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6 year old galvanised heating pipe - corrision
What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new.
image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R |
6 year old galvanised heating pipe - corrision
On Mon, 11 Mar 2019 10:37:31 -0700 (PDT)
misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R Accumulation of moisture inside the lagging plus warmth from lagging equals accelerated oxidation? |
6 year old galvanised heating pipe - corrision
"misterroy" wrote in message ... What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R Most likely significant electrolysis due to a ****ed mains earth system and bonding. |
6 year old galvanised heating pipe - corrision
On 11/03/2019 17:37, misterroy wrote:
What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R Do you, by any chance, have an electro-osmotic damp proof course fitted? I have had two instances of *earthed* components in contact with damp masonry corroding in a similarly dramatic fashion. One was a galvanised back-box (which I replaced by setting-in a plastic one), the other was the screws and after that four six inch lengths of 316 stainless steel 6mm studding which I set into the rubble stone wall to support radiator brackets. I havn't had any trouble with other galvanised back boxes, but this one was in a bit of wall which the DPC was spectacularly failing to protect. However given the distribution of corrosion in your case I would be more inclined to associate it with condensation within the insulation, especially in the presence of salts. |
6 year old galvanised heating pipe - corrision
water and air usually or maybe the plating was naff?
Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "misterroy" wrote in message ... What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R |
6 year old galvanised heating pipe - corrision
On 11/03/2019 21:20, Brian Gaff wrote:
water and air usually or maybe the plating was naff? Brian It is actually quite surprising how slowly iron corrodes under normal but adverse conditions. The upper bound on metal loss rate is usually assumed to be 0.1 mm / year even in marine environments. You can get *pitting* at much greater rates than this, which is why car bodywork was so dreadful a few decades ago before manufacturers bothered properly. But 0.1 mm/year explains why Victorian Piers and lock gate mechanisms are still there, even without repainting. |
6 year old galvanised heating pipe - corrision
newshound Wrote in message:
On 11/03/2019 21:20, Brian Gaff wrote: water and air usually or maybe the plating was naff? Brian It is actually quite surprising how slowly iron corrodes under normal but adverse conditions. The upper bound on metal loss rate is usually assumed to be 0.1 mm / year even in marine environments. You can get *pitting* at much greater rates than this, which is why car bodywork was so dreadful a few decades ago before manufacturers bothered properly. But 0.1 mm/year explains why Victorian Piers and lock gate mechanisms are still there, even without repainting. They weren't made of galvanised steel though were they? -- Jim K ----Android NewsGroup Reader---- http://usenet.sinaapp.com/ |
6 year old galvanised heating pipe - corrision
On Monday, March 11, 2019 at 8:33:38 PM UTC, newshound wrote:
On 11/03/2019 17:37, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R Do you, by any chance, have an electro-osmotic damp proof course fitted? I have had two instances of *earthed* components in contact with damp masonry corroding in a similarly dramatic fashion. One was a galvanised back-box (which I replaced by setting-in a plastic one), the other was the screws and after that four six inch lengths of 316 stainless steel 6mm studding which I set into the rubble stone wall to support radiator brackets. I havn't had any trouble with other galvanised back boxes, but this one was in a bit of wall which the DPC was spectacularly failing to protect. However given the distribution of corrosion in your case I would be more inclined to associate it with condensation within the insulation, especially in the presence of salts. Does the earthing cancel out the benefit of galvanising the steel, giving the electrons somewhere else to go? |
6 year old galvanised heating pipe - corrision
On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote:
What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. |
6 year old galvanised heating pipe - corrision
On 12/03/2019 06:47, misterroy wrote:
