EN ISO 15156-1:2020

Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production - Part 1: General principles for selection of cracking-resistant materials (ISO 15156-1:2020)

This document describes general principles and gives requirements and recommendations for the selection and qualification of metallic materials for service in equipment used in oil and gas production and in natural-gas sweetening plants in H2S-containing environments, where the failure of such equipment can pose a risk to the health and safety of the public and personnel or to the environment. It can be applied to help to avoid costly corrosion damage to the equipment itself. It supplements, but does not replace, the materials requirements given in the appropriate design codes, standards, or regulations.
This document addresses all mechanisms of cracking that can be caused by H2S, including sulfide stress cracking, stress corrosion cracking, hydrogen-induced cracking and stepwise cracking, stress-oriented hydrogen-induced cracking, soft zone cracking, and galvanically induced hydrogen stress cracking.
Table 1 provides a non-exhaustive list of equipment to which this document is applicable, including exclusions.
This document applies to the qualification and selection of materials for equipment designed and constructed using load controlled design methods. For design utilizing strain-based design methods, see Clause 5.
This document is not necessarily applicable to equipment used in refining or downstream processes and equipment.

Erdöl und Erdgasindustrie - Werkstoffe für den Einsatz in H2S haltiger Umgebung bei der Öl und Gasgewinnung - Teil 1: Allgemeine Grundlagen für die Auswahl von gegen Rissbildung beständigen Werkstoffen (ISO 15156 1:2020)

Dieses Dokument beschreibt allgemeine Grundlagen, nennt Anforderungen und gibt Empfehlungen für die Auswahl und Qualifizierung von metallischen Werkstoffen für den Einsatz in Einrichtungen der Öl  und Gasgewinnung und in Sauergasaufbereitungsanlagen im Bereich H2S haltiger Umgebungen, deren Versagen ein mögliches Gesundheits  und Sicherheitsrisiko für die Allgemeinheit und das Personal oder für die Umwelt darstellen kann. Es kann angewendet werden zur Vermeidung kostspieliger Beschädigungen infolge von Korrosion der Anlage selbst. Es ergänzt, ersetzt aber nicht die in einschlägigen Konstruktionsrichtlinien, Normen oder Regelwerken enthaltenen Anforderungen an Werkstoffe.
Dieses Dokument behandelt alle Rissbildungsarten, die durch H2S verursacht werden können, einschließlich H2S induzierte Spannungsrisskorrosion (SSC), Spannungsrisskorrosion (SCC), wasserstoffinduzierte Rissbil¬dung (HIC) und Stufenrissbildung (SWC), spannungsorientierte wasserstoffinduzierte Rissbildung (SOHIC), Weichzonenrissbildung (SZC) und galvanisch induzierte wasserstoffinduzierte Spannungsrisskorrosion (GHSC).
Tabelle 1 enthält als nicht erschöpfende Liste eine Übersicht von Ausrüstungen, die in den Anwendungsbereich dieses Dokumentes fallen, einschließlich Ausnahmen.
Dieses Dokument gilt für die Qualifizierung und Auswahl von Werkstoffen für Ausrüstungen, die unter Verwendung von lastgesteuerten Auslegungsverfahren ausgelegt und gebaut wurden. Siehe Abschnitt 5 bezüglich Konstruktionen, bei denen auf Dehnung beruhende Auslegungsverfahren zur Anwendung kommen.
Dieses Dokument ist nicht zwangsläufig auch für die Anwendung auf Ausrüstungen in Raffinerien oder Verfahren und Einrichtungen geeignet, die der Öl  und Gasgewinnung nachgeschaltet sind.

Industries du pétrole et du gaz naturel - Matériaux pour utilisation dans des environnements contenant de l'hydrogène sulfuré (H2S) dans la production de pétrole et de gaz - Partie 1: Principes généraux pour le choix des matériaux résistant à la fissuration (ISO 15156-1:2020)

Le présent document décrit les principes généraux, spécifie des exigences et donne des recommandations concernant le choix et la qualification de matériaux métalliques destinés à être exposés à des environnements contenant de l'H2S, dans les équipements utilisés dans la production de pétrole et de gaz ainsi que dans les installations de traitement du gaz naturel, où la rupture d'un équipement peut présenter un risque pour la santé et la sécurité du public et du personnel ou pour l'environnement. Il peut être appliqué pour aider à prévenir les dommages coûteux occasionnés par la corrosion aux équipements. Il complète, sans toutefois s'y substituer, les exigences concernant les matériaux des codes de construction, normes ou autres réglementations appropriées.
Le présent document traite de tous les mécanismes de fissuration pouvant être induits par l'H2S, à savoir la fissuration sous contrainte par l'H2S et/ou tout autre agent dépassivant, la décohésion interne et la fissuration en gradins, la décohésion interne sous contrainte, la fissuration des zones de plus faible dureté et la fissuration en milieu hydrogénant induite par couplage galvanique.
Le Tableau 1 donne une liste non exhaustive d'équipements relevant du domaine d'application du présent document et comprenant une liste d'équipements pouvant en être exclus.
Le présent document s'applique à la qualification et au choix des matériaux pour les équipements conçus et construits sur la base des méthodes de calcul sous charge contrôlée. Pour les conceptions effectuées sur la base de méthodes de calcul basées sur le niveau de déformation acceptable, voir l'Article 5.
L'application du présent document ne convient pas nécessairement aux processus et équipements de raffinage ou en aval.

