Are 2 story homes more prone to lightning strikes?
jackofalltrades777
| Posted in General Questions on
Is the above question true? If so, would a lightning rod system work to help prevent damage?
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Peter,
Coincidentally, I just finished writing a blog on lightning strikes. It will be published in a few weeks.
Briefly:
1. There is less scientific data on lightning protection systems than one might expect, and many published claims have their origins in marketing materials produced by manufacturers and installers of lightning rods.
2. That said, lightning protection systems work.
3. In any given neighborhood, a house on a hill is more vulnerable than a house in a hollow, and a house that is taller than neighboring houses is more vulnerable than low houses.
[Later edit: Here is a link to the article: "Preventing Lightning Damage."]
Martin,
I look forward to reading the article. In the meantime, any articles or links that would be good to read about lighting protection systems?
On the other hand, a two story house of the same sq ft will be smaller, which reduces risk. No idea how size and height balance out.
Good point. A 2-story has less surface area than a similar sized ranch. The question is does the height of the 2-story offset the risk of the larger wider ranch?
Also, do concrete homes fair better than wood frame homes in lightning strikes? Metal roofs vs composite shingle roofs?
Peter,
I'm not an expert, but I think height (altitude) trumps other factors. I don't think data exist on the "metal roof vs. asphalt shingle roof" question.
Lighting rod systems cost in the $3,000 to $5,000 range, and homeowner's insurance providers won't give you enough of a premium discount on their policies to justify the investment. That said, some homeowners are willing to make the investment because it provides some peace of mind. Your call.
Peter,
I found a brief paper that might interest you. Here is one of the author's findings:
"Lightning is a meteorological phenomenon. However, lightning strike location and lightning strike attributes appear to be controlled by geology. Telluric currents - which are modified by faults, mineralization, anisotropy, fluids, and geology like kimberlite pipes - control lightning strike locations."
If you want to check out the paper, you can find it at http://www.searchanddiscovery.com/documents/2013/41184nelson/ndx_nelson.pdf.
This calculator works with the firefox browser and reports various risk factors. Looks like hit risk depends roughly on the square of the height (so a two story house of equivalent sq ft has twice the risk). A metal roof is beneficial.
http://www.ecle.biz/riskcalculator
Conceptually, lightning protection is all about giving lighting a path to ground where it doesn't do too much damage as it follows it.
I wonder if installing a large steel pole that is grounded to the earth, near the home, would be helpful in creating a "lighting rod" device that would divert lightning away from the home?
Peter,
That's the basic principle. But it's usually cheaper (and less ugly) to put a short lightning rod on the ridge of your house rather than to build a 30-foot tall steel pole with a concrete footing.
For a little bit of fun with lightning and a bit of edification, see https://what-if.xkcd.com/16/
The link to the referenced video is broken, but the video can still be found at http://www.ztresearch.com, it's the second video, 33 seconds long.
Martin,
Funny you should say that as I currently have a 30 foot steel pole with a concrete footing buried over 2 feet into the ground. Although I have over 10+ acres of land so I have the room and space. I made my "lightning pole" into a weather station so it is more aesthetically pleasing than just a steel pole sticking out of the earth.
That tower provides no lightning protection for the building.