1
Schedule

2.1.1 Special Surveys are to be carried out at 5 years intervals to renew the Classification
Certificate.
2.1.2 The first Special Survey is to be completed within 5 years from the date of the initialclassification survey and thereafter within 5 years from the credited date of the previous
Special Survey. However, an extension of class of 3 months maximum beyond the 5th year
can be granted in exceptional circumstances. In this case, the next period of class will startfrom the expiry date of the Special Survey before the extension was granted.
2.1.3 For surveys completed within 3 months before the expiry date of the Special Survey,
the next period of class will start from the expiry date of the Special Survey. For surveys
completed more than 3 months before the expiry date of the Special Survey, the period ofclass will start from the survey completion date. In cases where the vessel has been laid up
or has been out of service for a considerable period because of a major repair or modificationand the owner elects to only carry out the overdue surveys, the next period of class will startfrom the expiry date of the special survey. If the owner elects to carry out the next due special
survey, the period of class will start from the survey completion date.
2.1.4 The Special Survey may be commenced at the 4th Annual Survey and be progressedwith a view to completion by the 5th anniversary date. When the Special Survey iscommenced prior to the 4th Annual Survey, the entire survey is to be completed within 15
months if such work is to be credited to the Special Survey.
2.1.5 Concurrent crediting to both Intermediate Survey (IS) and Special Survey (SS) for
surveys and thickness measurements of spaces are not acceptable.
2.2

Scope

2.2.1

General2.2.1.1 The Special Survey is to include, in addition to the requirements of the Annual Survey,
examination, tests and checks of sufficient extent to ensure that the hull and related piping,
as required in 2.2.1.3, is in a satisfactory condition and is fit for its intended purpose for the
new period of class of 5 years to be assigned, subject to proper maintenance and operationand to periodical surveys being carried out at the due dates.
2.2.1.2 All cargo tanks, Ballast Tanks, including double bottom tanks, pump rooms, pipetunnels, cofferdams and void spaces bounding cargo tanks, decks and outer hull are to be
examined, and this examination is to be supplemented by thickness measurement andtesting as required in 2.4 and 2.5, to ensure that the structural integrity remains effective. The
aim of the examination is to discover Substantial Corrosion, significant deformation, fractures,
damages or other structural deterioration, that may be present.
2.2.1.3 Cargo piping on deck and cargo and ballast piping within the above tanks and spaces
are to be examined and operationally tested to working pressure to attending Surveyor’s
satisfaction to ensure that tightness and condition remain satisfactory. Special attention is tobe given to any ballast piping in cargo tanks and cargo piping in ballast tanks and void

1 Some member Societies use the term “Special Periodical Survey” others use the term “Class Renewal Survey”

instead of the term “Special Survey”.

Page 10 of 63

IACS Req. 1996/Rev.21 2023

Z10.3and Surveyors are to be advised on all occasions when this piping, including valves
Z10.3 spaces,
and fittings are open during repair periods and can be examined internally.
(cont)

2.2.2

Dry Dock Survey

2.2.2.1 A survey in dry dock is to be a part of the Special Survey. The overall and close-up
surveys and thickness measurements, as applicable, of the lower portions of the cargo tanks
and ballast tanks are to be carried out in accordance with the applicable requirements for
special surveys, if not already performed.
Note: lower portions of the cargo and ballast tanks are considered to be the parts below lightballast water line.
2.2.3

Tank Protection

2.2.3.1 Where provided, the condition of the corrosion prevention system of cargo tanks is to
be examined.
A Ballast Tank is to be examined at subsequent annual intervals where:a.

a hard protective coating has not been applied from the time of construction, orb.

a soft or semi-hard coating has been applied, orc.

substantial corrosion is found within the tank, ord.

the hard protective coating is found to be in less than GOOD condition and the hardprotective coating is not repaired to the satisfaction of the Surveyor.

Thickness measurements are to be carried out as deemed necessary by the surveyor.
2.3

Extent of Overall and Close-up Survey

2.3.1

An Overall Survey of all tanks and spaces is to be carried out at each Special Survey.

2.3.2 The minimum requirements for Close-up Surveys at Special Survey are given in Table
I. The survey of stainless steel tanks may be carried out as an overall survey supplemented
by Close-up Survey as deemed necessary by the surveyor.
2.3.3 The Surveyor may extend the Close-up Survey as deemed necessary taking into
account the maintenance of the tanks under survey, the condition of the corrosion prevention
system and also in the following cases:a)

In particular, tanks having structural arrangements or details which have suffereddefects in similar tanks or on similar ships according to available information.

b)

In tanks which have structures approved with reduced scantlings due to an approved
corrosion control system.

2.3.4 For areas in tanks where hard protective coatings are found to be in a GOOD
condition as defined in 1.2.11, the extent of Close-up Surveys according to Table I may be
specially considered.

Page 11 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 2.4
(cont)

Extent of Thickness Measurement

2.4.1 The minimum requirements for thickness measurements at Special Survey are given
in Table II. Thickness measurement of stainless steel hull structure and piping may be waived,
except for clad steel plating.

2.4.2 Provisions for extended measurements for areas with Substantial Corrosion are given
in Table IV, and as may be additionally specified in the Survey Programme as required in 5.1.
These extended thickness measurements are to be carried out before the survey is credited
as completed. Suspect Areas identified at previous Special Surveys are to be examined.
Areas of substantial corrosion identified at previous surveys are to have thickness
measurements taken.
2.4.3

The Surveyor may further extend the thickness measurements as deemed necessary.

2.4.4 For areas in tanks where hard protective coatings are found to be in a GOOD
condition as defined in 1.2.11, the extent of thickness measurements according to Table II
may be specially considered.
2.4.5 Transverse sections are to be chosen where the largest reductions are suspected tooccur or are revealed from deck plating measurements.
2.4.6 In cases where two or three sections are to be measured, at least one is to include a
Ballast Tank within 0.5L amidships.
2.5

Extent of Tank Testing

2.5.1 The minimum requirements for ballast tank testing at Special Survey are given in
2.5.3 and Table III. The minimum requirements for cargo tank testing at Special Survey are
given in 2.5.4 and Table III. Cargo tank testing carried out by the vessel’s crew under the
direction of the Master may be accepted by the surveyor provided the following conditions arecomplied with:a)a tank testing procedure, specifying fill heights, tanks being filled and bulkheads being
tested, has been submitted by the owner and reviewed by the Society prior to thetesting being carried out;b)

there is no record of leakage, distortion or substantial corrosion that would affect thestructural integrity of the tank;c)the tank testing has been satisfactorily carried out within special survey window notmore than 3 months prior to the date of the survey on which the overall or close up
survey is completed;d)the satisfactory results of the testing is recorded in the vessel’s logbook;e)

the internal and external condition of the tanks and associated structure are foundsatisfactory by the surveyor at the time of the overall and close up survey.

2.5.2

The Surveyor may extend the tank testing as deemed necessary.

2.5.3 Boundaries of ballast tanks are to be tested with a head of liquid to the top of air pipes.
2.5.4 Boundaries of cargo tanks are to be tested to the highest point that liquid will rise
under service conditions.
Page 12 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 2.5.5 The testing of double bottom tanks and other spaces not designed for the carriage of(cont)

liquid may be omitted, provided a satisfactory internal examination together with an
examination of the tanktop is carried out.
2.6

Chemical Tankers over 10 Years of Age

2.6.1 Selected steel cargo pipes outside cargo tanks and ballast pipes passing throughcargo tanks are to be:-

Thickness measured at random or selected pipe lengths to be opened for internal
inspection;
Pressure tested to the maximum working pressure.

Special attention is to be given to cargo/slop discharge piping through Ballast Tanks and void
spaces.

Page 13 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 3.
(cont)

3.1

ANNUAL SURVEY
Schedule

3.1.1 Annual Surveys are to be held within 3 months before or after anniversary date fromthe date of the initial classification survey or of the date credited for the last Special Survey.
3.2

Scope

3.2.1

General3.2.1.1 The survey is to consist of an examination for the purpose of ensuring, as far aspracticable, that the hull and piping are maintained in a satisfactory condition and should take
into account the service history, condition and extent of the corrosion prevention system ofballast tanks and areas identified in the survey report file.
3.2.2

Examination of the Hull

3.2.2.1 Examination of the hull plating and its closing appliances as far as can be seen.
3.2.2.2 Examination of watertight penetrations as far as practicable.
3.2.3

Examination of weather decks

3.2.3.1 Examination of cargo tank openings including gaskets, covers, coamings and flame
screens.
3.2.3.2 Examination of cargo tanks pressure/vacuum valves and flame screens.
3.2.3.3 Examination of flame screens on vents to all bunker tanks.
3.2.3.4 Examination of cargo, bunker and vent piping systems, including vent masts andheaders.
3.2.4

Examination of Cargo pump rooms and pipe tunnels if fitted

3.2.4.1 Examination of all pump room bulkheads for signs of chemical leakage or fractures
and, in particular, the sealing arrangements of all penetrations of pump room bulkheads.
3.2.4.2 Examination of the condition of all piping systems.
3.2.5

Examination of Ballast Tanks

3.2.5.1 Examination of Ballast Tanks where required as a consequence of the results of theSpecial Survey (see 2.2.3) and Intermediate Survey (see 4.2.2.1 and 4.2.2.2) is to be carriedout. When considered necessary by the surveyor, or when extensive corrosion exists,
thickness measurements are to be carried out and if the results of these thickness
measurements indicate that Substantial Corrosion is found, the extent of thickness
measurements is to be increased in accordance with Table IV. These extended thickness
measurements are to be carried out before the survey is credited as completed. Suspect
Areas identified at previous Surveys are to be examined. Areas of substantial corrosion
identified at previous surveys are to have thickness measurements taken.

