Lightning strikes on buildings and why they are increasing

Lightning strikes pose a significant threat to buildings and the people inside them. They strike the Earth an estimated 44 times per second, translating to a staggering 1.4 billion strikes annually. While the exact number of lightning strikes on buildings is difficult to pinpoint, statistics reveal an ever-present risk, writes John Ridgeway.

In the United States alone, the National Fire Protection Association (NFPA) reports that lightning strikes cause an average of 12,000 structure fires per year, resulting in hundreds of millions of dollars in property damage. Europe experiences a similar story. A 2020 report by the European Commission's Joint Research Centre (JRC) estimated that lightning strikes cause over €1 billion in insured losses annually across the continent.

While data from Asia and Australia is less readily available, lightning strikes pose a considerable threat in these regions as well. Densely populated areas in these continents are particularly vulnerable due to a combination of factors, such as high-rise buildings, which act as lightning rods and the proliferation of power lines, communication towers and other conductive materials, which creates more pathways for lightning to enter buildings.

Because the risks are so high, building professionals across various disciplines are playing a crucial role in mitigating lightning strikes on buildings. During the design phase, architects and engineers are working more closely with lightning protection specialists to assess the risks. Factors like location, height and surrounding structures are considered and based on such risk assessments, architects and engineers will then collaborate with lightning protection specialists to design appropriate Lightning Protection System (LPS).

They also ensure that the chosen LPS complies with relevant building codes and lightning protection standards, such as the National Electrical Code (NEC) in North America or the European Lightning Protection Standard (EN 62305) in Europe.

Lightning protection specialists

These specialists are experts in the design and installation of LPS. They possess the knowledge and experience to select the appropriate components and ensure proper installation according to industry standards.

By working with architects, engineers and building owners, they have been able to develop a comprehensive risk management plan that considers not just lightning protection but also surge protection for sensitive electronic equipment.

They also work with building inspectors to ensure that newly constructed buildings comply with lightning protection codes and standards. This involves reviewing design plans and conducting inspections during construction.

Furthermore, contractors and electricians with expertise in lightning protection systems have been and continue to be crucial for the proper installation of LPS components, ensuring that safe work practices are followed during installation to protect workers and the building.

Lightning innovations

As well as assessing the risks, building professionals are increasingly exploring innovative solutions for lightning protection. We are increasingly seeing early streaming emission (ESE) air terminals. These air terminals, often resembling rods or wires mounted on the highest points of a structure, intercept lightning strikes before they reach the building itself.

Software tools are also helping building professionals assess lightning risk factors to determine the most appropriate LPS for a particular structure. In addition, Building Information Modelling (BIM), is allowing for the integration of lightning protection systems into the overall building model, enhancing design collaboration and identifying potential issues early in the process.

A global approach

Across the globe, various strategies are now employed to safeguard buildings from lightning. As already mentioned, strict regulations, such as the European Lightning Protection Standard (EN 62305), outline the design, installation, and maintenance of lightning protection systems (LPS) for structures. These systems typically include air terminals, conductors and earthing to safely channel lightning strikes away from the building.

Many Asian countries, like China and Japan, now place a strong emphasis on proper grounding techniques. This ensures a safe path for the lightning current to dissipate into the earth. Lightning detection and early warning systems are also gaining traction in some Asian regions. These systems alert authorities and building occupants of imminent lightning activity, allowing them to take precautions.

The National Electrical Code (NEC) in the United States provides guidelines for lightning protection systems. These guidelines are widely adopted by building codes across North America. In addition to LPS, surge protection devices (SPDs) are often used to safeguard electrical equipment from damaging voltage spikes caused by nearby lightning strikes.

Standards Australia (SA) sets the national standards for lightning protection systems in the country. These standards are similar to those used in Europe. However, due to the high risk of bushfires triggered by lightning strikes, Australia also places an emphasis on lightning protection systems in areas prone to wildfires.

Despite regional variations, some common threads run through lightning protection strategies worldwide. These include air terminals, as already discussed and conductors, typically made of copper or aluminium cable, which carry the lightning current safely down the exterior of the building.

Modern earthing systems are also ensuring that the lightning current is safely discharged into the ground alongside surge protection devices (SPDs), which protect sensitive electronic equipment from voltage spikes caused by nearby lightning strikes.

The future of lightning protection

And there is more to come as researchers continuously strive to improve lightning protection technologies. As well as ESE air terminals, we are also seeing nanocomposite lightning protection materials, which offer improved conductivity and may be lighter and more aesthetically pleasing than traditional lightning protection systems. Furthermore, advancements in weather monitoring could lead to real-time lightning tracking and prediction systems, allowing for targeted warnings and preventative measures.

Lightning, a force which is both awe-inspiring and destructive, demands respect. By understanding its risks and implementing appropriate safety measures, we can safeguard our buildings and ourselves. From robust lightning protection systems to individual preparedness, a multi-pronged approach is key. As research continues to develop innovative solutions, the future promises a more resilient built environment, allowing us to coexist safely with this powerful phenomenon.