IEC TS 61400-29:2023
(Main)Wind energy generation systems - Part 29: Marking and lighting of wind turbines
Wind energy generation systems - Part 29: Marking and lighting of wind turbines
IEC TS 61400-29:2023, which is a Technical Specification, instils good practice for aviation lighting and marking of wind turbines in both onshore and offshore domains. Consideration is given to visible lighting and infrared (IR) lighting, which is necessary to maintain conspicuity to users of night vision goggles (NVGs). ICAO Annex 14 Standards and Recommended Practices have been used as the basis to develop supplementary harmonised specifications to assist with implementation.
This document provides a set of technical requirements for marking and lighting of wind turbines with a tip height from/at 150 meters and below 315 meters Above Ground Level (AGL), or Above Mean Sea Level (AMSL) for offshore sites. This will improve situational awareness for airspace users, maintain safety of aircraft flying in the vicinity of wind turbines, and provide additional tools to assist with the reduction in environmental impacts consistent with aviation safety objectives.
General Information
Standards Content (Sample)
IEC TS 61400-29
®
Edition 1.0 2023-02
TECHNICAL
SPECIFICATION
colour
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Wind energy generation systems –
Part 29: Marking and lighting of wind turbines
IEC TS 61400-29:2023-02(en)
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IEC TS 61400-29
®
Edition 1.0 2023-02
TECHNICAL
SPECIFICATION
colour
inside
Wind energy generation systems –
Part 29: Marking and lighting of wind turbines
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.180 ISBN 978-2-8322-6401-0
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission
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– 2 – IEC TS 61400-29:2023 IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 10
4.1 Abbreviations . 10
5 Marking of a wind turbine and wind farms . 11
5.1 General . 11
5.2 Reflectance or luminance factor . 11
6 Lighting of a wind turbine and wind farms . 12
6.1 International Civil Aviation Organization requirements . 12
6.2 Planning considerations . 12
6.3 Wind turbines with a tip height less than 150 m . 13
6.4 Wind turbines with a tip height of 150 m or more . 13
6.5 Lighting of wind farms . 14
6.5.1 General . 14
6.5.2 Onshore wind farms . 16
6.5.3 Offshore wind farms. 17
6.5.4 Deconfliction with marine lighting . 18
6.6 Wind farms near aerodromes . 18
6.7 Lights specifications. 19
6.7.1 General . 19
6.7.2 Battery back-up time . 20
6.7.3 Night vision goggle compatibility . 20
6.7.4 Monitoring and control . 21
7 Considerations during construction . 21
8 Reduction of light pollution . 22
8.1 General . 22
8.2 Dimming . 22
8.2.1 Scope . 22
8.2.2 Operation . 22
8.2.3 Visible ranges . 22
8.3 Aircraft detection systems . 23
8.3.1 General . 23
8.3.2 Operation and boundaries . 23
8.3.3 Integrity monitoring . 24
Annex A (informative) Wind turbines located in areas with lengthy periods of snow . 25
Annex B (normative) Definition of colours for markings on wind turbines . 26
B.1 Specifications . 26
B.2 Provisions for practical implementation . 27
Annex C (normative) Definition of colours for wind turbine lights . 28
C.1 General . 28
C.2 Chromaticities for wind turbine lights with filament-type light sources . 28
C.3 Chromaticities for wind turbine lights with a solid state light source . 28
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IEC TS 61400-29:2023 IEC 2023 – 3 –
Annex D (normative) Light distribution for low, medium or high intensity aviation
obstacle lights . 30
Figure 1 – Lighting configurations for wind turbines exceeding 150 m . 14
Figure 2 – Linear configuration wind farm . 15
Figure 3 – Basic layout of a linear alignment . 15
Figure 4 – Lighting configuration of an onshore wind farm . 17
Figure 5 – Lighting configuration of an offshore wind farm . 18
Figure A.1 – Wind turbines in areas with lengthy periods of snow . 25
Figure B.1 – Ordinary colours for wind turbine marking . 27
Figure C.1 – Colours for wind turbine lights with filament-type light sources . 29
Figure C.2 – Colours for wind turbine lights with solid state light sources (LED) . 29
Table 1 – Wind turbines paint colours . 11
Table 2 – Characteristics of obstacle lights . 19
Table D.1 – Light distribution for low-intensity obstacle lights . 30
Table D.2 – Light distribution for medium- and high-intensity obstacle lights according
to benchmark intensities of Table D.1 . 30
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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND ENERGY GENERATION SYSTEMS –
Part 29: Marking and lighting of wind turbines
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC TS 61400-29 has been prepared by IEC technical committee 88: Wind energy generation
systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
88/894/DTS 88/913/RVDTS
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 Technical Specification is English.
