Risk Analysis of Lightning Protection System for Buildings

Abstract

Lightning strike is a very destructive and unavoidable phenomenon that can cause significant damage to the structures and destroys any object which comes in to its radar. Lightning risk assessment includes the study of actual measures that are the real reasons for the risk caused by the lightning strike. It evaluates the hazard and risks of lightning strikes to people, structure and systems. Risk assessment determines the need of lightning protection system and mitigation measures. Risk Assessment for lightning protection system is done by using EN 62305-2 standard by considering IEC standards as a reference. The dimensions of the building are put into the risk assessment software to analyse level of protection. The purpose of this is study is to consider a building and to do a proper risk assessment through software and to propose a lightning protection system for overall protection of the building. Internal protection of the electronic equipment from indirect effects of lightning strikes by using Surge protection devices (SPDs) is also crucial as it helps to protect the electronic devices from damaging effects of indirect lightning strikes.

Introduction

Lightning is a powerful electrical discharge occurring in the atmosphere due to charge separation within storm clouds. Positive charges accumulate at the upper portion of clouds and negative charges at the lower portion. When the insulating capacity of air breaks down due to charge disturbance, a rapid electrical discharge occurs, known as a lightning strike. Lightning can occur either between clouds (cloud-to-cloud) or between cloud and earth (cloud-to-ground). Cloud-to-ground lightning is particularly dangerous as it directly affects human life, buildings, and infrastructure.

Effects of Lightning on Buildings

Lightning strikes can cause significant physical, electrical, and economic damage:

• Electrical Effects: Destruction of electrical networks, surges, and grounding voltage rise.

• Fire Hazards: Ignition of flammable materials such as wood.

• Effects on Living Beings: Electric shocks, cardiac arrest, and respiratory problems due to smoke.

• Power Surge Damage: Explosions and damage to appliances.

• Induction Effects: Induced currents in conductors damaging connected electronic equipment.

• Shock Wave Damage: Thunder-generated shock waves damaging nearby structures (e.g., chimneys).

• Luminous Effects: Temporary visual confusion due to retinal impact.

• Arcing Effects: Poor grounding due to high soil resistance leading to improper current dissipation.

To minimize such risks, Surge Protection Devices (SPDs) are essential components of lightning protection systems. They protect electrical and electronic equipment from high-voltage surges, preventing fire and equipment failure.

Standards for Lightning Protection

Several international standards guide lightning risk assessment and protection system design:

• Spanish Standard (UNE 21-186:1996)

• French Standard (NFC 17102)

• British Standard (BS 6651:1999)

• American Standard (NFPA 780:1997)

• IEC Standard (IEC 62305)

Among these, IEC EN 62305 is widely used for systematic lightning risk assessment and protection design.

Risk Assessment

Risk assessment is conducted to identify hazards, analyze risk levels, evaluate tolerable limits, and determine control measures.

According to IEC EN 62305, lightning risk is categorized into four main types:

• R1: Risk of loss of human life

• R2: Risk of loss of public service

• R3: Risk of loss of cultural heritage

• R4: Risk of economic loss

Each risk is calculated using combinations of components such as injury due to touch voltage (RA), physical damage (RB), system failure (RC, RM), and overvoltage effects (RU, RV, RW, RZ).

Types of Lightning Events and Damages

Lightning can strike in four ways:

• S1: Direct flash to structure

• S2: Flash near structure

• S3: Flash to connected service lines

• S4: Flash near service lines

These may result in:

• D1: Injury to living beings

• D2: Physical damage (fire, explosion)

• D3: Failure of electrical/electronic systems

Losses are categorized as:

• L1: Loss of human life

• L2: Special hazards to life

• L3: Loss of public services or cultural heritage

• L4: Economic loss

Case Study: Concrete Structure Risk Assessment

A concrete building with the following characteristics was evaluated:

• Length: 98 m

• Width: 22 m

• Height: 10 m

• Total Area: 12,183.43 m²

• Concrete structure and covering

• Unscreened internal wiring

• Average fire risk

After entering structural and environmental data into risk assessment software (as per IEC 62305 methodology), the calculated risk values for R1, R2, and R4 exceeded tolerable limits.

Conclusion of Assessment:

A Level 1 Lightning Protection System (LPS) is required to adequately protect the building.

Indirect Lightning Strikes

Indirect lightning strikes, especially those affecting nearby transmission lines, induce overvoltages in wiring systems, leading to:

• Damage to power supplies and circuit boards

• Data loss in IT systems

• Malfunction of industrial control systems

• Communication system failures

These effects highlight the importance of surge protection devices and proper grounding systems.

Conclusion

The study demonstrates that a properly executed risk assessment is essential in determining whether a Lightning Protection System (LPS) is required and in defining the appropriate protection level. The proposed external lightning protection measures such as air termination systems, down conductors, and earthing arrangements help mitigate the direct effects of lightning strikes on the structure. Equally important is the implementation of internal protection measures through the installation of Surge Protection Devices (SPDs), which significantly reduce the impact of transient over voltages caused by indirect lightning effects.

References

[1] Rama Mohan, P., Neeli Mallikarjuna, A., & Niteesh Kumar, K. (2020). A Novel Over Voltage and Under Voltage Protecting System for Industrial and Domestic Applications. International Journal of Innovative Science and Research Technology, 5(10) [2] Ametani, A. (2009). Design Calculations of Lightning Protection Systems – Part Twenty. IEEE .. [3] Schwarz. (2012). Surge Protective Devices (SPDs) and Short Circuit Currents M. Wegmuller, J. P. von der Weid, P. Oberson, and N. Gisin, “High resolution fiber distributed measurements with coherent OFDR,” in Proc. ECOC’00, 2000, paper 11.3.4, p. 109. [4] IEC 62305-2, Protection against lightning –Part 2: Risk management”, 2010 [5] T. Thanasaksiri, “Improving the Lightning Performance of Overhead Distribution Lines”TENCON 2004 IEEE [6] IEC 62305-4- Protection against lightning –Part 4: Electrical and electronic systems within structures”, 2010. [7] Zipse, D. W. (2008). Lightning Protection Systems: Advantages and Disadvantages. IEEE

Copyright

Copyright © 2026 Mohsin Amin, Muhammed Attique. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.