Page 14 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 4.
(cont)

4.1

INTERMEDIATE SURVEY
Schedule

4.1.1 The Intermediate Survey is to be held at or between either the 2nd or 3rd Annual
Survey.
4.1.2 Those items which are additional to the requirements of the Annual Survey may besurveyed either at or between the 2nd and 3rd Annual Survey.
4.1.3 Concurrent crediting to both Intermediate Survey (IS) and Special Survey (SS) for
surveys and thickness measurements of spaces are not acceptable.
4.2

Scope

4.2.1

General4.2.1.1 The survey extent is dependent on the age of the vessel as specified in 4.2.2 to 4.2.4.
4.2.1.2 For weather decks, an examination as far as applicable of cargo, bunker, ballast,
steam and vent piping systems as well as vent masts and headers is to be carried out. If
upon examination there is any doubt as to the condition of the piping, the piping may berequired to be pressure tested, thickness measured or both.
4.2.2 Chemical Tankers between 5 and 10 Years of Age
The following is to apply:
4.2.2.1 For ballast tanks, an Overall Survey of Representative Tanks selected by theSurveyor is to be carried out. If such inspections reveal no visible structural defects, theexamination may be limited to a verification that the hard protective coating remains in GOOD
condition.
4.2.2.2 A Ballast Tank is to be examined at subsequent annual intervals where:a.

a hard protective coating has not been applied from the time of construction, orb.

a soft or semi-hard coating has been applied, orc.

substantial corrosion is found within the tank, ord.

the hard protective coating is found to be in less than GOOD condition and the hardprotective coating is not repaired to the satisfaction of the Surveyor.

4.2.2.3 In addition to the requirements above, suspect areas identified at previous surveys
are to be examined.
4.2.3 Chemical Tankers between 10 and 15 years of Age
The following is to apply:
4.2.3.1 The requirements of the Intermediate Survey are to be to the same extent as theprevious Special Survey as required in 2 and 5.1. However, pressure testing of cargo andballast tanks is not required unless deemed necessary by the attending Surveyor.

Page 15 of 63

IACS Req. 1996/Rev.21 2023

Z10.34.2.3.2 In application of 4.2.3.1, the intermediate survey may be commenced at the second
Z10.3 annual
survey and be progressed during the succeeding year with a view to completion at the(cont)

third annual survey in lieu of the application of 2.1.4.

4.2.3.3 In application of 4.2.3.1, an under water survey may be considered in lieu of therequirements of 2.2.2.
4.2.4 Chemical Tankers over 15 years of Age
The following is to apply:
4.2.4.1 The requirements of the Intermediate Survey are to be to the same extent as theprevious Special Survey as required in 2 and 5.1. However, pressure testing of cargo andballast tanks is not required unless deemed necessary by the attending Surveyor.
4.2.4.2 In application of 4.2.4.1, the intermediate survey may be commenced at the second
annual survey and be progressed during the succeeding year with a view to completion at thethird annual survey in lieu of the application of 2.1.4.
4.2.4.3 In application of 4.2.4.1, a survey in dry dock is to be part of the intermediate survey.
The overall and close-up surveys and thickness measurements, as applicable, of the lower
portions of the cargo tanks and water ballast tanks are to be carried out in accordance withthe applicable requirements for intermediate surveys, if not already performed.
Note: lower portions of the cargo and ballast tanks are considered to be the parts below lightballast water line.

Page 16 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 5.
(cont)

5.1

PREPARATION FOR SURVEY
Survey Programme

5.1.1 The Owner in co-operation with the Classification Society is to work out a specificSurvey Programme prior to the commencement of any part of:-

the Special Survey;-

the Intermediate Survey for chemical tankers over 10 years of age.

The Survey Programme at Intermediate Survey may consist of the Survey Programme at theprevious Special Survey supplemented by the Executive Hull Summary of that Special
Survey and later relevant survey reports.
The Survey Programme is to be worked out taking into account any amendments to thesurvey requirements implemented after the last Special Survey carried out.
The Survey Programme is to be in a written format based on the information in annex IIIA.
5.1.1.1 Prior to the development of the survey programme, the survey planning questionnaire
is to be completed by the owner based on the information set out in annex IIIB, andforwarded to the Classification Society.
5.1.2 In developing the Survey Programme, the following documentation is to be collected
and consulted with a view to selecting tanks, areas, and structural elements to be examined:.1

Survey status and basic ship information;.2

Documentation on-board, as described in 6.2 and 6.3;

.3

Main structural plans of cargo and ballast tanks (scantling drawings), including
information regarding use of high tensile steels (HTS), clad steel and stainless steel;.4

Executive Hull Summary;.5

Relevant previous damage and repair history;.6

Relevant previous survey and inspection reports from both Classification Society andthe owner;.7

Information regarding the use of the ship's tanks, typical cargoes and other relevant
data;

.8

details of the inert gas plant and tank cleaning procedures;.9

information and other relevant data regarding conversion or modification of the ship’s
cargo and ballast tanks since the time of construction;.10

description and history of the coating and corrosion protection system (previous classnotations), if any;

.11

inspections by the Owner’s personnel during the last 3 years with reference tostructural deterioration in general, leakages in tank boundaries and piping andPage 17 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

condition of the coating and corrosion protection system if any. Guidance for reportingis shown in Annex IIIC;(cont).12

information regarding the relevant maintenance level during operation including port
state control reports of inspection containing hull related deficiencies, Safety
Management System non-conformities relating to hull maintenance, including theassociated corrective action(s); and.13

any other information that will help identify suspect areas and critical structural areas.

5.1.3 The submitted Survey Programme is to account for and comply, as a minimum, withthe requirements of Tables I, II, 2.5 and 2.6 for close-up survey, thickness measurement, tanktesting and pipe testing, respectively, and is to include relevant information including at least:.1

Basic ship information and particulars;.2

Main structural plans (scantling drawings), including information regarding use of hightensile steels (HTS), clad steel and stainless steel;.3

Plan of tanks;.4

List of tanks with information on use, corrosion prevention and condition of coating;.5

Conditions for survey (e.g., information regarding tank cleaning, gas freeing,
ventilation, lighting, etc.);.6

Provisions and methods for access to structures;.7

Equipment for surveys;.8

Nomination of tanks and areas for close-up survey (per 2.3);.9

Nomination of sections for thickness measurement (per 2.4);.10

Nomination of tanks for tank testing (per 2.5); and the pipes that are to undergo pipe
testing as per 2.6;

.11

Identification of the thickness measurement firm;.12

Damage experience related to the ship in question;.13

Critical structural areas and suspect areas, where relevant.

5.1.4 The Classification Society will advise the Owner of the maximum acceptable structural
corrosion diminution levels applicable to the vessel.
5.1.5 Use may also be made of the Guidelines for Technical Assessment in Conjunction
with Planning for Enhanced Surveys of Chemical Tankers Special Survey - Hull, contained in
Annex I. These guidelines are a recommended tool which may be invoked at the discretion of
the Classification Society, when considered necessary and appropriate, in conjunction withthe preparation of the required Survey Programme.
5.2

Conditions For Survey

5.2.1

The Owner is to provide the necessary facilities for a safe execution of the survey.
Page 18 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 5.2.1.1 In order to enable the attending surveyors to carry out the survey, provisions for(cont)

proper and safe access are to be agreed between the owner and the Classification society
are to be in accordance with IACS PR 37.
5.2.1.2 Details of the means of access are to be provided in the survey planningquestionnaire.
5.2.1.3 In cases where the provisions of safety and required access are judged by theattending surveyors not to be adequate, the survey of the spaces involved is to not proceed.
5.2.2 Tanks and spaces are to be safe for access. Tanks and spaces are to be gas free andproperly ventilated. Prior to entering a tank, void or enclosed space, it is to be verified that theatmosphere in that space is free from hazardous gas and contains sufficient oxygen.

