Lightening Protection

Lightning In FieldI’ve had two experiences with lightning and they were as close as I ever want to get to one of Nature’s furies.  The first happened on a hot, humid Ohio summer afternoon.  I was in the house and looked out a window to see the brilliant blue sky of a few minutes ago being rapidly replaced by clouds that were a sickening grayish-greenish mass of something-horrible-about-to-happen.  All eight of my horses were out in our back pasture, grazing peacefully, completely oblivious to the approaching storm.

As the clouds advanced, I ran to the pasture gate and bellowed our standard “calling the group in” cry of “Blackie, Dinner.”  This usually brought an instant response since the herd leader, Dakoto Blackie, thought every meal was a gift from the gods.  If Blackie headed for the barn, so did everyone else.  But, of course, that didn’t happen this time when there was an actual emergency about to occur.  I could see Blackie, head down, munching away.  The back pasture was a quarter-mile down a lane and I headed that way, still calling out, “Blackie, Dinner” and getting no response.  My herd looked like a diorama of Breyer horses against the most ominious sky I ever saw in my life.  Lightning began to flash.  I reached the back pasture gate and yelled again.  This time Blackie heard me, snorted in pure joy at the word, “dinner,” and took off for the barn, leaving me to huff and puff my way back up the lane to the barn (I hadn’t quit smoking at the time—a horse with terminal pneumonia would have been in better shape than I was).

My horses were trained to leave and enter the barn via a runway, so when I staggered back to the barn/pasture gate, it took only a couple of minutes to get everyone inside.  No sooner had Amigo (low man on the totem pole) got his butt inside the barn door, then lightning struck our water trough, not six feet from where the horses had congregated while waiting for me.  The ground shook, my skin tingled, and when the thunder caught up to the flash, I thought I’d blown my eardrums.  Now, when a dark sky gets that greenish tinge, I shudder to think what might have happened if I’d been even a minute slower.

The second instance was one of those “messages from on high.”  It occurred just after the rain had ceased following a summer thunderstorm.  This time the horses were inside and I was cleaning stalls.  As soon as the last raindrop fell I pushed my heaped-high, steel-tray contractors wheelbarrow out to the manure pile.  I was almost there when a lightning bolt hit close enough to yank the wheelbarrow out of my hands, toss it about ten feet off the ground where it flipped and spilled all its contents right on top of me.  I barely escaped being hit by the wheelbarrow itself.  After I got done trembling, I realized how lucky I was to only need a shower, not an emergency room.  The message: just because the rain has stopped doesn’t mean the storm activity has also ended.  Wait about 30 minutes to make sure a storm is truly over.

I want to take a short break here so you can read David H. Levy’s article, “When the Big Clouds Gather” that first appeared in the May 18, 2003 issue of PARADE Magazine.  This article provides an excellent overview of what lightning is all about and what you can do to protect yourself.  As you read his article, picture your animals in pasture. Would you be able to get them quickly to shelter?

WHEN THE BIG CLOUDS GATHER
By David H. Levy
Reprinted with permission from PARADE, copyright 2003

     It started with the sky darkening—fast, as though by a dimmer switch—and sudden gusts of wind on a recent evening in the Northeast.  Instinctively, I raced into the house for safety as bolt after bolt of lightning flashed in the night sky, followed by deafening claps of thunder.  When the rain poured, it came not down but across, straight toward the house.  A huge bolt lit up the night like day, and I saw a tree split in two and crash to the ground less than 100 feet away.
Thunderstorms, among the most beautiful displays in Nature, are also a danger not to be taken lightly.  Those who ignore the warning signs, or don’t know what to do when they appear, put themselves in harm’s way from lightning, high winds, hail and sudden flooding.  While they can develop at any time, thunderstorms are most common between May and September in the U.S.  The storm season varies with the region: In the desert Southwest, storms can develop almost daily from July to September but are virtually nonexistent the rest of the year.  In general, the higher the temperature, the more often thunderstorms occur.
You usually will be safe to enjoy a storm’s beauty and power inside a house or an office building.  You’re decidedly more at risk by a lake or on open ground.  Do you know what to do if caught in a thunderstorm?  Here is some basic science to explain these spectacular events and a set of guidelines to help you to protect yourself and your family.

