Kapitel 3 | Das innere Blitzschutzsystem
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KapazitivKapazitive Einkopplung erfolgt, wenn zwischen zwei Punkten mit hohem Potenzialunterschied eine Span-nung anliegt. Der Ladungstransport ber das Medi-um, welches sich zwischen den Punkten befindet, versucht die Potenziale auszugleichen und erzeugt dadurch eine berspannung. (Bild 3.39)
3.3.1.3 Gebude- und Raumschirmung Kritische Infrastrukturen, wie Rechenzentren, Kraft-werke, chemische Analge oder Systeme der Energie- und Wasserversorgung knnen gegen die Auswir-kungen von elektromagnetischen Wellen durch geschirmte Rume geschtzt werden.
Zur Abschirmungen mssen alle Wnde, die Decke und der Boden mit leitfhigen Materialien (z. B.: Stahl-bleche oder Kupferfolien) ausgeschlagen werden. Tren und Fenster mssen durch Federkontakte mit der Schirmung der Wnde verbunden werden. Zu-stzlich sind alle Kabeldurchfhrungen geschirmt auszufhren.
Bild 3.39 Kapazitive Einkopplung bei Direkteinschlag
uere BlitzschutzanlageErdungssystem
Haupterdungsschiene
bertrager
Kapazitive Einkopplung
Datenleitung
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Lightning protection guideTo assist in the planning and design of lightning andsurge protection systems
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From our archives: a cartoon from 1958. The caption reads: Lightning protection provides safety.
Foreword
OBO Bettermann is one of the worlds most experi-enced manufacturers of lightning and surge protec-tion systems. For almost 100 years, OBO has been developing and producing standard-compliant light-ning protection components. The rise of the modern computer began in the 1970s, with the invention of the electronic typewriter. OBO responded by launch-ing its groundbreaking V-15 surge arrester. Count-less new products over the years, such as the first connectable type 2 surge protection device with VDE test mark, or the first connectable type 1 light-ning current arrester with carbon technology, laid the foundation for the uniquely comprehensive product range that we offer today.
OBO was the first manufacturer to publish a guide to lightning protection way back in the 1950s. This original guide focused on external lightning protec-tion and earthing systems. Since then, further infor-mation has been steadily added to the planner sec-tions of the guide to include information on surge protection for everything from energy to data sys-tems. The motto in the picture BLITZSCHUTZ GIBT SICHERHEIT (LIGHTNING PROTECTION PRO-VIDES SAFETY) is as relevant today as it ever was, with external lightning protection still providing valu-able passive fire protection in the event of a direct lightning strike.
Just like its predecessors, this edition of the lightning protection guide offers assistance in installing pro-fessional lightning protection systems in line with the very latest standards.
OBOs research and development activities received a boost in 1996 with the opening of a new BET re-search centre, home to one of the largest lightning surge current generators in Europe and numerous testing units. Today, lightning and surge protection components, lightning protection structures and surge protection devices are put through their paces there by highly qualified specialists in accordance with the relevant standards.
OBO supports and drives the development of nation-al and international lightning protection standards of the series IEC 62305 (VDE 0185-305).
Through its membership of the VDB (Association of German Lightning Protection Companies) and the VDE Committee for Lightning Protection and Re-search, OBO is always up to date with the latest in-sights from the worlds of science and lightning pro-tection practice.
Establishing partnerships with customers is a top pri-ority for OBO, and OBO staff are available to support customers in all aspects of their projects, including products, installation and planning advice. Through its policy of continuous improvement, OBO creates fertile conditions for the development of new prod-ucts and documents. This guide aims to provide practical assistance. We are always more than glad to incorporate suggested improvements.
We would like to wish all readers and lightning pro-tection specialists the greatest possible satisfaction as they go about their important task of keepingpeople, buildings and equipment safe from lightning currents and electrical surges.
Andreas Bettermann
OBO Bettermann GmbH & Co.KGwww.obo.de
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Contents
Chapter 1 General introduction 9
Chapter 2 The external lightning protection system 37
Chapter 3 The internal lightning protection system 121
Chapter 4 Testing, maintenance and documentation 209
Chapter 5 Brief glossary of surge protection 217
The Protected to the power of four principle: only if protection is coordinatedis it effective. Discover what our different systems do.
