Copper Pipe Corrosion Under Phenolic Foam Insulation 2 - Eng-Tips

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 ) 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 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.

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