Dent on jacketd half pipe

[jtseng123]

Dear all,

A vessel hydrotested,U-stamped and shipped to site, then found 3 mm deep dent on external jacketed half pipe. Half pipe was made of 3" CS pipe with 6 mm minimum thickness. Photos attached. What will be the criteria to justify that it is good for service ? Thanks.

 

[mk3223]

It's a good case to have an investigation per API-579 FFS.

 

[EdStainless]

What moron decided to sit the jacket on a cradle. They should be slapped.

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P.E. Metallurgy, consulting work welcomed

 

[r6155]

1) Where is the procedure of lifting and transport…..?

2) Leave as is if leak testing and penetrant test are without indications.

3) Also try with Ultrasonic test.

Regards

 

[LittleInch]

That's not a dent, it's a dimple.

Some common sense will tell you it's not an issue.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

Some common sense will tell you it's not an issue.

It's not an issue until it's an issue. And the Owner paid for an undamaged vessel.

Due diligence trumps common sense, and the damage should be assessed and mitigated as necessary.

My informal initial reaction to what I see is that:

i) the deformation of the steel should be assessed;
ii) the welds in the area should be inspected (not to the original requirements, but to an extent that provides assurance of integrity). This could include a leak test;
and possibly
iii) re-hydrotest the coil chamber if feasible.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[jtseng123]

As recommended by mk3223, we asked the original fabricator to perform API 579 part 12, Level 3 assessment. However, we don't think they have the knowledge to perform plastic deformation by FEA.
The local area will be PT, will not re-hydrotest the jacketed half pipe.

 

[LittleInch]

If you really really want to spend some money, get some hardness tests and do an MPI and dye pen test to check for cracks. Then check hardness for what the material can be to be within spec.

Or weld a semi circular patch to it.

Or just accept it is a minor defect with no impact on the strength and erect the thing.

If you look carefully enough I'm sure you could find a few little scratches or where the pint has chipped off. where do you stop??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

LI:
1) Hardness testing will not reveal useful information. Where in an ASME Construction Code is hardness testing a basis for acceptance?
2) MT and PT are surface examination methods that will only confirm the integrity of the outer surface. So that is fine as far as it goes.
3) Don't even think of welding a patch.
4) Don't handwave it away it as 'a minor defect'; assess the condition to determine acceptability in the current or remediated condition.
5) Where do you stop? When 4) above has been satisfied.
6) Some spending of money will be necessary. The spending should be done by the Constructor and/or the Shipper.


"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

a)Talk to the insurance company.
b)Think about how long the investigation will take and how it will impact the work schedule.

Regards

 

[mk3223]

I would say that, to resolve the "damage" of the sizable and "critical" equipment, it may need to involve all the parties, including fabricator, shipping contractor, and owner's procurement, management, & engineering. One option could be to have an individual Engineering party to perform an investigation and propose a solutions either to accept as it is or the necessary repair to the Owner for a final decision.