Petroleum and natural gas industries - Arctic operations - Material requirements for arctic operations (ISO/TS 35105:2018)

This document provides recommendations for material selection, manufacturing and fabrication requirements, testing and qualification of steel structures and components for offshore and onshore petroleum and natural gas facilities operating in Arctic and cold environments. This document is intended to be used as a supplement to existing standards for steel structures where the particular operating conditions in Arctic regions are not sufficiently addressed. This document gives particular requirements to ensure safe operation with respect to the risk of brittle fracture at low temperatures. These requirements will affect the selection of material grade and design class as well as the technical delivery conditions for steel. They will also affect the fabrication requirements as well as testing and qualification requirements. This document also gives recommendations: - to mitigate the operational and integrity aspects related to snow and ice accretion on topside structures; - to take into account the particular Arctic operating conditions in corrosion assessments and requirements for corrosion protection systems; - for particular operational requirements to ensure safe operation in Arctic regions. The requirements in this document are applicable to any operating temperatures, but particular requirements related to de-rating (loss of strength) at high temperatures are not addressed. Limitations to the applicable minimum design temperature caused by the capability of the materials’ low temperature performance can exist, but are not a limitation for the scope of this document. As a practical guideline for the use of this document, low temperature is defined as lowest anticipated service temperature (LAST) below -10 °C.

Erdöl- und Erdgasindustrie - Arktisbetrieb - Werkstoffanforderungen für den Arktisbetrieb (ISO/TS 35105:2018)

Industries du pétrole et du gaz naturel - Opérations en Arctique - Exigences applicables aux matériaux pour les opérations en Arctique (ISO/TS 35105:2018)

Le présent document fournit des recommandations pour le choix des matériaux, les exigences de production et de fabrication, l'essai et la qualification des structures et composants en acier pour les installations pétrolières et de gaz naturel en mer et terrestres exploitées en Arctique et dans les environnements froids.
Le présent document est destiné à être utilisé comme un supplément aux normes existantes relatives aux structures en acier dans lesquelles les conditions particulières d'exploitation régnant dans les régions arctiques ne sont pas suffisamment prises en compte.
Le présent document fournit des exigences particulières afin de garantir un fonctionnement sûr en ce qui concerne le risque de rupture fragile à basses températures. Ces exigences auront une incidence sur le choix de la nuance de matériau et de la classe de conception ainsi que sur les conditions techniques de livraison de l'acier. Elles auront également une incidence sur les exigences relatives à la fabrication ainsi que sur celles relatives aux essais et à la qualification.
Le présent document fournit également des recommandations visant à:
— atténuer les aspects opérationnels et relatifs à l'intégrité liés aux accumulations de neige et de glace sur les superstructures;
— prendre en compte les conditions d'exploitation particulières régnant en Arctique dans les évaluations de la corrosion et les exigences relatives aux systèmes de protection contre la corrosion;
— garantir, pour les exigences opérationnelles particulières, un fonctionnement sûr dans les régions arctiques.
Les exigences énoncées dans le présent document s'appliquent à toutes les températures de fonctionnement, mais les exigences particulières liées au déclassement (perte de résistance) à haute température ne sont pas traitées. Des limites à la température de conception minimale applicable dues à la capacité des performances à basse température des matériaux peuvent exister, mais elles ne constituent pas une limite pour le domaine d'application du présent document.
À titre de ligne directrice pratique pour l'utilisation du présent document, une basse température est définie comme étant la température en service la plus basse anticipée (LAST) inférieure à ?10 °C.
NOTE Pour la détermination de la température LAST, voir 6.3.2.

