EN ISO 19900:2013

SLOVENSKI STANDARD
01-februar-2014
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SIST EN ISO 19900:2004
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Petroleum and natural gas industries - General requirements for offshore structures (ISO
19900:2013)
Erdöl- und Erdgasindustrie - Allgemeine Anforderungen an Offshore-Bauwerke (ISO
19900:2013)
Industries du pétrole et du gaz naturel - Exigences générales pour les structures en mer
(ISO 19900:2013)
Ta slovenski standard je istoveten z: EN ISO 19900:2013
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 19900
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2013
ICS 75.180.10 Supersedes EN ISO 19900:2002
English Version
Petroleum and natural gas industries - General requirements for
offshore structures (ISO 19900:2013)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Allgemeine Anforderungen an
générales pour les structures en mer (ISO 19900:2013) Offshore-Bauwerke (ISO 19900:2013)
This European Standard was approved by CEN on 19 October 2013.

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
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19900:2013 E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 19900:2013) 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 2014, and conflicting national standards shall be withdrawn at
the latest by June 2014.
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 19900:2002.
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 19900:2013 has been approved by CEN as EN ISO 19900:2013 without any modification.

INTERNATIONAL ISO
STANDARD 19900
Second edition
2013-12-15
Petroleum and natural gas
industries — General requirements
for offshore structures
Industries du pétrole et du gaz naturel — Exigences générales pour
les structures en mer
Reference number
ISO 19900:2013(E)
©
ISO 2013
ISO 19900:2013(E)
© ISO 2013
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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 19900:2013(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 6
4.1 Symbols . 6
4.2 Abbreviated terms . 7
5 General requirements and conditions . 8
5.1 General . 8
5.2 Fundamental requirements . 8
5.3 Robustness . 8
5.4 Planning . 9
5.5 Durability, maintenance and inspection . 9
5.6 Hazards .10
5.7 Design basis .10
5.8 Service requirements .10
5.9 Operating requirements.11
5.10 Special requirements .11
5.11 Location and orientation .11
5.12 Structural configuration .12
5.13 Environmental conditions .14
5.14 Construction and deployment .18
5.15 Decommissioning and removal .18
6 Exposure levels.18
6.1 General .18
6.2 Life-safety categories .19
6.3 Consequence categories .20
6.4 Determination of exposure level .21
7 Limit states design .22
7.1 Limit states .22
7.2 Design .23
8 Basic variables .24
8.1 General .24
8.2 Actions .24
8.3 Resistances .26
9 Partial factor design approach .27
9.1 Principles .27
9.2 Actions and their combinations .28
9.3 Properties of materials and soils .30
9.4 Geometric parameters .31
9.5 Uncertainties of calculation models .31
9.6 Values for partial factors.31
9.7 Structural reliability analysis .32
10 Models and analysis .32
11 Quality management .33
11.1 General .33
11.2 Responsibilities .34
11.3 Quality management system .34
11.4 Quality control plan .34
ISO 19900:2013(E)
11.5 Installation inspection .35
11.6 In-service inspection, maintenance and repair .35
11.7 Records and documentation .36
12 Assessment of existing structures .37
12.1 General .37
12.2 Condition assessment .38
12.3 Action assessment .39
12.4 Resistance assessment .39
12.5 Component and system failure consequences and mitigation .39
12.6 Fatigue .39
12.7 Mitigation.39
Annex A (informative) Additional information and guidance .40
Bibliography .47
iv © ISO 2013 – All rights reserved

ISO 19900:2013(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 19900 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 19900:2002), which has been technically
revised.
ISO 19900 is one of a series of 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 (all parts), Petroleum and natural gas industries — Floating offshore structures
— ISO 19905 (all parts), Petroleum and natural gas industries — Site-specific assessment of mobile
offshore units
— ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
ISO 19900:2013(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 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 offshore structures International Standards are intended to provide wide latitude in the choice
of structural configurations, materials and techniques and to allow for innovative solutions. Sound
engineering judgement is, therefore, necessary in the use of these International Standards.
ISO 19900 applies to offshore structures and is in accordance with the principles of ISO 2394. ISO 19900
includes, where appropriate, additional provisions that are specific to offshore structures.
Figure 1 gives a general indication of the relationship among the various International Standards
applicable to types of offshore structure. ISO 19900 is the core of this set.
The ISO 19901 series of parts provides provisions on particular aspects of the design, construction,
and operation of offshore platforms for the petroleum and natural gas industries, whose provisions can
be applicable to platforms of different types, materials and operating environments. ISO 19901-7 has
specific relevance to floating structures.
In addition to the relationship among the specific provisions of the parts of ISO 19901 and the International
Standards for bottom-founded, floating, or Arctic structures, there is also some interdependence among
these latter International Standards, in that one International Standard can reference the design
provisions of one of the other International Standards in this set. Users need to be aware of these cross-
references when using any member of this set of International Standards.
vi © ISO 2013 – All rights reserved

