TSA thermal spray aluminium on small diameter piping
TSA thermal spray aluminium on small diameter piping
(OP)
Hi all,
This is a question about TSA.
I noticed on DEP 39.01.10.12 and couple of other client specs, that TSA on piping diameter < 2" is not recommended. I do not have any negative experience for these diameters. I think its possible there may have been difficulty even with flame spray or may not have met the optimal adhesion requirements.
Can anyone share if they know the reasons for this restriction or if you have some idea of what it could be.
SRPEngineer
This is a question about TSA.
I noticed on DEP 39.01.10.12 and couple of other client specs, that TSA on piping diameter < 2" is not recommended. I do not have any negative experience for these diameters. I think its possible there may have been difficulty even with flame spray or may not have met the optimal adhesion requirements.
Can anyone share if they know the reasons for this restriction or if you have some idea of what it could be.
SRPEngineer
RE: TSA thermal spray aluminium on small diameter piping
Steve Jones
Corrosion Management Consultant
www.linkedin.com/in/drstevejones
All answers are personal opinions only and are in no way connected with any employer.
RE: TSA thermal spray aluminium on small diameter piping
It takes almost as much time to properly cover 1.5" as it does 8".
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P.E. Metallurgy, consulting work welcomed
RE: TSA thermal spray aluminium on small diameter piping
a) Quality of TSA adhesion is lower due to inherent difficulty of TSA coating on curvatures of small diameters AND the use of flame spray instead of arc spray (read this difference in a TSA process in a handbook. Although they didn't speak explicitly about small diameters)
b) Applicators manhours are same...but they make less money on 1.5"?? I get the cost part, but does this mean, operators consider the choice of TSA cost prohibitive for small diameters?
The second part does make things more complex since small diameters have higher risk of CSCC on stainless steels. So, I would have thought it makes more sense to try and use TSA for smaller pipes (all else being equal).
Thanks again for your time.
RE: TSA thermal spray aluminium on small diameter piping
RE: TSA thermal spray aluminium on small diameter piping
It is more expensive, relatively speaking to get good TSA and small diameter.
What other options do you have?
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P.E. Metallurgy, consulting work welcomed
RE: TSA thermal spray aluminium on small diameter piping
Steve Jones
Corrosion Management Consultant
www.linkedin.com/in/drstevejones
All answers are personal opinions only and are in no way connected with any employer.
RE: TSA thermal spray aluminium on small diameter piping
Yes, we needed SS and cannot change that.
@Ed
Came across that from talking to few experts in conferences and I also saw DNV-RP-G109 endorsing that opinion. It has something to do with difficulty of coating small diameters and shorter coating life. Debatable... but seems that concern extends to TSA and then the overall cost-benefit analysis might tilt either side depending on one's experience.
Options - I can always foil wrap it.
@Steve
Got it.
About a decade ago there was hardly any standard beyond DEP procedure for TSA quality control (unless I missed something). Now, we have two international standards detailing applicator qualification and requisite testing. It has served my purpose in the past. May be that's why I didn't see the issue surfacing.
Thank you all again. This helps.
SRPengineer
RE: TSA thermal spray aluminium on small diameter piping
Two layers of heavy gage Al foil seems to be the way people usually go.
I know that wrapping is a pain, but then you do get the desired coverage.
In coastal plants you do see a lot of epoxy/urethane coated SS pipe and tube.
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P.E. Metallurgy, consulting work welcomed