5.2.3 In preparation for survey and thickness measurements and to allow for a thoroughexamination, all spaces are to be cleaned including removal from surfaces of all loose
accumulated corrosion scale. Spaces are to be sufficiently clean and free from water, scale,dirt, oil residues etc. to reveal corrosion, deformation, fractures, damages, or other structural
deterioration as well as the condition of the coating. However, those areas of structure whose
renewal has already been decided by the owner need only be cleaned and descaled to theextent necessary to determine the limits of the areas to be renewed.
5.2.4 Sufficient illumination is to be provided to reveal significant corrosion, deformation,
fractures, damages or other structural deterioration.
5.2.5 Where soft or semi-hard coatings have been applied, safe access is to be provided for
the Surveyor to verify the effectiveness of the coating and to carry out an assessment of theconditions of internal structures which may include spot removal of the coating. When safe
access cannot be provided, the soft or semi-hard coating is to be removed.
5.3

Access to Structures

5.3.1 For overall survey, means are to be provided to enable the surveyor to examine thehull structure in a safe and practical way.
5.3.2 For close-up survey, one or more of the following means for access, acceptable to theSurveyor, is to be provided:-

permanent staging and passages through structures;
temporary staging and passages through structures;
hydraulic arm vehicles such as conventional cherry pickers, lifts and movable
platforms;
boats or rafts;
portable ladders;
other equivalent means.

5.3.3 For Surveys conducted by use of a remote inspection technique, one or more of thefollowing means for access, acceptable to the Surveyor, is to be provided:
Unmanned robot arm.
Remote Operated Vehicles (ROV).
Unmanned Aerial Vehicles / Drones.
Other means acceptable to the Classification Society.

Page 19 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 5.4
(cont)

Equipment for Survey

5.4.1 Thickness measurement is normally to be carried out by means of ultrasonic test
equipment. The accuracy of the equipment is to be proven to the Surveyor as required.

5.4.2 One or more of the following fracture detection procedures may be required if deemednecessary by the Surveyor:-

radiographic equipment;ultrasonic equipment;
magnetic particle equipment;
dye penetrant.

5.4.3 Explosimeter, oxygen-meter, breathing apparatus, lifelines, riding belts with rope andhook and whistles together with instructions and guidance on their use are to be madeavailable during the survey. A safety check-list is to be provided.
5.4.4 Adequate and safe lighting is to be provided for the safe and efficient conduct of thesurvey.
5.4.5 Adequate protective clothing is to be made available and used during the survey (e.g.
safety helmet, gloves, safety shoes, etc.).
5.5

Rescue and emergency response equipment

If breathing apparatus and/or other equipment is used as ‘Rescue and emergency response
equipment’ then it is recommended that the equipment should be suitable for theconfiguration of the space being surveyed.
5.6

Survey at Sea or at Anchorage

5.6.1 Survey at sea or at anchorage may be accepted provided the Surveyor is given thenecessary assistance from the personnel onboard. Necessary precautions and proceduresfor carrying out the survey are to be in accordance with 5.1, 5.2, 5.3 and 5.4.
5.6.2 A communication system is to be arranged between the survey party in the tank andthe responsible officer on deck. This system is to include the personnel in charge of Ballast
pump handling if boats or rafts are used.
5.6.3 Surveys of tanks by means of boats or rafts may only be undertaken with theagreement of the Surveyor, who is to take into account the safety arrangements provided,
including weather forecasting and ship response under foreseeable conditions and provided
the expected rise of water within the tank does not exceed 0.25m.
5.6.4 When rafts or boats are used for close-up surveys, the following conditions are to beobserved:.1

only rough duty, inflatable rafts or boats, having satisfactory residual buoyancy andstability even if one chamber is ruptured, should be used;.2

the boat or raft should be tethered to the access ladder and an additional person
should be stationed down the access ladder with a clear view of the boat or raft;.3

appropriate lifejackets should be available for all participants;

Page 20 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 .4

the surface of water in the tank should be calm (under all foreseeable conditions the
expected rise of water within the tank should not exceed 0.25 m) and the water levelstationary. On no account should the level of the water be rising while the boat or raftis in use;.5

the tank or space must contain clean ballast water only. Even a thin sheen of cargo on
the water is not acceptable;.6

at no time should the water level be allowed to be within 1 m of the deepest underdeck web face flat so that the survey team is not isolated from a direct escape route to
the tank hatch. Filling to levels above the deck transverses should only becontemplated if a deck access manhole is fitted and open in the bay being examined,
so that an escape route for the survey party is available at all times. Other effectivemeans of escape to the deck may be considered;.7

if the tanks (or spaces) are connected by a common venting system, or inert gas
system, the tank in which the boat or raft should be used should be isolated to preventa transfer of gas from other tanks (or spaces).

(cont)

5.6.5 Rafts or boats alone may be allowed for inspection of the under deck areas for tanks
or spaces, if the depth of the webs is 1.5 m or less.
5.6.6

If the depth of the webs is more than 1.5 m, rafts or boats alone may be allowed only:.1

when the coating of the under deck structure is in GOOD condition and there is noevidence of wastage; or.2

if a permanent means of access is provided in each bay to allow safe entry and exit.
This means:i.
access direct from the deck via a vertical ladder and a small platform
fitted approximately 2 m below the deck in each bay; orii.

access to deck from a longitudinal permanent platform having ladders
to deck in each end of the tank. The platform shall, for the full length of
the tank, be arranged in level with, or above, the maximum water levelneeded for rafting of under deck structure. For this purpose, the ullage
corresponding to the maximum water level is to be assumed not morethan 3 m from the deck plate measured at the midspan of decktransverses and in the middle length of the tank (See Figure 1).

If neither of the above conditions are met, then staging or an “other equivalent means” is tobe provided for the survey of the under deck areas.

5.6.7 The use of rafts or boats alone in paragraphs 5.6.5 and 5.6.6 does not preclude theuse of boats or rafts to move about within a tank during a survey.
Page 21 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 Reference is made to IACS Recommendation 39 - Guidelines for the use of Boats or Rafts for(cont)

Close-up surveys.

5.7

Survey Planning Meeting

5.7.1 Proper preparation and close co-operation between the attending surveyor(s) and theowner’s representatives onboard prior to and during the survey are an essential part in thesafe and efficient conduct of the survey. During the survey on board safety meetings are to
be held regularly.
5.7.2 Prior to the commencement of any part of the Special and Intermediate Survey asurvey planning meeting is to be held between the attending Surveyor(s), the Owner’s
Representative in attendance and the TM firm representative, where involved, and the masterof the ship or an appropriately qualified representative appointed by the master or firm for the
purpose of ascertaining that all the arrangements envisaged in the survey programme are inplace, so as to ensure the safe and efficient conduct of the survey work to be carried out. See
also 7.1.2.
5.7.3

The following is an indicative list of items that are to be addressed in the meeting:.1

schedule of the vessel (i.e. the voyage, docking and undocking manoeuvres, periods
alongside, cargo and ballast operations etc.);.2

provisions and arrangements for thickness measurements (i.e. access, cleaning/descaling, illumination, ventilation, personal safety);.3extent of the thickness measurements;.4

acceptance criteria (refer to the list of minimum thicknesses);.5

extent of close-up survey and thickness measurement considering the coating
condition and suspect areas/areas of substantial corrosion;.6

execution of thickness measurements;.7

taking representative readings in general and where uneven corrosion/pitting is found;.8

mapping of areas of substantial corrosion; and.9communication between attending surveyor(s) the thickness measurement firm
operator(s) and owner representative(s) concerning findings.

Page 22 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 6.
(cont)

6.1

DOCUMENTATION ON BOARD
General6.1.1 The owner is to obtain, supply and maintain on board documentation as specified in
6.2 and 6.3, which is to be readily available for the Surveyor.
6.1.2

The documentation is to be kept on board for the lifetime of the ship.

6.2

Survey Report File

6.2.1

A Survey Report File is to be a part of the documentation on board consisting of-Reports of structural surveys;
Executive Hull Summary;Thickness measurement reports.

6.2.2 The Survey Report File is to be available also in the Owner's and the Classification
Society's management offices.
6.3

Supporting Documents

6.3.1

The following additional documentation is to be available onboard:-

Survey Programme as required by 5.1 until such time as the Special Survey orIntermediate Survey, as applicable, has been completed;
Main structural plans of cargo and ballast tanks;
Previous repair history;
Cargo and ballast history;
Extent of use of inert gas plant and tank cleaning procedures;
Inspections by ship's personnel with reference to- structural deterioration in general- leakage in bulkheads and piping- condition of corrosion prevention system, if any;
- A guidance for reporting is shown in Annex IIIC
Any other information that will help identify Critical Structural Areas and/or Suspect
Areas requiring inspection.

-

6.4

Review of Documentation On Board

6.4.1 Prior to survey, the Surveyor is to examine the completeness of the documentation
onboard, and its contents as a basis for the survey.

Page 23 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 7.
(cont)

7.1

PROCEDURES FOR THICKNESS MEASUREMENTS
General7.1.1 The required thickness measurements, if not carried out by the Society itself, are to bewitnessed by a Surveyor of the Society. The Surveyor is to be on board to the extent
necessary to control the process.
7.1.2 The thickness measurement firm is to be part of the survey planning meeting to beheld prior to commencing the survey.
7.1.3 Thickness measurements of structures in areas where close-up surveys are required
shall be carried out simultaneously with close-up surveys.
7.1.4 In all cases the extent of the thickness measurements are to be sufficient as torepresent the actual average condition.
7.2

Certification of Thickness Measurement Firm

7.2.1 The thickness measurements are to be carried out by a qualified firm certified by theClassification Society according to principles stated in Table V.
7.3

Reporting

7.3.1 A thickness measurement report is to be prepared. The report is to give the location of
measurements, the thickness measured as well as corresponding original thickness.
Furthermore, the report is to give the date when the measurements were carried out, type ofmeasurement equipment, names of personnel and their qualifications and has to be signedby the operator. The thickness measurement report is to follow the principles as specified in
the Recommended Procedures for Thickness Measurements of Chemical Tankers, containedin Annex II.
7.3.2 The Surveyor is to review the final thickness measurement report and countersign the
cover page.

