EN IEC 62305-3:2024
(Main)Protection against lightning - Part 3: Physical damage to structures and life hazard
Protection against lightning - Part 3: Physical damage to structures and life hazard
IEC 62305-3:2024 provides the requirements for protection of a structure against physical damage by means of a lightning protection system (LPS), and for protection against injury to human beings due to touch and step voltages in the vicinity of an LPS (see IEC 62305-1). This document is applicable to the: a) design, installation, inspection and maintenance of an LPS for structures without limitation of their height, b) establishment of measures for protection against injury to human beings primarily due to touch and step voltages. This third edition cancels and replaces the second edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) Minimum thicknesses of metal sheets or metal pipes are given in Table 4 for air-termination systems where it is necessary to prevent hot-spot problems. Maximum temperature rises ΔT (K) and time duration t50 (s) for different thicknesses and long strokes are also given. b) Cross-reference to the IEC 62561 series is made for the use of reliable, stable, safe and appropriate LPS components. c) The application of two methods – general and simplified – for separation distance calculation is clarified. d) Some changes to the requirements for continuity of steel reinforcement are made. e) Annex C is revised to address comments from IEC subcommittee 31J. f) Revision of positioning of air-termination conductors are modified according to the three accepted methods. A more precise description of the methods for positioning of the air-termination systems are made according to the complexity of structures to be protected. The main text has been simplified, Annex A has been deleted and all detailed information has been moved to Annex D. g) Information on the protection of green roofs is introduced in Annex D. h) Information on the protection of protruding parts on facades of tall buildings is introduced in Annex D. i) a new definition of “electrically insulated LPS” has been introduced to distinguish it from an LPS both electrically and physically isolated from the structure, with a slight modification of the other LPS definitions.
Blitzschutz - Teil 3: Schutz von baulichen Anlagen und Personen
Protection contre la foudre - Partie 3: Dommages physiques sur les structures et risques humains
L'IEC 62305-3:2024 spécifie les exigences pour la protection d'une structure contre les dommages physiques par un système de protection contre la foudre (SPF) et pour la protection contre les blessures d'êtres humains dues aux tensions de contact et de pas à proximité d'un SPF (voir l'IEC 62305-1). Le présent document s'applique: a) à la conception, l'installation, l'inspection et la maintenance d'un SPF pour des structures, sans limitation de leur hauteur; b) à la mise en œuvre de mesures pour la protection contre les blessures d'êtres humains essentiellement dues aux tensions de contact et de pas. Cette troisième édition annule et remplace la deuxième édition parue en 2010. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) les épaisseurs minimales des tôles ou canalisations métalliques sont indiquées dans le Tableau 4 pour les dispositifs de capture à utiliser si des mesures de prévention contre les problèmes de points chauds se révèlent nécessaires. Les échauffements maximaux ΔT (K) et la durée t50 (s) pour différentes épaisseurs et pour des coups de longue durée sont également donnés; b) un renvoi à la série IEC 62561 est établi en ce qui concerne l'utilisation de composants appropriés fiables, stables et sûrs du système de protection contre la foudre (SPF); c) l'application de deux méthodes (générale et simplifiée) de calcul de la distance de séparation est clarifiée; d) certaines exigences relatives à la continuité des armatures en acier ont été modifiées; e) l'Annexe C est révisée pour tenir compte des remarques formulées par le sous-comité 31J de l'IEC; f) Le positionnement des conducteurs de capture a été révisé en fonction des trois méthodes admises. Les méthodes de positionnement des dispositifs de capture sont décrites avec davantage de précision compte tenu de la complexité des structures à protéger. Le texte principal a été simplifié, l'Annexe A a été supprimée et toutes les informations supplémentaires ont été déplacées à l'Annexe D; g) des informations relatives à la protection de toitures végétalisées ont été ajoutées à l'Annexe D; h) des informations relatives à la protection des parties saillantes sur les façades de bâtiments hauts ont été ajoutées à l'Annexe D; i) une nouvelle définition de la “SPF isolée électriquement” a été introduite pour la distinguer de la SPF isolée électriquement et physiquement de la structure, avec une légère modification des autres définitions de la SPF.
