The Iowa Barn Foundation: Helping to preserve Iowa's agricultural heritage one barn at a time.

How to Protect Your Barn from Fire

Originally published in the Fall 2002 issue of the Iowa Barn Foundation Magazine.
Written by Larry T. Wyatt, agricultural safety engineer at Grinnell Mutual Group in Grinnell, Iowa. Jay Harmon, associate professor of agricultural engineering, Iowa State University, was an adviser on this article.

While driving through the Iowa countryside, many times you see on barns what is left of an old "lightning rod system". Sometimes the lightning rod "points" are still there.

"Why don't people put lightning rod systems on barns (or buildings) anymore?" someone will ask.

A barn fire can be devastating. In the past, the barn was the largest and most important building on the farm. The success or failure of early Iowa settlers depended on whether they could raise enough crops and/or livestock during the summer and store them to make it through the tough Iowa winters. The barn on an 1800's Iowa farm was usually the center of the farm's activity. The status symbol of an 1800's farm was the size of the barn you could afford to build. While it would be hard to justify to neighbors building a large and fancy house, building a large barn on the farm was totally acceptable. The goal was to protect the barn, and thus insure your ability to feed your family and earn a living.

Barns were especially vulnerable since there were few rural fire departments in the 1800's. This made lightning rod systems important. Many eastern insurance companies would not insure Iowa barns; once they caught fire, they were usually a total loss. This is why Iowa farmers formed their own "mutual" insurance companies in the late 1800's. Every member was an "owner" of the company. The first mutuals didn't collect money or premiums to help pay for losses. If a member suffered a loss, the other mutual members were instructed how many pigs, chickens, board feet of lumber, etc., to deliver to the member who suffered a loss.

Big old barns were especially exposed to lightning because of their height. Lightning is basically a huge static electric spark that usually occurs between the cloud and ground. The air between the cloud and the ground acts as an insulator. Once the electric charge in the cloud has built up a large enough charge to overcome the insulating effects of the air, a lightning strike occurs between the cloud and ground or the cloud and object on the ground. Since lightning (or electricity) almost always chooses the path of least resistance, the least resistance is usually the shortest distance between the charge in the cloud and an object on the ground. This is why the tallest objects on the landscape are usually hit by lightning. Since the old "hay mow" type barns in Iowa were usually the tallest buildings on the farmstead, they had the highest probability of being hit by lightning.

Should lightning rods be put on today's farm buildings? Yes! Lightning has not gone away and is potentially more dangerous to modern farm buildings then it was to the big old wooden barns. Many modern farm buildings have steel roofs and/or steel on the outside walls. Without a properly installed lightning protection system, lightning can strike one part of the building and could briefly "electrify" the whole building. This could be extremely dangerous and could be fatal to any livestock and/or people in the building or who touch the metal exterior.

On a new building, lightning protection systems are usually only a small percent of the total cost of the building. A reputable installer should do the work. Most insurance companies or companies that supply lightning protection materials will know the names of reputable installers. Remember that lightning protection systems consist of five parts:

  1. Air terminals - lightning rod points
  2. Main conductors - lightning rod cable between the points
  3. Down conductors - lightning rod cable from the main conductor to the ground rods
  4. Ground terminals - ground rods connected to the down conductors. The bottom tip of the ground rod should be 10 feet below the top of the soil
  5. Lightning surge arrestors - to protect the building's electrical system

Computers and computerized ventilation systems are very sensitive to electrical surges coming in over the electrical wires. Lightning can also come in over the phone wires and damage computers. This is why it is critical that each building be wired and grounded according to the most current version of the National Electrical Code published by the National Fire Protection Association (NFPA 70).

Each building should have a lightning surge arrestor on the building's electrical panel. If computers or computerized feeding and/or ventilation systems are being used, more sensitive protection may be necessary such as plug-in surge strips that would provide additional protection.

Since some electric fencing units plug into a 110-volt outlet, many owners of these units want to put them inside a barn and out of the weather. Do not place the electric fencing unit inside a barn or other farm building. Lightning could strike the electric fence-or close enough to it-- to send a surge of electricity into the barn or building where the fencer is plugged in, possibly causing a fire.

Run a heavy-duty extension cord to a small wooden box containing the fencer unit about 10 feet from the building. Even though the outlet to the fencer should be GFCI protected, it is best to have a regular outlet, so the GFCI protection doesn't "trip" the outlet (circuit) off, and allow the livestock to get out.

As a suggestion, 110-volt electric fencers will not work if the power goes out. Since the electrical power can go off during a lightning storm, put the livestock in the barn or other "permanently fenced area" prior to the lightning storm. This is so that a power outage will not allow the livestock to walk through a non-operating electric fence.

Other causes of fire

Trash and grass burning

Never burn trash, weeds, or dried grass around farm buildings. During the fall, winter, or dry months, even a spark from a steel burning barrel can cause a grass fire that can burn down buildings. Keep weeds and grass mowed or sprayed a minimum of 20 feet from all buildings.

Wood burners

Wood burners should not be installed in barns or farm buildings. If you have a fall or winter business that must have a warming shed, consult your insurance carrier for building specifications, woodburner installation details, and separation distances.

Heat lamps and heat pads

Heat lamps can also cause fires if they are used improperly or fall into combustible materials such as straw or rugs. If heat lamps must be used, install them at least 30 inches above the floor or eight inches above the back of the animal when standing, whichever distance is greater. Locate the heat lamp above a concrete floor only, with no bedding. If you must use a rug under the heat lamp, use an "indoor/outdoor type" carpet with very short weave height. No carpets or rugs should be put under a heat lamp. For heat pads specifically built for livestock or pets, place the unit on a concrete floor with no rugs or bedding material nearby.


Bad wiring and light bulbs too close to combustible materials can also cause fires. All barn wiring should meet the requirements of Article 547 (Agricultural Buildings) of the National Electrical Code [ NFPA 70 ]. All wiring connections should be in junction boxes, and extension cords should never be used as permanent wiring.

Use globed light fixtures in areas where straw, hay or cornstalks are present or in areas where there may be damp, dusty or corrosive atmospheres. Even a globed light fixture should never come into contact with any combustible material such as hay, straw, cornstalks, wood, fabrics, etc.

Outlets in barns should also have GFCI (Ground-Fault Circuit-Interrupter) protection to protect people from accidental electrical shocks. However, some devices such as electric fencers may need to be installed on a regular electrical outlet.

Fire Extinguishers

At least, one 10-pound ABC fire extinguisher should be kept on each "occupied" level of the barn. If there is a "frost free hydrant" in the barn, keep a 50-foot garden hose (with no water in it) and nozzle attached to the hydrant. If the barn is heated, keep, at least, one (depending on the size of the barn) 50-foot garden hose with a nozzle attached to a water faucet.

"Thunder is good, thunder is impressive; but it is lightning that does the work." --Mark Twain