A Crash Course on Lightning Safety

While lightning doesn’t get the same amount of media coverage or inspire the same fear as other natural disasters, it shares several traits with hurricanes, tornadoes, earthquakes and forest fires in that we can’t predict exactly when and where disasters will strike.

We can, however, control our response. “Lightning is a misunderstood danger, and not feared as much as it should be,” says EMC Loss Prevention Information Manager Jerry Loghry. He stresses that lightning is an occupational hazard, and employers must plan for it like other natural threats.

Outdoor workers are the most at risk. While it’s impossible to predict if lightning will strike your worksite, having a plan and watching weather conditions can help prevent disaster. Jerry offers three proactive steps you can take to protect outdoor workers.

1. Monitor weather conditions.

When you see lightning, it’s already too close. Use a combination of a NOAA Weather Radio and a commercial warning service to know about weather moving your way, allowing yourself time to move to safety. Also check weather reports and forecasts before sending employees outdoors, and schedule indoor work if the forecast predicts storms.

2. Develop an outdoor storm safety plan.

Supervisors and workers should know what to do if a thunderstorm rolls in, whether they work at a construction site, a golf course or a city park.

• Because lightning takes the path of least resistance to ground, it’s likely to strike the tallest objects in the area. That means workers are not safe near tall trees, hilltops, utility poles, cell phone towers, cranes, ladders and scaffolding.
• Open fields are also dangerous. A person would be the tallest object in the field.
• Water, wiring, plumbing, fencing and metal objects conduct electricity, so standing close to any of these objects can be dangerous.

Move workers to a safe area in a fully enclosed building such as a construction trailer, golf course clubhouse or school. The building should be wired and plumbed, as these features provide grounding. However, a building with concrete floors or walls may not be as safe because concrete often has metal bars embedded (and metal conducts electricity). While inside, keep workers away from electrical equipment and cords, plumbing fixtures and corded landline phones, as these items can conduct electricity from a lightning strike.

In a pinch, a truck or car can serve as a safe house because the rubber tires insulate the vehicle. The vehicle should have a metal hard top, and windows should be kept rolled up.

Whether you seek shelter in a building or a vehicle, stay inside for at least 30 minutes after the last thunder booms. That’s because lightning at the back edge of the storm can strike up to 10 miles away. Find more details about dangers and shelter at Lightning Safety When Working Outdoors, from OSHA.

3. Protect Your Building.

Because lightning strikes cause approximately 1,800 non-residential building fires and more than $1 billion in property damage every year, protecting your assets from this danger is a smart move. Installing a lightning protection system can protect your building, contents (equipment, warehoused materials and products) and the employees inside the building. A lightning protection system includes separate components to protect the building shell and the valuables inside the building.

Add lightning rods on the exterior, an old-fashioned practice that’s still applicable today. The rod (or air terminal) is the highest point of the building. When lightning strikes the rod, the energy is transmitted through cables (the conductors) into the ground, where the electricity is safely dissipated. It’s essential that all transmission lines be connected to the system to prevent damage, including telephone and cable TV, as well as antennas and any underground metal piping systems.

On the interior, surge protection devices (SPDs) protect electrical and electronic equipment from lightning and protect against electrical surges.