Zaščita pred delovanjem strele - 3. del: Fizična škoda na zgradbah in življenjska ogroženost
Standard IEC 62305-3:2024 določa zahteve za zaščito zgradb pred fizično škodo s pomočjo sistema zaščite pred delovanjem strele (LPS) ter zaščito pred poškodbami ljudi zaradi napetosti dotika in koraka v bližini takšnega sistema (glej standard IEC 62305-1).
Ta dokument se uporablja za:
a) načrtovanje, namestitev, pregledovanje in vzdrževanje sistema zaščite pred delovanjem strele za zgradbe brez omejitve glede njihove višine;
b) določanje zahtev glede zaščite pred poškodbami ljudi predvsem zaradi napetosti dotika in koraka.
Tretja izdaja razveljavlja in nadomešča drugo izdajo, objavljeno leta 2010. Ta izdaja je tehnično popravljena izdaja.
Ta izdaja v primerjavi s prejšnjo vključuje naslednje pomembne tehnične spremembe:
a) V preglednici 4 so navedene najmanjše debeline kovinskih plošč ali kovinskih cevi za lovilne sisteme, kjer je treba preprečiti težave zaradi nastanka vročih mest. Podano je tudi največje zvišanje temperature ΔT (K) in časovno trajanje t50 (s) za različne debeline in dolge udare.
b) Uporaba zanesljivih, stabilnih, varnih in ustreznih komponent sistema zaščite pred delovanjem strele je zagotovljena z navzkrižnim sklicevanjem na skupino standardov IEC 62561.
c) Pojasnjena je uporaba dveh metod – splošne in poenostavljene – za izračun ločilne razdalje.
d) Zahteve za neprekinjenost jeklene ojačitve so bile nekoliko spremenjene.
e) Dodatek C je bil spremenjen tako, da obravnava pripombe pododbora IEC 31J.
f) Postavitev lovilnih vodnikov je bila pregledana in spremenjena v skladu s tremi sprejetimi metodami. Metode za postavitev lovilnih sistemov so natančneje opisane glede na kompleksnost zgradb, ki jih je treba zaščititi. Glavno besedilo je bilo poenostavljeno, dodatek A je bil izbrisan in vse podrobne informacije so bile premaknjene v dodatek D.
g) Dodatek D vsebuje informacije o zaščiti zelenih streh.
h) Dodatek D vsebuje tudi informacije o zaščiti štrlečih delov na fasadah visokih zgradb.
i) Uvedena je bila nova definicija »električno izoliranega sistema zaščite pred delovanjem strele«, da ga je mogoče razlikovati od sistema zaščite pred delovanjem strele, ki je tako električno kot fizično izoliran od zgradbe, pri čemer so bile nekoliko spremenjene tudi druge definicije sistemov zaščite pred delovanjem strele.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2024
Nadomešča:
SIST EN 62305-3:2011
Zaščita pred delovanjem strele - 3. del: Fizična škoda na zgradbah in življenjska
ogroženost
Protection against lightning - Part 3: Physical damage to structures and life hazard
Blitzschutz - Teil 3: Schutz von baulichen Anlagen und Personen
Protection contre la foudre - Partie 3: Dommages physiques sur les structures et risques
humains
Ta slovenski standard je istoveten z: EN IEC 62305-3:2024
ICS:
91.120.40 Zaščita pred strelo Lightning protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 62305-3
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2024
ICS 29.020; 91.120.40 Supersedes EN 62305-3:2011
English Version
Protection against lightning - Part 3: Physical damage to
structures and life hazard
(IEC 62305-3:2024)
Protection contre la foudre - Partie 3: Dommages physiques Blitzschutz - Teil 3: Schutz von baulichen Anlagen und
sur les structures et risques humains Personen
(IEC 62305-3:2024) (IEC 62305-3:2024)
This European Standard was approved by CENELEC on 2024-10-17. CENELEC 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 CENELEC 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 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
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62305-3:2024 E
European foreword
The text of document 81/764/FDIS, future edition 3 of IEC 62305-3, prepared by TC 81 "Lightning
protection" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-10-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-10-31
document have to be withdrawn
This document supersedes EN 62305-3:2011 and all of its amendments and corrigenda (if any).