Industrija za predelavo nafte in zemeljskega plina - Materiali za uporabo v okoljih s H2S v proizvodnji olja in plina - 1. del: Splošna načela za izbiro materialov, odpornih proti razpokam (ISO 15156-1:2020)

General Information

• Status: Published
• Publication Date: 24-Nov-2020
• Withdrawal Date: 30-May-2021
• ICS: 75.180.01 - Equipment for petroleum and natural gas industries in general
• Technical Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Drafting Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 25-Nov-2020
• Completion Date: 25-Nov-2020
• Ref Project: SIST EN ISO 15156-1:2021 - Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production - Part 1: General principles for selection of cracking-resistant materials (ISO 15156-1:2020)

Relations

• Replaces: EN ISO 15156-1:2015 - Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production - Part 1: General principles for selection of cracking-resistant materials (ISO 15156-1:2015)
• Effective Date: 16-Oct-2019

Overview

EN ISO 15156-1:2020 - "Petroleum and natural gas industries - Materials for use in H2S-containing environments in oil and gas production - Part 1" defines general principles, requirements and recommendations for selecting and qualifying metallic materials for service in H2S (sour service) environments. The standard targets equipment used in oil and gas production and natural‑gas sweetening plants where equipment failure could affect health, safety or the environment. It supplements-but does not replace-applicable design codes, standards or regulations.

Key points

• Applies to equipment designed and constructed using load‑controlled design methods (see Clause 5 for guidance on strain‑based methods).
• Covers all cracking mechanisms caused by H2S, including:
  • Sulfide stress cracking (SSC)
  • Stress corrosion cracking (SCC)
  • Hydrogen‑induced cracking (HIC) and stepwise cracking
  • Stress‑oriented hydrogen‑induced cracking (SOHIC)
  • Soft‑zone cracking
  • Galvanically induced hydrogen stress cracking
• Includes a non‑exhaustive Table 1 listing applicable equipment and exclusions.
• Warns that materials selected per the standard are resistant to cracking in defined conditions but not necessarily immune under all service conditions; final selection remains the equipment user's responsibility.

Key technical topics and requirements

• Evaluation and definition of service conditions (environmental composition, H2S fugacity/partial pressure, temperature, pH) to enable appropriate material selection.
• Selection methods: use of established lists/tables and decision rules for materials resistant to SSC/SCC.
• Qualification routes: documentation and material description, qualification based on field experience, or qualification based on laboratory testing (sampling, test method selection, testing conditions, acceptance criteria).
• Reporting: requirements for documenting the method of selection or qualification for traceability and compliance.

Practical applications

• Use when specifying materials for subsea equipment, wellheads, tubing, pipelines, separators and other production components that may be exposed to H2S.
• Helps engineering, materials, inspection and procurement teams reduce risk of cracking failures and avoid costly corrosion damage.
• Useful for risk assessments, materials acceptance, and developing procurement specifications for sour service environments.

Who should use this standard

• Corrosion and materials engineers
• Well and production engineers
• Materials and procurement specialists in oil & gas operators and EPC contractors
• Inspection and integrity management professionals

Related standards

• ISO 15156 series (other parts covering specific alloys and testing)
• Historical/related documents: NACE MR0175 and NACE test methods (e.g., TM0177, TM0284)

