Copper Pipe Corrosion Under Phenolic Foam Insulation 2

[briand2]

I've seen various conflicting articles / reports / papers concerning corrosion of the outer surface of copper pipes (particularly carrying chilled water) insulated with phenolic foam insulation.
On the one hand, the viewpoint of the European Phenolic Foam Association (December 2000) is that "EPFA can state categorically that phenolic foam products manufactured by its members do not present an enhanced corrosion risk in comparison to other commonly used insulation materials."
On the other hand, the (UK) manufacturer Yorkshire Pressfit states "When insulation copper tube with pheolic foam it is important that moisture or condensate does not occur between pipework and insulation. In order to prevent agressive moisture inducing corrosion problems, some lagging manufacturers provide their products complete with a factory applied sodium silicate barrier, whilst others recommend the use of Densopaste."
Also the Copper Development Association states "Some manufacturers of rigid phenolic foam insulation materials recommend that a moisture barrier be installed at the tube/lagging interface. Moisture between the tube and lagging may lead to external corrosion of the copper tube."
Furthermore, the UK Mineral Wool Association states "Mineral wool pipe insulation is chemically inert and compatible with copper and steel pipework...This means that mineral wool, unlike some foamed plastic insulants which are inherently acidic, does not require any special coatings to prevent chemical attack. This chemical neutrality is important when leaks occur, because water picks up chemicals from the insulation material. Problems have arisen with phenolic foam insulation, which has a very low pH factor in the 1.5 to 3.5 range. Water leaching through phenolic foam therefore becomes very acidic and is highly corrosive to steel and copper pipework and fittings."
Finally, Kingspan Industrial Insulation Limited presents in its publication "Insulants and Corrosion" the methodology and results of various independent tests and concludes "In conclusion, based on Kingspan's extensive in-service experience over 17 years and third party tests, it has been proven that phenolic foams manufactured by British Petroleum / Kingspan technology do not give an enhanced corrosion risk compared to other insulation materials."

Given the broad range of (perhaps slightly partisan!) views, I'm a little confused as to what the true situation is. It looks like a HVAC job with which I'm to be involved has a corrosion problem on copper pipes (about two years old) insulated with rigid phenolic foam insulation, and I'd like to be fully prepared when the expected "discussion" begins! Can anyone provide real life examples to support (or otherwise!) the common industry views as presented above?

I've posted this in Piping & Fluid Mechanics; would it have been better posted in Corrosion?

Thanks,

Brian

 

[BigInch]

Sorry, no experience with that stuff.
I'm just wondering why you have reason to disbelieve what you're looking at right now. Thanks for the heads up on this stuff.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[briand2]

My "reason to disbelieve what you're looking at right now" is that the range of views runs all the way from phenolic is perfect (phenolic manufacturer) to phenolic is very risky (mineral wool manufacturer)!!

The truth may lie somewhere between (?), and I'm hoping someone has direct experience and can share that!!

Thanks,

Brian

 

[gerhardl]

I am not a corrosion expert, but let me try some views anyway:

Concentrate of your cited papers: For some instances involving certain phenolic materials corrosion have seemingly occured on some copper pipelines. For other cases not.

Facts:

a)Copper is not copper: types of fabrication, alloy components in datail, surface details and roughness and overall quality (impurities, variation on above data), temperature, layout of pipeline, couplings, fasteners, galvanic corrosion details will all more or less contribute to possible corrosion.

b)Phenolic insulation is not phenolic insulation: component details, fabricating methode, pores, internal structure, surface, and component application and fastening methode to piping, including protection agains air (moisture) to penetrate to copper pipeline, and water pockets allowed to rest against pipeline will be factors for and against possible corrosion.

c)Other factors will contribute:
Age of insulation? Temperature history? Surrounding conditions? etc...

First question in discussion: can any of the factors above, or some few in combination, be singeled out as the main reason for corrosion?

Second question:
Could it within reason be foreseen that the corrosion would occur, and should it within reason have been prevented?

If the installer/end user have used normal procedures and informed exatly about all factors possibly releasing any extra precautions, and layout and installment are OK, the responsibillity reflects back to the material suppliers in my opinion.

 

[wozza20]

To briand2
I am in a similar position to where you were in March . Phenolic insulation on copper pipework and premature failure of the pipework due to corrosion .
I would like to know how this worked out for you , what you discovered and your conculions

 

[specialk1020]

I work for a large rigid phenolic manufacturer operating in Canada. in my time of installing the product in this climate and in the tropics I have seen several examples of quick failure of the entire insulating system when the phenolic foam is used on cold applications, especially chilled water.
The problem with the insulation is that on paper and at first use it seems to be the solution to all problems.
-It has a closed cell structure,
-Supposedly it is non wicking,
- Manufacturers claim it can be used on cryogenic applications,
-It can be used on heating, and at half! the thickness of conventional fibreglass and mineral fibres, due to its high k-factor.

Unfortunatley only some of this is true. It is not in fact closed cell, it does wick, and once its wet it never dries especially with a vapour barrier. And it releases highly corrosive chemicals once its wet, and on cold applications it will never dry. Especially in the tropics where systems operate constantly.
Dont use it on cold work is definatly my stance and I live in fear of callbacks from every job on which I used the material. A seemingly unimportant componenet of the entire system can bring down the entire system by ncorroding the piping and shortening the lifespan, increasing the headaches and maintainance, mold growth is also a huge side effect of wet insulation.

 

[gerhardl]

specialk1020 - thank you for enlightening information!

Do I understand you correctly that this could occur even if the insulation is applied under ideal conditions, and that the cold filling / warm & moist surroundings occur later by startup and normal running?

 

[Chalky1]

It would seeem from the media that corrosion caused by phenolic foam is a widespread occurence: I have read numerous stories about steel roofs (particularly in the US)corroding well before their time because of phenolic foam insulation.

I started looking into this because a building near where I work in the City of London recently filed a £3.5 million lawsuit against a contractor because of widespread corrosion on their pipework.

http://www.thelawyer.com/links-sues-builders-over-leaking-pipes/1002369.article

What the betting they used phenolic foam?

 

[briand2]

Chalky1,

"What the betting they used phenolic foam?"

Keep your money in your wallet, there's no such thing as a poor bookmaker! The particular London job to which you refer did not involve phenolic foam insulation.

Regards,

Brian

 

[Chalky1]

Hi briand2

I didnt expect such a quick repsonse!! Thanks though...