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Lightning Protection vs. Lightning Elimination
6

Lightning Protection vs. Lightning Elimination

Lightning Protection vs. Lightning Elimination

(OP)
I'm currently doing a study of existing lightning protection at a chemical plant. I will be making recommendations to the client about maintaining his current NFPA 780 style protection with air terminals, conductors and ground rods.

I have also been reading much about the Dissipation Array Systems promoted by companies that claim to eliminate lightning in the area protected. I've also read many critiques, some in this forum,  of these systems that call the techniques non-scientific, snake oil, etc. In fact there seems to be a real war going on over whether this works or not. After all I've read, I have to admit to being a skeptic also.

My question is this: Is there anyone who HAS tried these techniques and believes that there is some merit to them?

RE: Lightning Protection vs. Lightning Elimination

You may have already stumbled across my opinion on this topic already:

It borders on being trivial to conduct a rigorous scientific experiment to prove that these so-called Lightning Prevention systems work. Once this has been done, documented, peer reviewed, published, duplicated, etc., - then there wouldn't be any argument. Until then, file under snake oil.

RE: Lightning Protection vs. Lightning Elimination

nothing is lost nor created, only modified.
then i do not belive it is possible not to eliminate the lighing but I may belive it is possible not to eliminate the consequence of lighing but to catch the consequence ( overvoltage, heating) to avoid any trouble on the plant.

Whatever, I did not get involved in such stuff yet.

RE: Lightning Protection vs. Lightning Elimination

Suppose the system does suppress spontaneous lightning.  It always works, flawlessly, under all weather conditions.  So you remove all conventional overvoltage protection equipment from the plant.

Now any disgruntled employee can fry the plant by drawing down a bolt of artificial lightning, using a spool of fine wire and a model rocket.  Now any ecoterrorist can fry the plant by discharging a big capacitor into your power feed.

P.S.  If you find yourself needing more paranoia, try working for a defense contractor for a few years.

RE: Lightning Protection vs. Lightning Elimination

(OP)
I will never recommend to the client that he replace the conventional methods, I'm just wondering whether or not to add any of these "elimination" techniques.

I will be trying to contact some of the references given but this forum seems to work so well I thought I'd try here also.

Also-In the promotional material I've read I have not read anything about factoring  in wind strength and direction. They may create ions but ions are still molecules and can still be dissipated by wind.  In other words, even if it did work as claimed it seems that it would only work on very still air.

RE: Lightning Protection vs. Lightning Elimination

I worked for an explosives manufacturer on a large mile square site,  the site had a single grided mat underground at 12 foot pitch and all the buildings had overkill lightning conductor instalations.  In 16 years I only new of one strike and this was to a 150 foot poplar tree.
I was informed by the safety folks that this low strike rate is to be expected when a large area is held at equal potential by the grounding mats, maybe this is what they call lightning elimination scheme.

RE: Lightning Protection vs. Lightning Elimination

Interesting bogeyman,
I'd expect laying all that wire wasn't done on a whim and sounds reasonable based on that history.
It might be worth researching other explosive sites to see if they have similar, or different lightning strike solutions.
Possibly the edge of the metal grid at the explosives site has some elevated lightning rods on it to help keep strikes off the center area. Was this site in a valley or slight depression too?

kch

RE: Lightning Protection vs. Lightning Elimination

A ground mat/grid would be effective in mitigating the destructive effects of a lightning strike but would not have any effect on the likelihood of a lightning strike. That is controlled by the atmospheric conditions that generate static electricity.  

RE: Lightning Protection vs. Lightning Elimination

If Lightning Prevention schemes actually work, then why couldn't they be wired to ground using 22-ga wire?

RE: Lightning Protection vs. Lightning Elimination

I worked at a 40 acre plant in Florida.  They had this lightning system that had lots of things that looked like wire brushes sticking into the air and grounded.  They were placed about every 25 feet along the highest parts of every structure.

During the summer when we get lots of lightning storms, you could see the effect.  The lighnting gets "pushed" off of the plant and strikes all around the perimeter in the trees.  To my knowledge, they never had a strike at the plant.  I don't understand the theory behind it, but it definently worked.

