EN ISO 19901-3:2014

SLOVENSKI STANDARD
01-marec-2015
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SIST EN ISO 19901-3:2012
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Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 3: Topsides structure (ISO 19901-3:2014)
Erdöl- und Erdgasindustrie - Spezielle Anforderungen an Offshore-Anlagen - Teil 3:
Topsides structure (ISO 19901-3:2014)
Industries du pétrole et du gaz naturel - Exigences spécifiques aux structures en mer -
Partie 3: Superstructures (ISO 19901-3:2014)
Ta slovenski standard je istoveten z: EN ISO 19901-3:2014
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 19901-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2014
ICS 75.180.10 Supersedes EN ISO 19901-3:2010
English Version
Petroleum and natural gas industries - Specific requirements for
offshore structures - Part 3: Topsides structure (ISO 19901-
3:2014)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Spezielle Anforderungen an
spécifiques relatives aux structures en mer - Partie 3: Offshore-Anlagen - Teil 3: Topsides structure (ISO 19901-
Superstructures (ISO 19901-3:2014) 3:2014)
This European Standard was approved by CEN on 4 December 2014.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-3:2014 E
worldwide for CEN national Members.

Contents Page
Foreword .3
Foreword
This document (EN ISO 19901-3:2014) has been prepared by Technical Committee ISO/TC 67 "Materials,
equipment and offshore structures for petroleum, petrochemical and natural gas industries" in collaboration
with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures for petroleum,
petrochemical and natural gas industries” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2015, and conflicting national standards shall be withdrawn at
the latest by June 2015.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 19901-3:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 19901-3:2014 has been approved by CEN as EN ISO 19901-3:2014 without any modification.
INTERNATIONAL ISO
STANDARD 19901-3
Second edition
2014-12-15
Petroleum and natural gas
industries — Specific requirements
for offshore structures —
Part 3:
Topsides structure
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 3: Superstructures
Reference number
ISO 19901-3:2014(E)
©
ISO 2014
ISO 19901-3:2014(E)
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
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Published in Switzerland
ii © ISO 2014 – All rights reserved

ISO 19901-3:2014(E)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 2
3  Terms and definitions . 2
4 Symbols and abbreviated terms . 6
4.1 Symbols . 6
4.2 Abbreviated terms . 8
5 Overall considerations . 9
5.1 Design situations . 9
5.2 Codes and standards . 9
5.3 Deck elevation and green water .10
5.4 Exposure level .10
5.5 Operational considerations .10
5.6 Selecting the design environmental conditions .11
5.7 Assessment of existing topsides structures .11
5.8 Reuse of topsides structure.11
5.9 Modifications and refurbishment .11
6  Design requirements .11
6.1 General .11
6.2 Materials selection .11
6.3 Design conditions .11
6.4 Structural interfaces .12
6.5 Design for serviceability limit states (SLS) .12
6.6 Design for ultimate limit states (ULS) .14
6.7 Design for fatigue limit states (FLS) .15
6.8 Design for accidental limit states (ALS) .15
6.9 Robustness .15
6.10 Corrosion control .16
6.11 Design for fabrication and inspection .16
6.12 Design considerations for structural integrity management .17
6.13 Design for decommissioning, removal and disposal .17
7 Actions .17
7.1 General .17
7.2 In-place actions.18
7.3 Action factors.20
7.4 Vortex-induced vibrations .21
7.5 Deformations .21
7.6 Wave and current actions .22
7.7 Wind actions .22
7.8 Seismic actions .22
7.9 Actions during fabrication and installation .24
7.10 Accidental situations .24
7.11 Other actions.34
8 Strength and resistance of structural components .36
8.1 Use of local building standards .36
8.2 Cylindrical tubular member design .36
8.3 Design of non-cylindrical sections .37
8.4 Connections .37
8.5 Castings .38
9 Structural systems .39
ISO 19901-3:2014(E)
9.1 Topsides design .39
9.2 Topsides structure design models .39
9.3 Support structure interface .40
9.4 Flare towers, booms, vents and similar structures.40
9.5 Helicopter landing facilities (helidecks) .41
9.6 Crane support structure.44
9.7 Derrick design .47
9.8 Bridges .47
9.9 Bridge bearings .48
9.10 Anti-vibration mountings for modules and major equipment skids .48
9.11 System interface assumptions .48
9.12 Fire protection systems .49
9.13 Penetrations .49
9.14 Difficult-to-inspect areas .49
9.15 Drainage .49
9.16 Actions due to drilling operations .49
9.17 Strength reduction due to heat .49
9.18 Walkways, laydown areas and equipment maintenance .50
9.19 Muster areas and lifeboat stations .50
10 Materials .50
10.1 General .50
10.2 Carbon steel .51
10.3 Stainless steel .53
10.4 Aluminium alloys .54
10.5 Fibre-reinforced composites .55
10.6 Timber .55
11  Fabrication, quality control, quality assurance and documentation .55
11.1 Assembly .55
11.2 Welding .56
11.3 Fabrication inspection .56
11.4 Quality control, quality assurance and documentation .56
11.5 Corrosion protection .57
12 Corrosion control .57
12.1 General .57
12.2 Forms of corrosion, associated corrosion rates and corrosion damage .57
12.3 Design of corrosion control .57
12.4 Fabrication and installation of corrosion control .58
12.5 In-service inspection, monitoring and maintenance of corrosion control .59
13 Loadout, transportation and installation .59
14 In-service inspection and structural integrity management .60
14.1 General .60
14.2 Particular considerations applying to topsides structures .60
14.3 Topsides structure default inspection scopes .61
15 Assessment of existing topsides structures .62
16 Reuse of topsides structure .63
Annex A (informative) Additional information and guidance .64
Annex B (informative) Example calculation of building code correspondence factor .108
Annex C (informative) Regional information .114
Bibliography .115
iv © ISO 2014 – All rights reserved

ISO 19901-3:2014(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19901-3 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures.