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 62305-3:2024 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61400-24 NOTE Approved as EN IEC 61400-24
ISO 1182 NOTE Approved as EN ISO 1182
ISO 11925-2 NOTE Approved as EN ISO 11925-2
IEC 60071-2 NOTE Approved as EN IEC 60071-2
IEC 60079-17 NOTE Approved as EN IEC 60079-17
IEC 62858 NOTE Approved as EN IEC 62858
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.
Publication Year Title EN/HD Year
IEC 60079-10-1 2020 Explosive atmospheres - Part 10-1: EN IEC 60079-10-1 2021
Classification of areas - Explosive gas
atmospheres
IEC 60079-10-2 2015 Explosive atmospheres - Part 10-2: EN 60079-10-2 2015
Classification of areas - Explosive dust
atmospheres
IEC 60079-14 - Explosive atmospheres - Part 14: Electrical EN IEC 60079-14 -
installation design, selection and
installation of equipment, including initial
inspection
IEC 60364-5-53 - Low-voltage electrical installations -- Part - -
5-53: Selection and erection of electrical
equipment - Protection, isolation,
switching, control and monitoring
IEC 61643-11 - Low-voltage surge protective devices - Part EN 61643-11 -
11: Surge protective devices connected to
low-voltage power systems - Requirements
and test methods
IEC 61643-21 - Low voltage surge protective devices - Part EN 61643-21 -
21: Surge protective devices connected to
telecommunications and signalling
networks - Performance requirements and
testing methods
IEC 62305-1 2024 Protection against lightning - Part 1: EN IEC 62305-1 2024
General principles
IEC 62305-2 2024 Protection against lightning - Part 2: Risk EN IEC 62305-2 2024
management
IEC 62305-4 2024 Protection against lightning - Part 4: EN IEC 62305-4 2024
Electrical and electronic systems within
structures
IEC 62561 series Lightning protection system components EN IEC 62561 series
(LPSC) - Part 1: Requirements for
connection components
Publication Year Title EN/HD Year
IEC 62561-1 2017 Lightning protection system components EN 62561-1 2017
(LPSC)
IEC/TS 62561-8 2018 Lightning protection system components - -
(LPSC) - Part 8: Requirements for
components for isolated LPS
ISO 3864-1 - Graphical symbols - Safety colours and - -
safety signs - Part 1: Design principles for
safety signs and safety markings
IEC 62305-3 ®
Edition 3.0 2024-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Protection against lightning –
Part 3: Physical damage to structures and life hazard
Protection contre la foudre –
Partie 3: Dommages physiques sur les structures et risques humains
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.020, 91.120.40 ISBN 978-2-8322-9059-0
– 2 – IEC 62305-3:2024 © IEC 2024
CONTENTS
FOREWORD . 7
INTRODUCTION . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 13
4 Lightning protection system (LPS) . 18
4.1 Class of LPS . 18
4.2 Design of the LPS . 19
5 External lightning protection system . 19
5.1 General . 19
5.1.1 Application of an external LPS . 19
5.1.2 Application of an isolated LPS or an electrically insulated LPS . 19
5.1.3 Use of natural components . 20
5.2 Air-termination systems . 20
5.2.1 General . 20
5.2.2 Positioning . 20
5.2.3 Air terminations against flashes to the side of tall structures . 25
5.2.4 Construction . 26
5.2.5 Natural components . 26
5.3 Down-conductor systems . 29
5.3.1 General . 29
5.3.2 Positioning of an isolated LPS . 29
5.3.3 Positioning of an attached LPS . 29
5.3.4 Construction . 30
5.3.5 Natural components . 32
5.3.6 Test joints and test points . 33
5.4 Earth-termination system . 33
5.4.1 General . 33
5.4.2 Earthing arrangement in general conditions . 33
5.4.3 Installation of earth electrodes . 35
5.4.4 Natural earth electrodes . 36
5.5 Components . 36
5.5.1 General . 36
5.5.2 Fixing . 37
5.5.3 Connections . 38
5.5.4 Components of an electrically insulated LPS . 38
5.6 Materials and dimensions . 38
5.6.1 Materials . 38
5.6.2 Dimensions . 38
6 Internal lightning protection system . 41
6.1 General . 41
6.2 Lightning equipotential bonding . 41
6.2.1 General . 41
6.2.2 Lightning equipotential bonding for metal installations . 42
6.2.3 Lightning equipotential bonding for external conductive parts . 43