Surge protection systems
Surge protection systems form a multi-stage barrierwhich no surge voltage can break through.
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Air-termination and down-conductor systems
Interception systems reliably intercept direct lightning strikes carrying up to 200,000 A of energy and conduct them down into an earthing system through the arrester system.
Earthing systems
When the derived lightning current reaches the earthing system, around 50% of the energy is discharged into the earth while the other half is distrib-uted via the equipotential bonding.
Equipotential bonding systems
These form the interface between external andinternal lightning protection. They ensure that dangerouspotential differences do not come about in the building.
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Chapter 1 | General introduction
Every year, lightning strikes and surge voltages put at risk or cause harm to people, animals and property. Damage to property is becoming an ever greater problem as the failure of electronic devices can cause financial loss in industry and inconve-nience for individuals. Building regulations mean that it is a legal requirement today that buildings incorpo-rate personal safety elements. The work of public agencies, such as the police, ambulance and fire services, is also particularly worthy of protection.
Whether a lightning protection system is needed in a given situation can be determined on the basis of the latest standards. Alternatively, the cost of damage to equipment can be compared with the cost of fitting a protection system that would prevent that damage from occurring. The latest standards also explain in technical terms how protective measures should be executed. Certain specialised components are re-quired for installing a lightning protection system.
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Chapter 1: General introduction
1. General introduction 91.1 Lightning 101.1.1 How lightning is formed 111.1.1.1 Types of thunderstorm 111.1.1.2 Charge separation 111.1.1.3 Charge dispersion 121.2 Risks posed by lightning discharges 131.2.1 Risk to humans 131.2.2 Risk to buildings and equipment 141.2.2.1 Transient surges 151.2.2.2 Lightning surges 151.2.2.3 Effects of surges 151.3 Sources and causes of damage according to standards 151.4 Test currents and simulated surge voltages 211.5 Legal regulations defining what lightning protection is required 221.5.1 Lightning and surge protection standards 231.5.2 Hierarchy of standards: international/European/national 251.5.3 Latest German national lightning protection standards 251.5.4 Responsibility of the erection engineer 261.5.5 Responsibility of the operator 261.6 Financial implications of lightning and surge voltage damage 271.7 Lightning protection risk analysis and categorisation by lightning protection class 281.7.1 Frequency of lightning strikes by region 301.7.2 Equivalent interception area 301.7.3 Estimation of the damage risk 311.7.4 Empirical lightning protection classification of buildings 321.7.5 Cost-effectiveness calculation for lightning protection systems 321.7.5.1 Costs without lightning protection system 321.7.5.2 Costs with lightning protection system 32
1.7.5.3 Comparing the costs of lightning damage in buildings with and without a lightning protection system
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1.8 Laboratory testing of lightning and surge protection components 341.9 Components of a lightning and surge protection system 35
Chapter 1 | General introduction
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The protection of oneself from lightning strikes on a building
is most reliably achieved through the installation of a lightning down- conductor, which carries the elec-trical matter from the thundercloud safely down into the earth without allowing it to touch even a single
beam of the house.
Joseph Kraus Catechism of Lightning, 1814
Chapter 1 | General introduction
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1. General introduction
Lightning is a naturally occurring spark discharge or short-lived electric arc. Lightning discharges can take place from one cloud to another, or between a cloud and the ground. Lightning one of the electromete-ors generally occurs during thunderstorms, where it is accompanied by thunder. Lightning involves an exchange of electric charges (electrons or gas ions), in other words the flow of electric currents. Depend-ing on the polarity of the electrostatic charge, light-ning can alternatively start from the ground.
90% of all lightning discharges between a cloud and the ground are negative, i.e. negative cloud-to-ground strikes. Here, the lightning begins in an area of negative charge in the cloud and spreads to the positively charged ground.
However, the vast majority of discharges take place within clouds, or from one cl