This second edition cancels and replaces the first edition (ISO 19901-3:2010), which has been technically
revised.
ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries —
Specific requirements for offshore structures:
— Part 1: Metocean design and operating considerations
— Part 2: Seismic design procedures and criteria
— Part 3: Topsides structure
— Part 4: Geotechnical and foundation design considerations
— Part 5: Weight control during engineering and construction
— Part 6: Marine operations
— Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
— Part 8: Marine soil investigations
A future Part 9 dealing with structural integrity management is under preparation.
The first edition of ISO 19901-3:2010 included a number of serious typographical errors. A ‘Corrected’
version of the first edition was issued in December 2011. This ‘Corrected’ version first edition was
subsequently issued by some national standards organisations. To ensure all national standards bodies
issue a ‘Corrected’ version of the document, TC 67/SC 7 decided to produce a second edition of 19901-3
which incorporates the following changes from the original issue in 2010:
— in 4.1, the symbol S for design internal force or moment has been added;
d
— in 8.1, Formulae (7), (8) and (9) have been amended to include symbol S and the second paragraph
d
has been reworded to reflect the changes in the equations;
— in 9.18, first paragraph, new values have been given for variable action for the grating and plating as
well as for the contribution of personnel to the total variable action allowance;
ISO 19901-3:2014(E)
— in A.7.10.4.2.2, the text has been reworded and Formula (A.1) has been amended, in line with the
modifications in 8.1;
— in A.8.1, Formula (A.5) has been corrected by changing “max” to “min”;
— in B.2, Table B.1, the value of Young’s modulus has been amended so as to be in accordance with the
default value recommended in ISO 19902;
— in Tables B.3, B.4, B.5, B.7, B.8 and B.9, some values have been updated to reflect the change in
Young’s modulus;
— in B.3.3, Table B.4, the symbol for utilization has been corrected;
— in B.4.5, Table B.10, all values for compression and for compression and bending have been amended,
as well as the value for the minimum ratio;
— in B.4.5, first and second paragraphs, the building code correspondence factor has been amended
and a sentence about its applicability has been added;
— in Annex C, Table C.1, the existing building code correspondence factor has been amended and a
second correspondence factor, relating to CSA S16-09, has been added;
[3]
— in the Bibliography, Reference has been updated with a more recent edition; references in the text
(see A.5.2, A.8.3.1, A.8.3.2, A.8.3.3 and A.8.3.4) have been updated accordingly.
In producing the second edition the following additional minor corrections have been applied to the
2011 ‘Corrected’ version of the first edition:
— in 9.5.3.4 the units of the area-imposed action corrected to kN/m ;
— in 9.6.2 the description of off-lead and side-lead in Table 5 improved;
— in A.7.10.4.2.3 the reference to section A.7.10.2.4 changed to A.7.10.4.2.4;
— in A.11.3 minor text correction;
— in Annex B Table B.1, symbols for bending amplification reduction factor corrected to C and C
m,y m,z
ISO 19901 is one of a series of International Standards for offshore structures. The full series consists of
the following International Standards:
— ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
— ISO 19901 (all parts), Petroleum and natural gas industries — Specific requirements for offshore
structures
— ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
— ISO 19903, Petroleum and natural gas industries — Fixed concrete offshore structures
— ISO 19904-1, Petroleum and natural gas industries — Floating offshore structures — Part 1: Monohulls,
semi-submersibles and spars
— ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 1: Jack-ups
— ISO/TR 19905-2, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 2: Jack-ups commentary and detailed sample calculation
— ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
vi © ISO 2014 – All rights reserved

ISO 19901-3:2014(E)
Introduction
The series of International Standards applicable to types of offshore structure, ISO 19900 to ISO 19906,
constitutes a common basis covering those aspects that address design requirements and assessments
of all offshore structures used by the petroleum and natural gas industries worldwide. Through their
application, the intention is to achieve reliability levels appropriate for manned and unmanned offshore
structures, whatever the type of structure and the nature or combination of the materials used.