6.2.4 Lightning equipotential bonding for internal systems . 43
IEC 62305-3:2024 © IEC 2024 – 3 –
6.2.5 Lightning equipotential bonding for lines connected to the structure to
be protected . 44
6.3 Separation distance . 45
6.3.1 General approach . 45
6.3.2 Simplified approach . 46
7 Maintenance and inspection of an LPS . 47
7.1 General . 47
7.2 Maintenance . 47
7.3 Objective of inspections . 47
7.4 Need for inspection . 48
8 Protection measures against injury to human beings due to touch and step
voltages . 48
8.1 Protection measures against touch voltages . 48
8.2 Protection measures against step voltages . 49
Annex A (normative) Minimum cross-section of the entering cable screen to avoid
dangerous sparking . 50
Annex B (informative) Evaluation of the separation distance s . 51
Annex C (normative) Additional requirements for LPSs in the case of structures with a
risk of explosion . 56
C.1 General . 56
C.2 Basic requirements . 56
C.2.1 General . 56
C.2.2 Required information . 56
C.2.3 Earthing . 56
C.3 Structures containing solid explosive material . 57
C.4 Structures with hazardous areas . 57
C.4.1 General . 57
C.4.2 Structures with Zones 2 and 22 . 58
C.4.3 Structures with Zones 1 and 21 . 58
C.4.4 Structures with Zones 0 and 20 . 58
C.4.5 Specific applications . 58
C.5 Maintenance and inspection . 59
Annex D (informative) Explanatory text concerning the design, construction,
maintenance and inspection of lightning protection systems . 60
D.1 General . 60
D.2 Structure of Annex D . 60
D.3 Additional information . 60
D.4 Design of lightning protection systems (LPSs) . 60
D.4.1 General remarks . 60
D.4.2 Design of the LPS . 62
D.5 External lightning protection system . 66
D.5.1 General . 66
D.5.2 Air-termination systems . 67
D.5.3 Down-conductor systems . 87
D.5.4 Earth-termination systems . 108
D.5.5 Components . 117
D.5.6 Materials and dimensions . 117
D.6 Internal lightning protection system . 122
D.6.1 General . 122
– 4 – IEC 62305-3:2024 © IEC 2024
D.6.2 Lightning equipotential bonding (EB) . 122
D.6.3 Electrical isolation of the external LPS . 128
D.6.4 Protection against effects of induced currents in internal systems . 132
D.7 Maintenance and inspection of the LPS . 132
D.7.1 General . 132
D.7.2 Inspection . 132
D.7.3 Testing . 134
D.7.4 Maintenance . 135
Bibliography . 136
Figure 1 – Protection angle corresponding to the class of LPS . 22
Figure 2 – Contacting the rolling sphere with the structure to be protected. 23
Figure 3 – Application of the protection angle method . 24
Figure 4 – Loop in a down conductor . 31
Figure 5 – Minimum length l of each earth electrode according to the class of LPS . 34
Figure B.1 – Values of coefficient k in the case of a wire air-termination system . 51
c
Figure B.2 – Values of coefficient k in the case of a multiple down-conductor system . 52
c
Figure B.3 – Values of coefficients k in the case of multiple down conductors with an
c
interconnecting ring of down conductors at each level . 53
Figure B.4 – Values of coefficient k in the case of a meshed air-termination system,
c
with a multiple down-conductor system . 54
Figure D.1 – LPS design flow diagram . 61
Figure D.2 – Space protected by two parallel air-termination horizontal wires or two
air-termination rods (r > d/2) . 69
Figure D.3 – Designing the protection volume of catenary wire . 70
Figure D.4 – Horizontal section of the protected area at a given height . 71
Figure D.5 – Three examples of design of attached LPS air termination according to
the mesh method air-termination design . 73
Figure D.6 – Lateral protected volume constructed from the rolling sphere and the
lateral protection angle methods near the height equal to the radius of the sphere . 74
Figure D.7 – Application of the protection angle method for lateral impact with heights
up to 60 m . 75
Figure D.8 – Air termination and visually concealed conductors for buildings less than
20 m high with sloping roofs. 76
Figure D.9 – Construction of an LPS using natural components on the roof of the
structure . 78
Figure D.10 – Positioning of the external LPS on a structure made of insulating