On Monday, March 11, 2019 at 8:33:38 PM UTC, newshound wrote: On 11/03/2019 17:37, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R Do you, by any chance, have an electro-osmotic damp proof course fitted? I have had two instances of *earthed* components in contact with damp masonry corroding in a similarly dramatic fashion. One was a galvanised back-box (which I replaced by setting-in a plastic one), the other was the screws and after that four six inch lengths of 316 stainless steel 6mm studding which I set into the rubble stone wall to support radiator brackets. I havn't had any trouble with other galvanised back boxes, but this one was in a bit of wall which the DPC was spectacularly failing to protect. However given the distribution of corrosion in your case I would be more inclined to associate it with condensation within the insulation, especially in the presence of salts. Does the earthing cancel out the benefit of galvanising the steel, giving the electrons somewhere else to go? I was going to say no, that earthing is necessary to close the circuit. Making the DPC conductor positive steals electrons from the piece of metal, turning them into ions which are then mobile instead of being part of the structure. But on reflection I think you are saying the same thing. It's electroplating in reverse. Similar to the way that sacrificial anodes are used to prevent corrosion of marine hulls, etc. |
6 year old galvanised heating pipe - corrision
On 12/03/2019 00:04, Jim K.. wrote:
newshound Wrote in message: On 11/03/2019 21:20, Brian Gaff wrote: water and air usually or maybe the plating was naff? Brian It is actually quite surprising how slowly iron corrodes under normal but adverse conditions. The upper bound on metal loss rate is usually assumed to be 0.1 mm / year even in marine environments. You can get *pitting* at much greater rates than this, which is why car bodywork was so dreadful a few decades ago before manufacturers bothered properly. But 0.1 mm/year explains why Victorian Piers and lock gate mechanisms are still there, even without repainting. They weren't made of galvanised steel though were they? No, galvanising allows even thinner sections (corrugated iron, for example) to survive for decades. |
6 year old galvanised heating pipe - corrision
newshound Wrote in message:
On 12/03/2019 00:04, Jim K.. wrote: newshound Wrote in message: On 11/03/2019 21:20, Brian Gaff wrote: water and air usually or maybe the plating was naff? Brian It is actually quite surprising how slowly iron corrodes under normal but adverse conditions. The upper bound on metal loss rate is usually assumed to be 0.1 mm / year even in marine environments. You can get *pitting* at much greater rates than this, which is why car bodywork was so dreadful a few decades ago before manufacturers bothered properly. But 0.1 mm/year explains why Victorian Piers and lock gate mechanisms are still there, even without repainting. They weren't made of galvanised steel though were they? No, galvanising allows even thinner sections (corrugated iron, for example) to survive for decades. And Victorian piers & lock gates are probably cast iron not steel? -- Jim K ----Android NewsGroup Reader---- http://usenet.sinaapp.com/ |
6 year old galvanised heating pipe - corrision
On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote:
On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT |
6 year old galvanised heating pipe - corrision
On Tuesday, 12 March 2019 18:52:04 UTC, wrote:
On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The reason why galv water tanks rusted was the copper pipes they were attached to. Now we have plastic tanks. Generally, any inhibitor in the system won't be in the header tank, just in the pipework. Obviously, a problem if it's a galv.steel tank. But it protects steel radiators in a copper pipe system. (Somewhat) Another reason to use plastic pipe instead of copper. |
6 year old galvanised heating pipe - corrision
On Tuesday, 12 March 2019 18:52:04 UTC, wrote:
On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The way galv tanks are protected is with a magnesium "sacrificial anode" Has to be replaced every few years as it "rots" away instead of the tank. https://en.wikipedia.org/wiki/Cathodic_protection http://www.waterheaterrescue.com/Lon...er-anodes.html |
6 year old galvanised heating pipe - corrision
In article , harry
wrote: On Tuesday, 12 March 2019 18:52:04 UTC, wrote: On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The reason why galv water tanks rusted was the copper pipes they were attached to. Now we have plastic tanks. Generally, any inhibitor in the system won't be in the header tank, just in the pipework. Obviously, a problem if it's a galv.steel tank. You normally pour the inhibitor into the header tank from where it circulates round the system. -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
6 year old galvanised heating pipe - corrision
On Wednesday, 13 March 2019 10:26:56 UTC, charles wrote:
In article , harry wrote: On Tuesday, 12 March 2019 18:52:04 UTC, wrote: On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The reason why galv water tanks rusted was the copper pipes they were attached to. Now we have plastic tanks. Generally, any inhibitor in the system won't be in the header tank, just in the pipework. Obviously, a problem if it's a galv.steel tank. You normally pour the inhibitor into the header tank from where it circulates round the system. You won't get much in the system if you do that. The system has to be partially drained and then the inhibitor added to get in in the pipework/radiators. |