It is important to recognize that structural integrity is an overall concept comprising models for
describing actions, structural analyses, design rules, safety elements, workmanship, quality control
procedures and national requirements, all of which are mutually dependent. The modification of one
aspect of design in isolation can disturb the balance of reliability inherent in the overall concept or
structural system. The implications involved in modifications, therefore, need to be considered in
relation to the overall reliability of all offshore structural systems.
The series of International Standards applicable to types of offshore structure is intended to provide
wide latitude in the choice of structural configurations, materials and techniques, without hindering
innovation. Sound engineering judgement is therefore necessary in the use of these International
Standards.
This part of ISO 19901 has been prepared for those structural components of offshore platforms which
are above the wave zone and are not part of the support structure or of the hull. Previous national
and international standards for offshore structures have concentrated on design aspects of support
structures, and the approach to the many specialized features of topsides has been variable and
inconsistent, with good practice poorly recorded.
Historically, the design of structural components in topsides has been performed to national or regional
codes for onshore structures, modified in accordance with experience within the offshore industry, or
to relevant parts of classification society rules. While this part of ISO 19901 permits use of national or
regional codes, and indeed remains dependent on them for the formulation of component resistance
equations, it provides modifications that result in a more consistent level of component safety between
support structures and topsides structures.
In some aspects, the requirements for topsides structures are the same as, or similar to, those for fixed
steel structures; in such cases, reference is made to ISO 19902, with modifications where necessary.
Annex A provides background to, and guidance on, the use of this part of ISO 19901, and is intended to be
read in conjunction with the main body of this part of ISO 19901. The clause numbering in Annex A follows
the same structure as that in the body of the normative text in order to facilitate cross-referencing.
Annex B provides an example of the use of national standards for onshore structures in conjunction
with this part of ISO 19901.
Regional information on the application of this part of ISO 19901 to certain specific offshore areas is
provided in Annex C.
In International Standards, the following verbal forms are used:
— “shall” and “shall not” are used to indicate requirements strictly to be followed in order to conform
to the document and from which no deviation is permitted;
— “should” and “should not” are used to indicate that, among several possibilities, one is recommended
as particularly suitable, without mentioning or excluding others, or that a certain course of action is
preferred but not necessarily required, or that (in the negative form) a certain possibility or course
of action is deprecated but not prohibited;
— “may” is used to indicate a course of action permissible within the limits of the document;
— “can” and “cannot” are used for statements of possibility and capability, whether material, physical
or causal.
INTERNATIONAL STANDARD ISO 19901-3:2014(E)
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 3:
Topsides structure
1 Scope
This part of ISO 19901 gives requirements for the design, fabrication, installation, modification and
structural integrity management for the topsides structure for an oil and gas platform. It complements
ISO 19902, ISO 19903, ISO 19904-1, ISO 19905-1 and ISO 19906, which give requirements for various
forms of support structure. Requirements in this part of ISO 19901 concerning modifications and
maintenance relate only to those aspects that are of direct relevance to the structural integrity of the
topsides structure.
The actions on (structural components of) the topsides structure are derived from this part of
ISO 19901, where necessary in combination with other International Standards in the ISO 19901 series.
The resistances of structural components of the topsides structure can be determined by the use of
international or national building codes, as specified in this part of ISO 19901. If any part of the topsides
structure forms part of the primary structure of the overall structural system of the whole platform, the
requirements of this part of ISO 19901 are supplemented with applicable requirements in ISO 19902,
ISO 19903, ISO 19904-1, ISO 19905-1 and ISO 19906.
This part of ISO 19901 is applicable to the topsides of offshore structures for the petroleum and natural
gas industries, as follows:
— topsides of fixed offshore structures;
— discrete structural units placed on the hull structures of floating offshore structures and mobile
offshore units;
— certain aspects of the topsides of arctic structures.
This part of ISO 19901 is not applicable to those parts of the superstructure of floating structures
that form part of the overall structural system of the floating structure; these parts come under the
provisions of ISO 19904-1. This part of ISO 19901 only applies to the structure of modules on a floating
structure that do not contribute to the overall integrity of the floating structural system.
This part of ISO 19901 is not applicable to the structure of hulls of mobile offshore units.
