Aluminum Foil wrapping as corrosion protection instead of coating

[LouisRichter]

Hello together,

I am currently reviewing a coating specification written by an oil-and-gas company from Saudi-Arabia.
They specify for "surface of hot insulated stainless steel pipe up to 540 °C: Aluminum foil wrap with minimum thickness of 64 microns'" as corrosion protection.
I really doubt that this system is giving sufficient corrosion protection and I am afraid that it will even promote crevice corrosion.

Has anyone experience with the performance of such system?

Thanks for your support!

[KevGarty]

This is a common application for Thermal Spray. There have been many specs written for the application of TSA (Thermal Sprayed Aluminium) on gas lines for protection against CUI (Corrosion Under Insulation).

When the insulation is wrapped around the pipe, any moisture that is present stays there and eventually corrodes the pipe. Best method for protection is 250 - 350 microns of 1100 grade aluminium.

Just jump on google and search corrosion under insulation / TSA. Im sure you'll find a spec from somewhere. If you cant find anything let me know and I'll see if I have anything lying around

Cheers

[madan.pal]

foil wrapping may not be ideal if the environment can ingress between the substrate and the foil wrapping. Obviously, Al foil will sacrificially corrode to protect the substrate, therefore, the duration of corrosion protection will depend on the rate of corrosion and the thickness of foil.
TSA is a better solution. but as the experts will argue, TSA's also have the inherent porosity which unless sealed naturally or artificially would also promote corrosion. on balance, TSA would be a better solution.
or you can look into more novel solutions, such as; low and high-pressure cold metal sprayed which claims to produce dense (low porosity) and residual stress-free coatings. And, electroless plating of aluminum such as http://ma.ecsdl.org/content/MA2016-02/18/1540.abstract