Tag Archives: metal roof

Lightning and Steel Covered Pole Buildings

Lightening and Steel Covered Pole Barns

From a www.kmbz.com story of March 8, 2018 by Jim Cunningham:

“Each year more than 100 people are killed by lightning in the U.S., according to the National Weather Service. Another 300 people are injured in the electrical strikes. 

Severe Weather Awareness Week is March 4-10. 

In most cases victims of lightning strikes are outdoors, but some structures do not provide adequate protection from lightning, said Al Pietrycha, NWS Meteorologist.

“Several years ago in my pole barn, only 200 feet from my house, this storm came up and I wanted to watch it, thinking I’m okay, I’m okay,” Pietrycha said. “Lightning struck the barn and I got knocked off my feet in the compression wave, and since then I’ve lost some hearing.”

Pietrycha says he should have listened to his own advice that day to take lightning safety more seriously.

Lightning can strike up to 10 miles from a thunderstorm. Vehicles and enclosed buildings offer the best protection. Pietrycha says people should wait at least 30 minutes after a storm has passed before going back outdoors.”

Here is what Bryan Arlington, PE of Star Building Systems has to say about metal roofs and lightning:

“It has been observed that installing a metal roof makes building owners think more about lightning and the dangers of lightning strikes. There is a perception, or at least a suspicion, that a metal roof will increase the likelihood of lightning striking the building. After all, metal is highly conductive, just like the materials used in lightning rods that are used to attract lightning strikes, so doesn’t it stand to reason that the metal roof will attract lightning, too?

The short answer is, no, a metal roof will not make lightning more likely to strike, but it may make a lightning strike less dangerous if it occurs. That’s right, less dangerous, not more.

The Metal Construction Association, in its Technical Bulletin MCA13a, breaks the issue down into two issues: probability of a lightning strike at any particular location, and the consequences of that strike.

Lightning has been studied for hundreds of years, and there is good general information about how it works, but many of the details of how it forms and where it strikes are still unknown. That lack of knowledge means that its behavior remains unpredictable.

Lightning is a rapid discharge of atmospheric static electricity. There are three major types of lightning strike: Intra Cloud (IC), discharges inside a single cloud, from a highly-charged area of the cloud to a less-charged portion; Cloud-to-Cloud (CC) discharges from a highly-charged cloud to a less-charged cloud; and Cloud-to-Ground (CG) discharges from a highly-charged cloud to the earth. CG is the type that is best understood, and the type we are most concerned with in terms of dangers to life and property.

The exact location where lightning discharges appears to be governed by geography and topography, as well as the movements of the storm.  When lightning is ready to discharge, it will, whether there is a metal roof handy or not. It is faulty logic to assume that a metal roof attracts lightning strikes similarly to a lightning rod, because lightning rods are not made to “attract” lightning. Rather, they are made to channel lightning safely to the ground if it happens to strike the location of the building.”

Come back tomorrow for the conclusion on lightning and metal covered pole buildings.

Steel Roofing: Hail, Hail the Gang’s all Here

A couple weeks ago I posted about vinyl siding damage due to hail storms in the Knoxville, Tennessee area. Vinyl siding was not the only thing damaged – on my four mile running loop are numerous yard signs from roofers. The roofers are replacing shingles which were damaged by the same storm.

When I first began providing building kits in the Midwest, I was stymied by the number of clients in Michigan who were asking for shingled roofs, instead of steel.

Initially, I thought this must be a regional aesthetics thing. My curiosity finally got the best of me, so I asked about it. The answer – fear of steel roofing being damaged by hail! I never would have guessed.

My first reaction was to call each of the six steel companies who supply steel roofing and siding for our buildings. Only one of them had ever even had a claim submitted to them for hail damage! This certainly seemed contrary to the perception of pole building clients in Michigan.

Metal roofs are very tough and highly resistant to hail damage.  Hail will not penetrate a metal roof.  Even a new asphalt shingle roof won’t protect a home from the next hailstorm.  In fact, many metal roofing products have the highest impact resistance and hail rating (Class 4) granted by Underwriters’ Laboratory (UL).  This means that a sample of the product did not crack when hit twice in the same spot by a 2-inch steel ball, which, in a storm, would translate into a huge hailstone.  As a result of metal roofing’s superior performance in hail prone areas, some insurance companies even provide a reduced rate for homes protected by metal roofs.

The durability of the metal roofs along my running route would seemingly back up the tested results – nowhere along my running loop was a single steel roof being replaced, or even showing signs of cosmetic damage.  My son’s new garage in Maryville, TN, (built less than a year ago), has a steel roof and has not a dent or even a hint of one on his roof.  I’d like to think this is where we got the phrase, “Strong as Steel!”

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