EN ISO 19901-1:2026
(Main)Specific requirements for offshore structures - Part 1: Metocean design and operating considerations (ISO 19901-1:2026)
- Abstract
This document provides two broad types of requirements for the determination and use of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures:
those related to the determination of environmental conditions in general, together with the metocean parameters that are required to adequately describe them;
those related to the characterization and use of metocean parameters for the design, the construction activities or the operation of offshore structures.
This document covers the following environmental conditions and metocean parameters:
extreme and abnormal values of metocean parameters that recur with given return periods that are considerably longer than the design service life of the structure;
long-term distributions of metocean parameters in the form of cumulative, conditional, marginal or joint statistics of metocean parameters;
normal environmental conditions that are expected to occur frequently during the design service life of the structure.
Metocean parameters specified in this document are applicable to:
the determination of actions for the design of new structures;
the determination of actions for the assessment of existing structures;
the site-specific assessment of mobile offshore units;
the determination of limiting environmental conditions, weather windows, actions and action effects for pre-service and post-service situations (i.e. fabrication, transportation and installation or decommissioning and removal of a structure);
the operation of the platform, where appropriate.
It is beyond the scope of this document to provide detailed instructions that can be followed to produce reliable estimates of extreme or abnormal conditions in all areas and in all cases.
- Status
- Published
- Publication Date
- 18-Aug-2026
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 19-Aug-2026
- Completion Date
- 19-Aug-2026
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EN ISO 19901-1:2026 is a European Standard published by CEN that adopts ISO 19901-1:2026 for offshore structures. It sets out metocean design and operating considerations for determining meteorological and oceanographic (metocean) conditions and for using those conditions in design, construction and operation. Engineers, metocean specialists, project teams and operators use it to define the environmental conditions that affect offshore structures and the way those conditions are applied in practice.
What does EN ISO 19901-1:2026 specify?
EN ISO 19901-1:2026 specifies requirements for determining metocean conditions and for using metocean parameters in offshore structural work. The focus is on two connected tasks: describing the environment properly, and turning that description into design, construction and operating input.
The scope covers:
- environmental conditions in general, together with the metocean parameters needed to describe them;
- characterization and use of metocean parameters for design, construction activities and operation of offshore structures.
It addresses three kinds of metocean conditions:
- extreme and abnormal values with return periods much longer than the structure’s design service life;
- long-term distributions expressed as cumulative, conditional, marginal or joint statistics;
- normal environmental conditions expected to occur frequently during the design service life.
The standard is aimed at offshore structures and related work in the oil and gas industries including lower carbon energy. The visible front matter includes a European foreword, and the adopted ISO text is presented as EN ISO 19901-1:2026.
What are the key requirements of EN ISO 19901-1:2026?
How metocean conditions are to be handled
EN ISO 19901-1:2026 requires metocean conditions to be treated in two ways: first as environmental conditions to be determined and described, and second as parameters to be used in engineering decisions. In practice, this means the user must not stop at gathering weather or sea-state data - the data has to be translated into usable design and operating inputs.
The standard distinguishes between extreme, abnormal and normal conditions. That matters because offshore decisions are not based on a single weather case: design and operation need separate treatment of rare events, long-term statistical behavior and conditions that occur regularly.
What the conditions are used for
EN ISO 19901-1:2026 applies its metocean parameters to several tasks:
- design actions for new structures;
- assessment of existing structures;
- site-specific assessment of mobile offshore units;
- limiting environmental conditions, weather windows, actions and action effects for pre-service and post-service situations;
- operation of the platform where appropriate.
In practice, this means the same metocean basis can support engineering design, integrity checks and planning for fabrication, transportation, installation, decommissioning and removal.
How extremes and distributions are treated
EN ISO 19901-1:2026 calls for extreme and abnormal values to be considered with return periods longer than the structure’s design service life. It also uses long-term distributions in cumulative, conditional, marginal and joint form. That matters because offshore engineering often depends on combinations of wind, waves, current and other environmental variables, not on one variable alone.
What is outside its promise
EN ISO 19901-1:2026 does not try to give detailed instructions that guarantee reliable estimates of extreme or abnormal conditions in every area and every case. For the reader, this means local data, regional knowledge and project-specific analysis still matter. The standard frames the problem, but it does not replace professional metocean assessment.
Who uses EN ISO 19901-1:2026?
EN ISO 19901-1:2026 is used by offshore structural engineers, metocean specialists, design teams, construction planners, operators and assessors of existing structures. It is also relevant to teams working on mobile offshore units and on activities such as fabrication, transportation, installation, decommissioning and removal.
In practice, these users rely on the standard to decide which environmental conditions to use, how to describe them statistically, and how to turn them into actions, limits and operating rules for offshore work.
What changed in EN ISO 19901-1:2026 from the previous edition?
EN ISO 19901-1:2026 supersedes EN ISO 19901-1:2015.
What does the EN ISO 19901-1:2026 document contain?
The visible front matter contains a European foreword and an endorsement notice. The foreword records CEN approval, the obligation for national implementation, and the withdrawal of conflicting national standards by the stated deadline. The endorsement notice says the text of ISO 19901-1:2026 has been approved by CEN without modification.
