How to test pressure vessel corrosion in field

[Gfhurex]

We have to test few sand media filters pressure vessels in the field after emptying them to determine if they suffer corrosion due to service and repair them if necessary.

We need a quantitative test that can be performed at site that will tell if they actually suffered corrosion.

What is the best method to do this?

 

[StoneCold]

Ultra sonic thickness testing would be the best method. However you are going to be in a little bit of a quandary because you don't have baseline thicknesses to start with. In this case you will have to use nominal plate thickness given on the U1 reports. If your plates were under or over it will throw off your assessment and your estimated corrosion rate. But UT will tell you if the vessels are too thin to continue to use.

Regards
StoneCold

 

[Gfhurex]

Thank you stonecold

Is this test the only one?

Or there are other alternatives?

Will xray testing or dye penetrating tests work as well?

 

[SJones]

What happened to good old close visual inspection, or are the vessels not suitable for entry? If entry is not possible then have a read of this document:

https://exchange.dnv.com/Publishing/Codes/download.asp?url=2011-01/rp-g103.pdf

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[darthsoilsguy2]

As far as NDT goes for normal pressure vessels (not knowing the particulars of yours), the UTT is the way to go. Also, Wet Florescent Mag Particle for a percentage of seam welds is also an appropriate and regularly performed NDT for vessels.

you should have no problem finding an experienced engineer, api 510, or national board inspector to look at that. Do be aware that there are a lot of firms out there that do this as side-work to their normal business which is new construction NDT. Those should be avoided because they too often get lost playing to their strength, which is NDT, and often are weak in the understanding of the vessel and thorough visual inspection departments.