Industrija za predelavo nafte in zemeljskega plina - Obratovanje v arktičnem okolju - Zahteve za materiale za obratovanje v arktičnem okolju (ISO/TS 35105:2018)

Ta standard podaja priporočila za izbiro materiala, zahteve za proizvodnjo in izdelavo, preskušanje in kvalifikacijo jeklenih struktur ter sestavnih delov za obrate za predelavo nafte in zemeljskega plina na morju in kopnem, ki delujejo v arktičnem okolju ter drugih hladnih okoljih. Standard ISO/TS 35105:2018 se uporablja kot dodatek k obstoječim standardom za jeklene konstrukcije, za katere določeni obratovalni pogoji v arktičnem območju niso zadovoljivo obravnavani. Standard ISO/TS 35105:2018 podaja določene zahteve, ki zagotavljajo varno delovanje v zvezi z nevarnostjo lomov pri nizkih temperaturah. Te zahteve vplivajo na izbiro kakovostnega razreda materiala in razreda načrtovanja ter na tehnične dobavne pogoje za jeklo. Prav tako vplivajo na zahteve glede izdelave ter preskušanja in kvalifikacije. Standard ISO/TS 35105:2018 podaja tudi priporočila:
– za ublažitev operacijskih in integracijskih vidikov, povezanih s kopičenjem snega in ledu na palubnih konstrukcijah;
– za upoštevanje določenih obratovalnih pogojev v arktičnem območju pri ocenjevanju korozije in zahtev za korozijske zaščitne sisteme;
– za določene obratovalne zahteve, ki zagotavljajo varno obratovanje v arktičnih območjih.
Zahteve v tem dokumentu se uporabljajo pri vseh obratovalnih temperaturah, vendar posamezne zahteve, ki so povezane z zmanjšano zmogljivostjo (izguba moči) pri visokih temperaturah, niso obravnavane. Obstajajo lahko omejitve za ustrezne najnižje načrtovane temperature, ki jih povzroči zmožnost učinkovitosti materiala pri nizki temperaturi, vendar te omejitve ne predstavljajo omejitev za področje uporabe tega dokumenta. Za namene praktične uporabe tega dokumenta so nizke temperature opredeljene kot najnižje pričakovane temperature med obratovanjem (LAST) pod –10 °C.
OPOMBA: Za določitev najnižje pričakovane temperature med obratovanjem glej točko 6.3.2.

General Information

Status
Published
Publication Date
17-Nov-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
04-Nov-2019
Due Date
09-Jan-2020
Completion Date
18-Nov-2019

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SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 35105:2020
01-januar-2020

Industrija za predelavo nafte in zemeljskega plina - Obratovanje v arktičnem okolju

- Zahteve za materiale za obratovanje v arktičnem okolju (ISO/TS 35105:2018)

Petroleum and natural gas industries - Arctic operations - Material requirements for arctic

operations (ISO/TS 35105:2018)

Erdöl- und Erdgasindustrie - Arktisbetrieb - Werkstoffanforderungen für den Arktisbetrieb

(ISO/TS 35105:2018)

Industries du pétrole et du gaz naturel - Opérations en Arctique - Exigences applicables

aux matériaux pour les opérations en Arctique (ISO/TS 35105:2018)
Ta slovenski standard je istoveten z: CEN ISO/TS 35105:2019
ICS:
75.020 Pridobivanje in predelava Extraction and processing of
nafte in zemeljskega plina petroleum and natural gas
SIST-TS CEN ISO/TS 35105:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN ISO/TS 35105:2020
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SIST-TS CEN ISO/TS 35105:2020
CEN ISO/TS 35105
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
October 2019
TECHNISCHE SPEZIFIKATION
ICS 75.020
English Version
Petroleum and natural gas industries - Arctic operations -
Material requirements for arctic operations (ISO/TS
35105:2018)

Industries du pétrole et du gaz naturel - Opérations en Erdöl- und Erdgasindustrie - Arktisbetrieb -

Arctique - Exigences applicables aux matériaux pour Werkstoffanforderungen für den Arktisbetrieb (ISO/TS

les opérations en Arctique (ISO/TS 35105:2018) 35105:2018)

This Technical Specification (CEN/TS) was approved by CEN on 13 October 2019 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to

submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS

available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in

parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 35105:2019 E

worldwide for CEN national Members.
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CEN ISO/TS 35105:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST-TS CEN ISO/TS 35105:2020
CEN ISO/TS 35105:2019 (E)
European foreword