material (e.g. wood or bricks) with a height up to 60 m with flat roof and with roof
fixtures . 79
Figure D.11 – Connection of natural air-termination rod to air-termination conductor . 81
Figure D.12 – Construction of the bridging between the segments of the metallic
facade plates . 82
Figure D.13 – Air-termination rod used for protection of a metallic roof fixture with
electric power installations which are not bonded to the air-termination system . 83
Figure D.14 – Method of achieving electrical continuity on metallic parapet capping . 84
Figure D.15 – Examples of air termination for a house with an antenna using an
attached LPS . 86
IEC 62305-3:2024 © IEC 2024 – 5 –
Figure D.16 – Installation of external LPS on a structure of insulating material with
different roof levels . 90
Figure D.17 – LPS design for a cantilevered part of a structure . 91
Figure D.18 – Use of a metallic facade covering as a natural down-conductor system
on a structure of steel-reinforced concrete . 93
Figure D.19 – Use of metallic facade as natural down-conductor system and
connection of facade supports . 94
Figure D.20 – Connection of the continuous strip windows to a metal facade covering . 95
Figure D.21 – Measuring the overall electrical resistance of steel reinforcement . 96
Figure D.22 – Equipotential bonding in a structure with a steel reinforcement . 98
Figure D.23 – Typical methods of joining reinforcing rods in concrete (where permitted) . 99
Figure D.24 – Examples of clamps used as joints between reinforcing rods and
conductors . 100
Figure D.25 – Examples of connection points to the reinforcement in a reinforced
concrete wall . 101
Figure D.26 – Internal down conductors in industrial structures . 104
Figure D.27 – Installation of bonding conductors on plate-like prefabricated reinforced
concrete parts by means of bolted or welded conductor links . 106
Figure D.28 – Installation of bonding conductors in reinforced concrete structures and
flexible bonds between two reinforced concrete parts . 107
Figure D.29 – Combined foundation earth electrode . 112
Figure D.30 – Construction of foundation earth ring for structures of different
foundation design . 113
Figure D.31 – Example of a Type A earthing arrangement with a vertical conductor
type electrode . 114
Figure D.32 – Example of a Type A earthing arrangement with a vertical rod type
electrode . 115
Figure D.33 – Meshed earth-termination system of a plant . 118
Figure D.34 – Example of an equipotential bonding arrangement . 124
Figure D.35 – Example of bonding arrangement in a structure with multiple entry points
of external conductive parts using a ring electrode for interconnection of bonding bars . 125
Figure D.36 – Example of bonding in the case of multiple entry points of external
conductive parts and an electric power or communication line, using an internal ring
conductor for interconnection of the bonding bars . 126
Figure D.37 – Example of bonding arrangement in a structure with multiple entry points
of external conductive parts entering the structure above ground level. 127
Figure D.38 – Directions for calculations of the separation distance, s, for a worse case
lightning interception point at a distance, l, from the reference point according to 6.3 . 130
Table 1 – Relation between lightning protection levels (LPL) and class of LPS (see
IEC 62305-1) . 18
Table 2 – Values of rolling sphere radius, mesh size and protection angle
corresponding to the class of LPS . 21
Table 3 – Minimum thickness of metal sheets or metal pipes in air-termination systems . 27
Table 4 – Maximum temperature rises ∆T (K) of inner surface and time duration t (s)
for different thickness t’’ (mm) and long strokes according to LPL I (Q = 200 C) . 28
LONG
Table 5 – Preferred values of the distance between down conductors by LPS according
to the class of LPS . 30
– 6 – IEC 62305-3:2024 © IEC 2024
Table 6 – LPS materials and conditions of use . 37
Table 7 – Material, configuration and minimum cross-sectional area of air-termination
conductors, air-termination rods, earth lead-in conductors and down conductors . 39