Page 24 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 8.
(cont)

8.1

REPORTING AND EVALUATION OF SURVEY
Evaluation of Survey Report

8.1.1 The data and information on the structural condition of the vessel collected during thesurvey is to be evaluated for acceptability and continued structural integrity of the vessel.
8.2

Reporting

8.2.1

Principles for survey reporting are shown in Table VI.

8.2.2 When a survey is split between different survey stations, a report is to be made foreach portion of the survey. A list of items examined and / or tested (pressure testing,thickness measurements etc.) and an indication of whether the item has been credited, are to
be made available to the next attending Surveyor(s), prior to continuing or completing thesurvey.
8.2.3 An Executive Hull Summary of the survey and results is to be issued to the Owner asshown in Table VII and placed on board the vessel for reference at future surveys. The
Executive Hull Summary is to be endorsed by the Classification Society's head office orregional managerial office.

Page 25 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE I.1

(cont)MINIMUM REQUIREMENTS FOR CLOSE-UP SURVEY AT
SPECIAL SURVEY OF SINGLE SKIN CHEMICAL TANKERS
Special Survey No.1
age < 5Special Survey No.2
5 < age < 10Special Survey No.3
10 < age < 15A

ONE WEBFRAME RING
- in a ballast
wing tankA

ALL WEB FRAME
RINGS- in a ballast wingtank or double
bottom ballast tank(see Note I)A

ALL WEB FRAME
RINGS- in all ballast
tanks

B

ONE DECKTRANSVERSE- in a cargo tankor on deckB

ONE DECKTRANSVERSE- in each remaining
ballast tank or ondeck

A

ALL WEB FRAME
RINGS- in a cargo wingtank

B

ONE DECKTRANSVERSE- in a cargo wingtank or on deck

D

ONE
TRANSVERSE
BULKHEAD- lower part in aballast tankB

ONE DECKTRANSVERSE- in two cargo centre
tanks or on deckA

ONE WEBFRAME RING
- in eachremaining cargo
tank

D

ONE
TRANSVERSE
BULKHEAD- lower part in acargo wing tankC

BOTH
TRANSVERSE
BULKHEADS- in a ballast wing
tank

C

ALL
TRANSVERSE
BULKHEADS- in all cargo tanks

D

ONE
TRANSVERSE
BULKHEAD- lower part in acargo centre
tank (see NoteII)D

ONE TRANSVERSE
BULKHEAD- lower part in eachremaining ballast
tank

C

ALL
TRANSVERSE
BULKHEADS- in all ballast
tanks

D

ONE TRANSVERSE
BULKHEAD- lower part in two
cargo centre tanks(see Note II)

D

ONE TRANSVERSE
BULKHEAD- lower part in acargo wing tank

Page 26 of 63

Special Survey No.4
and Subsequent:age > 15
As special survey
No.3

Additional transverse
areas as deemednecessary by theSociety

IACS Req. 1996/Rev.21 2023

Z10.3
I: Ballast double hull tank: means double bottom tank plus double side tank plus double deck tank, as
Z10.3 Noteapplicable, even if these tanks are separate.

(cont)

Note II: Where no centre cargo tanks are fitted (as in case of centre longitudinal bulkhead), transverse bulkheads
in wing tanks are to be surveyed.
A-D: are areas to be subjected to close-up surveys and thickness measurements (see Fig. 2.1 and 2.2).
A)
B)
C)
D)

Complete transverse web frame ring including adjacent structural members.
Deck transverse including adjacent deck structural members.
Transverse bulkhead complete - including girder system and adjacent structural members.
Transverse bulkhead lower part - including girder system and adjacent structural members.

Page 27 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3(cont)TABLE I.2
MINIMUM REQUIREMENTS FOR CLOSE-UP SURVEY
AT SPECIAL SURVEY OF DOUBLE SKIN CHEMICAL TANKERS
Special Survey No.1
age < 5Special Survey No.2
5 < age < 10Special Survey No.3
10 < age < 15

(1)

ONE WEBFRAME RING
- in a ballast
double hull tank(see Note I)(1)

ALL WEB FRAME
RINGS- in a ballast wingtank or ballast
double hull tank (seeNote I)(1)

ALL WEB FRAME
RINGS- in all ballast
tanks

(2)

ONE DECKTRANSVERSE- in a cargo tankor on deck

(6)

THE KNUCKLEAREA AND THE
UPPER PART
(3 metres approx) of
one web frame ineach remaining
ballast tank

(7)

ALL WEB FRAME
RINGS- in a cargo wing
tank

(4)

ONE
TRANSVERSE
BULKHEAD- in a ballast
tank (see Note I)(7)

ONE WEBFRAME RING
- in eachremaining cargo
tank

(5)

ONE
TRANSVERSE
BULKHEAD- in a cargo wing
tank

(2)

ONE DECKTRANSVERSE- in two cargo tanks

(3)

ALL
TRANSVERSE
BULKHEADS- in all cargo tanks

(5)

ONE
TRANSVERSE
BULKHEAD- in a cargo
centre tank (seeNote II)(4)

ONE TRANSVERSE
BULKHEAD- in each ballast tank(see Note I)

(4)

ALL
TRANSVERSE
BULKHEADS- in all ballast
tanks

(5)

ONE TRANSVERSE
BULKHEAD- in two cargo centre
tanks (see Note II)(5)

ONE TRANSVERSE
BULKHEAD- in a cargo wingtank

Page 28 of 63

Special Survey No.4
and Subsequent:age > 15
As special survey
No.3

Additional transverse
areas as deemednecessary by theSociety

IACS Req. 1996/Rev.21 2023

Z10.3(2), (3), (4), (5), (6) and (7) are areas to be subjected to close-up surveys and thickness measurements (seeZ10.3 (1),Figures 2.1 - 2.3).

(cont)(1): Web frame in a ballast tank means vertical web in side tank, hopper web in hopper tank, floor in double
bottom tank and deck transverse in double deck tank (where fitted), including adjacent structural members. In fore
and aft peak tanks web frame means a complete transverse web frame ring including adjacent structuralmembers.
(2): Deck transverse, including adjacent deck structural members (or external structure on deck in way of the tank,where applicable).
(3): Transverse bulkhead complete in cargo tanks, including girder system, adjacent structural members (such as
longitudinal bulkheads) and internal structure of lower and upper stools, where fitted.
(4): Transverse bulkhead complete in ballast tanks, including girder system and adjacent structural members,
such as longitudinal bulkheads, girders in double bottom tanks, inner bottom plating, hopper side, connecting
brackets.
(5): Transverse bulkhead lower part in cargo tank, including girder system, adjacent structural members (such as
longitudinal bulkheads) and internal structure of lower stool, where fitted.
(6): The knuckle area and the upper part (3 metres approximately), including adjacent structural members.
Knuckle area is the area of the web frame around the connections of the slope hopper plating to the inner hullbulkhead and the inner bottom plating, up to 2 metres from the corners both on the bulkhead and the double
bottom.
(7): Web frame in a cargo tank means deck transverse, longitudinal bulkhead structural elements and cross ties,
where fitted, including adjacent structural members.
Note I: Ballast double hull tank: means double bottom tank plus double side tank plus double deck tank, asapplicable, even if these tanks are separate.
Note II: Where no centre cargo tanks are fitted (as in the case of centre longitudinal bulkhead), transverse
bulkheads in wing tanks are to be surveyed.

B, (2)A, (1)
Fig. 2.1 Representative transverse section of chemical tanker. Areas A & B and 1 and 2

Page 29 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3(cont)

C, (3)

D, (5)(4)

Fig. 2.2 Representative transverse section of chemical tanker. Areas C & D and 3, 4 and 5

(6)

(7)
(7)

Fig. 2.3 Representative transverse section of chemical tanker. Areas 6 and 7(6)

Page 30 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3(cont)TABLE IIMINIMUM REQUIREMENTS FOR THICKNESS MEASUREMENTS AT
SPECIAL SURVEY OF CHEMICAL TANKERS

Special Survey No.1
age < 5
1.

Suspect areas

Special Survey No.2
5 < age ≤ 10

Special Survey No.3
10 < age ≤ 15

Special Survey No.4
and Subsequent
age > 15

1.

Suspect areas

1.

Suspect areas

1.

Suspect areas

2.

Within the cargo area:

2.

Within the cargo area:

2.

Within the cargo area:.1

Each deck plate.1

Each deck plate.1

Each deck plate.2

One transverse
section.2

Two transverse
sections (1).2Three transverse
sections (1).3All wind and water
strakes.3

Each bottom plate3.

Selected wind andwater strakes outside
the cargo area

3.

