Hydrostatic Test using Water vs Lubricating Oil

[jcat4]

Hi All,

What is your opinion on the use of water versus lubricating oil when performing a shell side hydrostatic test on a tube bundle (according to ASME BPVC Section VIII - Division 1)? We are mostly concerned with discovering leaks at the tube-to-tubesheet joints.

The fabrication of our tube bundle is nearing completion and our manufacturer recently advised that they prefer to perform the shell side hydrostatic pressure test with water instead of our specified lubricating oil. We initially stipulated the use of lubricating oil in our contract documents to ensure there would be no water contamination of the lubricating oil system once the tube bundle was placed in service. However, we are considering the possibility of allowing this change request.

I realize that ASME BPVC Section VIII - Division 1 indicates that "Any nonhazardous liquid at any temperature may be used for the hydrostatic test if below its boiling point." So, either water or lubricating oil seems to be acceptable.

However, are we making it "easier" for the manufacturer to pass the shell side hydrostatic test by using water instead of the lubricating oil? Or could a test with water be considered technically equivalent to a test with lubricating oil?

Any information would be greatly appreciated. If there is already a thread on this topic, then please provide the link. I tried using the search tool but could not find any relevant results.

 

[SnTMan]

jcat4, is your oil more likely to penetrate into a leak than water, is it thinner?

With proper measures it should be possible to completely dry the shell side of the unit unless some unusual design feature prevents it. Is your manufacturer able to, for example, hot air dry and N2 purge?

Water is a whole lot easier to get rid of following the test, and it can be bad enough these days.

Regards,

Mike

 

[jcat4]

Thank you very much for your quick response SnTMan.

Considering a temperature of 15°C for comparison, the lubricating oil has a higher dynamic viscosity than water. So, the lubricating oil is thicker than water. As per your reply, I guess this indicates that it would be more difficult to pass a shell side test with water because it is more likely to penetrate a leak than the thicker lubricating oil.

Yes, the manufacturer has advised they would be able to hot air dry the shell side of the tube bundle but I am unsure of a N2 purge.

So, I believe testing with water will not give an "advantage" to the manufacturer and with a careful drying procedure, we can ensure there would be no water contamination of our lubricating oil system.

Thanks again for all of your help.

Jennifer

 

[rmw]

Our LO Hx's are hydrotested with water, dried, and then flushed with LO to a tight cleanliness standard.

rmw

 

[jcat4]

Your input is greatly appreciated rmw.

Thanks,

Jennifer