Construction activity and the Code

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don_resqcapt19 said:
You keep using the word "theory" and that is a very good thing as we really don't understand lightning and lightning protection systems. In fact a few years ago the CMP for NFPA 780 voted to withdraw the standard at the proposal stage because there is a lack of technical information to support the current theories of lightning protection.
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After Francklin's introduction of lightning protection system,there is a tremendous reduction in the damages to life and property caused by lightning over the years.The lightning protection system method is incorporated in NFPA 780.

To the extent our lightning protection works,we can say we have an understanding of lightning and lightning protection systems to that extent.

Regarding 'Theory',you can trust it,if it can 'predict'.
 
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T.M.Haja Sahib said:
After Francklin's introduction of lightning protection system,there is a tremendous reduction in the damages to life and property caused by lightning over the years.The lightning protection system method is incorporated in NFPA 780.

To the extent our lightning protection works,we can say we have an understanding of lightning and lightning protection systems to that extent.

Regarding 'Theory',you can trust it,if it can 'predict'.
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We just don't have as good of an understanding of lightning behavior as you seem to think we do. If you can find the ROP (report on proposals) for NFPA 780 when they voted to withdraw the standard you will find a lot of differing ideas. The panel voted to withdraw the standard because of a lack of a technical justification for the Franklin system. It was reversed in the ROC (report on comments).
 
don_resqcapt19 said:
We just don't have as good of an understanding of lightning behavior as you seem to think we do. If you can find the ROP (report on proposals) for NFPA 780 when they voted to withdraw the standard you will find a lot of differing ideas. The panel voted to withdraw the standard because of a lack of a technical justification for the Franklin system. It was reversed in the ROC (report on comments).
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The end result is Franklin lightning protection system is the approved method of lightning protection system in almost all countries.

I want to submit only some of lightning behavior NOT CONNECTED with the topic of this thread is not understood.For example see

http://discovermagazine.com/2011/apr/08-lightning-unleashes-antimatter-storms

If you still have in mind that even 'some ordinary lightning behavior is not explained/understood,please mention that here.
 
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T.M.Haja Sahib said:
The end result is Franklin lightning protection system is the approved method of lightning protection system in almost all countries.
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I never said that Franklin systems don't, in general work, I just said we really don't have a full understanding of lightning behavior.
 
don_resqcapt19 said:
I never said that Franklin systems don't, in general work, I just said we really don't have a full understanding of lightning behavior.
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As you have meant it, that we really don't have a full understanding of lightning behavior has not prevented us from providing an effective (Franklin) lightning protection system, for our understanding of lightning behavior is good enough.
 
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T.M.Haja Sahib said:
As you have meant it, that we really don't have a full understanding of lightning behavior has not prevented us from providing an effective (Franklin) lightning protection system, for our understanding of lightning behavior is good enough.
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I won't say it is good enough and I won't say that Franklin system will prevent all lightning damage.
 
Here is one example of where the understanding of lightning and NFPA 780 appears to be incorrect.
Rim-seal fires. [FONT=Adobe Garamond Pro,Adobe Garamond Pro][FONT=Adobe Garamond Pro,Adobe Garamond Pro]Rim-seal fires are the most common type of fire for floating-roof tanks, especially external floating-roof tanks. ...[/FONT][/FONT][FONT=Adobe Garamond Pro,Adobe Garamond Pro][FONT=Adobe Garamond Pro,Adobe Garamond Pro][/FONT][/FONT][FONT=Adobe Garamond Pro,Adobe Garamond Pro][FONT=Adobe Garamond Pro,Adobe Garamond Pro]To comply with NFPA 780, operators install roof shunts to dissipate the energy of the lightning to prevent fires. [/FONT][/FONT][FONT=Adobe Garamond Pro,Adobe Garamond Pro][FONT=Adobe Garamond Pro,Adobe Garamond Pro]However, tests for the API RP 545 task group have shown that, rather than reducing the risk of fire from lightning strikes, they may actually be increasing the risk
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[/FONT][/FONT]
 
Let me point out a few things that we can observe from the event of the accident in your original post of this thread that started this discussion.

First is the fact that that we know there was some kind of current that struck the workers, now lets try to see why?