Selected wind andwater strakes outside
the cargo area3.

All wind and water
strakes, full length4.

Measurements, forgeneral assessment
and recording of
corrosion pattern, of
those structuralmembers subject toclose-up survey
according to Table I.1
or I.2, as applicable.

4.

Measurements, forgeneral assessment
and recording of
corrosion pattern, of
those structuralmembers subject toclose-up survey
according to Table I.1
or I.2, as applicable.

4.

Measurements, forgeneral assessment
and recording of
corrosion pattern, of
those structuralmembers subject toclose-up survey
according to Table I.1 or
I.2, as applicable.

(1): at least one section is to include a ballast tank within 0.5L amidships.

Page 31 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3(cont)TABLE IIIMINIMUM REQUIREMENTS FOR TANK TESTINGAT SPECIAL SURVEY OF CHEMICAL TANKERS
Special Survey No.1
age ≤ 5Special Survey No.2 and Subsequent
age > 5All ballast tank boundaries

All ballast tank boundaries

Cargo tank boundaries facing ballast tanks,
void spaces, pipe tunnels, pump rooms or
cofferdams

All cargo tank bulkheads

Page 32 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3(cont)TABLE IV/Sheet 1
REQUIREMENTS FOR EXTENT OF THICKNESSMEASUREMENTS AT THOSE AREAS OF SUBSTANTIAL CORROSION.
SPECIAL SURVEY OF CHEMICAL TANKERS WITHINTHE CARGO AREA LENGTH.
BOTTOM, INNER BOTTOM AND HOPPER STRUCTURE
Structural member
Bottom, inner bottom andhopper structure plating

Bottom, inner bottom andhopper structure longitudinals
Bottom girders, including thewatertight ones

Bottom floors, including thewatertight ones
Hopper structure web framering
Hopper structure transverse
watertight bulkhead or swash
bulkhead

Panel stiffening

Extent of measurement

Pattern of measurement

Minimum of three bays
across tank, including aft bay

5-point pattern for each panel
between longitudinals andfloorsMeasurements around andunder all suction bell mouths
Minimum of threelongitudinals in each bay
where bottom plating
measured
At fore and aft watertightfloors and in centre of tanks

Three floors in bays where
bottom plating measured,with measurements at bothends and middle
Three floors in bays where
bottom plating measured- lower 1/3 of bulkhead

Three meaurements in line
across the flange and threemeasurements on vertical
web
Vertical line of single
measurements on girder
plating with one
measurement between eachpanel stiffener, or a minimumof three measurements.
Two measurements acrossface flat where fitted.
5-point pattern over twosquare metre area
5-point pattern over one
square metre of plating.
Single measurements onflange- 5-point pattern over one
square metre of plating- upper 2/3 of bulkhead- 5-point pattern over twosquare metre of plating- stiffeners(minimum of three)- For web, 5-point patternover span (twomeasurements across web
at each end and one at
centre of span). For flange,
single measurements ateach end and centre of spanSingle measurements

Where applicable

Page 33 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE IV/Sheet 2(cont)REQUIREMENTS FOR EXTENT OF THICKNESSMEASUREMENTS AT THOSE AREAS OF SUBSTANTIAL CORROSION.
SPECIAL SURVEY OF CHEMICAL TANKERS WITHINTHE CARGO AREA LENGTH.
DECK STRUCTURE
Structural member

Extent of measurement

Pattern of measurement

Deck plating

Two transverse bands acrosstank

Minimum of threemeasurements per plate perband

Deck longitudinals

Every third longitudinal ineach of two bands with aminimum of one longitudinal

Three measurements in line
vertically on webs and two
measurements on flange (iffitted)Deck girders and brackets

At fore and aft transverse
bulkhead, bracket toes and incentre of tanks

Vertical line of single
measurements on web platingwith one measurement
between each panel stiffener,
or a minimum of threemeasurements.
Two measurements acrossflange. 5-point pattern on
girder/bulkhead brackets

Deck transverse webs

Minimum of two webs, withmeasurements at both ends
and middle of span

5-point pattern over one
square metre area.
Single measurements onflangeVertical web and transverse
bulkhead in wing ballast
tank for double hull design(two metres from deck)

Minimum of two webs, andboth transverse bulkheads

5-point pattern over one
square metre area

Panel stiffening

Where applicable

Single measurements

Page 34 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE IV/Sheet 3(cont)REQUIREMENTS FOR EXTENT OF THICKNESSMEASUREMENTS AT THOSE AREAS OF SUBSTANTIAL CORROSION.
SPECIAL SURVEY OF CHEMICAL TANKERS WITHINTHE CARGO AREA LENGTH.
SIDE SHELL AND LONGITUDINAL BULKHEADSStructural member
Side shell and longitudinalbulkhead plating:

Extent of measurement-

Deckhead and bottom
strakes, and strakes in wayof horizontal girders-

Plating between each pair of
longitidinals in a minimum of
three bays (along the tank)-

All other strakes-

Plating between every thirdpair of longitudinals in same
three bays

Each longitudinal in same
three bays

Side shell and longitudinalbulkhead longitudinals on:-

Deckhead and bottom
strakes--

All other strakes-

Longitudinals - brackets
Vertical web and transverse
bulkheads of double side tanks(excluding deck area):

Every third longitudinal insame three bays
Minimum of three at top, middle
and bottom of tank in same
three bays-

Strakes in way of horizontal
girders--

Other strakes-

Web frames and cross ties forother tanks than double sidetanks

Pattern of measurement

Single measurement

3 measurements across web
and 1 measurement on flange

5-point pattern over area ofbracketMinimum of two webs andboth transverse bulkheads-

Minimum of two webs andboth transverse bulkheads
Three webs with minimumof three locations on eachweb, including in way ofcross tie connections and lower
end bracket-

Horizontal girders

Plating on each girder in aminimum of three bays

Panel stiffening

Where applicable

Page 35 of 63

5-point pattern over approx.
two square metre area

Two measurements between
each pair of vertical stiffeners
5-point pattern overapproximately two square
metre area of webs, plus
single measurements onflanges of web frame andcross ties
Two measurements between
each pair of longitudinal girder
stiffeners
Single measurements

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE IV/Sheet 4(cont)REQUIREMENTS FOR EXTENT OF THICKNESSMEASUREMENTS AT THOSE AREAS OF SUBSTANTIAL CORROSION.
SPECIAL SURVEY OF CHEMICAL TANKERS WITHINTHE CARGO AREA LENGTH.
TRANSVERSE WATERTIGHT AND SWASH BULKHEADSStructural member
Upper and lower stool, where
fittedDeckhead and bottom
strakes, and strakes in wayof horizontal stringers
All other strakes
Strakes in corrugatedbulkheads
Stiffeners

Brackets
Horizontal stringers

Deep webs and girders

Extent of measurement- Transverse band within
25mm of welded
connection to inner
bottom/deck plating- Transverse band within
25mm of welded
connection to shelf plate
Plating between pair ofstiffeners at three locations:approximately 1/4, 1/2 and3/4 width of tank
Plating between pair ofstiffeners at middle location
Plating for each change ofscantling at centre of panel
and at flange of fabricatedconnection
Minimum of three typicalstiffeners

Minimum of three at top,
middle and bottom of tank
All stringers withmeasurements at both ends
and middle.
Measurements at toe ofbracket and at centre of span

Page 36 of 63

Pattern of measurement
5-point pattern between
stiffeners over one metre
length5-point pattern between
stiffeners over one metre
lengthSingle measurement
5-point pattern over about
one square metre of plating
For web, 5-point pattern overspan between bracket
connections (twomeasurements across web at
each bracket connection and
one at centre of span).
For flange, single
measurements at eachbracket toe and at centre ofspan
5-point pattern over area ofbracket5-point pattern over one
square metre area, plus
single measurements nearbracket toes and on flanges
For web, 5 point pattern overabout 1 square metre.
3 measurements across faceflat.

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE V

(cont)PROCEDURES FOR CERTIFICATION OF FIRMS ENGAGED IN THICKNESSMEASUREMENT OF HULL STRUCTURES
1.

Application
This guidance applies for certification of the firms which intend to engage in the
thickness measurement of hull structures of the vessels.

2.

Procedures for Certification(1)

Submission of Documents:
Following documents are to be submitted to the society for approval:
a)
b)
c)
d)
e)
f)
g)

(2)

Outline of firms, e.g. organisation and management structure.
Experience of the firms on thickness measurement inter alia of hull structuresof the vessels.
Technicians’ careers, i.e. experience of technicians as thickness measurement
operators, technical knowledge of hull structure etc. Operators, are to bequalified according to a recognized industrial NDT Standard.
Equipment used for thickness measurement such as ultra-sonic testingmachines and its maintenance/calibration procedures.
A guide for thickness measurement operators.
Training programmes of technicians for thickness measurement.
Measurement record format in accordance with the Recommended
Procedures for Thickness Measurements of Chemical Tankers, contained in
Annex II.

Auditing of the firms:
Upon reviewing the documents submitted with satisfactory results, the firm is audited
in order to ascertain that the firm is duly organised and managed in accordance withthe documents submitted, and eventually is capable of conducting thickness
measurement of the hull construction of the ships.