The text of ISO/TS 35105:2018 has been prepared by Technical Committee ISO/TC 67 "Materials,

equipment and offshore structures for petroleum, petrochemical and natural gas industries” of the

International Organization for Standardization (ISO) and has been taken over as

CEN ISO/TS 35105:2019 by Technical Committee CEN/TC 12 “Materials, equipment and offshore

structures for petroleum, petrochemical and natural gas industries” the secretariat of which is held by

NEN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO/TS 35105:2018 has been approved by CEN as CEN ISO/TS 35105:2019 without any

modification.
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SIST-TS CEN ISO/TS 35105:2020
TECHNICAL ISO/TS
SPECIFICATION 35105
First edition
2018-04
Petroleum and natural gas
industries — Arctic operations —
Material requirements for arctic
operations
Industries du pétrole et du gaz naturel — Opérations en Arctique —
Exigences relatives au matériel requis pour les opérations en Arctique
Reference number
ISO/TS 35105:2018(E)
ISO 2018
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SIST-TS CEN ISO/TS 35105:2020
ISO/TS 35105:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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ISO/TS 35105:2018(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Abbreviated terms .............................................................................................................................................................................................. 2

5 Symbols .......................................................................................................................................................................................................................... 3

6 Technical basis ........................................................................................................................................................................................................ 3

6.1 Design considerations....................................................................................................................................................................... 3

6.1.1 Present applications and industrial achievements ............................................................................ 3

6.1.2 Developments for future applications ........................................................................................................... 4

6.1.3 Areas of concern in design for Arctic structures .................................................................................. 4

6.1.4 Fracture assessment ..................................................................................................................................................... 4

6.2 Effects of low temperatures on mechanical properties of steels ................................................................. 5

6.2.1 Tensile properties ........................................................................................................................................................... 5

6.2.2 Fracture toughness ........................................................................................................................................................ 8

6.2.3 Arrest toughness .............................................................................................................................................................. 9

6.2.4 Fatigue ...................................................................................................................................................................................10

6.2.5 Residual stresses and crack pattern.............................................................................................................11

6.3 Environmental conditions ..........................................................................................................................................................11

6.3.1 General...................................................................................................................................................................................11

6.3.2 Temperature and definition of LAST ...........................................................................................................11

6.3.3 Seawater conditions ........................................................................................................................................... ........12

6.4 Principles for qualification and quality assurance ................................................................................................12

6.4.1 Steel making technology ........................................................................................................................................12

6.4.2 Welding technology ....................................................................................................................................................12

7 Material and fabrication requirements .....................................................................................................................................12

7.1 Material selection and qualification ..................................................................................................................................12

7.2 Mechanical properties ...................................................................................................................................................................13

7.2.1 Tensile properties ........................................................................................................................................................13

7.2.2 Fracture toughness .....................................................................................................................................................13

7.2.3 Pre-qualification testing .........................................................................................................................................16

7.3 Crack arrest assessment ..............................................................................................................................................................16

7.4 Fatigue properties, alternative testing ............................................................................................................................17

7.5 Welding and fabrication requirements ...........................................................................................................................18

7.5.1 Contractor certification ...........................................................................................................................................18

7.5.2 Base material ...................................................................................................................................................................18

7.5.3 Welding consumables ...............................................................................................................................................18

7.5.4 Welding procedure qualification.....................................................................................................................18

7.6 Welding procedure qualification test requirements ...........................................................................................18

7.6.1 General requirements ...............................................................................................................................................18

7.6.2 Welding procedure qualification testing ..................................................................................................18

7.6.3 Testing requirements ................................................................................................................................................19

7.6.4 Fillet weld on plates ...................................................................................................................................................20

7.7 Protection against corrosion and wear ...........................................................................................................................20

7.7.1 General...................................................................................................................................................................................20

7.7.2 Corrosion protecting coating at low temperature ...........................................................................20

7.7.3 Cathodic protection (CP) .......................................................................................................................................20