Table 8 – Material, configuration and minimum dimensions of earth electrodes . 40
Table 9 – Minimum dimensions of conductors connecting different bonding bars or
connecting bonding bars to the earth-termination system . 42
Table 10 – Minimum dimensions of conductors connecting internal metal installations
to the bonding bar . 42
Table 11 – Separation distance – Values of coefficient k . 45
i
Table 12 – Separation distance – Values of coefficient k . 45
m
Table 13 – Separation distance – Approximated values of coefficient k . 47
c
Table A.1 – Cable length to be considered according to the condition of the screen . 50
Table D.1 – Suggested fixing centres . 75
IEC 62305-3:2024 © IEC 2024 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROTECTION AGAINST LIGHTNING –
Part 3: Physical damage to structures and life hazard
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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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
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shall not be held responsible for identifying any or all such patent rights.
IEC 62305-3 has been prepared by IEC technical committee 81: Lightning protection. It is an
International Standard.
This third edition cancels and replaces the second edition published in 2010. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Minimum thicknesses of metal sheets or metal pipes are given in Table 4 for air-termination
systems where it is necessary to prevent hot-spot problems. Maximum temperature rises
ΔT (K) and time duration t (s) for different thicknesses and long strokes are also given.
b) Cross-reference to the IEC 62561 series is made for the use of reliable, stable, safe and
appropriate LPS components.
– 8 – IEC 62305-3:2024 © IEC 2024
c) The application of two methods – general and simplified – for separation distance calculation
is clarified.
d) Some changes to the requirements for continuity of steel reinforcement are made.
e) Annex C is revised to address comments from IEC subcommittee 31J.
f) Revision of positioning of air-termination conductors are modified according to the three
accepted methods. A more precise description of the methods for positioning of the air-
termination systems is made according to the complexity of structures to be protected. The
main text has been simplified, Annex A has been deleted and all detailed information has
been moved to Annex D.
g) Information on the protection of green roofs is introduced in Annex D.
h) Information on the protection of protruding parts on facades of tall buildings is introduced in
Annex D;
i) a new definition of “electrically insulated LPS” has been introduced to distinguish it from an
LPS both electrically and physically isolated from the structure, with a slight modification of
the other LPS definitions.
The text of this International Standard is based on the following documents:
Draft Report on voting
81/764/FDIS 81/767/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 International Standard 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.
A list of all parts in the IEC 62305 series, published under the general title Protection against
lightning, can be found on the IEC website.
The following differing practices of a less permanent nature exist in the countries indicated
below.
In Austria, Annex C shall not be applied and is replaced by the National standard ÖVE/ÖNORM
EN 62305-3 Beiblatt 1:2013-11-01 Blitzschutz – Teil 3: Schutz von baulichen Anlagen und
Personen – Beiblatt 1: Zusätzliche Informationen für bauliche Anlagen mit
explosionsgefährdeten Bereichen. In Austria, Annex C shall be classified as "Informative".
In Germany, the need for lightning protection is determined by, and the class of required LPS
shall be selected according to, a national annex to the third edition of IEC 62305-1 (including
an option for a risk assessment following the third edition of IEC 62305-2).
In Germany, for a metallic or electrically-continuous connected reinforced concrete framework,
in addition, DIN EN 62305-3 Beiblatt 1 shall be applied.
