Lightning Protection FAQ

Below are some of the most common questions and answers regarding lightning strikes and lightning protection.

Very simply, the lightning rod, which Benjamin Franklin invented in 1749, is a metal rod mounted on top of a structure connected to a cable that leads into the ground. Lightning rods may not be much bigger than a pencil—at 12 inches tall and 3/8 inch in diameter. They are rarely noticeable when installed as a seamless blend with new or existing structures. Many famous buildings—the White House, Sears Tower, Washington Monument, and Empire State Building—routinely rely on lightning rods for protection.

Originally created centuries ago, the lightning rod has been updated and integrated into a modern system of lightning protection that safely diverts the dangerous and damaging electrical charge from lightning away from homes, businesses, and public buildings. More lightning protection systems are installed now than ever before. Even though they are inconspicuous, they have become an important architectural asset. Twenty-first century lightning rods protect structures and help preserve the important equipment and devices that are essential to our modern lifestyles.

A lightning rod intercepts the electrical charge that occurs just before a lighting strike. It directs the dangerous charge safely through an attached
cable to the ground. The National Fire Protection Association (NFPA) has maintained a strict standard for the installation of lightning rods for more than 100 years.

No. Ben Franklin’s neighbors may have started this rumor. Lightning rods provide the path of least resistance for a bolt of lightning that, based on atmospheric conditions, could be traveling at approximately 3,700 miles per second or 224,000 miles per hour.

Nothing can prevent a lightning strike. A lightning rod will not increase or decrease the chance of lightning striking your house—but a professionally installed lightning protection system will provide a route for the electricity to navigate to the ground safely without damaging wiring, destroying electrical equipment, or starting a fire.

Lightning protection systems are designed to protect structures from damage by redirecting lightning strikes. They redirect the lightning and force it to travel safely from the top of a structure to the ground. Commercial and residential protection systems can include lightning rods, down conductors, cables, and electrodes buried in the ground. According to the Underwriters Laboratories—a worldwide safety consulting and certification company—a properly installed system can safeguard any type of structure.

The US alone receives more than 40 million lightning strikes every year. Any square mile can expect 40 lightning strikes yearly. Lightning always travels the shortest path it can find—tall buildings, trees, steeply pitched roofs, and structures mounted on top of houses are most often the point of contact for a
lighting bolt. Since these features are everywhere in our environment, we all need to understand the potential danger of lightning.

The light you see in the sky from a flash of lightning travels at 186,000 miles per second (~670 million miles per hour). But lightning itself travels nowhere near as fast as the speed of light. Although it moves at different speeds during different stages of its journey, lightning moves at approximately 3,700 miles per second (~13.3 million miles per hour).

Thunder travels at the speed of sound, which is relatively much slower at ~760 miles per hour. So you can quickly figure how far you are from the lightning flash by timing the pause between seeing the flash and hearing the thunder. When you see the flash, begin counting the seconds. Every five seconds equals ~1 mile in distance. So if you count 10 seconds between seeing the flash and hearing the thunder, you are about 2 miles away from the strike.

Five percent of all commercial insurance claims are lightning related. Lightning can strike anywhere. Every structure has an internal network of viable pathways for lightning to travel as it flashes its way from the sky to the ground. Gas and water pipes, electric lines, phone lines, cable TV/internet lines, gutters, downspouts, and metal window frames all are willing and able conductors for the lightning express. The NFPA “780 Risk Assessment Guide” is a useful tool in evaluating the vulnerability of a structure.

You probably know the Ben Franklin proverb: An ounce of prevention is worth a pound of cure. But you may not have known that it was originally a reference to fire safety. That idea continues to be true today. The cost of a lightning protection system can vary depending on the size and construction of the building or house. Generally a lightning protection system costs less than you might think. It is a fairly modest investment for a lifetime of protection and can add architectural interest to your structure and value to your property.

There are different guidelines across the nation. For instance, the state of Florida requires that all schools and healthcare agencies—including outpatient and extended care facilities—have lightning protection systems.

Utility companies and our national power grid are sometimes over-burdened by the demands of our high-tech, electronic-device driven needs—especially in the summer months when air conditioning and refrigeration usage increases. This can cause a surge in power and a disruption in the supply of electricity. In much the same way, a lightning strike can cause a catastrophic surge. Ironically, power strips are powerless to prevent damage to electrical equipment. Professionally installed lightning-surge protection systems that include quality surge suppressors stand out as a difference-maker. A lighting rod can save you thousands of dollars in replacement costs. In fact, lightning rods could save your home and business.

You may want to ask yourself, “How much am I willing to lose.” In addition to the people and pets you may work and live with, your home and business contains all kinds of sensitive devices and costly equipment. We live in a plugged-in world. From TVs to computers, from sound systems to air-conditioning, from appliances to sump pumps — you and those around you depend on electricity. Just one lightning event could create a power surge strong enough to turn your world upside down. The cost of recovery will be valued many times higher than the price of a lightning rod protection system.

Designers and architects working in new construction and remodeling should be familiar with the importance and value in lightning protection systems. They will often include this feature in the design of new construction for your home or business. However, always rely on qualified lightning protection contractors to perform this work.
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