Nature Rages to Restore Calm

Lightning In Field     Thunderstorms are Nature’s way of maintaining stability in the atmosphere.  The air above us is stable or balanced when heavier, cooler air is near the surface and lighter, warmer air is above it.  Instability occurs when the air at the ground becomes hot and humid while the higher air is cool and dry.  The atmosphere is then “upside down.”  Nature will restore stability through a process called convection: The warm, moist air begins producing droplets of water that fall as rain in a thunderstorm, bringing cooler, drier air down with them.  The air has become stable.  The storm has done its job.
To understand how droplets form, it is helpful to look inside a thundercloud.  Imagine a tiny speck of dust wandering about at the bottom of a rapidly growing cumulonimbus (mountain-shaped) cloud.  It is a humid day.  The speck, carried along by winds, rises through the cloud into cooler air.  The air is cooling so rapidly that the moisture in it is condensing.  Particles of water adhere to the speck, making it heavier and heavier until—along with millions of similar droplets—it falls as rain.  The droplets high-speed movement through the cloud builds up an electric charge, released as lightning.
Simply put, lightning is an enormous electric spark.  When you walk on a carpet, the friction you create builds up a static-electric charge in your body.  If you then touch an object that has an opposite charge (a wall, a doorknob, a person), a spark jumps from you to that object, and you feel a shock.
Lightning is basically the same thing—but on Nature’s grander scale, it can be devastating.  As water droplets race through the cloud, the friction they create builds up a huge static-electric charge—mainly negative at the bottom of the cloud, positive at the top.  Much of a storm’s lightning remains within the cloud, leaping the gap between top and bottom.  But when an object on the ground, such as a building or a tree, becomes positively charged, the lightning sparks to the ground as a brilliant bolt.
When this happens, enormous heat is generated, so that the air around the bolt virtually explodes—the sound of thunder.  You hear the thunder after you see the lightning flash, because the speed of sound is much slower than that of light.
You can tell how close you are to a lightning flash by counting the seconds that pass between the lightning and the time you first hear thunder.  Sound travels at 1100 feet a second.  So, if the thunder began 5 seconds after the lightning, the strike was 5500 feet away (1100 feet x 5 seconds), or just over a mile.  If the interval was 15 seconds, then the lightning bolt was about 3 miles away.

Count The Hazards

As you read this article, an average of 1800 thunderstorms are creating havoc somewhere on Earth in one or more of the following ways:
Lightning.  In a typical year, 73 people are killed and more than 300 injured by lightning.  Lightning kills far more people than any other weather event, including tornadoes.  A bolt of lightning can force an enormous amount of electricity through your body.  Consider an electric shock in the home.  Its 120 volts can cause severe injury.  Compare that to 15 million volts from a lightning bolt!
Although the overall odds of being struck by lightning in the U.S. are estimated at one in 615,000, the likelihood increases depending on where you are when a storm comes up.  “Half the casualties of lightning occur during activities in open fields, such as soccer and baseball,” warns Conrad Lautenbacher, administrator of the National Oceanic and Atmospheric Administration.  “Parents and coaches have to know: If you hear thunder, get your children inside a substantial building.  A vehicle with a metal roof and sides is a good second choice.”
High Winds.  Strong winds are typical of thunderstorms, but some weather patterns produce a microburst—a violent, localized downdraft covering 2.5 miles or less, with winds up to 150 mph.  Some, called “dry” microbursts, have little rain, as most of the water stays above 10,000 feet.  Microbursts can blow down trees and rip manufactured homes off their foundations.
Floods.  Slow-moving storms can produce sudden large torrents that flood streets.  The enormous pressure of large amounts of water rushing through a low-lying area can move a car a mile or more.
Hail.  If the humid air rises far enough and stays in the cloud long enough, the water droplets can freeze and grow and fall as hail.  Hailstones can be as large as softballs—yet another reason to go indoors.  In 1995, a hailstorm in Dallas damaged so many planes that some airlines temporarily lost portions of their fleets while repairs were made.
Tornadoes.  Thunderstorms come in various sizes.  A storm can grow from a single-cell storm—a small, solitary thundercloud—to a multicell cluster that covers a large area.  “Supercell” storms are the most likely to produce tornadoes.  They form when lower-atmosphere winds are moving at a radically different speed and/or direction from ground winds, causing the whole system to rotate rapidly.  Supercells are most common in the Midwest, where cold air rushing in from the North attacks warm and humid Southern air to produce incredibly tall, swirling clouds and violent winds that can toss a car and level a house.