RE: Lightning Protection vs. Lightning Elimination

(OP)
Thank you Filtration Engineer. That is exactly an example that helps. I've recently heard of other examples as well. I'm just having trouble believing the reasoning given. For example the ionizing current for each of the dissipation array elements is given as being in the order of milliamps. This ionization current is supposed to neutralize the potential difference between cloud and ground to diminish the chance of a lightning strike. I can imagine that except for the magnitudes involved.
The lightning strike itself is going to have thousands of amps-nature's way of neutralizing the potential difference- and how could milliamps ever be enough? Then there is the wind question I had earlier. It's all very puzzling but I've pretty much decided to concentrate on empirical evidence. If I can find a compelling number of people who have witnessed the benefits, I'll relay that to the client.
Could you share with me the name of the company you mentioned.

RE: Lightning Protection vs. Lightning Elimination

"...concentrate on empirical evidence..."

That's called anecdotal evidence.


http://en.wikipedia.org/wiki/Lightning_rod#Lightning_prevention

Review some of the citations linked from Wiki. Dig further through the links. There's a fairly clear consensus, at least from those applying rigorous scientific thinking.

RE: Lightning Protection vs. Lightning Elimination

(OP)
Thanks to VE1BLL for the references and I'll certainly check them out.
In the meantime though, I still have an open question about actual results. If anyone else has experience or observation (good or bad results) of ESE or dissipation array lightning "preventors" use, please let me know.
The first ESE company I've contacted seem to be reluctant to give me an up-to-date customer reference list. Hmmmm.

RE: Lightning Protection vs. Lightning Elimination

Loopee
I have been on a cooling tower when a very dark and low cloud rolled over the tower.  The tower was a mechanical draft tower with 10 cells and was about 35' or 40' high.  
There were 5 points on each cell.  All of the points started arcing into the air.  The arcs were very visable against the dark cloud. It looked like a Frankenstein movie or something. I was with the superintendant of the subcontractor that built the tower.
when the sparks started he said "Lets get the H_ _ _  out of here and took off running.  I followed.
There is no doubt the system was disapating charge, the question was how much and if that was sufficient to prevent a strike.  The same superintendant has just finished another job rebuilding a duplicate tower ( complete with the same lightning protection system) that had been struck by lightning and burned down.
This was one of the last wooden tower built in the US.  There was enough redwood in them for hundreds of picnic tables.    

RE: Lightning Protection vs. Lightning Elimination

(OP)
BJC
Thanks for that anecdote. I think I would have been moving along pretty fast also if I'd seen that.
By "points" did you mean the standard air terminals? I wonder what kind of lightning protection, if any, the wooden tower had?

RE: Lightning Protection vs. Lightning Elimination

Standard points, right out of the Thompson catalog.  They were 18" or 2' long copper with plated points. Five on each cell, with 10 cells per tower.  There were two towers about 4o yards apart.  The protection system was pretty standard designed by Thompson.
As I though I wrote in another post here ( it either got deleted or I screwed up poosting it) the system was a requirement of Factory Mutual.  Other systems may work just as well or better but if the insurance companies doesn't accept them  they wont's cover the structure.  Acceptance by them usually requires a UL masters license.

If your ever through the Denver Airport and have time walk around on the upper elevations and look out on the roof(S).  If your stuck in a lightning storm I am sure you can see blue sparks going into the air.

RE: Lightning Protection vs. Lightning Elimination

A little bit more anecdotal information,
I was under the impression that the electrical charge was dissipated due to the presence of the large number of finials atop all the buildings on the explosives site, geographicaly the site was (it is alas now closed) situated on the lancashire plain south of preston at about 200' above sea level some 5 miles away from the rising penine hills.  The last vestiges are still visible on google maps.
In our instrument workshop (bang in the middle of the site) we had a pole mounted VHF whip antenna on the roof (about 30' up with 28" of whip)  when the thunder storm risk was high the N type connector in the radio test area used to arc over at a rate seemingly proportional to the severity of risk... tick..    tick..     tick..  etc.
even when this occurred there were no on site strikes but often several around the perimiter.
The arc legnth would have been about 2.5mm, shorting the cable may have been sensible.