(3)

Certification is conditional on an onboard demonstration at thickness measurements
as well as satisfactory reporting.

3.

Certification(1)

Upon satisfactory results of both the audit of the firm in 2(2) and the demonstration
tests in 2(3) above, the Society will issue a Certificate of Approval as well as a noticeto the effect that the thickness measurement operation system of the firm has beencertified by the Society.

(2)

Renewal/endorsement of the Certificate is to be made at intervals not exceeding 3
years by verification that original conditions are maintained.

Page 37 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3 4.
(cont)

Information of any alteration to the Certified Thickness Measurement Operation
SystemIn case where any alteration to the certified thickness measurement operation systemof the firm is made, such an alteration is to be immediately informed to the Society.
Re-audit is made where deemed necessary by the Society.

5.

Cancellation of Approval
Approval may be cancelled in the following cases:(1)

Where the measurements were improperly carried out or the results were improperly
reported.

(2)

Where the Society's surveyor found any deficiencies in the approved thickness
measurement operation systems of the firm.

(3)

Where the firm failed to inform of any alteration in 4 above to the Society.

Page 38 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE VI

(cont)SURVEY REPORTING PRINCIPLESAs a principle, for chemical tankers subject to ESP, the surveyor is to include the following
content in his report for survey of hull structure and piping systems, as relevant for the survey.
The structure of the reporting content may be different, depending on the report system forthe respective Societies.
1. General
1.1 A survey report is to be generated in the following cases:-

In connection with commencement, continuation and / or completion of periodical hullsurveys, i.e. annual, intermediate and special surveys, as relevant
When structural damages / defects have been found
When repairs, renewals or modifications have been carried out
When condition of class has been imposed or deleted

1.2 The purpose of reporting is to provide:-

Evidence that prescribed surveys have been carried out in accordance with applicableclassification rules
Documentation of surveys carried out with findings, repairs carried out and condition ofclass imposed or deleted
Survey records, including actions taken, which shall form an auditable documentary
trail. Survey reports are to be kept in the survey report file required to be on board
Information for planning of future surveys
Information which may be used as input for maintenance of classification rules andinstructions

1.3 When a survey is split between different survey stations, a report is to be made for eachportion of the survey. A list of items surveyed, relevant findings and an indication of whether
the item has been credited, is to be made available to the next attending surveyor, prior tocontinuing or completing the survey. Thickness measurement and tank testing carried out isalso to be listed for the next surveyor.
2. Extent of the survey
2.1 Identification of compartments where an overall survey has been carried out.
2.2 Identification of locations, in each tank, where a close-up survey has been carried out,
together with information of the means of access used.
2.3 Identification of locations, in each tank, where thickness measurement has been carriedout.
Note: As a minimum, the identification of location of close-up survey and thickness
measurement is to include a confirmation with description of individual structuralmembers corresponding to the extent of requirements stipulated in Z10.3 based ontype of periodical survey and the ship's age.
Where only partial survey is required, i.e. one web frame ring / one deck transverse,
the identification is to include location within each tank by reference to frame numbers.

Page 39 of 63

IACS Req. 1996/Rev.21 2023

Z10.3For areas in tanks where protective coating is found to be in GOOD condition and theZ10.3 2.4
extent of close-up survey and / or thickness measurement has been specially considered,(cont)

structures subject to special consideration are to be identified.
2.5 Identification of tanks subject to tank testing.

2.6 Identification of cargo piping on deck and cargo and ballast piping within cargo and ballast
tanks, pump rooms, pipe tunnels and void spaces, where:-

Examination including internal examination of piping with valves and fittings andthickness measurement, as relevant, has been carried out
Operational test to working pressure has been carried out

3. Result of the survey
3.1 Type, extent and condition of protective coating in each tank, as relevant (rated GOOD,
FAIR or POOR).
3.2 Structural condition of each compartment with information on the following, as relevant:--Identification of findings, such as:• Corrosion with description of location, type and extent• Areas with substantial corrosion• Cracks / fractures with description of location and extent• Buckling with description of location and extent• Indents with description of location and extent
Identification of compartments where no structural damages / defects are foundThe report may be supplemented by sketches / photos.
3.3 Thickness measurement report is to be verified and signed by the surveyor controllingthe measurements on board.
4. Actions taken with respect to findings
4.1 Whenever the attending surveyor is of the opinion that repairs are required, each item tobe repaired is to be identified in the survey report. Whenever repairs are carried out, details of
the repairs effected are to be reported by making specific reference to relevant items in thesurvey report.
4.2 Repairs carried out are to be reported with identification of:-Compartment
Structural member
Repair method (i.e. renewal or modification) including:•
Steel grades and scantlings (if different from the original),•
Sketches/photos, as appropriate
Repair extent
NDT / Tests

4.3 For repairs not completed at the time of survey, condition of class is to be imposed with a
specific time limit for the repairs. In order to provide correct and proper information to thesurveyor attending for survey of the repairs, condition of class is to be sufficiently detailed
with identification of each item to be repaired. For identification of extensive repairs, reference
may be given to the survey report.
Page 40 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE VII (i)(cont)

IACS UNIFIED REQUIREMENTS FOR ENHANCED SURVEYSEXECUTIVE HULL SUMMARY
Issued upon Completion of Special Survey
GENERAL PARTICULARSSHIP’S NAME:

CLASS IDENTIFY NUMBER:
IMO IDENTIFY NUMBER:

PORT OF REGISTRY:NATIONAL FLAG:

DEADWEIGHT (M. TONNES):GROSS TONNAGE:
NATIONAL:
ITC (69):

DATE OF BUILD:

CLASSIFICATION NOTATION:DATE OF MAJOR CONVERSION:
TYPE OF CONVERSION:a)

The survey reports and documents listed below have been reviewed by theundersigned and found to be satisfactoryb)

A summary of the survey is attached herewith on sheet 2c)

The hull special survey has been completed in accordance with the Regulations on[date]

Executive Summary
Report completed by:
OFFICE
Executive Summary
Report verified by:
OFFICE

Name

Title

Signature
DATE
Name

Title

Signature
DATE

Attached reports and documents:
1)
2)
3)
4)
5)
6)

Page 41 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE VII (ii)(cont)EXECUTIVE HULL SUMMARYA)

General Particulars: -Ref. Table VII (i)B)

Report Review:-

Where and how survey was done

C)

Close-up Survey:-

Extent (Which tanks)

D)

Cargo & Ballast
Piping System:-

Examined-

Operationally tested-

Reference to Thickness Measurement report-

Summary of where measured-

Separate form indicating the tanks/areas with
Substantial Corrosion, and correspondingE)

F)

Thicknessmeasurements:

Tank Protection:

G)

Repairs:

H)

Conditions of Class:

I)

Memoranda:

J)

Conclusion:*

Thickness diminution*

Corrosion pattern

Separate form indicating:-Location of coating-

Condition of coating (if applicable)-

Identification of tanks/areas-

Acceptable defects-

Any points of attention for future surveys, e.g. forSuspect Areas.

-

Extended Annual/Intermediate survey due to coating
breakdown-

Statement on evaluation/verification of survey report

Page 42 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE VII (iii)(cont)EXTRACT OF THICKNESS MEASUREMENTS
Reference is made to the thickness measurements report:
1)

2)

Position of substantially Thickness
diminution [%]corroded Tanks/Areas
or Areas with deep
pitting

Corrosion pattern

Remarks:e.g. Ref. attachedsketches

Remarks:
1)

Substantial corrosion, i.e. 75 – 100% of acceptable margins wasted

2)

P = Pitting
C = Corrosion in General
Any bottom plating with a pitting intensity of 20% or more, with wastage in thesubstantial corrosion range or having an average depth of pitting of 1/3 or more ofactual plate thickness is to be noted.

Page 43 of 63

IACS Req. 1996/Rev.21 2023

Z10.3

Z10.3

TABLE VII (iv)(cont)TANK PROTECTION

1)

2)

3)

Tank Nos.

Tank protection

Coating condition

Remarks

Remarks:
1)

All segregated ballast tanks and combined cargo/ballast tanks to be listed.

2)

C = Coating

3)

Coating condition according to the following standard

NP = No Protection

GOOD

condition with only minor spot rusting.

FAIR

condition with local breakdown at edges of stiffeners and weld
connections and/or light rusting over 20% or more of areas underconsideration, but less than as defined for POOR condition.

POOR

condition with general breakdown of coating over 20% or more of areasor hard scale at 10% or more of areas under consideration.

If coating condition less than “GOOD" is given, extended annual surveys are to be
introduced. This is to be noted in part I) of the Executive Hull Summary.

End ofFirst Section
Page 44 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I

Z10.3

ANNEX I

(cont)GUIDELINES FOR TECHNICAL ASSESSMENT IN CONJUNCTION WITH
PLANNING FOR ENHANCED SURVEYS OF CHEMICAL TANKERS
SPECIAL SURVEY - HULL
Contents:
1.

INTRODUCTION

2.

