K8MHZ
Senior Member
- Occupation
- Electrician
While I am waiting for a response I will try to see if I can find a blue print.
Lugo says he and the others were on overtime when the fast moving storm hit. Others Action News spoke with said they had already left for the day and the job should have stopped till the storm past.
"He made his decision to work. You're responsible for your own safety, but somebody should have said something. Tragedy could have been averted. It's a shame," carpenter John Hoban said.
The non-function shunts are required by NFPA 780, the document you say is the cure all for all lightning protection issues.
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?
But prior to the subject lightning incident,the bucket was so close to the building structure that necessitated its bonding to building structure per NFPA780.
First I want to express my sincere appreciation for your efforts.
5.4 Metal Towers and Tanks.
Metal towers and tanks constructed so as to receive a stroke of lightning without damage shall require
only bonding to ground terminals as required in Chapter 4, except as provided in Chapter 7.
I render to the jury that the provisions outlined in NFPA 780 be considered moot based upon the fact that it does not cover the equipment in question, nor does it indicate any flaw in the construction of the tower supporting the equipment in question.
The way you are dealing with the subject is highly interesting.
As you have mentioned in post no.106,let us wait for four weeks or so till OHSA publishes their report and I hope you may arrange for a link to it.
I did learn something here and that is how bad NFPA 780 really is. Anyone that has grown up in an area with many lightning storms can tell you for sure that the rolling sphere theory is totally inaccurate.
I know of a house fire that was started when lighting hit the electrical / telephone entrance. The surge in the wiring started the fire, but what was interesting was that the homeowner was talking on a cordless phone at the time. When the bolt hit the land line telephone service it surged the house so bad the the hand held the customer was talking on exploded. This was very odd. The firefighter that told me about the incident said he had never heard of that happening before.
The more you are exposed to lightning the more you realize that there is no way to control it or harness it and every system is prone to failure. Sure, we have lightning protection that works 99.9 percent of the time, I know that to be true due to my work with public service radios. I also know, and have witnessed directly what happens when the very best protection system money can buy takes a direct high energy hit. That system was our county central police and fire dispatch system. They were down for nearly two days while repairs were being made.
Cell towers take hundreds of hits and have the best lightning protection known to man, but every once in a while, one can't handle it and goes down.
You misunderstood the way the rolling sphere method works:It is not designed for intercepting ALL lightning.
Perhaps the side flash again the culprit?
Your report is vague.Please support with data.What were damaged?What are the rating of SPD's employed?What are the remedial actions proposed to prevent recurrence of same lightning incident etc.,
Lightning "prevention" or "protection" (in an absolute sense) is impossible. A diminution of its consequences, together with incremental safety improvements, can be obtained by the use of a holistic or systematic hazard mitigation approach, described below in generic terms.
The link also says the munition bunkers can not be provided with lightning protection system.But seeT
http://www.lightningsafety.com/nlsi_lhm/lpts.html
I challenge you to find anything that says any different.
The link also says the munition bunkers can not be provided with lightning protection system.But see
http://www.apd.army.mil/pdffiles/p385_64.pdf which provides detailed procedure for the same.
III. Design Options. The most common lightning protection to structures is external in design. Lightning rods, downconductor wires, and ground rods incorporate the typical approach. In some situations, this configuration may be harmful, inadequate or even unnecessary. Air terminals, for example, on a munitions bunker or on a golf course rain shelter may lead to problems rather than to solutions. Not-so-common external configurations may include catenary screening and other partial Faraday designs. Finally, there are a number of unsubstantiated arrays such as the so called "dissipators" and "streamer modification" products. Caveat emptor.
I read it to mean that the bunkers didn't have air terminals as the system employed did not use them, not that they didn't have any system at all.
What kind of lightning protection they had which would satisfy Richard Kithil?
First some general comments about lightning. It has its own agenda. It is entirely capricious, random, and unpredictable. Man's attempts to fit lightning into a convenient box, with Codes and Standards to describe its behavior, are a best guess.
This is a better explanation:
III. Design Options. The most common lightning protection to structures is external in design. Lightning rods, downconductor wires, and ground rods incorporate the typical approach. In some situations, this configuration may be harmful, inadequate or even unnecessary. Air terminals, for example, on a munitions bunker or on a golf course rain shelter may lead to problems rather than to solutions. Not-so-common external configurations may include catenary screening and other partial Faraday designs. Finally, there are a number of unsubstantiated arrays such as the so called "dissipators" and "streamer modification" products. Caveat emptor.