RE: Lightning Protection vs. Lightning Elimination

More lightning war stories.
I had a crew of surveyors sitting in a truck waiting for a little dark cloud to blow over.  It was only raining a little so I had the window down with my arm resting on the bottom of it.  I noticed that every hair on my arm was sticking straight out. Not just mussed up a little but STRAIGHT out!  I pulled in my arm and rolled up the window. About 30 seconds later lightning struck a tree about 30 yards away.  It was like a 105 going off beside your ear.  I though we were going to have to go back to camp and change underwear.

RE: Lightning Protection vs. Lightning Elimination

There was an excellent science show (maybe Nova?) on TV a few years ago. They seemed to have all the latest footage and up-to-date theories.

One thing I clearly remember was the upward streamers trying to make contact with the interconnected 'puddles' of charge on the way down. The first streamer that happens to make contact gets the full blast, and then all the other 'puddles' of charge along the way are subsequently discharge down the same path. This is why you often see pulsating strokes.

But even the unconnected streamer (a 100-foot long 'spark') is a serious event and will certainly take out your home theatre system.

There was a nice picture of a streamer from a house and a streamer from a tree. The tree happened to make first contact with the charge 'puddle' and it took the hit. The house was lucky.

The whole explanation provided by the show all made perfect sense and also fits smoothly into my overall understanding of physics.

But 'Lightning Prevention' doesn't fit and doesn't make sense. You would have to ignore several 'order-of-magnitude issues' for it to even begin to make sense.


Also, in the court case previously linked, they weren't even claiming Lightning Prevention. They were only claiming a slightly larger protection zone. Even that modest claim was found to be unsubstantiated.

RE: Lightning Protection vs. Lightning Elimination

(OP)
Bogeyman - Did you notice that there was a "quiet" time in the "ticking" after an actual stroke?
 BJC - Thanks for the anecdote, I think it was interesting that you had 30 sec of warning.
VE1BLL - what exactly do you mean by puddles?

Everyone- I appreciate all the input!

RE: Lightning Protection vs. Lightning Elimination

According to what I've seen, the charges coming down from above leap from one spot to another over spans of something like 150m (?). The charges accumulate into 'puddles' (I don't recall what the official name is). These accumulations or puddles are interconnected by ionized channels. Once the major stroke to ground starts, then the puddles discharge in sequence along these channels and onto the same stroke resulting in a pulsation as you've no doubt seen in person.

I'll bet that there are probably many variations on the theme. In other words, lightning probably doesn't feel obligated to always perform in exactly the same way. So any particular simple theory is only correct most or some of the time. I've seen one photo where lighting was hitting the base (bottom) of a very tall tower.

RE: Lightning Protection vs. Lightning Elimination

A note on lightning when it strikes the ground near you.

 The further your two feet are apart, the more voltage between your two feet and the more current that goes up one leg and down the other, and the more dead you may become. Keep your feet together or better yet, stand on one foot in a lightning storm. If you're traveling take little bunny steps, having one foot on the ground at a time only (just my guess of course). I've heard staying low, but who knows if being 2 feet shorter has much impact.

Regarding the sound of lightning near you, I had a bolt hit about 100-150 feet away on a golf course about 20 years ago. I can still remember how bright the flash was, even in my peripheral vision. Fairly loud too but not horrific. I had my golf clubs in hand and used to carry a 1 iron. "not even god can hit a 1 iron" Lee Trevino used to say, he was right that day.

Kevin.

RE: Lightning Protection vs. Lightning Elimination

"A note on lightning when it strikes the ground near you."

Perhaps more accurately, just ~before~ it strikes. winky smile


I've seen advice like, "Be sure to disconnect your antenna during lightning storms."

During ?  Yikes !