If lightning did strike the bucket, why didn't it hit the top of the much higher crane boom?
Why didn't the lightning hit the top of the much higher building?
Why did the lightning hit the less grounded workers when there most likely was better grounding paths in close proximity of this bucket including the crane cable(wire rope) that held the bucket, re-bar in the forms they were pouring?

Again with all this grounding in and around this bucket it would seem that these workers would have been the last path the lightning would have taken, now if we go back and apply the theory RF energy and how it propagates and how much variable's can play a significance into what the lightning will strike we can see how difficult it would be to say a simple means of just bonding this bucket would guarantee that these workers would have been protected, and that right there is the problem.

If I was the company that was responsible for providing the protection for these workers and I installed this bond and these workers still got hurt or killed I would have most likely been trying to defend my company in a law suit, and I think this is the point that we are trying to make, when you try to make something safer it can open you and your company up to the liability when it fails.

Here in the states there is an old saying, if you remove snow from a sidewalk and someone falls you can be liable for their injuries, but if you just let the snow build up it is an act of god and you can't be found at fault, yes I know that this should not be this way as we should be protected when we act in good faith to lessen the danger for others, but in the real world this doesn't happen, we live in a very litigation world and people will sue over anything they think they can win, I know some other countries don't allow this but not so here in the US.

For this reason is why we see the warnings that most UL certified companies that do lightning protection installs that these installs are only to reduce the damage caused by lightning and in no way will remove the danger that lightning can still pose nor the damage that it can still do, because there is no perfect solution to stop lightning that can be guaranteed to always work, sure we can lower the the effect like in the Franklin rods, but we can not remove all damage that it can cause simply because just like in this event you posted about, it chose to strike a bucket dangling from a steel cable with many much higher metal points of contact including the building and crane.

I'm all about safety and try to apply as much as I can, but at the same time not open myself up to a law suit in doing so.
 
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K8MHZ said:
Would you consider Franklin to have been an authority on the subject?

:lol:
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Back in his time sure since the knowledge in that time was very limited including with Ben himself, but in todays world no, much has been learned, but much more still needs to be learned.

Take the rolling ball theory while widely accepted it has been proven false when lower side mounted antennas were still taking direct strikes on high towers that would have been in this theory's 96% zone of protection, the 15' high tree next to a 300' tower that I have posted about also debunks this theory, even the bucket in the OP event should have been protected in this 96% zone.
 
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Here is the University of Florida's web site on lightning studies and research if anyone wishes to do allot of reading on the subject, look in the left list for "Publications" for papers on test and results.

http://www.lightning.ece.ufl.edu/

Back in 2006 bphgravity posted a great paper on how ineffective a ground rod was at protecting a structure, but I haven't been able to get the forum search function to find it.
 
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hurk27 said:
Back in his time sure since the knowledge in that time was very limited including with Ben himself, but in todays world no, much has been learned, but much more still needs to be learned.

Take the rolling ball theory while widely accepted it has been proven false when lower side mounted antennas were still taking direct strikes on high towers that would have been in this theory's 96% zone of protection, the 15' high tree next to a 300' tower that I have posted about also debunks this theory, even the bucket in the OP event should have been protected in this 96% zone.
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I was being facetious.

Look at Don's sig line....:D
 
hurk27 said:
Back in his time sure since the knowledge in that time was very limited including with Ben himself, but in todays world no, much has been learned, but much more still needs to be learned.

Take the rolling ball theory while widely accepted it has been proven false when lower side mounted antennas were still taking direct strikes on high towers that would have been in this theory's 96% zone of protection, the 15' high tree next to a 300' tower that I have posted about also debunks this theory, even the bucket in the OP event should have been protected in this 96% zone.
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This is one of my favorite lightning pics:

57894main_Shuttle_and_Lightning.jpg

I think this illustrates your point as much as short trees getting hit next to tall towers.
 
Here are some interesting statistics:

Lightning may injure an individual in 6 ways.[2, 3, 4]

Direct strike (approximately 3-5% of injuries)

Side splash from another object (approximately 30% of injuries)

Contact voltage from touching an object that is struck (approximately 1-2% of injuries)

Ground current effect as the energy spreads out across the surface of the earth when lightning hits a distance away from the person (approximately 40-50% of injuries)

Upward leader that does not connect with the downward leader to complete a lightning channel (approximately 20-25% of injuries)

Blunt trauma if a person is thrown and barotrauma from being close enough to experience the explosive force of lightning
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From: http://emedicine.medscape.com/article/770642-overview#a0104

Outside of the reduction of possibility of a direct hit to a human, would someone please explain how perfect bonding and grounding would eliminate the hazards in the other five.