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.
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IEC TS 61400-29:2023 IEC 2023 – 5 –
A list of all parts in 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,
• replaced by a revised edition, or
• amended.
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.
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– 6 – IEC TS 61400-29:2023 IEC 2023
INTRODUCTION
As the Wind Industry grows, airspace users (military, civil and emergency aircraft) need to
continue to operate safely in an environment that includes wind turbines, and the two industries
need to exist harmoniously.
To assist in creating a safe environment, some wind turbines are required to have aeronautical
lights so they can be seen by airspace users. Unfortunately, some of these lights can have an
adverse visual impact, which produces lighting pollution for nearby communities.
Annex 14 to the Convention on International Civil Aviation published by the International Civil
Aviation Organization (ICAO) contains Standards and Recommended Practices (specifications)
that prescribe the marking and lighting of wind turbines. However, many countries have
interpreted these specifications differently and issued their own guidelines and conditions to
suit their local requirements. Therefore, there is little homogeneity and wind turbine
manufacturers are obliged to produce bespoke designs to suit specific markets.
There are currently approximately 20 different marking and lighting specifications for countries
such as Belgium, Brazil, Canada, Finland, France, Germany and Japan. In many cases, those
requirements are very similar. However, they often differ in terms of light intensity, positioning
and markings, which could lead to confusion and reduction in air safety.
In some cases wind farms that are separated by only a few kilometers are marked and
illuminated in accordance with different guidelines. This includes the transition from the onshore
to the offshore wind environment, and vice versa.
This document reflects the need to allow the coexistence of wind turbines and aviation, ensuring
that the ICAO Standards and Recommended Practices are followed but also balances with the
environmental impact on nearby residents.
References to national regulations are important in this document, given the regional specific
circumstances required in many cases. Users should be aware that national and/or "local"
regulations can apply. The aim is to encourage safe airspace but with minimum light pollution.
NOTE Throughout the drafting process for this document, the National Guidelines, related to lighting and marking
wind turbines, of many ICAO Member States have been used as a resource. However, the guidance documents are
too numerous to list and, therefore, reference to any non-normative documents has been omitted.
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IEC TS 61400-29:2023 IEC 2023 – 7 –
WIND ENERGY GENERATION SYSTEMS –
Part 29: Marking and lighting of wind turbines
1 Scope
This part of IEC 61400, which is a Technical Specification, instils good practice for aviation
lighting and marking of wind turbines in both onshore and offshore domains. Consideration is
given to visible lighting and infrared (IR) lighting, which is necessary to maintain conspicuity to
users of night vision goggles (NVGs).
ICAO Annex 14 Standards and Recommended Practices have been used as the basis to
develop supplementary harmonised specifications to assist with implementation.
This document provides a set of technical requirements for marking and lighting of wind turbines
with a tip height from/at 150 meters and below 315 meters Above Ground Level (AGL), or Above
Mean Sea Level (AMSL) for offshore sites. This will improve situational awareness for airspace
users, maintain safety of aircraft flying in the vicinity of wind turbines, and provide additional
tools to assist with the reduction in environmental impacts consistent with aviation safety
objectives. In the event that the wind turbine development exceeds 315 m tip height and the
regulatory frameworks is updated to cater for these heights, this document will be reviewed and
amended as necessary. In the absence of an update to the regulatory framework, the guidance
in this document is to be followed as a minimum.
In some cases, lighting may be required for wind turbines at or below 150 meters tip height.