RE: Lightning Protection vs. Lightning Elimination

I was at sea just of Bermuda when we were overtaken by a huge squall. We saw about 20 to 30 lightning strikes within a 1 or 2 mile radius around us, the closest one about 300 feet away. I never could figure out how a metal mast 100 feet tall in the middle of an relatively flat sea could avoid a strike in those situations.

With respect to the OP. Have you checked the marine stores like West Marine or Boat US, I have installed a few of those lightning dissipators on top of masts, bought from those stores they might have a record or some feedback from users as to their effectiveness.

RE: Lightning Protection vs. Lightning Elimination

Look up Saint Elmos fire.
A friend of the family was in the Pacific in WWII. At one tiem the whole fleet he was in was glowing with St. Elmos fire.  HE said  every ship was clearly visable even though it was a moonless night.  Extra watches were put out for submarines.
Gregory Peck gets a handle on St. Elmos fire in "Moby Dick".  Good flick if you have never seen it.

RE: Lightning Protection vs. Lightning Elimination

I think the salty ocean is pretty darn conductive too and the mast of a ship may not stand out electrically speaking in a choppy sea.

I'd expect that the sea spray due to the wind puts a fine conductive mist in the air too which probably shrouds the ship and hence no strikes. I've been on Norweigen ships Sovereign of the Seas during a lightning storm with light rain, the ship did get a lot of hits, probably 5 or more. Although we were in the bar and things were a little fuzzy by midnight.

Maybe a misting sea water sprinkler system is a lightning strike preventative measure.

kch

RE: Lightning Protection vs. Lightning Elimination

Just some random comments. Fiberglass sailboats may not have a good ground to the water, although I've read articles recommending grounding the mast.  Also, I was biking the Blue Ridge Parkway up around Mt Mitchel when a thunderstorm hit.  Crouching along the side of the road was OK, but if I stood up, I could feel things start to tingle.  I stayed down.

RE: Lightning Protection vs. Lightning Elimination

After a lightning strike has travelled through a few thousand feet of air, do you think the GRP hull of a sailboat is going to impede its progress toward mother earth?

We've taken a good few direct hits on the exhaust stacks and cooling tower at out plant, and I've seen other direct hits on a cooling tower visible from my office. It's deeply disturbing when  you are out working on a breakdown on the top of the HRSG (≈ boiler on the back end of a gas turbine) and you see the stack about 30m above you get hit. On reflection the steel structure is probably not a bad place to be in terms of safety, but that was a real brown trouser moment.
 

----------------------------------
  Sometimes I only open my mouth to swap feet...

RE: Lightning Protection vs. Lightning Elimination

"After a lightning strike has travelled through a few thousand feet of air, do you think the GRP hull of a sailboat is going to impede its progress toward mother earth?"


No, the hull is going to get a big hole blown in it if the lightning decides thats the way it wants to go. The problem is no-one seems to be able to predict the path.

Most sailboats I am familiar with have some form of grounding plate from a small bronze plate to large sintered bronze plates to a direct connection from the mast to the lead keel. Although many builders/electricians can't make up their mind if this is lightning protection or corrosion protection.

I have given up trying to predict the path and now simply unplug all electronics that I can and hope for the best. Lightning seems to behave erratically at best. I have seen 1x19 rigging wire with one single strand blackened from a strike, and the rest of the wires with which it is tightly packed apparently untouched.

If the OP is still interested another possible resource could be the cities in S Florida that are installing those spiked dissipators on their lifting bridges and light poles nearby. They would probably have records of strikes before and after installation. When I was there I seem to remember Delray Beach, Fort Lauderdale and Hollywood were experimenting.

RE: Lightning Protection vs. Lightning Elimination

NASA tried it. FAA with Office of Naval Research wrote extensively about it. Recently, Mssrs. Uman and Rakov wrote
about "Unconventional Air Terminals..." in a Amer. Meteorological Bulletin. International Committee on Lightning Protection (ICLP) and IEC both have discounted the psuedo-science behind the claims of perfection. See much more at: www.lightningsafety.com  CAVEAT EMPTOR !

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