passivation for syltherm CS pipe and fittings

[chinwar]

I got one spec from my client for syltherm CS (API 5L) piping. It asked all piping system to be shot blasted to SA 2.5 internally and passivated after blasting. Could anyone commented what's the purpose for this?

Thanks and Regards,

 

[kenvlach]

Maybe force of habit since SOP to passivate stainless after shot blasting.

Passivation should clean up the CS surface; depending upon passivation agent, it might also slightly smooth the surface. So, it could help & can't hurt the corrosion resistance.

What passivation solution do you intend to use?

 

[chinwar]

thank you, kenvlach.

The spec does really not mention how to do passivation. I am not familiar with Syltherm XLT and totally have no idea about this requirement.

 

[unclesyd]

Here is the Dow recommendations for piping systems for their heat transfer fluids. I don't see any recommendation for blasting and pickling and passivating standard weight pipe though there are recommendations that tubing be pickled and oiled.

I would give Dow a call and there there recommendations for procedure for standard weight pipe. Since Syltherm XLT is silicone material I would be hesitant to use use anything without Dow's approval.
They are good people to work with.

http://www.dow.com/heattrans/info/info3.htm?filepath=&fromPage=BasicSearch