No Lighting Strikes!

[bphgravity]

Back in 1999, the NLSI set up a 6 year experiment to study the comparitive behavior of various styles of strike termination (air terminal) devices. The test site was on Niwot Ridge, CO. elevation 12,000 ft. and was selected because of the high (100+TDY) assumed level of thunderstorm days.

The equipment consisted of 80 copper-clad steel air terminals, 5/8 dia. X 4 ft high, are mounted in clusters of four rods per wooden sawhorse platform. 20A fused sensors were attached to each platform to provide lightning attachment verification. Four AT tip designs were being studied: blunt; hemispheric, bullet-shaped; and sharp?one of each at each sawhorse platform.

Well, the study is over and the results are in. No lightning strikes! Not even one! Here is a pic of the setups and the 4 tip geometries that were under study.

 

[George Stolz]

Well, I guess I know where I'm building my next house.

 

[Johnmcca]

No George, you just need to set up those devices around your house. They seem to work well as lightning repellants.

 

[petersonra]

obviously the tip shapes being studied repel lightning.

 

[bphgravity]

What’s interesting is that the flash density at the area of their test increased during the 6 year study. This indicates flash density values which are one of the primary considerations when evaluating strike risk may not have as much value as originally thought. (This is exclusively my conclusion)

If I live in an area with a flash density of 10 strikes per mile? per year and over a period of 6 years, the density increases to 20 strikes per mile? per year, the IEEE-81 and NPFA-780 would lead you to believe the risk hazard doubles as well over the six year period. I'm not sure this is acurate.

It appears based on this study that even structures placed in an elevated risk area does not indicate the structure is any more likely to be struck in a less risk area.

 

[charlie tuna]

there is a reason that people who talk about lightning always discribe it as "unpredictable".. this test record means little --- they could have six strikes next year. i know of a building that was twenty years old and had a lighning protection system installed when it was built. never had a hit in twenty years. then they had two strikes within a week! one of them blew a large chunk of concrete out of the corner of the building........

 

[rbalex]

What I think is interesting is the photo almost looks like a crude "dissapative array" hawked by Lightning Eliminators.

http://www.lightningeliminators.com/

They were the outfit that brought suit a few years ago that had NFPA 780 shelved a few years.

 

[77401]

The best thing I have found is whats called a Lightning Preventer. Yes Lightning can't hit this!!

I carry one in my golf bag just in case I'm caught in a lightning storm. I just hold it up high in the air & finish my round.
It is a #2 Iron, God can't even hit a 2 Iron!

 

[hockeyoligist2]

Just wondering.... are big rocks more attractive to lightning? where i live we have a large rock that goes for miles. There is a rock quarry about 5 miles from me and its supposed to be the same rock! WE have a lot of strikes in the area, especially well pumps and they are bored thru the rock. Has there been a study? Maybe i'll get one of those things!