ISO 19900:2013(E)
Figure 1 — Relationship among standards
INTERNATIONAL STANDARD ISO 19900:2013(E)
Petroleum and natural gas industries — General
requirements for offshore structures
1 Scope
This International Standard specifies general principles for the design and assessment of offshore
structures subjected to known or foreseeable types of actions. These general principles are applicable
worldwide to all types of offshore structures, including, bottom-founded structures as well as floating
structures, and to all types of materials used including steel, concrete and aluminium.
This International Standard specifies design principles that are applicable to:
— the successive stages in the construction of the structure (i.e. fabrication, transportation and
installation);
— use during its intended life; and
— its decommissioning.
The principles are also generally applicable to the assessment or modification of existing structures.
Aspects related to quality control are also addressed.
This International Standard is applicable to the design of complete structures, including substructures,
topsides structures, vessel hulls, foundations and mooring systems.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 2394:1998, General principles on reliability for 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 19901-4, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 4: Geotechnical and foundation design considerations
ISO 19901-5, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 5: Weight control during engineering and construction
ISO 19901-6, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 6: Marine operations
ISO 19901-7, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO 19900:2013(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.
3.2
accidental situation
design situation involving exceptional conditions of the structure or its exposure
EXAMPLE Impact, fire, explosion, loss of intended differential pressure.
3.3
action
external load applied to the structure (direct action) or an imposed deformation or acceleration (indirect
action)
EXAMPLE An imposed deformation can be caused by fabrication tolerances, differential settlement,
temperature change or moisture variation.
Note 1 to entry: An earthquake typically generates imposed accelerations.
3.4
action effect
effect of actions on structural components
EXAMPLE Internal force, moment, stress or strain.
3.5
air gap
clearance between the highest water or ice surface that occurs during the extreme environmental
conditions and the lowest exposed part not designed to withstand wave or ice impingement
3.6
appurtenance
part of the structure that is installed to assist installation, to provide access or protection
3.7
basic variable
one of a specified set of variables representing physical quantities which characterize actions,
environmental influences, geometric quantities, or material properties, including soil properties
3.8
calibration
process used to determine partial factors using structural reliability analysis and target reliabilities
3.9
catenary mooring
mooring system where the restoring action is provided by the distributed weight of mooring lines
3.10
characteristic value
value assigned to a basic variable associated with a prescribed probability of not being violated by
unfavourable values during some reference period
Note 1 to entry: The characteristic value is the main representative value. In some design situations, a variable
can have two characteristic values, an upper and a lower value.
2 © ISO 2013 – All rights reserved

ISO 19900:2013(E)
3.11
compliant structure
structure that is sufficiently flexible that applied lateral dynamic actions are substantially balanced by
inertial reactions
3.12
conductor
tubular pipe extending upward from or beneath the sea floor containing pipes that extend into the
petroleum reservoir
3.13
consequence category
classification system for identifying the environmental, economic, and indirect personnel safety
consequences of failure of a platform
3.14
decommissioning
process of shutting down a platform and removing it from its current location at the end of its service
life
3.15
design criteria
quantitative formulations that describe the conditions to be fulfilled for each limit state
3.16
design service life
assumed period for which a structure is used for its intended purpose with anticipated maintenance,
but without substantial repair being necessary
3.17
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
3.18
design value
value derived from the representative value for use in the design verification procedure
3.19
durability
ability of a structure or structural component to maintain its function throughout its design service life
3.20
exposure level
classification system used to define the requirements for a structure based on consideration of life-
safety and consequences of failure
3.21
fit-for-purpose
meeting the intent of an International Standard although not meeting all provisions of that International
Standard, such that not meeting the specific provisions does not cause unacceptable risk to life-safety
or the environment
3.22
fixed structure
structure that is bottom founded and transfers most of the actions on it to the seabed
3.23
floating structure
structure where the full weight is supported by buoyancy
ISO 19900:2013(E)
3.24
hazard
situation or event with the potential to cause any, or all, of human injury, damage to the environment,
and damage to property
3.25
jack-up
mobile offshore unit with a buoyant hull and one or more legs that can be moved up and down relative
to the hull
Note 1 to entry: A jack-up reaches its operational mode by lowering the leg(s) to the seabed and then raising
the hull to the required elevation. The majority of jack-ups have three or more legs, each of which can be moved
independently and which are supported in the seabed by spudcans.
3.26
life-safety category
classification system for identifying the applicable level of life-safety for a platform
3.27
mobile offshore unit
offshore structure designed such that it can be routinely relocated
Note 1 to entry: Mobile offshore unit is also known as MOU.
3.28
limit state
state beyond which the structure no longer satisfies the relevant design criteria
3.29
nominal value
value assigned to a basic variable determined on a non-statistical basis, typically from acquired
experience or physical conditions
3.30
normal conditions
permanent, variable and environmental actions associated with operating conditions of the platform
Note 1 to entry: Normal conditions are sometimes referred to as persistent conditions.
3.31
offshore structure
structure used for the development and production of offshore petroleum and natural gas fields in
offshore areas
3.32
operator
representative of the company or companies leasing the site
Note 1 to entry: The operator is normally the oil company acting on behalf of co-licensees.
3.33
operations manual
manual that defines the operational characteristics, procedures and capabilities of an offshore platform
and associated essential systems
3.34
owner
representative of the company or companies owning or leasing a development
3.35
platform
complete assembly, including structure, topsides, foundations and stationkeeping systems
4 © ISO 2013 – All rights reserved

