Assess, Measure, Mitigate Your Lightning Risk

By Kelley Collins, Director of Business Development and Communications, Lightning Protection Institute

Our lives are filled with risk assessment and mitigation. From grabbing an umbrella for a rainy day to stocking up on supplies for an impending natural disaster, we assess and measure the potential risks before an event occurs to be prepared and protect ourselves from unwanted consequences.

For many, however, assessing and mitigating lighting risk isn’t necessarily top of mind. We know lightning is going to strike – more than 31 million cloud-to-ground strikes occur annually. But being personally affected seems so unlikely that people may think preparation isn’t necessary or even possible. Understanding how to mitigate risks associated with lightning is essential to individuals and property owners.

Lightning strikes about 100 times every second. Incorporate assessment of lightning risk into our daily lives.

Impact of Lightning: Homes, Businesses, Critical Facilities

About 6,000 times a minute, there is a lightning strike that contains an electrical discharge hotter than the sun. One strike can cause immense damage that goes beyond fire. The damage to the electrical infrastructure and the electronics connected to that infrastructure can be destroyed – bringing communication, security and productivity to a halt. 

Convective storms – which are associated with thunder, lightning, and other weather changes – caused $38 billion in insured losses in the first half of 2023. 

“Assessing your risk to lightning before a storm enables homeowners and business owners to predict and mitigate their risks to losses due to a lightning strike,” said Triple-I CEO Sean Kevelighan. 

If any of the following structures are hit by lightning, there are consequences beyond the repairs from a fire. When there are surges and/or damages to the electrical system, here are just a few consequences that impact time, money, and – in the worst cases – can cost lives:

Homes: Costly repairs and equipment replacement (TVs, washer/dryer, computers);  

Businesses: Emails and communication stopped, production downtime and loss of revenue; and

Critical Facilities: Inability to meet the emergencies of individuals or the community. 

Lightning protection systems are scientifically proven to mitigate these risks. When properly installed, a lightning protection system makes a building resilient to the damage of lightning strike. These systems protect the structure, the electrical system, and the humans within the building.

Lightning risk assessment

From homeowners to design/build experts, learning how to measure and mitigate the risks of lightning is vital to the prevention of lightning damage. For personal safety, assess the current and future weather conditions; if you see lightning, get indoors. For protecting homes, buildings, and structures, there are a few ways to conduct an assessment to determine the risks of lightning. If the assessment determines that there are perceived risks of lightning, lightning protection systems can be installed to mitigate those risks.

Key assessment factors

The NFPA 780 standard for lightning protection is one option that offers a simple and complex approach to assessments. At the advanced level, an assessment involves a complex equation with several variables (ie., Nd= Ngx Aex C1 x10-6). At the very least, consider the key assessment factors within three general areas of a structure: 

External criteriaStructure, design, and useInternal activity

External Criteria

When you first walk up to a building or structure, scan the surroundings and conduct a visual inspection. This involves identifying potential lightning strike paths, such as tall trees, antennas, or nearby structures. Evaluate the building’s height and design. Now, assess how that structure compares to other buildings or objects near it. 

Is it the tallest building? Is it situated on a hill or by itself?

If you are designing a new building, assess how that building will be incorporated into these surroundings to ensure proper consideration for making that building more sustainable to a lightning strike.

What is the propensity for lightning strikes in that city, county, or state? Different regions have varying levels of lightning activity, and this information is crucial in determining the necessary level of protection. Lightning frequency data can be obtained from local weather services or scientific experts, such as Vaisala, who collect data on lightning activity. 

Structure Design and Use

Evaluate the materials and use of the building.

What are the building materials: Glass, wood, brick, etc.? Does the design impact the propensity for a lightning strike: Taller points or roof attachments?What is the use of the building: Does it contain hazardous or flammable objects?Does it store valuable and/or historical objects?Does it perform critical services?

Internal Activity

Identify people and activity on the inside of the structure. 

Are there many people inside this structure? What’s the likely panic level if a building evacuation is necessary? Can the people move quickly? For instance: In a nursing home or hospital, all occupants cannot quickly exit a building that was hit by lightning. In a large high-rise with large groups of occupants, a speedy exit may not be possible.

What is the building’s function? Identify the services that are being conducted in that building. If lightning hits the structure you are assessing, what happens to the people and services inside? Here are some key structures to protect in high-risk areas:

Data centersDistribution centersSchools and churchesPublic works facilitiesCritical facilities, such as fire, police, hospitals, emergency operation centers

Assessment leads to mitigation and protection. Having a general understanding of a lightning risk assessment enables all of us to make better choices. Individuals and homeowners can protect themselves and their homes. Design/build experts and facility managers can make choices to ensure their buildings are more resilient, sustainable, and safer with lightning protection systems.

Proper steps for a formal assessment and installation

If your general assessment leads you to question the structure’s vulnerability, the NFPA 780 guidelines specify that the formal assessment process should be carried out by qualified professionals who are knowledgeable about lightning protection systems. These professionals may include lightning protection system designers, engineers, or certified installers who have undergone specific training and have a comprehensive understanding of the guidelines. 

By following the lightning assessment process outlined by NFPA 780, property owners can ensure that their lightning protection systems are properly designed, installed, and maintained. Proper installation protects structures from the devastating effects of lightning strikes and promotes the safety of individuals inside.