8 Quality control, quality assurance and documentation ...........................................................................................21

8.1 Structural steel requirements .................................................................................................................................................21

8.2 Welding and fabrication requirements ...........................................................................................................................21

© ISO 2018 – All rights reserved iii
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9 Operational topics ............................................................................................................................................................................................21

9.1 Requirements for operations in remote areas ..........................................................................................................21

9.1.1 General...................................................................................................................................................................................21

9.1.2 Low temperature operations .............................................................................................................................21

9.1.3 Ice and snow removal ...............................................................................................................................................22

9.2 Corrosion and wear control ......................................................................................................................................................22

9.2.1 General...................................................................................................................................................................................22

9.2.2 Splash zone surfaces in direct contact with sea ice ........................................................................22

9.2.3 Submerged surfaces and cathodic protection .....................................................................................22

9.2.4 Topside surfaces ............................................................................................................................................................23

Bibliography .............................................................................................................................................................................................................................24

iv © ISO 2018 – All rights reserved
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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.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore

structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 8, Arctic operations.

© ISO 2018 – All rights reserved v
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Introduction

Operations in an Arctic environment are characterized by low ambient temperatures, the presence of

sea ice and ice bergs and icing of structures and components. In many cases they are also associated

with remote locations relative to infrastructure and logistics. Maintenance operations are therefore

expensive and accidents leading to emissions can have severe environmental consequences.

Structural failure is in most cases failure of materials and caused by well-known degradation

mechanisms such as fatigue and corrosion. Under Arctic conditions, failure due to possible brittle

materials behaviour needs to be given special consideration.

This document was developed to bridge the gap between the functional requirements to offshore

structures in Arctic environments given in design standards and the material requirements given in

material and fabrication specifications where Arctic operating conditions have not been considered in

sufficient detail.
vi © ISO 2018 – All rights reserved
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SIST-TS CEN ISO/TS 35105:2020
TECHNICAL SPECIFICATION ISO/TS 35105:2018(E)
Petroleum and natural gas industries — Arctic operations
— Material requirements for arctic operations
1 Scope

This document provides recommendations for material selection, manufacturing and fabrication

requirements, testing and qualification of steel structures and components for offshore and onshore

petroleum and natural gas facilities operating in Arctic and cold environments.

This document is intended to be used as a supplement to existing standards for steel structures where

the particular operating conditions in Arctic regions are not sufficiently addressed.

This document gives particular requirements to ensure safe operation with respect to the risk of

brittle fracture at low temperatures. These requirements will affect the selection of material grade and

design class as well as the technical delivery conditions for steel. They will also affect the fabrication

requirements as well as testing and qualification requirements.
This document also gives recommendations:

— to mitigate the operational and integrity aspects related to snow and ice accretion on topside

structures;

— to take into account the particular Arctic operating conditions in corrosion assessments and

requirements for corrosion protection systems;

— for particular operational requirements to ensure safe operation in Arctic regions.

The requirements in this document are applicable to any operating temperatures, but particular

requirements related to de-rating (loss of strength) at high temperatures are not addressed.

Limitations to the applicable minimum design temperature caused by the capability of the materials’

low temperature performance can exist, but are not a limitation for the scope of this document.

As a practical guideline for the use of this document, low temperature is defined as lowest anticipated

service temperature (LAST) below –10 °C.
NOTE For determination of LAST, see 6.3.2.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 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 19901-4, Petroleum and natural gas industries — Specific requirements for offshore structures —

Part 4: Geotechnical and foundation design considerations

ISO 19902:2007, Petroleum and natural gas industries — Fixed steel offshore structures

© ISO 2018 – All rights reserved 1
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ISO/TS 35105:2018(E)
ISO 19906, Petroleum and natural gas industries — Arctic offshore structures

EN 10225:2009, Weldable structural steels for fixed offshore structures — Technical delivery conditions

API RP 2Z, Preproduction Qualification for Steel Plates for Offshore Structures
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 19900, ISO 19901-1,