KNOW HOW AND WHEN TO PLAY IT SAFE

Lightning In Field     Weather forecasters issue thunderstorm warnings as if all storms are equally dangerous.  One result is that many of us regard them as “crying wolf” and ignore the warnings.  Often they’ll say, “chance of thunderstorms,” because it’s hard to know precisely when and where a storm will burst—one can arrive suddenly, with little warning except the darkening sky as it approaches.
Outdoor activities are fun when it’s fair but can be lethal in a thunderstorm.  Golf, cycling and swimming expose us to metal and water, which conduct electricity.  Continuing your fun in a storm is like inviting lightning to strike.
Prevention is much better than treating a victim.  Get into the habit of observing the weather and paying attention to forecasts.  And know what safety measures to take.  (See how to Stay Safe).
Like other grand spectacles of Nature, thunderstorms—at once extraordinarily beautiful, dangerous and frightening—must be respected.  A little knowledge about them can help you to protect yourself and those in your care when the big clouds gather.

HOW TO STAY SAFE

Thunderstorms arrive suddenly, with little warning except the darkening sky as the thundercloud approaches.  If you see tall, puffy cumulus clouds growing and daylight rapidly dimming, observe these safety measures.

If you’re near a house or other building…

  • Make sure that all children are accounted for.
  • Secure outdoor furniture.
  • Go indoors.  If the storm is severe, with frequent and close lightning bursts, head for a basement or a room in the middle of a house or other building.
  • Keep away from objects that might conduct electricity (such as radiators, pipes and metal door frames).
  • Stay away from windows.
  • Do not take a bath or shower during a storm.  Water helps to conduct electricity and walls don’t always protect from the high energy of a lightning bolt.
  • Do not get close to electrical appliances such as plug-in radios and TVs.  Use battery-operated radios.
  • Restrict all calls to cell phones.

In an open field or on a golf course…

  • If you feel your hair start to stand on end or your skin tingle, or if you hear crackling sounds, lightning may be about to strike you.  Drop down quickly, bend forward, feet together, hands on knees.  Do not lie flat: You want to make yourself as small as possible and have minimal contact with the ground.

In the city…

  • Don’t stand on an apartment house roof during a thunderstorm (Last summer, a young man was fatally struck by lightning in New York City while doing just that.)

If you’re swimming…

  • Get out of the pool, lake or ocean at the first sign of lightning or thunder.  Find indoor shelter or get into a car.  Stay out of the water for at least 30 minutes without thunder.
  • Stay away from metal fences or flagpoles.

If someone is struck…

  • Heart attacks are the usual cause of lightning fatalities.  If breathing stops, seek medical help at once.

Now, back to our discussion of lightning protection:

Before moving on to how we can protect our horses and barns from lightning strikes, I’d like to give you a few more numbers to consider, courtesy of the Lightning Protection Institute: A typical lightning flash is four-tenths of a second long, generates about 25,000 amperes (an ampere measures the rate of flow of electrons that flow past any point in a wire each second) and 30,000,000 volts (volt measures the force that makes the electrons flow), and has temperatures of from 30,000 to 50,000°F.  In comparison, your house current is 110 or 220 volts and most people set their thermostats at around 70°F.

The Lightning Protection Institute did a study of 250 equine lightning deaths and found:

  • 103 horses burned to death or were asphyxiated in barns that were ignited by lightning bolts (41.2%)
  • 70 horses were struck directly in open fields (28.0%)
  • 40 horses were standing under trees that were hit by lightning (16.0%)
  • 21 horses were killed at watering troughs (8.4%)
  • 10 horses were killed either standing in streams or fording them at the time of the strike (4.0%)
  • 4 horses were killed by lightning current conducted through wire fences (1.6%)
  • 2 horses were standing next to utility poles that were struck by lightning (0.8%)

This study shows that 64% of those deaths (in barns, under trees, at water troughs, near wire fences) could have been prevented. (continues after picture)

Lightning In Field

PROTECTING OUR BARNS AGAINST LIGHTNING STRIKES

The Lightning Protection Institute also found that nine out of ten barns struck by lightning burn to the ground and are total losses.  And it happens very, very fast.  One owner saw lightning strike the metal roof on his bank barn, raising it up, and flames immediately erupted in the upper level.  All the horses in the lower level were found dead from the lightning strike, and a pet rabbit in a metal hutch next to the barn was also killed.  It all happened too fast for him to react.  In the minute or two it took him to get his wits about him and call the fire department, all the damage was done.  There was nothing left for the fire department to save.

