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Knowledge Share: Why is lightning protection considered during a building fire risk assessment?

Jul 17, 2023

Lightning protection is important for buildings because it helps to prevent or lessen lightning strike damage to buildings. It protects the internal electrical components of a building, helping to prevent fires or electrocution. A lightning protection system intercepts, conducts and disperses a lightning strike safely to earth. Without such a system, a building’s structure, electronic systems, and the people working around or within it are all at risk.

When we carry out fire risk assessments for buildings, whether a school, public house, warehouse, care home or commercial property, we always consider the risk of lightning and the measures that are in place to provide protection. Often customers find this to be a bit strange so we thought it would be helpful to share some knowledge about lightning risk to property and therefore to life safety.

What is lightning protection system?

Lightning protection is a system that’s put in place to protect a structure or a building from lightning damage, and to protect either persons or livestock inside or around the building. Lightning strikes can result in large impulse currents of up to 200kA. The function of a lightning protection system is to protect structures from fire or mechanical destruction and persons in the buildings from injury or even death. A lightning protection system requires a connection to earth, a metal rod, and surge protection devices. It should be inspected regularly and after major weather events or modifications. A lightning protection system consists of the following five parts: air terminals (lightning rods), conductors, ground connections (electrodes), bonding, and lightning arrestors. Air terminals are metal rods that serve as the first exposure point for lightning strike. These are set up on the top of a structure. Conductors are metal cables that connect the air terminals to the ground electrodes. Ground electrodes are metal rods that are driven into the ground and connected to the conductors. Bonding is the process of connecting all metal components of a structure together so that they have the same electrical potential. Lightning arrestors are devices that protect electrical equipment from power surges caused by lightning strikes.

Do I need lightning protection?

This is a complicated question and is not always as simple as definitely ‘yes’ or ‘no.’ It depends on the structure of your building, its height and the area you live in. If you live in an area that experiences frequent thunderstorms, it’s recommended to have a lightning protection system installed. It’s best to consult with a professional lightning specialist to determine if your building needs a lightning protection system. When we carry out fire risk assessments, we check to find out if you already have lightning protection in place and if you do, we check to ensure it is serviced annually. If lightning protection is not in place, we always advise that a risk assessment should be completed, in accordance with BS EN 62305-2, to determine if there is adequate lightning protection for the building.

Is there a big risk from lightning in the UK?

Yes, there is a big risk from lightning in the UK. On average, three people are killed each year by lightning in UK, according to the Royal Society for the Prevention of Accidents. What is even more interesting is the ROSPA report that 30-60 people are struck by lightning each year. Lightning risk is often greater in the summer where the weather can bring storms that produce lightning.

Lightning can, and often does, cause extensive damage to buildings. The damage can include fracturing concrete, brick, cinderblock and stone; severely damaging brick and stone chimneys; blowing out plaster walls, shattering glass, creating trenches in soil and cracking foundations; causing shrapnel to embed in walls; breaking glass and destroying plaster walls; igniting fires and sparking explosions that can devastate a structure. There is a risk of it leading to causing chunks of concrete to fall or become airborne missiles that can injure people and damage lower portions of a structure. Furthermore, it damages electrical wiring and devices and can lead to related fires. As a result, it is very clear that lightning is a big risk to buildings and to people.

What do I need to do for lightning safety?

It is good idea to start by determining your existing lightning protection. Have you got any or not? If you aren’t sure, check your fire risk assessment which should comment about this. If you haven’t got a fire risk assessment, completed in the last 12 months, please get in touch to book an appointment. If you find out that you have a system in place, ensure it has been serviced in the last 12 months. If it hasn’t been maintained, please arrange for a competent specialist to service your installation. If you haven’t got lightning protection, arrange for a specialist to carry out a lightning protection risk assessment. Then, follow their recommendations.

JCH Safety are specialist health and safety consultants and third-party accredited fire risk assessors. We work with a wide variety of clients ranging from schools to offices, from care homes, hotels, churches, and pubs. We provide our services across Coventry, Warwickshire, Leicestershire, and the West Midlands. Please get in touch to find out more.

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