ISO 19900:2013(E)
3.36
reference period
period of time used as the basis for determining values of basic variables
3.37
reliability
ability of a structure or a structural component to fulfill the specified requirements
3.38
representative value
value assigned to a basic variable for verification of a limit state
3.39
resistance
capacity of a component, or a cross-section of a component, to withstand action effects without failure
3.40
return period
average period between occurrences of an event or of a particular value being exceeded
Note 1 to entry: The offshore industry commonly uses a return period measured in years for environmental
events. The return period in years is equal to the reciprocal of the annual probability of exceedance of the event.
3.41
riser
tubular used for the transport of fluids between the sea floor and a termination point on the platform
Note 1 to entry: For a fixed structure, the termination point is usually the topsides. For floating structures, the
riser can terminate at other locations of the platform.
3.42
robustness
ability of a structure to withstand accidental and abnormal events without being damaged to an extent
disproportionate to the cause
3.43
scour
removal of seabed soils caused by currents, waves and ice
3.44
splash zone
part of a structure that is intermittently exposed to air and immersed in the sea
3.45
structural system
load-bearing components of a structure and the way in which these components function together
3.46
structural component
physically distinguishable part of a structure
EXAMPLE Column, beam, stiffened plate, tubular joint, or foundation pile.
3.47
structural integrity management system
structured methodology, consisting of a multi-step cyclic activity, including feedback, intended to assure
the life and functionality of a structure
Note 1 to entry: Typical steps include data collection, data evaluation, development of an inspection strategy,
development and execution of an inspection programme, and consequent remedial works.
Note 2 to entry: Structural integrity management is also known as SIM.
ISO 19900:2013(E)
3.48
structural reliability analysis
procedure for the determination of the level of safety against failure of a structure or structural
component
3.49
structure
organized combination of connected components designed to withstand actions and provide adequate
rigidity
3.50
structure orientation
position of a structure in plan referenced to a fixed direction, such as true north
3.51
taut-line mooring
mooring system where the restoring action is predominately provided by elastic deformation of mooring
lines
3.52
topsides
structures and equipment placed on a supporting structure (fixed or floating) to provide some or all of
a platform’s functions
Note 1 to entry: For a ship-shaped floating structure, the deck is not part of the topsides.
Note 2 to entry: For a jack-up, the hull is not part of the topsides.
Note 3 to entry: A separate fabricated deck or module support frame is part of the topsides.
4 Symbols and abbreviated terms
4.1 Symbols
A accidental action
a design value of geometric parameter
d
a characteristic value of geometric parameter
k
a representative value of geometric parameter
r
E environmental action
F design value of action
d
F representative value of action
r
f design value of material property, for example strength
d
f characteristic value of material property, for example yield strength
k
G permanent action
G characteristic value of permanent action
k
G representative value of permanent action
r
L ,L ,L exposure levels of structures
1 2 3
p annual probability of occurrence
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ISO 19900:2013(E)
p probability of failure
f
Q variable action
Q variable action of long duration
Q variable action of short duration
Q characteristic value of variable action
k
R reliability of a structural system
R design value of component resistance
d
R characteristic value of component resistance, based on characteristic values of material properties
k
R representative value of component resistance
r
S action effect
d
T annual return period of an action
γ factor related to model uncertainty or other circumstances that are not taken into account by the
d
other γ values
γ partial action factor the value of which reflects the uncertainty or randomness of the action (see
f
9.2.3)
γ partial material factor the value of which reflects the uncertainty or variability of the material prop-
m
erty (see 9.3.2)
γ partial resistance factor the value of which reflects the uncertainty or variability of the component
R
resistance including those of material properties (see 9.3.2)
Δ additive partial geometric quantity the value of which reflects the uncertainties of the geometric
a
parameter (see 9.4.2)
4.2 Abbreviated terms
ALS accidental limit state
ALE abnormal level earthquake
EER escape, evacuation and rescue
ELE extreme level earthquake
FLS fatigue limit state
PFD partial factor design
QA quality assurance
QC quality control
QMS quality management system
SLS serviceability limit state
ULS ultimate limit state
ISO 19900:2013(E)
5 General requirements and conditions
5.1 General
Offshore structures shall be designed/assessed in accordance with this International Standard, with
the relevant parts of ISO 19901, and the appropriate ISO standard for the actual platform type.
This International Standard describes a limit state based design procedure that, in combination with
construction and operational guidance, is intended to result in a structure with an appropriate level of