ISO 19901-2, ISO 19901-4, ISO 19902 and ISO 19906 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Abbreviated terms
BCC body centred cubic
BM base material
DC design class
CJP complete joint penetration
C-Mn carbon manganese
CP cathodic protection
CTOD crack-tip opening displacement
ECA engineering critical assessment
HAZ heat affected zone
LAST lowest anticipated service temperature
PWHT post weld heat treatment
RT room temperature
SAW submerged arc welding
SENB single edge notch bend
SMYS specified minimum yield strength
SN stress number approach for fatigue design
UEL uniform elongation
ULS ultimate limit state
WM weld metal
Y/T yield to tensile stress ratio
2 © ISO 2018 – All rights reserved
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5 Symbols

The following is a summary of the main symbols that are used throughout this document. Other

symbols are defined where they are used. This use includes main symbols with one or more subscripts

when a more specific use and associated definition of the symbol is intended.
a defect height
c defect half length
h characteristic height
char
K crack arrest toughness
T temperature
t thickness
X constraint correction factor for CTOD
γ safety factor on characteristic CTOD
CTOD
γ materials safety factor
σ average bending stress acting over the characteristic height
σ effective stress
eff
σ tensile strength
σ average tensile stress acting over the characteristic height
σ yield strength
σ 0,2 % yield strength
0,2
τ average shear stress acting over the characteristic height
6 Technical basis
6.1 Design considerations
6.1.1 Present applications and industrial achievements

Offshore field developments have been carried out in the northern part of the Atlantic Sea offshore

New Foundland, United Kingdom and Norway with successful application of structural steels designed

for LAST equal to –10 °C with technical delivery conditions specified by EN 10225 and corresponding

API standards with weldability qualification in accordance with API RP 2Z. NORSOK N-004 has also

extended the application range of the design requirements to –14 °C.

Developments have also taken place in colder areas, such as the Barents Sea, offshore Sakhalin and the

Caspian Sea. In these cases, project-specific requirements to structural steel qualification have been

provided to compensate for the lack of industry standards. After delivery of these projects, the steel

industry has promoted “Arctic steel grades” as available for more industrial applications. However,

unified requirements and documentation of performance are still missing.
© ISO 2018 – All rights reserved 3
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6.1.2 Developments for future applications

As the offshore industry moves to Arctic and other cold areas, cost efficient solutions for low

temperature applications are needed. Therefore, the low temperature performance, testing

requirements and acceptance criteria as well as alternative steel grades have been investigated to reach

this goal. In addition to the field experience, results from such investigations form the basis for this

document. Investigations have been carried out at temperatures down to –60 °C. A short-term realistic

temperature limit is –40 °C, unless very specialized alloying systems are implemented.

As a design consideration, it should be taken into account that it is not sufficient to demonstrate

acceptable properties at low temperatures. It is also recommended to demonstrate that these properties

can be combined with cost efficient fabrication procedures including e.g. heat input, pre-heating and

post weld heat treatment.
6.1.3 Areas of concern in design for Arctic structures

At low temperatures, the risk of brittle fracture in structural steels will be more significant and it is

required to establish a specific fracture limit state to verify a safe design. A particular feature of a

brittle fracture mechanism is that it can affect the redundancy of the structure after a local overloading,

as it is difficult to predict the extent and path of brittle crack extension.

The introduction of a fracture limit state includes an á priori assumption that a crack is present at

the location considered. As the combination of high stress level and crack is associated with certain

likelihood, this is inevitably a probabilistic issue, and it is highly dependent on the fabrication quality

and inspection level of the structure.

The most critical failure locations associated with low temperature behaviour of welded steel

structures are WM and HAZ. The BM is usually less critical, because the properties are normally better

and the likelihood of defects is smaller. However, in forged and cast steel, also BM should be considered.

The brittle fracture resistance is controlled by the steel temperature, while the LAST is defined on the

basis of environmental temperature data in combination with operational factors. The minimum steel

temperature should be estimated as part of the design process, but can be conservatively estimated

from the ambient temperature.
The main e
...

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