6 year old galvanised heating pipe - corrision
On 13/03/2019 10:25, charles wrote:
You normally pour the inhibitor into the header tank from where it circulates round the system. Or if no header tank, the highest rad after you have de pressurised the system a bit and let some air in. -- €œSome people like to travel by train because it combines the slowness of a car with the cramped public exposure of €¨an airplane.€ Dennis Miller |
6 year old galvanised heating pipe - corrision
In article , harry
wrote: On Wednesday, 13 March 2019 10:26:56 UTC, charles wrote: In article , harry wrote: On Tuesday, 12 March 2019 18:52:04 UTC, wrote: On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The reason why galv water tanks rusted was the copper pipes they were attached to. Now we have plastic tanks. Generally, any inhibitor in the system won't be in the header tank, just in the pipework. Obviously, a problem if it's a galv.steel tank. You normally pour the inhibitor into the header tank from where it circulates round the system. You won't get much in the system if you do that. The system has to be partially drained and then the inhibitor added to get in in the pipework/radiators. That goes without saying. and you will stll have some inhibitot in the header tank -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
6 year old galvanised heating pipe - corrision
On Wednesday, 13 March 2019 08:08:49 UTC, harry wrote:
On Tuesday, 12 March 2019 18:52:04 UTC, tabby wrote: On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The way galv tanks are protected is with a magnesium "sacrificial anode" Has to be replaced every few years as it "rots" away instead of the tank. https://en.wikipedia.org/wiki/Cathodic_protection http://www.waterheaterrescue.com/Lon...er-anodes.html thanks, useful. Galv tanks are so much cheaper than copper. NT |
6 year old galvanised heating pipe - corrision
On 12/03/2019 18:15, Jim K.. wrote:
newshound Wrote in message: On 12/03/2019 00:04, Jim K.. wrote: newshound Wrote in message: On 11/03/2019 21:20, Brian Gaff wrote: water and air usually or maybe the plating was naff? Brian It is actually quite surprising how slowly iron corrodes under normal but adverse conditions. The upper bound on metal loss rate is usually assumed to be 0.1 mm / year even in marine environments. You can get *pitting* at much greater rates than this, which is why car bodywork was so dreadful a few decades ago before manufacturers bothered properly. But 0.1 mm/year explains why Victorian Piers and lock gate mechanisms are still there, even without repainting. They weren't made of galvanised steel though were they? No, galvanising allows even thinner sections (corrugated iron, for example) to survive for decades. And Victorian piers & lock gates are probably cast iron not steel? Cast iron and "ordinary" steels (like anchor chain, for example) have very similar corrosion rates in marine environments. |
More Heavy Trolling by Senile Nym-Shifting Rot Speed!
On Tue, 12 Mar 2019 07:32:07 +1100, Jac Brown, better known as cantankerous
trolling senile geezer Rot Speed, wrote: Most likely significant electrolysis due to a ****ed mains earth system and bonding. No mains earth system could ever be as ****ed as your senile head, senile Rot! -- Bod addressing abnormal senile quarreller Rot: "Do you practice arguing with yourself in an empty room?" MID: |
6 year old galvanised heating pipe - corrision
On Wednesday, 13 March 2019 12:59:32 UTC, wrote:
On Wednesday, 13 March 2019 08:08:49 UTC, harry wrote: On Tuesday, 12 March 2019 18:52:04 UTC, tabby wrote: On Tuesday, 12 March 2019 07:41:21 UTC, harry wrote: On Monday, 11 March 2019 17:37:33 UTC, misterroy wrote: What could have caused the heating pipe to corrode so badly that it failed? It was next to an external wall and lagged. The are a couple of lengths of the pipe lying outside the building unused for the same 6 years, other than the threaded ends, they look new. image https://drive.google.com/open?id=1o8...cqBdRGYatmQb6R If it is attached to copper pipe elsewhere in the system, zinc and copper are perfect for galvanic action. Depends too on the quality of the water in the system. Inhibitors are available. Is there some way to stop this corrosion in a CH system using copper pipes & a galvanised steel cylinder/tank? NT The way galv tanks are protected is with a magnesium "sacrificial anode" Has to be replaced every few years as it "rots" away instead of the tank. https://en.wikipedia.org/wiki/Cathodic_protection http://www.waterheaterrescue.com/Lon...er-anodes.html thanks, useful. Galv tanks are so much cheaper than copper. NT There's the cost of the sacrificial anode replacements to consider too. |
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