Lightning strikes a barn (or any other building) because the materials in it are better conductors than air.  Lightning protection systems are designed and installed to protect all the points where a lightning bolt would most likely strike and all objects to which the current might sideflash. This is where the current jumps from one object to another, for example, a herd of cows standing under a tree that is hit could be killed by current that jumps from the tree to the cows’ bodies. It makes no difference, by the way, whether or not a horse is shod—it’s the water in his body that is the conductor—and the current will not “go around” the horse to hit his shoes, it will go straight through the horse into the ground.

The part of the system most easily recognized is the air terminal, or lightning rod.  These are pointed metal rods, usually copper or aluminum, installed on a building’s high points.  On a barn that’s commonly the roof ridge.  How many terminals are needed depends on the length of the barn.

Down conductors, also known as main conductors, are heavy braided copper cables that connect the air terminals with each other and with the grounds.  Their job is to conduct a lightning bolt from the terminal struck to the ground, and to do that, each down conductor requires its own ground.

Secondary conductors connect metal parts of a building together to keep lightning from jumping across the gap between metal parts.  All secondary conductors are connected to the main conductors.  We may have more metal in our barns than we realize.  Some things to be protected, besides a metal roof, may be stall door tracks, water lines, and any iron pipe enclosures or stanchions.

Arresters protect a building’s wiring system from electrical surges entering through phone or electric lines because ordinary circuit breakers can’t handle the massive power surge caused by lightning.  Arresters are installed at the fuse box or breaker panel and are connected to the lightning protection grounds.

The ground connections cause lightning charges to dissipate intothe ground without causing harm.  Ground rods, usually made of copper, are driventen feet deep and set at least two feet from the foundation.
Installation of a lightning protection system must be done by a professional.  There are too many components, each needing to be tied in correctly to each other for the job to be done by anyone but an expert.  In fact, there are steps recommended by the Lightning Protection Institute and others that you should follow when considering installers.

Briefly, they are:

  • Check and record the salesperson’s identification and verify that the salesperson is connected with a lightning protection company that has bank references and is registered with a Chamber of Commerce or the Better Business Bureau.
  • Get customer references and verify them.
  • Make sure, before work commences, that the company or individual carries Workers’ Compensation insurance.
  • Check with the Lightning Protection Institute (P.O. Box 6336, St. Joseph MO 64501, 1-800-488-6864, lpimain@stjoelive.com, website http://www.lightning.org)  to determine if the installer is an Associate Member.  It’s not a mandatory membership, but does indicate a responsible installer.
  • Insist on a contract that lists all parts necessary for an Underwriters Laboratories (U/L) installation.
  • Check to see that every component—rods, ground rods, connectors—carry a U/L label and that arresters show the manufacturer’s name.
  • Your installer must have you sign an application form for a U/L “Master Label” plate.  This form will go in the mail directly for Underwriters Laboratories through the manufacturer of your equipment.

If any one part of a lightning protection system is not done correctly and/or with the proper materials, the entire system can fail.  Lightning is your horse’s worst enemy inside the barn or out, so you can’t take any chances with the installation.
Lightning In FieldObviously, outdoor protection can’t be as precise as what you would do for your barn and other outbuildings, but there are a number of protective devices that can be installed, such as:

  • Special tree systems that bring the lightning charge into the ground outside the root system, cutting the ground charge, which is usually what kills horses standing under trees.
  • Water troughs can be protected by erecting two ground poles at either end of the area to support a ground wire over the area of the trough.
  • Wire fences should be grounded at 150-foot intervals or less so a lethal charge is confined to that span, and utility poles can be protected using the same system as that used for trees.