Side splash is caused by ionization. Otherwise, the air around the bolt would be an insulator. All the bonding in the world won't help a person that is touching a metal object that has taken a direct hit. Ground effect, or earth gradient, can't be controlled. It also kills people when HV lines drop to the ground. The difference of potential across a couple feet of ground can be many times more that that which is fatal. Upward leaders are the result of ionization. And, right there at the end is blunt trauma. How can a person not be affected by being inches from an explosion?

Here is a good description of the 'rolling sphere' concept. (Try applying that to my shuttle picture)

http://docs.google.com/viewer?a=v&q...jWsWS5&sig=AHIEtbQ708XTWu_mjENGYuUGIPReHBtlRQ
 
K8MHZ said:
Here are some interesting statistics:



From: http://emedicine.medscape.com/article/770642-overview#a0104

Outside of the reduction of possibility of a direct hit to a human, would someone please explain how perfect bonding and grounding would eliminate the hazards in the other five.

Side splash is caused by ionization. Otherwise, the air around the bolt would be an insulator. All the bonding in the world won't help a person that is touching a metal object that has taken a direct hit. Ground effect, or earth gradient, can't be controlled. It also kills people when HV lines drop to the ground. The difference of potential across a couple feet of ground can be many times more that that which is fatal. Upward leaders are the result of ionization. And, right there at the end is blunt trauma. How can a person not be affected by being inches from an explosion?

http://docs.google.com/viewer?a=v&q...jWsWS5&sig=AHIEtbQ708XTWu_mjENGYuUGIPReHBtlRQ
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This is misleading.You should have quoted from cases of failure of lightning protection systems,if they exist,and in which structures were protected and lightning systems therein maintained per NFPA 780.
 
T.M.Haja Sahib said:
This is misleading.You should have quoted from cases of failure of lightning protection systems,if they exist,and in which structures were protected and lightning systems therein maintained per NFPA 780.
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Was the situation in NJ an NFPA 780 violation?

Let's start there.

For clarification, since the link you posted is now dead, they were on a 53 story building on the fifth level roof deck. They were pouring cement and working with a cement pourer. The basket of the pourer got struck while one worker was touching it.

http://www.jerseycitypersonalinjury...ghtning-at-new-jersey-construction-site.shtml

Now, the only way to have reduced the amount of current that traveled through the worker's body would have been to somehow provide a very low impedance path from the bucket to the metal roofing deck that the worker was standing on. Even so, since lightning seeks any and all paths to ground, some current would still have flowed through the worker, only at a reduced level.

Now, consider the logistics of that. The bucket is moving up and down all day long, sometimes traveling hundreds of feet.

It is not clear if there was any warning of the impending storm or not. What was clear was that the workers were at least 50 feet off the ground, outside, standing on a metal deck while touching a basket supported from a very tall metal structure.

The rolling sphere theory falls all to pieces here. The bucket was supported by a metal structure much higher than the bucket, plus they were standing next to a building that was 53 stories tall. The bolt ignored the top of the crane or support tower, the 500 plus foot tall building, and went in between the two and struck a metal bucket about 50 feet off the ground.

Since I don't have a copy of the regs here, would you please tell me if you think there were any violations to any codes that may have contributed to the accident?
 
Well, I have found different numbers of the total number of building stories, but I did find a picture complete with cranes and towers on Wiki.

http://en.wikipedia.org/wiki/Revel_Atlantic_City

451px-Revel_Atlantic_City_Construction_Summer_2010.JPG

I hope this pic will help you explain the mechanics of your supposed solution to the hazards of a lighting strike while standing on a metal roof along side a 45 plus story building to me.
 
Bing has a great view of the project, right down to the partially finished roof with a boom over it, likely the one that lowered the bucket down.

http://www.bing.com/maps/#JndoZXJlM...5MjEzNTk1OTQzMDclN2UtNzQuNTQ0MjQyODU4ODg2Nw==

If that link doesn't work, go to Bing and search 'Revel' or 'Revel Casino Security Trailer' in Atlantic city.

Just more info for you to help you explain to us what your plan would have been that would have prevented the accident.
 
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