This part of ISO 19901 does not apply to those parts of floating offshore structures and mobile offshore
units that are governed by the rules of a recognized certifying authority and which are wholly within
the class rules.
Some aspects of this part of ISO 19901 are also applicable to those parts of the hulls of floating offshore
structures and mobile offshore units that contain hydrocarbon processing, piping or storage.
This part of ISO 19901 contains requirements for, and guidance and information on, the following
aspects of topsides structures:
— design, fabrication, installation and modification;
— in-service inspection and structural integrity management;
— assessment of existing topsides structures;
ISO 19901-3:2014(E)
— reuse;
— decommissioning, removal and disposal;
— prevention, control and assessment of fire, explosions and other accidental events.
This part of ISO 19901 applies to structural components including the following:
— primary and secondary structure in decks, module support frames and modules;
— flare structures;
— crane pedestal and other crane support arrangements;
— helicopter landing decks (helidecks);
— permanent bridges between separate offshore structures;
— masts, towers and booms on offshore structures.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 2631-1, Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration —
Part 1: General requirements
ISO 2631-2, Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration —
Part 2: Vibration in buildings (1 Hz to 80 Hz)
ISO 13702, Petroleum and natural gas industries — Control and mitigation of fires and explosions on
offshore production installations — Requirements and guidelines
ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
ISO 19901-1, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 1: Metocean design and operating considerations
ISO 19901-2, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 2: Seismic design procedures and criteria
ISO 19901-6, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 6: Marine operations
ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
ISO 19903, Petroleum and natural gas industries — Fixed concrete offshore structures
ISO 19904-1, Petroleum and natural gas industries — Floating offshore structures — Part 1: Monohulls,
semi-submersibles and spars
ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore units —
Part 1: Jack-ups
ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
3  Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19900, ISO 19902 and the
following apply.
2 © ISO 2014 – All rights reserved

ISO 19901-3:2014(E)
3.1
abnormal value
design value of a parameter of abnormal severity used in accidental limit state checks in which a
structure is intended not to suffer complete loss of integrity
Note 1 to entry: Abnormal events are typically accidental and environmental (including seismic) events having
−3 −4
probabilities of exceedance of the order of 10 to 10 per annum.
[SOURCE: ISO 19900:2013, definition 3.1]
3.2
accidental situation
design situation involving exceptional conditions of the structure or its exposure
EXAMPLE Impact, fire, explosion, loss of intended differential pressure.
[SOURCE: ISO 19900:2013, definition 3.2]
3.3
active fire protection
system of fire protection that reacts to a fire by discharging water or an inert or reactive substance in
the vicinity of the fire to extinguish it
Note 1 to entry: There is a possibility that such a system fails to operate as designed.
3.4
caisson
appurtenance used for abstracting water from the sea or as a drain
3.5
conductor
tubular pipe extending upward from or beneath the sea floor containing pipes that extend into the
petroleum reservoir
[SOURCE: ISO 19900:2013, definition 3.12]
Note 1 to entry: A conductor is generally vertical, and is continuous from below the sea floor to the wellbay in
the topsides and can be laterally supported in both the support structure and topsides structure. The vertical
support is in the seabed.
Note 2 to entry: In a few cases, conductors are rigidly attached to the topsides or to the support structure above
sea level. In these cases, the conductor’s axial stiffness can affect the load distribution within the overall structure.
3.6
critical component
structural component, failure of which would cause failure of the whole structure, or a significant part
of it
Note 1 to entry: A critical component is part of the primary structure.
[SOURCE: ISO 19902:2007, definition 3.12]
3.7
design accidental action
−3 −4
accidental action with a probability of occurrence greater than 10 to 10 per year
3.8
design service life
assumed period for which a structure is used for its intended purpose with anticipated maintenance,
but without substantial repair being necessary
[SOURCE: ISO 19900:2013, definition 3.16]
ISO 19901-3:2014(E)
3.9
design situation
set of physical conditions representing real conditions during a certain time interval, for which the
design demonstrates that relevant limit states are not exceeded
[SOURCE: ISO 19900:2013, definition 3.17]
3.10
design value
value derived from the representative value for use in the design verification procedure
[SOURCE: ISO 19900:2013, definition 3.18]
3.11
explosion
rapid chemical reaction of gas or dust in air
Note 1 to entry: An explosion results in increased temperatures and pressure impulses. A gas explosion on an
offshore platform is usually a deflagration in which flame speeds remain subsonic.
[SOURCE: ISO 19902:2007, definition 3.17]
3.12
exposure level
classification system used to define the requirements for a structure based on consideration of life
safety and consequences of failure
Note 1 to entry: An exposure level 1 platform is the most critical and exposure level 3 the least. A normally
manned platform which cannot be reliably evacuated before a design event wil
...