SIST EN IEC 61400-6:2020/A1:2025
(Amendment)Wind energy generation systems - Part 6: Tower and foundation design requirements (IEC 61400-6:2020/AMD1:2025)
Wind energy generation systems - Part 6: Tower and foundation design requirements (IEC 61400-6:2020/AMD1:2025)
Windenergieanlagen - Teil 6: Auslegungsanforderungen an Türme und Fundamente (IEC 61400-6:2020/AMD1:2025)
Systèmes de génération d'énergie éolienne - Partie 6: Exigences en matière de conception du mât et de la fondation (IEC 61400-6:2020/AMD1:2025)
Sistemi za proizvodnjo energije na veter - 6. del: Stolp in obravnava temeljnih zahtev - Dopolnilo A1 (IEC 61400-6:2020/AMD1:2025)
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Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2025
Sistemi za proizvodnjo energije na veter - 6. del: Stolp in obravnava temeljnih
zahtev - Dopolnilo A1 (IEC 61400-6:2020/AMD1:2025)
Wind energy generation systems - Part 6: Tower and foundation design requirements
(IEC 61400-6:2020/AMD1:2025)
Windenergieanlagen - Teil 6: Auslegungsanforderungen an Türme und Fundamente
(IEC 61400-6:2020/AMD1:2025)
Systèmes de génération d'énergie éolienne - Partie 6: Exigences en matière de
conception du mât et de la fondation (IEC 61400-6:2020/AMD1:2025)
Ta slovenski standard je istoveten z: EN IEC 61400-6:2020/A1:2025
ICS:
27.180 Vetrne elektrarne Wind turbine energy systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 61400-6:2020/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM August 2025
ICS 27.180
English Version
Wind energy generation systems - Part 6: Tower and foundation
design requirements
(IEC 61400-6:2020/AMD1:2025)
Systèmes de génération d'énergie éolienne - Partie 6: Windenergieanlagen - Teil 6: Auslegungsanforderungen an
Exigences en matière de conception du mât et de la Türme und Fundamente
fondation (IEC 61400-6:2020/AMD1:2025)
(IEC 61400-6:2020/AMD1:2025)
This amendment A1 modifies the European Standard EN IEC 61400-6:2020; it was approved by CENELEC on 2025-07-18. CENELEC
members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this amendment 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 CENELEC member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as
the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61400-6:2020/A1:2025 E
European foreword
The text of document 88/1088/FDIS, future edition 1 of IEC 61400-6/AMD1, prepared by TC 88 "Wind
energy generation systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 61400-6:2020/A1:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-08-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-08-31
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61400-6:2020/AMD1:2025 was approved by CENELEC as
a European Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Add the following references:
Publication Year Title EN/HD Year
IEC 61400-1 2019 Wind energy generation systems - Part 1: EN IEC 61400-1 2019
Design requirements
+A1 2024 +A1 —
ISO 898-1 - Mechanical properties of fasteners made of EN ISO 898-1 -
carbon steel and alloy steel - Part 1: Bolts,
screws and studs with specified property
classes - Coarse thread and fine pitch
thread
ISO 898-2 - Fasteners - Mechanical properties of EN ISO 898-2 -
fasteners made of carbon steel and alloy
steel - Part 2: Nuts with specified property
classes
ISO 898-3 - Mechanical properties of fasteners made of EN ISO 898-3 -
carbon steel and alloy steel - Part 3: Flat
washers with specified property classes
ISO 965-2 - ISO general purpose metric screw threads - -
- Tolerances – Part 2: Limits of sizes for
general purpose external and internal
screw threads - Medium quality
ISO 965-5 - ISO general purpose metric screw threads - -
- Tolerances - Part 5: Limits of sizes for
internal screw threads to mate with hot-dip
galvanized external screw threads with
maximum size of tolerance position h
before galvanizing
ISO 4759-1 - Tolerances for fasteners - Part 1: Bolts, EN ISO 4759-1 -
screws, studs and nuts - Product grades A,
B and C
ISO 4759-3 - Tolerances for fasteners - Part 3: Washers EN ISO 4759-3 -
for bolts, screws and nuts - Product grades
A, C and F
Under preparation. Stage at the time of publication: EN IEC 61400-1/prA1:2023.
IEC 61400-6 ®
Edition 1.0 2025-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Wind energy generation systems –
Part 6: Tower and foundation design requirements
Systèmes de génération d'énergie éolienne –
Partie 6: Exigences en matière de conception du mât et de la fondation
ICS 27.180 ISBN 978-2-8327-0435-6
IEC 61400-6:2020-04/AMD1:2025-06(en-fr)
– 2 – IEC 61400-6:2020/AMD1:2025
© IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND ENERGY GENERATION SYSTEMS –
Part 6: Tower and foundation design requirements
AMENDMENT 1
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
Amendment 1 to IEC 61400-6:2020 has been prepared by IEC technical committee TC 88: Wind
energy generation systems.
The text of this Amendment is based on the following documents:
Draft Report on voting
88/1088/FDIS 88/1096/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.
IEC 61400-6:2020/AMD1:2025 – 3 –
© IEC 2025
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with 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/.
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.
___________
INTRODUCTION
Clauses and subclauses as given in this document are replacing or amending the respective
clauses and subclauses of IEC 61400-6:2020. The main part of this amendment concerns
updated knowledge for the design of L-flanges and modifications required due to changes to
IEC 61400-1.
The previous method of fatigue assessment using the Schmidt/Neuper trilinear bolt force curve
approximation has been removed as the default method from the document. It has been
replaced with a physically more accurate method.
The updated methodology for fatigue assessment of L-flanges has been calibrated so that the
target failure probability defined in IEC 61400-1 is achieved. Where existing flange designs are
checked with the updated method, over-utilization can be found, which in some cases can show
an order of magnitude higher than nominally acceptable damage.
This does not impose an immediate risk for the turbines affected, though, due to the following
factors:
a) in most cases, such designs have significant conservatism in the fatigue loads assumed,
e.g. due to the assumption of uni-directional wind combined with type class turbulence
conditions,
b) experience shows that broken bolts are almost always found and replaced before a turbine
collapses.
It is not necessary to re-assess existing flange designs using the new method. In cases where
broken bolts are found in operating turbines, the affected flange should be checked with the
new methodology. Based on the assessment results and the root causes analysis for the failure,
further measures should be defined (e.g. shorter inspection intervals).
2 Normative references
Add the following new references to the existing list:
IEC 61400-1:2019/AMD1:2024
ISO 898-1, Mechanical properties of fasteners made of carbon steel and alloy steel – Part 1:
Bolts, screws and studs with specified property classes – Coarse thread and fine pitch thread
– 4 – IEC 61400-6:2020/AMD1:2025
© IEC 2025
ISO 898-2, Fasteners – Mechanical properties of fasteners made of carbon steel and alloy steel
– Part 2: Nuts with specified property classes
ISO 898-3, Mechanical properties of fasteners made of carbon steel and alloy steel – Part 3:
Flat washers with specified property classes
ISO 965-2, ISO general purpose metric screw threads – Tolerances – Part 2: Limits of sizes for
general purpose external and internal threads – Medium tolerance quality
ISO 965-5, ISO general purpose metric screw threads –Tolera
...
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