The body of the standard is organized around metocean design and operating considerations for offshore structures. Its substantive content is centered on environmental characterization, statistical treatment of metocean parameters, and their use in design, assessment and operational planning.
Relations
- Effective Date
- 29-Jun-2022
- Refers
ISO 19900:2019 - Petroleum and natural gas industries — General requirements for offshore structures - Effective Date
- 23-Sep-2026
- Effective Date
- 23-Sep-2026
- Effective Date
- 25-Aug-2026
- Consolidated By
ISO 19901-1:2026 - Specific requirements for offshore structures — Part 1: Metocean design and operating considerations - Effective Date
- 12-Feb-2026
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Frequently Asked Questions
EN ISO 19901-1:2026 is a standard published by the European Committee for Standardization (CEN). Its full title is "Specific requirements for offshore structures - Part 1: Metocean design and operating considerations (ISO 19901-1:2026)". This standard covers: This document provides two broad types of requirements for the determination and use of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures: those related to the determination of environmental conditions in general, together with the metocean parameters that are required to adequately describe them; those related to the characterization and use of metocean parameters for the design, the construction activities or the operation of offshore structures. This document covers the following environmental conditions and metocean parameters: extreme and abnormal values of metocean parameters that recur with given return periods that are considerably longer than the design service life of the structure; long-term distributions of metocean parameters in the form of cumulative, conditional, marginal or joint statistics of metocean parameters; normal environmental conditions that are expected to occur frequently during the design service life of the structure. Metocean parameters specified in this document are applicable to: the determination of actions for the design of new structures; the determination of actions for the assessment of existing structures; the site-specific assessment of mobile offshore units; the determination of limiting environmental conditions, weather windows, actions and action effects for pre-service and post-service situations (i.e. fabrication, transportation and installation or decommissioning and removal of a structure); the operation of the platform, where appropriate. It is beyond the scope of this document to provide detailed instructions that can be followed to produce reliable estimates of extreme or abnormal conditions in all areas and in all cases.
This document provides two broad types of requirements for the determination and use of meteorological and oceanographic (metocean) conditions for the design, construction and operation of offshore structures: those related to the determination of environmental conditions in general, together with the metocean parameters that are required to adequately describe them; those related to the characterization and use of metocean parameters for the design, the construction activities or the operation of offshore structures. This document covers the following environmental conditions and metocean parameters: extreme and abnormal values of metocean parameters that recur with given return periods that are considerably longer than the design service life of the structure; long-term distributions of metocean parameters in the form of cumulative, conditional, marginal or joint statistics of metocean parameters; normal environmental conditions that are expected to occur frequently during the design service life of the structure. Metocean parameters specified in this document are applicable to: the determination of actions for the design of new structures; the determination of actions for the assessment of existing structures; the site-specific assessment of mobile offshore units; the determination of limiting environmental conditions, weather windows, actions and action effects for pre-service and post-service situations (i.e. fabrication, transportation and installation or decommissioning and removal of a structure); the operation of the platform, where appropriate. It is beyond the scope of this document to provide detailed instructions that can be followed to produce reliable estimates of extreme or abnormal conditions in all areas and in all cases.
EN ISO 19901-1:2026 is classified under the following ICS (International Classification for Standards) categories: 75.180.10 - Exploratory, drilling and extraction equipment. The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 19901-1:2026 has the following relationships with other standards: It is inter standard links to EN ISO 19901-1:2015, ISO 19900:2019, ISO 19906:2019, EN IEC 61400-3-2:2025, ISO 19901-1:2026. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 19901-1:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2026
Posebne zahteve za naftne ploščadi - 1. del: Določila za načrtovanje in obratovanje
ob upoštevanju oceanografskih in meteoroloških vidikov (ISO 19901-1:2026)
Specific requirements for offshore structures - Part 1: Metocean design and operating
considerations (ISO 19901-1:2026)
Öl- und Gasindustrie einschließlich kohlenstoffarmer Energieträger - Spezielle
Anforderungen für Offshore-Anlagen - Teil 1: Grundsätze für die Auslegung und den
Betrieb auf dem offenen Meer (ISO 19901-1:2026)
Exigences spécifiques relatives aux structures en mer - Partie 1: Dispositions océano-
météorologiques pour la conception et l'exploitation (ISO 19901-1:2026)
Ta slovenski standard je istoveten z: EN ISO 19901-1:2026
ICS:
75.180.10 Oprema za raziskovanje, Exploratory, drilling and
vrtanje in odkopavanje extraction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 19901-1
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2026
EUROPÄISCHE NORM
ICS 75.180.10 Supersedes EN ISO 19901-1:2015
English Version
Specific requirements for offshore structures - Part 1:
Metocean design and operating considerations (ISO
19901-1:2026)
Exigences spécifiques relatives aux structures en mer - Öl- und Gasindustrie einschließlich kohlenstoffarmer
Partie 1: Dispositions océano-météorologiques pour la Energieträger - Spezielle Anforderungen für Offshore-
conception et l'exploitation (ISO 19901-1:2026) Anlagen - Teil 1: Grundsätze für die Auslegung und den
Betrieb auf dem offenen Meer (ISO 19901-1:2026)
This European Standard was approved by CEN on 10 July 2026.
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,
...