Keywords: EN ISO 15156-1:2020, H2S, sour service, sulfide stress cracking, hydrogen-induced cracking, materials selection, petroleum and natural gas, cracking-resistant materials.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2021
Nadomešča:
SIST EN ISO 15156-1:2015
Industrija za predelavo nafte in zemeljskega plina - Materiali za uporabo v okoljih s
H2S v proizvodnji olja in plina - 1. del: Splošna načela za izbiro materialov,
odpornih proti razpokam (ISO 15156-1:2020)
Petroleum and natural gas industries - Materials for use in H2S-containing environments
in oil and gas production - Part 1: General principles for selection of cracking-resistant
materials (ISO 15156-1:2020)
Erdöl- und Erdgasindustrie - Werkstoffe für den Einsatz in H<(Index)2>S-haltiger
Umgebung bei der Öl- und Gasgewinnung - Teil 1: Allgemeine Grundlagen für die
Auswahl von gegen Rissbildung beständigen Werkstoffen (ISO 15156-1:2020)
Industries du pétrole et du gaz naturel - Matériaux pour utilisation dans des
environnements contenant de l'hydrogène sulfuré (H2S) dans la production de pétrole et
de gaz - Partie 1: Principes généraux pour le choix des matériaux résistant à la
fissuration (ISO 15156-1:2020)
Ta slovenski standard je istoveten z: EN ISO 15156-1:2020
ICS:
75.180.10 Oprema za raziskovanje, Exploratory, drilling and
vrtanje in odkopavanje extraction equipment
77.060 Korozija kovin Corrosion of metals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 15156-1
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2020
EUROPÄISCHE NORM
ICS 75.180.01 Supersedes EN ISO 15156-1:2015
English Version
Petroleum and natural gas industries - Materials for use in
H2S-containing environments in oil and gas production -
Part 1: General principles for selection of cracking-
resistant materials (ISO 15156-1:2020)
Industries du pétrole et du gaz naturel - Matériaux Erdöl und Erdgasindustrie - Werkstoffe für den
pour utilisation dans des environnements contenant de Einsatz in H2S haltiger Umgebung bei der Öl und
l'hydrogène sulfuré (H2S) dans la production de Gasgewinnung - Teil 1: Allgemeine Grundlagen für die
pétrole et de gaz - Partie 1: Principes généraux pour le Auswahl von gegen Rissbildung beständigen
choix des matériaux résistant à la fissuration (ISO Werkstoffen (ISO 15156 1:2020)
15156-1:2020)
This European Standard was approved by CEN on 12 October 2020.

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, 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15156-1:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 15156-1:2020) 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 NEN.
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 May 2021, and conflicting national standards shall be
withdrawn at the latest by May 2021.
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.
This document supersedes EN ISO 15156-1:2015.
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 15156-1:2020 has been approved by CEN as EN ISO 15156-1:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 15156-1
Fourth edition
2020-11
Petroleum and natural gas
industries — Materials for use in H₂S-
containing environments in oil and
gas production —
Part 1:
General principles for selection of
cracking-resistant materials
Industries du pétrole et du gaz naturel — Matériaux pour utilisation
dans des environnements contenant de l'hydrogène sulfuré (H₂S) dans
la production de pétrole et de gaz —
Partie 1: Principes généraux pour le choix des matériaux résistant à la
fissuration
Reference number
ISO 15156-1:2020(E)
©
ISO 2020
ISO 15156-1:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 15156-1:2020(E)
Contents Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references .2
3  Terms and definitions .2
4 Abbreviated terms . 6
5 General principles . 6
6  Evaluation and definition of service conditions to enable material selection .7
7  Selection of materials resistant to SSC/SCC in the presence of sulfides from existing
lists and tables . 8
8  Qualification of materials for HS service . 8
8.1 Material description and documentation . 8
8.2 Qualification based upon field experience . 8
8.3 Qualification based upon laboratory testing . 8
8.3.1 General. 8
8.3.2 Sampling of materials for laboratory testing . 9
8.3.3 Selection of laboratory test methods . 9
8.3.4 Conditions to be applied during testing . 9
8.3.5 Acceptance criteria . 9
9  Report of the method of selection or qualification . 9
Bibliography .11
ISO 15156-1:2020(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.
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 of 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 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, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 12, Materials, equipment and
offshore structures for petroleum, petrochemical and natural gas industries, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 15156-1:2015), which has been
technically revised. The main changes compared to the previous edition are as follows:
— new definition on "galvanically induced hydrogen stress cracking" (see 3.14), "chemical activity"
(see 3.27) and "fugacity" (see 3.28);
— inclusion of an expanded description of factors affecting the susceptibility of materials to cracking
caused by H S. The expanded description includes specific guidance provided in ISO 15156-2:2020,
Annex C for gas phase containing systems using H S fugacity (as an alternative to H S partial
2 2
pressure) and application of non-ideal thermodynamic rules for gas-free liquid systems.
A list of all parts in the ISO 15156 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