reliability. The owner, designer and/or national authorities can apply more stringent criteria.
The limit state design methodology inherent to the series of International Standards applicable to
offshore structures is based on the partial factor design (PFD) approach with specified factors. There
are some aspects of design for which the PFD design formulations have not been developed and for these,
other approaches are used. Although reliability concepts are discussed in this International Standard, a
full reliability-based approach is only recommended in certain defined situations (see 7.1.1).
The structure shall be designed, constructed, transported, installed, and operated in such a way that
the structure meets the intended performance requirements and that all functional and structural
requirements are met. In addition to this International Standard, designers shall comply with national
regulations and standards applicable to the location under consideration when making design decisions
related to safety, reliability and durability for all phases of planning, design, construction, transportation,
installation, service in-place and possible removal.
5.2 Fundamental requirements
A structure and its structural components shall be designed, constructed and maintained so that they
are suited to their intended use for the design service life. In particular, the structure and its structural
components shall
a) withstand extreme actions liable to occur during their construction and anticipated use;
b) perform adequately under all expected normal actions during their operation;
c) not fail under repeated actions ;
d) provide an appropriate level of robustness against damage and failure (see 5.3) taking due account
of
— the cause and mode of failure,
— the possible consequences of failure in terms of risk to life, environment and property,
e) meet the requirements at national, regional or local level.
5.3 Robustness
A structure design shall incorporate sufficient robustness to ensure that consequent damage is not
disproportionate to the cause. For a robust structure, local damage does not lead to complete loss of
integrity of the structure. Robustness can also ensure that structural integrity in a damaged state is
sufficient to allow a process system shutdown, isolation of the reservoir and a safe evacuation where
applicable
Robustness can be achieved
a) by ensuring (by design or by protective measures) that no critical component exposed to hazard
can be made ineffective; or
b) by providing alternate load-carrying paths (structural redundancy) in such a way that any single
load-bearing component exposed to a hazard can be made ineffective without causing collapse,
sinking, or capsize of the structure or any significant part of it; or
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ISO 19900:2013(E)
c) by a combination of a) and b).
A floating structure shall incorporate sufficient damaged stability and reserve of buoyancy to ensure
that credible scenarios of unintended flooding do not result in loss of the structure.
The stationkeeping systems of floating structures shall incorporate sufficient redundancy to ensure
that the structure can withstand loss of a stationkeeping component (e.g. mooring line(s)) in accordance
with the provisions of ISO 19901-7.
5.4 Planning
Adequate planning shall be done before design is started in order to have sufficient basis to obtain a
safe, workable and economical structure that fulfils the required operational functions. Planning shall
also consider all relevant and related sustainability aspects impacting the environment, the economy
and society along with their interdependence and interrelationships.
The initial planning shall include specification of operational functions, design requirements and design
criteria for the structure. Site-specific data, such as water depth, physical environmental conditions
and soil properties, shall be sufficiently known and documented to serve as a basis for the design. The
functional and operational requirements in temporary and in-service phases, as well as robustness
against accidental situations and earthquakes that can influence the layout and the structural design,
shall be considered.
The functional requirements affecting the layout and design of the structure shall be established in a
clear format such that these can form the basis for the engineering process and the structural design.
Investigation of site-specific data, such as seabed topography, geohazards, soil conditions and
environmental conditions including ice, as appropriate, shall be carried out in accordance with the
requirements of ISO 19901-1, ISO 19901-2, ISO 19901-4 and ISO 19906.
5.5 Durability, maintenance and inspection
The durability of the structure in its environment shall be such that the general state of the structure
is kept at an acceptable level during its design service life. Account shall be taken of the effects of
corrosion, loss of material by abrasion, and other forms of degradation that can affect the resistance of
the structure or structure components.
A maintenance and inspection program shall be consistent with the design and function of the structure
and the environmental conditions to which it is exposed. Maintenance should include the performance
of appropriately scheduled inspections, inspections on special occasions (e.g. after an earthquake or
other severe or abnormal environmental or accidental event), the upgra
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