PURPOSE AND PRINCIPLES
2.1
2.2
2.3
2.4

3.

PurposeMinimum Requirements
TimingAspects to be Considered

TECHNICAL ASSESSMENT
3.1
3.2
3.2.1
3.2.2
3.2.3

General
Methods
Design Details
Corrosion
Locations for Close-up Survey and Thickness Measurement

REFERENCES
1. IACS Unified Requirement Z10.3, "Hull Surveys of Chemical Tankers."
2. TSCF, "Guidelines for the Inspection and Maintenance of Double Hull Tanker Structures,
1995."
3. TSCF, "Guidance Manual for Tanker Structures, 1997."
1

INTRODUCTION

These guidelines contain information and suggestions concerning technical assessments
which may be of use in conjunction with the planning of enhanced special surveys ofchemical tankers. As indicated in section 5.1.5 of IACS Unified Requirement Z10.3, "HullSurveys of Chemical Tankers," (Ref. 1), the guidelines are a recommended tool which may
be invoked at the discretion of an IACS Member Society, when considered necessary andappropriate, in conjunction with the preparation of the required Survey Programme.
2

PURPOSE AND PRINCIPLES

2.1
PurposeThe purpose of the technical assessments described in these guidelines is to assist in
identifying critical structural areas, nominating suspect areas and in focusing attention on
structural elements or areas of structural elements which may be particularly susceptible to,or evidence a history of, wastage or damage. This information may be useful in nominating
locations, areas and tanks for thickness measurement, close-up survey and tank testing.
Critical Structural Areas are locations which have been identified from calculations to requiremonitoring or from the service history of the subject ship or from similar or sister ships (ifPage 45 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I
to be sensitive to cracking, buckling or corrosion which would impair the structuralZ10.3 available)
integrity of the ship.
(cont)

2.2
Minimum Requirements
However, these guidelines may not be used to reduce the requirements pertaining tothickness measurement, close-up survey and tank testing contained in Tables I, II and III,
respectively, of Z10.3; which are, in all cases, to be complied with as a minimum.
2.3
TimingAs with other aspects of survey planning, the technical assessments described in theseguidelines should be worked out by the Owner or operator in cooperation with theClassification Society well in advance of the commencement of the Special Survey, i.e., prior
to commencing the survey and normally at least 12 to 15 months before the survey's
completion due date.
2.4
Aspects to be ConsideredTechnical assessments, which may include quantitative or qualitative evaluation of relative
risks of possible deterioration, of the following aspects of a particular ship may be used as abasis for the nomination of tanks and areas for survey:-

Design features such as stress levels on various structural elements, design details andextent of use of high tensile steel.
Former history with respect to corrosion, cracking, buckling, indents and repairs for theparticular ship as well as similar vessels, where available.
Information with respect to types of cargo carried, use of different tanks for cargo/ballast,protection of tanks and condition of coating, if any.

Technical assessments of the relative risks of susceptibility to damage or deterioration ofvarious structural elements and areas are to be judged and decided on the basis ofrecognised principles and practices, such as may be found in publications of the Tanker
Structure Cooperative Forum (TSCF), (Refs. 2 and 3).
3

TECHNICAL ASSESSMENT

3.1
GeneralThere are three basic types of possible failure which may be the subject of technicalassessment in connection with planning of surveys; corrosion, cracks and buckling. Contact
damages are not normally covered by the survey plan since indents are usually noted inmemoranda and assumed to be dealt with as a normal routine by Surveyors.
Technical assessments performed in conjunction with the survey planning process are, in
principle, to be as shown schematically in Figure 1 depicts, schematically, how technicalassessments can be carried out in conjunction with the survey planning process.
The approach is basically an evaluation of the risk based on the knowledge and experience
related to design and corrosion.
The design is to be considered with respect to structural details which may be susceptible tobuckling or cracking as a result of vibration, high stress levels or fatigue.
Corrosion is related to the ageing process, and is closely connected with the quality ofcorrosion protection at newbuilding, and subsequent maintenance during the service life.
Corrosion may also lead to cracking and/or buckling.

Page 46 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I

Z10.3 3.2
(cont)

Methods

3.2.1 Design Details
Damage experience related to the ship in question and similar ships, where available, is themain source of information to be used in the process of planning. In addition, a selection of
structural details from the design drawings are to be included.

Typical damage experience to be considered will consist of:
Number, extent, location and frequency of cracks;
Location of buckles.
This information may be found in the survey reports and/or the Owner's files, including theresults of the Owner's own inspections. The defects are to be analyzed, noted and marked on
sketches.
In addition, general experience is to be utilized. For example, reference is to be made to the
two TSCF’s publications mentioned in Ref.2 and Ref.3, which contain a catalogue of typicaldamages and proposed repair methods for various tanker structural details.
Such figures are to be used together with a review of the main drawings, in order to comparewith the actual structure and search for similar details which may be susceptible to damage.
An example is shown in Figure 2. In particular, Chapter 3 of Ref.2 deals with various aspects
specific to double hull tankers, such as stress concentration locations, misalignment during
construction, corrosion trends, fatigue considerations and areas requiring special attention,
which are to be considered in working out the survey planning.
The review of the main structural drawings, in addition to using the above mentioned figures,is to include checking for typical design details where cracking has been experienced. The
factors contributing to damage are to be carefully considered.
The use of high tensile steel (HTS) is an important factor. Details showing good service
experience where ordinary, mild steel has been used may be more susceptible to damage
when HTS, and its higher associated stresses, are utilized. There is extensive and, in general,
good experience, with the use of HTS for longitudinal material in deck and bottom structures.
Experience in other locations, where the dynamic stresses may be higher, is less favourable,
e.g. side structures.
In this respect, stress calculations of typical and important components and details, inaccordance with the latest Rules or other relevant methods, may prove useful and are to beconsidered. The selected areas of the structure identified during this process are to berecorded and marked on the structural drawings to be included in the Survey Programme.
3.2.2 Corrosion
In order to evaluate relative corrosion risks, the following information is generally to beconsidered:-

Usage of Tanks and Spaces
Condition of Coatings
Cleaning Procedures
Previous Corrosion Damage
Ballast use and time for Cargo Tanks
Corrosion Risk Scheme (See Ref. 3, Table 2.1)
Location of Heated Tanks

Page 47 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I
3 gives definitive examples which can be used for judging and describing coating
Z10.3 Ref.
condition, using typical pictures of conditions.
(cont)The evaluation of corrosion risks is to be based on information in Ref. 3, together with
relevant information on the anticipated condition of the ship as derived from the informationcollected in order to prepare the Survey Programme and the age of the ship.
The various tanks and spaces are to be listed with the corrosion risks nominated accordingly.
Special attention is to be given to the areas where the double hull tanker is particularly
exposed to corrosion. To do this end, the specific aspects addressing corrosion in double hulltankers indicated in 3.4 (Corrosion trends) of Ref.2 are to be taken into account.
3.2.3 Locations for Close-up Survey and Thickness Measurement
On the basis of the table of corrosion risks and the evaluation of design experience, thelocations for initial close-up survey and thickness measurement (areas and sections) may be
nominated.
The sections subject to thickness measurement are to normally be nominated in tanks andspaces where corrosion risk is judged to be the highest.
The nomination of tanks and spaces for close-up survey is to, initially, be based on highest
corrosion risk, and is to always include ballast tanks. The principle for the selection is to bethat the extent is increased by age or where information is insufficient or unreliable.

Page 48 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I

Z10.3(cont)

Input:
Drawings, Reports,
Acceptable Corrosion
Allowance

Collection of Information

Coating Condition
Usage of Tanks
Corrosion Risk

Design Related Risk
Analyse:Hull Damage
This Ship

Coating condition
Usage of Tanks

Corrosion
Damage This
Ship

Analyse:Hull Damage
for Similar Ships
Where Available

Corrosion
Damage Similar
Ship where
Available

Hull Damage:
General Experience
Present Areas
where Damage has
been found andRisks consideredhigh. Mark Sketches
or Drawings

Location for Thickness Measurement and Close-Up Survey

SurveyProgramme

Acceptance byClass & Owner

SurveyFigure 1: Technical Assessment and the Survey Planning Process

Page 49 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex I

Z10.3(cont)

Figure 2: Typical Damage and Repair Example (Reproduced from Ref. 2)
End ofAnnex I

Page 50 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex II

Z10.3

ANNEX II

(cont)

RECOMMENDED PROCEDURES FOR THICKNESS MEASUREMENTS
OF CHEMICAL TANKERS**
Note 1: Annex II is recommendatory
Note 2: For Single Hull Chemical Tankers, please refer to Annex II of URZ10.1
Note 3: For Double Hull Chemical Tankers, please refer to Annex II of URZ10.4
End ofAnnex II
Page 51 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex III

Z10.3(cont)

ANNEX III

Page 52 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA
ANNEX IIIA

Z10.3

SURVEY PROGRAMME(cont’d)

Basic information and particulars

Name of ship:
IMO number:
Flag State:
Port of registry:
Gross tonnage:
Deadweight (metric tonnes):
Length between perpendiculars (m):Shipbuilder:
Hull number:Classification Society:
Class ID:
Date of build of the ship:
Owner:
Thickness measurement firm:

