Lightning protection of steel water tank

[MikiBg]

Hi all.
Steel tank for potable water is on the top of steel supporting structure. Early streamer emission device is planned to be installed on the top of it, in order to protect other facilities. Steel supporting structure can be used as natural down conductor. My question is should I use non insulated or insulated protection system, since steel structure as well as tank itself is directly connected to well pumps via steel pipes and water. Is there a potential danger to water users or pumps during lightning discharge?
On the other hand, even if I use a insulated system (which will be far more difficult to install because it will require insulated distance holders) earth termination electrode will still be in touch with pipes and water via surrounding soil and steel structure.
Hope that someone can give me an advice what is a good solution in this case.

 

[magoo2]

I would not trust an early streamer emmision device to provide adequate protection from lightning. There's too much hype on them and their guidelines for application have resulting in a significant number of failures around the world. The standard Franklin rods in my opinion are much more effective and cost-effective besides.

If you're interested in more details, check out a paper by Bill Rison from New Mexico Tech on this subject.

If the down conductor is of adequate size, the pumps should be protected. I favor bare conductor for down leads in addition to the steel supporting structure.

 

[itsmoked]

If you leave bare copper visible and unprotected anywhere it WILL be stolen. Please keep that in mind or it might not be there when it's really needed.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[MikiBg]

magoo, that is a solution by existing and approved design. Personally, I also prefer standard rods or mesh instead of ESE. Can you give me a link to that paper? I couldn't find it online. It might help as additional argument for future projects.

 

[magoo2]

This link has a reference paper on the subject.

http://www.lightningsafety.com/nlsi_lhm/magic.pdf

 

[jmbelectrical]

Just to reinforce what magoo already told you, Early Streamer Emissions systems do not prevent lightning strikes, as advertised. I recall reading a study which contained numerous cases, with accompanying photographic evidence, of buildings equipped with ESE systems that were damaged by lightning strikes. NFPA refuses to recognize it as a legitimate lightning protection strategy for a reason.

 

[MikiBg]

Thank you for the link, magoo.
IEC standard doesn't recognize ESE as a variant of air termination system either, but as I told it's a previously approved solution.

 

[recs]

I would not use an ESE device to provide proper lightning protection. As told, in spite of a ferocious war waged by specialized lightning air terminals suppliers, NFPA and IEEE did not find any credible evidence that they work, on the contrary. But they have an excellent marketing machine.

Regarding the down conductors if they need to be insulated or not. I would run the unisulated. I do not see a safety problem even if for the few milliseconds the lighting current is flowing through the down conductors. If there is proper bonding an following the rules of the NFPA 780 you should be safe with uninsulated down conductors.