However, this is not in the scope of this document and in these situations, the developer should
contact the relevant National Aviation Authority or Planning Authority for further guidance.
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.
IEC 61400-3-1:2019, Wind energy generation systems - Part 3-1: Design requirements for fixed
offshore wind turbines
IEC 62443-4-2:2019, Security for industrial automation and control systems - Part 4-2:
Technical security requirements for IACS components
International Civil Aviation Organization, Annex 14, Aerodromes – Volume I – Aerodromes
th
Design and Operations. 8 Edition, July 2018
International Civil Aviation Organization, Aerodrome Design Manual – Part 4 – Visual Aids
th
(Doc 9157 – Part 4). 5 Edition. 2021
European Union Aviation Safety Agency (EASA), Certification Specifications and Guidance
Material for Aerodromes Design CS-ADR-DSN, Issue 5, June 2021
Federal Aviation Administration. Advisory Circular 150/5345-43J – Specification for Obstruction
Lighting Equipment, 11 March 2019
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Federal Aviation Administration. 70/7460-1M – Obstruction Marking and Lighting, 16 November
2020
IALA Recommendation R0139 (O-139) ,The Marking of Man-Made Offshore Structures, Edition
3.0, December 2021
NOTE Although too many to list explicitly, in drafting this document the national guidelines of many ICAO Member
States, for lighting and marking wind turbines, have been given due consideration. In some cases, specific examples
have been provided from national guidelines to enhance the international guidance in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
aerodrome
defined area (including any buildings, installations and equipment) intended to be used either
wholly or in part for the arrival, departure and surface movement of aircraft
3.2
aviation Obstacle Lights
warning lights (visual and infrared) used to reduce hazards to aircraft by indicating the presence
of the obstacles
3.3
aviation Obstacle Markings
warning markings used to reduce hazards to aircraft by indicating the presence of the
obstacles
3.4
candela
International System of Units (SI) base unit of luminous intensity that denotes the luminous
power per unit solid angle emitted by a point light source in a particular direction
3.5
cluster configuration wind farm
wind turbines arranged in a non-linear configuration (see 3.10)
3.6
daytime light
2
period(s) of the day when the background luminance is above 500 cd/m
3.7
effective luminous intensity
effective luminous intensity of a flashing light is equal to the intensity of a steady-burning (fixed)
light of the same colour which produces the same visual range under identical conditions of
observation
3.8
grid configuration wind farm
wind turbines arranged in a geographical shape such as a square or a rectangle, with each
turbine placed a consistent distance apart in rows
3.9
LED technology
light emitting diode (LED) is a semiconductor light source that emits light if electrical current
flows through it
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IEC TS 61400-29:2023 IEC 2023 – 9 –
Note 1 to entry: It can emit visible, IR or ultraviolet radiation depending on the semiconductor material and the
doping wavelength. LEDs are energy efficient and have a long lifespan.
3.10
linear configuration wind farm
wind turbines arranged in linear configuration are placed in a row along a ridgeline, the face of
a mountain, or along the borders of a hill or field
Note 1 to entry: The line may be ragged in shape or be periodically broken.
3.11
luminance
luminous intensity per unit emitting area. It is a photometric quantity which may be applied to
light sources but also to light which is reflected or passes through a particular area
2
Note 1 to entry: Its unit is 'Candela per Square Meter' (cd/m ).
3.12
nanometer
unit of length in the metric system, equal to one billionth of a meter
Note 1 to entry: The international unit for nanometer, nm is 10^(-9) m.
3.13
nautical mile
unit of measurement used in both air and marine navigation
Note 1 to entry: The international nautical mile is exactly 1 852 meters.