ISO 15156-1:2020(E)
Introduction
The consequences of sudden failures of metallic oil and gas field components, associated with their
exposure to H S-containing production fluids, led to the preparation of the first edition of NACE MR0175,
which was published in 1975 by the National Association of Corrosion Engineers, now known as NACE
International.
The original and subsequent editions of NACE MR0175 established limits of H S partial pressure above
which precautions against sulfide stress cracking (SSC) were always considered necessary. They
also provided guidance for the selection and specification of SSC-resistant materials when the H S
thresholds were exceeded. In more recent editions, NACE MR0175 has also provided application limits
for some corrosion-resistant alloys, in terms of environmental composition and pH, temperature, and
H S partial pressures.
In separate developments, the European Federation of Corrosion issued EFC Publication 16 in 1995 and
EFC Publication 17 in 1996. These documents are generally complementary to those of NACE though
they differed in scope and detail.
In 2003, the publication of the ISO 15156 series and NACE MR0175/ISO 15156 was completed for the
first time. These technically identical documents utilized the above sources to provide requirements
and recommendations for materials qualification and selection for application in environments
containing wet H S in oil and gas production systems. They are complemented by NACE TM0177 and
NACE TM0284 test methods.
The revision of this document, i.e. ISO 15156-1, involves a consolidation of all changes agreed and
published in the Technical Circular 1, ISO 15156-1:2015/Cir.1:2017, published by the ISO 15156 series
Maintenance Agency secretariat at DIN.
The changes were developed by, and approved by the ballot of, representative groups from within
the oil and gas production industry. The great majority of these changes stem from issues raised by
document users. A description of the process by which these changes were approved can be found at
the ISO 15156 series maintenance website: www .iso .org/ iso15156maintenance.
When found necessary by oil and gas production industry experts, future interim changes to this
document will be processed in the same way and will lead to interim updates to this document in
the form of Technical Corrigenda or Technical Circulars. Document users should be aware that such
documents can exist and can impact the validity of the dated references in this document.
The ISO 15156 series Maintenance Agency at DIN was set up after approval by the ISO Technical
Management Board given in document 34/2007. This document describes the makeup of the agency,
which includes experts from NACE, EFC, and ISO/TC 67, and the process for approval of amendments.
It is available from the ISO 15156 series maintenance website and from the ISO/TC 67 Secretariat. The
website also provides access to related documents that provide more detail of the ISO 15156 series
maintenance activities.
INTERNATIONAL STANDARD  ISO 15156-1:2020(E)
Petroleum and natural gas industries — Materials
for use in H₂S-containing environments in oil and gas
production —
Part 1:
General principles for selection of cracking-resistant
materials
WARNING — Metallic materials selected using this document are resistant to cracking in defined
HS-containing environments in oil and gas production but not necessarily immune to cracking
under all service conditions. It is the equipment user's responsibility to select materials suitable
for the intended service.
1  Scope
This document describes general principles and gives requirements and recommendations for the
selection and qualification of metallic materials for service in equipment used in oil and gas production
and in natural-gas sweetening plants in H S-containing environments, where the failure of such
equipment can pose a risk to the health and safety of the public and personnel or to the environment.
It can be applied to help to avoid costly corrosion damage to the equipment itself. It supplements, but
does not replace, the materials requirements given in the appropriate design codes, standards, or
regulations.
This document addresses all mechanisms of cracking that can be caused by H S, including sulfide stress
cracking, stress corrosion cracking, hydrogen-induced cracking and stepwise cracking, stress-oriented
hydrogen-induced cracking, soft zone cracking, and galvanically induced hydrogen stress cracking.
Table 1 provides a non-exhaustive list of equipment to which this document is applicable, including
exclusions.
This document applies to the qualification and selection of materials for equipment designed and
constructed using load controlled design methods. For design utilizing strain-based design methods,
see Clause 5.
This document is not necessarily applicable to equipment used in refining or downstream processes
and equipment.
ISO 15156-1:2020(E)
Table 1 — List of equipment
This document is applicable to materials used for  Exclusions
the following equipment
Drilling, well construction, and well-servicing Equipment exposed only to drilling fluids of controlled
a
equipment composition
Drill bits
b
Blowout preventer (BOP) shear blades
Drilling riser systems
Work strings
c
Wireline and wireline equipment
Surface and intermediate casing
d
Wells, including subsurface equipment, gas-lift Sucker rod pumps and sucker rods
equipment, wellheads, and christmas trees
Electric submersible pumps
Other artificial lift equipment
Slips
Flowlines, gathering lines, field facilities, and field Crude-oil storage and handling facilities operating at a
processing plants total absolute pressure below 0,45 MPa (65 psi)
Water-handling equipment Water-handling facilities operating at a total absolute
pressure below 0,45 MPa (65 psi)
Water injection and water disposal equipment
Natural-gas treatment plants —
Transportation pipelines for liquids, gases, and Lines handling gas prepared for general commercial
multiphase fluids and domestic use
For all equipment above Components loaded only in compression
a
See ISO 15156-2:2020, A.2.3.2.3 for more information.
b
See ISO 15156-2:2020, A.2.3.2.1 for more information.
c
Wireline lubricators and lubricator connecting devices are not excluded.
d
For sucker rod pumps and sucker rods, reference can be made to NACE MR0176.
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 15156-2, Petroleum and natural gas industries — Materials for use in H S-containing environments in
oil and gas production — Part 2: Cracking-resistant carbon and low alloy steels, and the use of cast irons
ISO 15156-3, Petroleum and natural gas industries — Materials for use in H S-containing environments in
oil and gas production — Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses
...