In Germany, 8.1 condition b) is not applied – see DIN EN 62305-3 Beiblatt 1. Instead, the
alternate measures, as described in DIN EN 62305-3 Beiblatt 1, shall be applied.
In Germany, for 8.2, the alternate measures, as described in DIN EN 62305-3 Beiblatt 1, shall
be applied.
IEC 62305-3:2024 © IEC 2024 – 9 –
In Japan, when using country-specific lightning protection components, the manufacturer and/or
lightning protection designer shall explain that the component will withstand the electromagnetic
effects of lightning currents and possible accidental stresses without damage.
In Italy, a separation distance is not required in structures with metallic or electrically-
continuous connected reinforced concrete framework according to 5.3.5.
In Italy, in reinforced concrete structures, the reinforcement may be used for equipotential
bonding. In this case, if a ring electrode is not yet installed and connected to the reinforcement
steels, a ring conductor welded or bolted to the steel reinforcement will be installed, to which
the bonding bars should be connected via welded conductors.
In the Netherlands, in some situations, special fasteners which are necessary and which are
not available on the commercial market and are not tested according to IEC 62561-4 (because
of a small number of required special fasteners), must comply with the lateral and axial test
mentioned in IEC 62561-4. A written statement of passing these lateral and axial tests must be
issued by the designer and/or the installer of the LPS and must be a part of the commissioning
documents.
In South Africa, the class of required LPS shall be selected on the basis of a risk assessment
of either the second edition of IEC 62305-2 or the third edition of IEC 62305-2 . This note
applies also for D.4.1 and D.4.2.1.
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.
– 10 – IEC 62305-3:2024 © IEC 2024
INTRODUCTION
This part of IEC 62305 deals with the protection, in and around a structure, against physical
damage and injury to human beings due to touch and step voltages.
The main and most effective measure for protection of structures and its content against
physical damage is considered to be a lightning protection system (LPS). It usually consists of
both external and internal lightning protection measures.
An external LPS is intended to
a) intercept a lightning flash to the structure (with an air-termination system),
b) conduct the lightning current safely towards earth (using a down-conductor system),
c) disperse the lightning current into the earth (using an earth-termination system).
NOTE The purpose of the external LPS is to protect the structure from a direct lightning strike by providing the
preferred attachment points, conducting and dispersing the lightning current. It will not significantly influence the
attachment process between the structure and the lightning to increase or reduce the number of direct lightning
strikes (S1) to the structure.
An internal LPS prevents dangerous sparking within the structure using either equipotential
bonding or a separation distance (and hence isolation) between the external LPS (as defined
in 3.2) and other electrically conducting elements internal to the structure.
Main protection measures against injury to human beings due to touch and step voltages are
intended to:
1) reduce dangerous current flowing through bodies by either insulating exposed conductive
parts, or by increasing the surface soil resistivity, or both,
2) reduce the occurrence of dangerous touch and step voltages by either physical restrictions
or warning notices, or both.
The type and location of an LPS should be carefully considered in the initial design of a new
structure, thereby enabling maximum advantage to be taken of the electrically conductive parts
of the structure. By so doing, design and construction of an integrated installation is made
easier, the overall aesthetic aspects can be improved, and the effectiveness of the LPS can be
increased at minimum cost and effort.
Access to the ground and the proper use of foundation steelwork for the purpose of forming an
effective earth termination may well be impossible once construction work on a site has
commenced. Therefore, soil resistivity and the nature of the earth should be considered at the
earliest possible stage of a project. This information is fundamental to the design of an earth-
termination system and can influence the foundation design work for the structure.
Regular consultation between LPS designers and installers, architects and builders is essential
in order to achieve the best result at minimum cost.
If lightning protection is to be added to an existing structure, every effort should be made to
ensure that it conforms to the principles of this document. The design of the type and location
of an LPS should take into account the features of the existing structure.
When safety is involved and significant changes are made to the structure or its use changes,
consideration of updating the lightning protection installation to the present edition of this
document is recommended.
IEC 62305-3:2024 © IEC 2024 – 11 –
National or local laws and regulations can provide guidance or minimum requirements on the
application of this document. This inclu
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