FOREWORD

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IEC 61400-3-2 has been prepared by IEC technical committee 88: Wind energy generation systems. It is an International Standard.

This first edition cancels and replaces IEC TS 61400‑3‑2, published in 2019. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to IEC TS 61400‑3‑2:

a) The relevant contents of IEC 61400‑3‑1 have been migrated into IEC 61400‑3‑2, making IEC 61400‑3‑2 a self-standing document that does not have to be read directly in conjunction with IEC 61400‑3‑1.
b) Several modifications have been made regarding metocean conditions in Clause 6 considering the nature of FOWT and the offshore site where FOWT will be installed, including: (1) the importance of wave directional spreading has been highlighted as it may result in larger loads for FOWT, including the addition of the new informative Annex O and Annex P and (2) the characteristic of swell has been explained, which may be relevant for some FOWT projects, including the addition of new informative Annex R regarding the characteristic of swell.
c) Subclauses 7.1, 7.2, 7.3, 7.4 and 7.5 have been changed to include a revised DLC table and its related descriptions, including amongst others updated requirements on directionality, wave conditions, redundancy check and damage stability cases, and a robustness check case; further updates are made related to guidance and necessities provided on load calculations and simulation requirements.
d) Subclause 7.6 has been updated with guidance on fatigue assessment along with clarifications on serviceability analysis and the applicable material for WSD; related Annex L has been updated and a new Annex M has been added for clarification of the safety factors and load and load effect approach for floating substructures.
e) The concept of floater control system that will interact with the wind turbine controller has been introduced in Clause 8.
f) Clause 11 has been renamed from "Foundation and substructure design" to "Anchor design" and requirements for the transient conditions have been added.
g) A more detailed clause regarding concrete design has been added to Clause 16 together with an informative Annex Q.
h) Clause 15 has been updated with the aim to improve ease of use, using experience from oil and gas and considering unique wind turbine characteristics; updates included guidance for TLPs, damage stability, dynamic stability, testing and the addition for Annex S regarding how to analyse collision probability.

This International Standard is to be read in conjunction with IEC 61400‑1, Wind energy generation systems - Part 1: Design requirements.

The text of this International Standard is based on the following documents:

Draft	Report on voting
88/1028/FDIS	88/1050/RVD

Full information on the voting for the approval of this International Standard can be found in the report on voting indicated in the above table.

The language used for the development of this International Standard is English.

This publication was drafted in accordance with the ISO/IEC Directives, Part 2, and developed in accordance with the ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are described in greater detail at www.iec.ch/publications.

A list of all parts of the IEC 61400 series, published under the general title Wind energy generation systems, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC website under webstore.iec.ch in the data related to the specific document. At this date, the document will be

• reconfirmed,
• withdrawn, or
• revised.

IMPORTANT

The "colour inside" logo on the cover page of this document indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.

BS EN IEC 61400-3-2:2025

Wind energy generation systems - Design requirements for floating offshore wind turbines

Current

Published:

31 Mar 2025