Pipeline failure (through hole) due to lightning 1

While I don't think it is out of the question (it has been known since on or before the time of our Benjamin Franklin that the many thousands of volts and amperes of some lightning strikes can pretty much do what/go where they want to!), I believe I have heard of a great many more, though perhaps non-obvious failures of plastic piping in lightning strikes (even though same are relative newcomers to the field, with a whole lot less out there) then legacy iron and steel, perhaps for the reasons you describe. In addition to normally quite catastrophic splits of e.g. pvc water and irrigation pipes in lightning events, polyethylene plastic pipe has also been reported to be perforated by build-up and eventual discharge of static electricity e.g. per .

The article in the OP is about lightning striking PE coated pipe. It is possible for lightning to strike a hole through the PE coating. This would concentrate corrosion into this small area, which could result in a hole in the steel pipe after some time.

CostasV said:

Is it only me who finds this explanation groundless?

Click to expand...

Nah, I'd say it's shocking.

Lightning supposedly can be blamed for many pipeline leaks. Somebody was making that claim in the US a few years ago, having plotted pipeline leak locations with known lightning strike locations. As I recall there was some question as to the accuracy of the lightening strike locations.

This article in Pipelines OZ appears to substantiate the possibility,

I have sort of seen one: A smooth clean conical shaped hole about 15mm on the outer surface . SEM found high AL in the surface metal. The power company told us lightening knocked down one of their AL lines , it fell into the open ditch before the new line was buried and melted the hole in the pipe. So , sort of caused by lightning.

Thank you for your comments.

Compositepro: The article says that the hole in the steel pipe was not due to corrosion. The crater formation was an indication or proof that lightning, or other electrical discharge caused it. Which I doubt it.

Gator:

BigInch: Yes, I have read it...

blacksmith37: Yes, this makes sense.


When electric transmission cables are hit by lightning, do they melt? Anyone knows?

I agree that lightning cannot directly create a hole in thick metal. Aluminum aircraft are struck by lightning quite frequently, without significant damage.

however aircraft skins are thin
flight instructor

That picture is of a composite (non-metallic) nose cone, likely with a radar behind it. The rows of dots are lightning directors, which try to direct lightning to the metal fuselage, and are only used on non-conductive parts.. Composites are very susceptible to explosive damage due to lightning strike. Radomes must be transparent to radar and therefore cannot be metallic. Most composite aircraft have a metal mesh on the outer surface, under the paint, for lighting protection.

Either way, not especially comforting to see those.

There is perhaps a similar parallel in sorts of composite flex pipes that have made their way via low cost and convenience into even various domestic natural gas service lines and connections (per reports e.g. seems just don't drain the current quite as well as the old, thicker or hard-piped metal systems - also not too comforting, as same can be closer to the homes of many than those birds normally at 30-40K feet!)

They are also usually a lot farther away from the lightning. Don't use them for grounding connections though.

Yes, I believe so because I have seen a failure due to lightning, or at least we could come up with no other explanation. The issue is the coating on the pipeline, which is dielectric, but where you get entry and exit of the current due to coating damage/holidays, the current becomes concentrated, in that it will leave the steel all at one small area, and presumably cause the failure. In our case, and others, the corrosion like indication left is perfectly circular, ours looked almost like a bullet hole. Of course, there was a thunderstorm in the area the night of the failure.

I likewise heard several years ago of a "perfectly circular" hole found in a cross-country pipeline many years ago that also had many folks struggling for an "explanation" (i.e. until a drill bit was eventually found broken off in the pipe wall down the line!)

I think you need to look at age of the pipeline, quality of the coating, thickness of the pipe and ground type.

When a lighting bolt strikes the ground there is clearly some voltage gradient existing there, hence the reason they tell you not to stand with your legs apart next to tree in a thunderstorm.

I've seen a simple graph saying it could be 3kV/m at some distance (5m) from the strike.

If the strike is directly above a buried line 1m deep, this implies the ground around it is possibly at 10 - 100kV or more for a short duration.

Assuming you have a good quality coating, then it shouldn't affect the pipe - even a thin FBE coating can withstand 10,000V during holiday testing so with PE it's probably a lot more.

However a small existing hole in an otherwise well coated pipe will concentrate that current into a small point before it dissipates in the rest of the pipe. The pipe will conduct electricity much better than the ground so will become the lightning rod in effect for the local ground within 5m or os from direct strike.

I still think you've got to be quite unlucky and I would like to guess that all the failures are in pipes <5mm, though one article did not that they found depressions in thicker pipes from intelligent pig runs.

So groundless - no. Likely, also no. Possible - Yes

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

LittleInch,
...if a fraction of the total lightning current is concentrated because of a hole in the coating, and this concentration is able to melt the 5 mm wall, then the 100% of the lightning current that hits electrical cables, cars and air terminals should also melt at least 5mm around the hitting point. Which, as far as I know, does not happen.

The skin effect applies to all metallic objects hit by high frequency current, isn't it?

Well that because the area affected in sheet steel is much much bigger - that's the point. As soon as the lightning strikes a car the voltage and current spreads over a much bigger area. The FBE and PE coating are really good insulators - that's what is around your high voltage wires.

It's pretty rare and I would hazard a guess only happens in fairly dry sandy soils where the ground conductivity isn't as good as it is in a lot of other places and hence the voltage gradient is much higher by the time it gets to the pipe.

Still kind of heats up the car a bit though...
skin effect and high frequency current are different things to lightning strikes I think.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

I was in a DC-9 on landing approach in a snow storm when we were struck by lightening. It blew through the galley like it is supposed to. Knocked out all aux power on the plane (lights, AC, and so on) and left a hole in the floor plate the size of you fist.

Saw a structural column nearly cut off by lightening once. It struck an adjacent tower, when it got to about 6' above ground the building was close enough to offer a better ground path. It was melted, twisted, and a lot of metal was missing.




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P.E. Metallurgy, Plymouth Tube

Yes skin effect shouldn't apply.

I have trouble with a melted hole in a buried pipeline. Before I'd expect the pipe to melt, with its superior electrical and thermal conductivity, verse the 'dirt's lousy conductivity', you should probably see melted dirt and glass-like fingers near any pipe insulation holes.

Keith Cress
kcress -