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Preface � � � � � � � � � � � � � � � � � � � � � � � 6 3.3.2.1 Nodal analysis . . . . . . . . . . . . . . . . . . 52
1 State of the art for the installation of 3.3.2.2 Information on the DEHN Distance Tool . . . . . 54
lightning protection systems � � � � � � 8 3.3.3 DEHN Earthing Tool; calculation of the length
1.1 Installation standards . . . . . . . . . . . . . . . 9 of earth electrodes according to IEC 62305-3
(EN 62305-3). . . . . . . . . . . . . . . . . . . 54
1.2 Work contracts. . . . . . . . . . . . . . . . . . 11
3.3.4 DEHN Air-Termination Tool; calculation of the
1.3 Product standards . . . . . . . . . . . . . . . . 11 length of air-termination rods according to
2 Characteristics of lightning current � � �14 IEC 62305-3 (EN 62305-3) . . . . . . . . . . . . 55
2.1 Lightning discharge and lightning current curves 15 3.4 Inspection and maintenance . . . . . . . . . . . 55
2.2 Peak value of the lightning current . . . . . . . 17 3.4.1 Types of inspection and qualification of
inspectors . . . . . . . . . . . . . . . . . . . . 55
2.3 Steepness of the lightning current rise. . . . . . 20
3.4.2 Inspection measures . . . . . . . . . . . . . . . 56
2.4 Charge of the lightning current . . . . . . . . . 20
3.4.3 Documentation. . . . . . . . . . . . . . . . . . 57
2.5 Specific energy . . . . . . . . . . . . . . . . . . 21
3.3.4 Maintenance . . . . . . . . . . . . . . . . . . . 58
2.6 Lightning current components . . . . . . . . . . 23
2.7 Assignment of lightning current parameters to 4 Lightning protection system � � � � � �60
lightning protection levels . . . . . . . . . . . . 23
5 External lightning protection � � � � � �62
2.8 Lightning current measurements for upward 5.1 Air-termination systems . . . . . . . . . . . . . 63
and downward flashes. . . . . . . . . . . . . . 24
5.1.1 Types of air-termination systems and design
3 Designing a lightning protection methods . . . . . . . . . . . . . . . . . . . . . 63
system � � � � � � � � � � � � � � � � � �26 5.1.2 Air-termination systems for buildings with gable
3.1 Necessity of a lightning protection system – roofs . . . . . . . . . . . . . . . . . . . . . . . 73
Legal regulations. . . . . . . . . . . . . . . . . 27 5.1.3 Air-termination systems for buildings with flat
3.2 Explanatory notes on the IEC 62305-2 roofs . . . . . . . . . . . . . . . . . . . . . . . 75
(EN 62305-2) standard: Risk management. . . . 31 5.1.4 Air-termination systems on metal roofs . . . . . 76
3.2.1 Sources of damage, types of damage and types 5.1.5 Air-termination system for buildings with
of loss . . . . . . . . . . . . . . . . . . . . . . 31 thatched roof. . . . . . . . . . . . . . . . . . . 78
3.2.2 Fundamentals of risk analysis . . . . . . . . . . 32 5.1.6 Accessible roofs . . . . . . . . . . . . . . . . . 82
3.2.3 Frequency of dangerous events . . . . . . . . . 34 5.1.7 Air-termination system for green and flat roofs . 82
3.2.4 Probabilities of damage . . . . . . . . . . . . . 36 5.1.8 Isolated air-termination systems . . . . . . . . . 83
3.2.5 Loss . . . . . . . . . . . . . . . . . . . . . . . 40 5.1.9 Air-termination system for steeples and churches 87
3.2.6 Relevant risk components for different types of 5.1.10 Air-termination systems for wind turbines . . . 88
lightning strikes . . . . . . . . . . . . . . . . . 45
5.1.11 Air-termination rods subjected to wind loads . . 89
3.2.7 Tolerable risk of lightning damage. . . . . . . . 45
5.1.12 Safety systems and lightning protection . . . . . 93
3.2.8 Selection of lightning protection 5.2 Down conductors . . . . . . . . . . . . . . . . 95
measures. . . . . . . . . . . . . . . . . . . . . 45
5.2.1 Determination of the number of down con-
3.2.9 Loss of economic value / Profitability of pro- ductors. . . . . . . . . . . . . . . . . . . . . . 95
tection measures. . . . . . . . . . . . . . . . . 46
5.2.2 Down conductors for a non-isolated lightning
3.2.10 Calculation assistances . . . . . . . . . . . . . 49
protection system . . . . . . . . . . . . . . . . 96
3.3 DEHNsupport Toolbox design assistance. . . . . 49
5.2.2.1 Installation of down conductors . . . . . . . . . 96
3.3.1 DEHN Risk Tool; risk analysis according to 5.2.2.2 Natural components of a down conductor . . . 97
IEC 62305-2 (EN 62305-2) . . . . . . . . . . . . 49
5.2.2.3 Test joints . . . . . . . . . . . . . . . . . . . . 99
3.3.2 DEHN Distance Tool; calculation of the
separation distance according to IEC 62305-3 5.2.2.4 Internal down conductors . . . . . . . . . . . . 99
(EN 62305-3). . . . . . . . . . . . . . . . . . . 52 5.2.2.5 Courtyards . . . . . . . . . . . . . . . . . . . 100

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