water pipe issue

[driverman]

Hi again, another one to wet your appetite. This has been seen on several different bollards around a particular caravan site. The site will be investigated at some point to establish exactly what is happening and why.
The Bollards have electric sockets, water meter + taps on them. Hopefully the photos are attached. As you can see the water pipe has been affected by something. Cheap piping has been ruled out. All the distribution circuits to the bollards are RCD protected as well as the sockets on the bollards.
I've got a sneaky feeling it could be..electrolysis somehow via the water, but not going through any RCD's. Is it possible? Any one had experience of this before?
i suppose could disconnect earthing t.o bollard, then see if any volts founds across pipe and neutral

 

[GB.Kayak]

Hi again, another one to wet your appetite. This has been seen on several different bollards around a particular caravan site. The site will be investigated at some point to establish exactly what is happening and why.
The Bollards have electric sockets, water meter + taps on them. Hopefully the photos are attached. As you can see the water pipe has been affected by something. Cheap piping has been ruled out. All the distribution circuits to the bollards are RCD protected as well as the sockets on the bollards.
I've got a sneaky feeling it could be..electrolysis somehow via the water, but not going through any RCD's. Is it possible? Any one had experience of this before?
i suppose could disconnect earthing t.o bollard, then see if any volts founds across pipe and neutral
View attachment 29528

d, was there a brass fitting on the end of the copper pipe in the foreground like the one in the background?

 

[Darkwood]

I would suggest poor manufacture and or installation practices has caused this and maybe due to a lube or flux used to allow the gland to be slid on easier, it could also be a anti corrosion coating applide to the brass gland reacting with the copper. Lubricants and flux can contain corrosive elements and should be applied sparingly and clean or flushed out after use to ensure no residual coating/pools exist.

That copper pipe looks like its painted (not bare) and it could even be this reacting with the brass gland.... hard to tell if it is painted.

 

[DPG]

Looks like the old red-lead paint to me. Daz

 

[driverman]

I would suggest poor manufacture and or installation practices has caused this and maybe due to a lube or flux used to allow the gland to be slid on easier, it could also be a anti corrosion coating applide to the brass gland reacting with the copper. Lubricants and flux can contain corrosive elements and should be applied sparingly and clean or flushed out after use to ensure no residual coating/pools exist.

That copper pipe looks like its painted (not bare) and it could even be this reacting with the brass gland.... hard to tell if it is painted.

re pipe: not painted.......that is the color of the pipe when affected, possibly through heat? Just one sweated joint done whilst in production. No force applied when installing apart from doing nuts up. You can just make out the water meter, the other end is just a tap. One pipe discovered has even had small holes in. I'll try to upload another pic.

 

[driverman]

this may be a better pic

 

[GB.Kayak]

this may be a better picView attachment 29531

d, it looks to be cold water pitting corrosion https://en.m.wikipedia.org/wiki/Cold_water_pitting_of_copper_tube ... though I am at a loss as to why it is occurring on the outside of the pipe. It may be that the insulation is keeping water in contact with the pipe. The red colouration appears to be cuprous oxide.

Is the water 'soft' and does it come from a borehole?

 

[ifindoubtdont]

That looks very much like galvanic corrosion i've seen a lot of it on my boat propellers. A sacrifice piece is needed. ( FAQ: What is galvanic corrosion and how can it be avoided? )

 

[GB.Kayak]

I would suggest poor manufacture and or installation practices has caused this and maybe due to a lube or flux used to allow the gland to be slid on easier, it could also be a anti corrosion coating applide to the brass gland reacting with the copper. Lubricants and flux can contain corrosive elements and should be applied sparingly and clean or flushed out after use to ensure no residual coating/pools exist.

That copper pipe looks like its painted (not bare) and it could even be this reacting with the brass gland.... hard to tell if it is painted.

d, it is unlikely to be the pipe 'reacting with the brass gland'. Brass being an alloy of Copper and Zinc is more electropositive than Copper, and Zinc is right at the top end of the scale. That is why in some areas of the UK it is vital to use dezincification resistant brass alloys; the Zinc is leached out of the alloy by the acidity in the water and it looses its strength. However, if there was any carbon on the surface of the copper it may have caused this type of corrosion but there needs to be an electrolyte, water + CO₂ for example, in order for the process to occur. Where did the moisture in the joint, where the corrosion appears to have occurred, come from?

 

[Redvanman]

Looks like something my ex had in her top draw

 

[driverman]

Thanks for that........I'll read digest later

 

[GB.Kayak]

That looks very much like galvanic corrosion i've seen a lot of it on my boat propellers. A sacrifice piece is needed. ( FAQ: What is galvanic corrosion and how can it be avoided? )

i, in order for the Copper to undergo galvanic corrosion, there needs to be electrical and electrolytic contact with a substance that is more electronegative than it. There are not many things that are more electronegative than copper ... Bronze, Stainless, Monel, Silver, Carbon and Gold on the scale that I was looking at.

 

[alanl]

I'd second galvanic corrosion.
Look at the first pic - mains cables going through a steel enclosure then touching a copper pipe.
Perfect conditions for galvanic corrosion - just a little dampness in the air will trigger it.

 

[driverman]

I'd second galvanic corrosion.
Look at the first pic - mains cables going through a steel enclosure then touching a copper pipe.
Perfect conditions for galvanic corrosion - just a little dampness in the air will trigger it.

Those cables touching the pipes are for frost protection. (heat trace cables)

 

[alanl]

But, they will also induce a current in any metalwork they run against, promoting the corrosion you see.

 

[driverman]

But, they will also induce a current in any metalwork they run against, promoting the corrosion you see.

The thing is though..............these are sold / installed all over the country to the exact same spec. Problem is on just one particular site / installation.

 

[GB.Kayak]

The thing is though..............these are sold / installed all over the country to the exact same spec. Problem is on just one particular site / installation.

... I refer you to my earlier posts ... cold water pitting corrosion ... galvanic corrosion requires dissimilar metals and the metal that corrodes is the more reactive not less reactive material; copper appears at first sight here to be the least reactive metal ... unless it is in contact with gold or silver!

 

[alanl]

Have a read of what happens to canal boat hulls and fittings. It is common for non-protected copper alloys to corrode away to nothing.
From the first page when googling: "The most common casualty of galvanic corrosion is a bronze or aluminum propeller on a stainless steel shaft, but metal struts, rudders, rudder fittings, outboards, and stern drives are also at risk. The way we counteract galvanic corrosion is to add a third metal into the circuit, one that is quicker than the other two to give up its electrons. This piece of metal is called a sacrificial anode, and most often it is zinc. In fact, most boaters refer to sacrificial anodes simply as zincs."