Page 53 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA

Z10.3
(cont’d)Preamble
1.1

Scope

1.1.1 The present survey programme covers the minimum extent of overall surveys, close-up
surveys, thickness measurements and pressure testing within the cargo area, cargo tanks,
ballast tanks, including fore and aft peak tanks, required by UR Z10.3.
1.1.2 The arrangements and safety aspects of the survey are to be acceptable to theattending surveyor(s).
1.2Documentation

All documents used in the development of the survey programme are to be available onboard
during the survey as required by section 6.
2

Arrangement of tanks and spaces

This section of the survey programme is to provide information (either in the form of plans ortext) on the arrangement of tanks and spaces that fall within the scope of the survey.
3

List of tanks and spaces with information on their use, extent of coatings andcorrosion protection system

This section of the survey programme is to indicate any changes relating to (and is to update)the information on the use of the tanks of the ship, the extent of coatings and the corrosion
protective system provided in the Survey Planning Questionnaire.
4

Conditions for survey

This section of the survey programme is to provide information on the conditions for survey,
e.g. information regarding cargo hold and tank cleaning, gas freeing, ventilation, lighting, etc.
5

Provisions and method of access to structures

This section of the survey programme is to indicate any changes relating to (and is to update)the information on the provisions and methods of access to structures provided in the Survey
Planning Questionnaire.
6

List of equipment for survey

This section of the survey programme is to identify and list the equipment that will be madeavailable for carrying out the survey and the required thickness measurements.
7

Survey requirements

7.1

Overall survey

This section of the survey programme is to identify and list the spaces that are to undergo an
overall survey for the ship in accordance with 2.3.1.

Page 54 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA

Z10.3
(cont’d)

7.2

Close-up survey

This section of the survey programme is to identify and list the hull structures that are toundergo a close-up survey for the ship in accordance with 2.3.2.
8Identification of tanks for tank testing and pipes for pipe testingThis section of the survey programme is to identify and list the tanks that are to undergo tanktesting for the ship in accordance with 2.5 and the pipes that are to undergo pipe testing inaccordance with 2.6.
9Identification of areas and sections for thickness measurements

This section of the survey programme is to identify and list the areas and sections where
thickness measurements are to be taken in accordance with 2.4.1.
10

Minimum thickness of hull structures

This section of the survey programme is to specify the minimum thickness for hull structuresof the ship that are subject to UR Z10.3 (indicate either (a) or preferably (b), if suchinformation is available):(a)

Determined from the attached wastage allowance table and the original thickness tothe hull structure plans of the ship;(b)

Given in the following table(s):Area or location

Original asbuilt thickness
(mm)

Deck
Plating
Longitudinals
Longitudinal girders
BottomPlating
Longitudinals
Longitudinal girders
Ship side
Plating
Longitudinals
Longitudinal girders
Longitudinal bulkhead
Plating
Longitudinals
Longitudinal girders
Inner bottom
Plating
Longitudinals
Longitudinal girders
Transverse bulkheads
Plating
Stiffeners
Page 55 of 63

Minimum
thickness(mm)

Substantial
corrosion
thickness(mm)

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA

Z10.3
(cont’d)

Transverse web frames, floors
and stringers and diaphragms
Plating
Flanges
Stiffeners
Note: The wastage allowance tables are to be attached to the survey programme.
11
Thickness measurement firmThis section of the survey programme is to identify changes, if any, relating to the informationon the thickness measurement firm provided in the Survey Planning Questionnaire.
12

Damage experience related to the ship

This section of the survey programme is to, using the tables provided below, provide detailsof the hull damages for at least the last three years in way of the cargo and ballast tanks andvoid spaces within the cargo area. These damages are subject to survey.
Hull damages sorted by location for the ship
Tank or
space
number or
area

Possiblecause, if
known

Descriptionof thedamages

Page 56 of 63

Location

RepairDate ofrepair

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA
Hull damages for sister or similar ships (if available) in the case ofdesign related damage

Z10.3(cont’d)Tank or
space
number or
area

13

Possiblecause, if
known

Descriptionof thedamages

Location

RepairDate ofrepairAreas identified with substantial corrosion from previous surveys

This section of the survey programme is to identify and list the areas of substantial corrosion
from previous surveys.
14

Critical structural areas and suspect areas

This section of the survey programme is to identify and list the critical structural areas and thesuspect areas, if such information is available.
15

Other relevant comments and information

This section of the survey programme is to provide any other comments and information
relevant to the survey.

Page 57 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIA

Z10.3
(cont’d)Appendices
Appendix 1 - List of plans
Paragraph 5.1.3.2 requires that main structural plans of cargo and ballast tanks (scantling
drawings), including information regarding use of high tensile steel (HTS), clad steel andstainless steel to be available. This appendix of the survey programme is to identify and list
the main structural plans which form part of the survey programme.
Appendix 2 - Survey Planning Questionnaire
The Survey Planning Questionnaire (annex IIIB), which has been submitted by the owner, is
to be appended to the survey programme.
Appendix 3 - Other documentation
This part of the survey programme is to identify and list any other documentation that forms
part of the Plan.

Prepared by the owner in co-operation with the Classification Society for compliance with
5.1.3.

Date:…………………………………. (name and signature of authorized owner’s
representative)
Date:…………………………………. (name and signature of authorized representative of theClassification Society)

Page 58 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIB

Z10.3

ANNEX IIIB

(cont’d)SURVEY PLANNING QUESTIONNAIRE
The following information will enable the owner in co-operation with the Classification Society
to develop a survey programme complying with the requirements of UR Z10.3. It is essentialthat the owner provides, when completing the present questionnaire, up-to-date information.
The present questionnaire, when completed, is to provide all information and material
required by UR Z10.3.
Particulars
Ship's name:
IMO number:
Flag State:
Port of registry:
Owner:Classification Society:
Class ID:
Gross tonnage:
Deadweight (metric tonnes):
Date of build:
Information on access provision for close-up surveys and thickness measurement:
The owner is to indicate, in the table below, the means of access to the structures subject toclose-up survey and thickness measurement. A close-up survey is an examination where thedetails of structural components are within the close visual inspection range of the attending
surveyor, i.e. normally within reach of hand.
Tank
No.

Structure

F.P.
A.P.

Fore peak
Aft peak
Under deck
Side shell
Bottomtransverse
Longitudinal
Transverse
Under deck
Bottomtransverse
Transverse

Wing
Tanks

CentreTanks

C(Cargo)/B(Ballast)

Temporarystaging

Page 59 of 63

Rafts

Ladders

DirectaccessOther
means(pleasespecify)

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIB

Z10.3
(cont’d)History of heated cargo for the last 3 years together with indication as to whether
cargo was heated

Owner’s inspections
Using a format similar to that of the table below (which is given as an example), the owner isto provide details of the results of their inspections for the last 3 years on all cargo and ballast
tanks and void spaces within the cargo area, including peak tanks.
Tank No.

Corrosion
protection(1)

Coating
extent(2)

Cargocentre tanks

Coating
condition(3)

Structural
deterioration
(4)

Tank
damagehistory(5)

Cargo wingtanks

Page 60 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIB

Z10.3

Tank No.

(cont’d)Corrosion
protection(1)

Coating
extent(2)

Coating
condition(3)

Structural
deterioration(4)

Ballast tanks

Tankdamagehistory(5)

Fore peak
Aft peakMiscellaneous
spaces

Note:

Indicate tanks which are used for cargo/ballast.

1)

HC=hard coating; SC=soft coating;SH=semi-hard coating; NP=no protection

2)

U=upper part; M=middle part;
L=lower part; C=complete

3)

G=good; F=fair; P=poor;
RC=recoated (during the last 3 years)

4)

N=no findings recorded; Y=findings recorded,(Description of findings is to be attached to the questionnaire)

5)

DR=damage & repair; L=leakages;
CV=conversion(Description is to be attached to this questionnaire)

Name of owner’s representative:
Signature:
Date:

Page 61 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIB

Z10.3
(cont’d)Reports of Port State Control inspections
List the reports of Port State Control inspections containing hull structural related
deficiencies and relevant information on rectification of the deficiencies:

Safety Management System

List non-conformities related to hull maintenance, including the associated corrective
actions:

Name and address of the approved thickness measurement firm:

Page 62 of 63

IACS Req. 1996/Rev.21 2023

Z10.3 Annex IIIC

Z10.3

ANNEX IIIC

(cont)OWNER’S INSPECTION REPORT
Structural condition
Ship’s name:For tank No:
Grade of steel:

Elementsdeck:bottom:CracksBucklesside:
longitudinal bulkhead:
Corrosion

Deck

Coating
condition

Pitting

Modification/
repairOther

BottomSide
Longitudinalbulkhead
Transverse
bulkhead
Repairs carried out due to:Thickness measurements carried out(dates):Results in general:
Overdue surveys:
Outstanding conditions of class:Comments:

Date of inspection:
Inspected by:
Signature:

End of Annex III
End of Document
Page 63 of 63

IACS Req. 1996/Rev.21 2023