3.14
night-time light
2
period(s) of the day when the background luminance is below 50 cd/m
3.15
night vision goggles
helmet mounted night vision enhancement aid that utilises image intensifier technology and is
sensitive to light wavelengths between 660 and 920 nanometers
3.16
obstacle
fixed (whether temporary or permanent) and mobile objects, or parts thereof, that:
a) are located on an area intended for the surface movement of aircraft; or
b) extend above a defined surface intended to protect aircraft in flight; or
c) stand outside those defined surfaces assessed as being a hazard to air navigation
3.17
offshore wind turbine
wind turbine that converts kinetic energy in the wind into electrical energy and has a sub-
structure that is subject to hydrodynamic loading and is founded on the seabed, including
floating structures
3.18
onshore wind turbine
wind turbine that converts kinetic energy in the wind into electrical energy located on a land
mass
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3.19
tip height of a wind turbine
maximum height AGL (onshore) and AMSL (offshore), of the tip of the turbine blades at their
highest point
3.20
twilight-time light
light during the period(s) of the day when the background luminance is between 50 and
2
500 cd/m
3.21
visibility
aeronautical visibility is the greater of:
a) the greatest distance at which a black object of suitable dimensions, situated near the
ground, can be seen and recognised when observed against a bright background,
represented by the meteorological optical range (MOR)
b) the greatest distance at which lights in the vicinity of 1000 candelas (cd) can be seen and
identified against an unlit background, which varies with the background illumination
3.22
wind farm
group of two or more wind turbines in the same geographical area, used to produce electricity
3.23
wind turbine
structure intended for the production of electrical power; comprising a support tower, a nacelle,
a generator unit, and rotor blades that are caused to rotate by the wind
4 Symbols and abbreviated terms
4.1 Abbreviations
ADS aircraft detection system
AGL above ground level
AIP Aeronautical Information Publication
AMSL above mean sea level
cd candela
CIE International Commission on Illumination
EASA European Union Aviation Safety Agency
FAA Federal Aviation Administration
fpm flashes per minute
IALA International Association of Lighthouse Authorities
ICAO International Civil Aviation Organization
IEC International Electrotechnical Commission
IR infrared
ISO International Organization for Standardization
JORF Journal officiel de la République française (Official Journal of the French Republic)
LED light emitting diode
MOR meteorological optical range
NM nautical mile
NOTAM notice to airmen
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IEC TS 61400-29:2023 IEC 2023 – 11 –
NVG night vision goggles
PAS Publicly Available Specifications
RAL Reichs-Ausschuß für Lieferbedingungen und Gütesicherung (Imperial Commission
for Delivery Terms and Quality Assurance)
SARPs Standards and Recommended Practices
SI International System of Units
TS Technical Specification
UK United Kingdom
USA United States of America
UTC coordinated universal time
VFR visual flight rules
5 Marking of a wind turbine and wind farms
5.1 General
ICAO recommends rotor blades, nacelle and upper 2/3 of the supporting tower of all wind
turbines be painted white. Due to a number of factors, including gaining planning permission,
grey is the generally accepted colour choice for onshore turbines, to enhance conspicuity.
Colours are based on colorimetric quantities and luminance factor.
This document only recommends the use of colour bands in geographic areas that have lengthy
periods of snow cover, such as Alaska or Nordic countries, and where it is deemed necessary,
the rotor blades and the tower of the turbine may have a band of Traffic Red as given in Annex A
to provide additional contrast against the snow in accordance with national requirements.
In the offshore environment, if there are railings on the nacelle for a helicopter winch area, it is
recommended that the railings are painted a conspicuous colour, preferably red, in accordance
with IEC 61400-30, Safety of Wind Turbine Generator Systems – General principles for design.
Should railings be installed, the 360° visibility of the light must be maintained.
5.2 Reflectance or luminance factor
The luminance factor of grey colours shall be greater than or equal to 0,4. The luminance factor
of white colours is to be greater than or equal to 0,6.
Table 1 shows a list of the most commonly white and grey colours used on wind turbines. Any
other colour may be used as long as it complies with the above mentioned requirements of
luminance factor.
Table 1 – Wind turbines paint colours
Luminance
Name RAL
Factor (ß)
Grey white 9002 0,68
Signal white 9003 0,84
Pure white 9010 0,85
Traffic white 9016 0,85
Papyrus white 9018 0,61
Light grey 7035 0,56
Agate grey 7038 0,43
Telegrey 4 7047 0,57
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The specifications of surface colours given above are described in Annex B.
6 Lighting of a wind turbine and w
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