Hydrotest for the vessel involed in the train incident 1

[kjy313]

I have three vessels which are involved in the train incident during transportation. These vessels are U Stamped vessels. During the survey, I couldn't find any visual damage, dent and scratch on pressure vessels.
So, I and a vendor decided to do MPI for detecting the possible crack. And we concluded that hydrotest would be undertaken as per NBIC accroding to the following criteria.

[Crack will be found --> Repair --> Hydrotest.]
[Crack will not be found --> No repair --> No hydrotest.]

However, my client asked me to do hydrotest the vessels no matter whether or not vessels will be repaired, because these vessels were just involved in the incident. And my client and I have the big argument for this issue so far.

Is my decision for the necessity of hydrotest is correct?
If correct, Dose anyone let me know references and/or experiences for persuading my client?

 

[metengr]

Based on the information you provided above, I would say that your approach is indeed valid from a technical perspective. I would go back to the client after the NDT results are completed, and if no cracks are reported, ask them why they would insist on a hydrotest that would result in no benefit. Have the NDT and inspection of the vessel performed by a 3rd party that is independent to add credibility.

I suppose if the client is willing to pay for the hydrotest, it is their prerogative. But I suspect from your post that the client wants you or someone else to pay for the expense of the hydrotest.

 

[kjy313]

Thanks for reply Mr. Metengr.
You are right. They asked us to pay the expense of the hydrotest.
These vessels were made from carbon steel(SA516-60).
And I found the following statment in ASME Sec.VIII, Div.1.

UCS-56(f)(6):"The vessel shall be hydrostatically tested after making the welded repair."

Could I adversely interpret the above statement as below?
"The vessel is not necessory to be hydrostatically tested in case of no welding repair, forming process.

Also I found that the hydrotest is not mandatory in NBIC RC-2051, even though the repair work is undertaken.

RC-2051 states that "Base on the nature and scope of the repair activity, one or a combination of the following examination and test methods shall be applied to ...."
a. Liquid pressure test
b. Pneumatic test
c. Initial service leak test
d. Vacuum test
e. NDE

Does anyone let me have other supporting references?

 

[metengr]

You covered the essentials.

 

[waskillywabbit]

We had a vessel in transit on a tractor trailer crash into a bridge as the bridge was too low, so the vessel took the brunt of the crash. After numerous inspections, tests and x-rays there was no damage other than the external stiffening ring. It was a good thing that the trucking company had to pay for the repairs as the customer required several that were unnecessary.

If your vessels have no damage and you don't have to repair them, it is pointless to re-hydrotest according to the ASME code and you are crazy if you pay for it. The transportation company should be responsible for any repairs anyway while the vessels were in their care.

Good luck.

Brian

 

[arcer]

Just a couple of thoughts. This sounds like one of those situations we fabricators all dread. There weren't many details provided concerning the 'incident'. In my mind, if the car carrying the vessels came to an abrupt stop, that would be much different from say, being derailed and turning over. I assume it was more like the former. I assume also that the vessels were completed, ( stamped), and enroute to the customer's site, and also the contract was written so that you were responsible for freight? If so, what is the rail carrier's position? Can he be held responsible for costs associated with testing should it be necessary to satisfy your customer? Sometimes we have found it necessary to go beyond what we feel is really necessary just to keep a good customer happy and coming back. Anyway, good luck with resolving this.

 

[kjy313]

The incident details are followings.
"the three disconnected flatbed cars having our three vessels traveling at 3 to 4 mph collided with other set of flatbed cars with my vessels traveling at 4 to 6 mph in opposite direction. The vessels tie-down broke loose and vessels slid forward approx 2 ft to 7 ft. However, the vessels did not contacted with each other or with any other object loaded on the other rail cars. No turning over."

My vendor, a vessel fabricator, contracted a transportation company. And this transportation company took out insurance on the transportation.
So we(I and vendor) can charged the insurance company on most of expenses.
However, I just worry that we can charge the insurance company on the expense for the un-necessity.

Anyway, could you anyone recommend any convenient alternative instead of hydrotest for the worst case?

The packing conditions are
a. several piping spools are assembled with a vessel.
b. all nozzles are blinded with steel plate cover for shipment.
c. Internals, which are suspicious to be plugged during hydrotest, are installed.
d. internal piping is installed.
e. several instruments are installed at the nozzles of vessel.
f. insulation is covered on a vessel.

 

[kjy313]

I would like to correct the details of the incident agaist the above tread as below.

"the three disconnected flatbed cars having our three vessels traveling at 3 to 4 mph collided with other set of cars traveling at 4 to 6 mph in opposite direction. The vessels tie-down broke loose and vessels slid forward approx 2 ft to 7 ft. However, the vessels did not contacted with each other or with any other object loaded on the other rail cars. No turning over."

 

[unclesyd]

I don't have the information available to verify the whys and wherefores but we had 3 instances with railcars(tank). The DOT got involved with all the tank cars.

Two of the cars were designed for FV and 15 psig and were involved in derailments. The damage was minimal on both but one had a spill of hazardous material when it overturned. Both of these were fully inspected using all disciplines of NDT with no defects found. I don't recall the reason but the one involved in the spill was required to have a hydrotest. The second one was sent through the paint shop and returned to service.

The third car was an anhydrous ammonia tank car that wrecked while empty. We had to jump through hoops to get this car back in service. The car was completely inspected as per the original design requirements and some then it was AE tested while hydro testing. No defects were found. The car sat on our siding for nearly a year before it was allowed back in service.


Another incident involved 2 Pressure Swing Absorption Vessels that were involved in traffic accidents. One accident involved a serious injury to a driver and this tied up the vessel for several months that required us to run the process with 2 vessels short. Both vessels received several gouges from sliding down the highway. The scratches were longitudinal, not more than 1/16" deep, with sharp edges. The only concern was that one on of the vessels the gouge crossed the head to shell weld. The scratches were blended out and the vessels were accepted by us and our AI. The fabricators AI insisted on a hydrotest. While we discussing the point about the necessity of same and the added time, the transport companies insurance agreed to pay for the testing for our signature on an unconditional release. We hydrotested both and supposedly spit the cost and the lawyers were to argue the problem with the release.

These vessels were 2 of 16 new that were replacing ones that had failed from H2 assisted fatigue cracking.

 

[deanc]

Why not contact the Jurisdiction where the vessels will be installed for an opinion?

Ask the client to contact their insurance company or whoever writes the certificate.

It already sounds like a major issue. These 2 opinions should help. Make sure you have a detailed report and photos.

 

[eyec]

you have given your customer the technical information they need on the un-warranted additional hydros.

the problem may be that if the (railroad) insurance company also gets the same information they will deny the claim & a judge will end up settling the disagreemnt.

try to explain this to your customer and if they still insist on the additional hydros then explain that you will perform them at an additional cost and they can go back to the railroad's insurance company.

as a side note most jurisdictions require either a hydro or operational pressure test after the vessel has been installed to the attachment welds/nozzles, so the point may be moot and the customer has to pay for this anyway.

 

[Millar]

I agree with deanc. Contact the jurisdiction where the vessels will be installed and ask for their opinion. Where we are located, the jurisdiction would insist on having some input into the matter. I understand that this is not always the case, but if so, whatever agreement you reach with the client might be overurned by the jurisdiction.

 

[chicopee]

Were the three vessels involved in the train accident exposed to heat?

 

[kjy313]

The problem is that the vessels wil be installed in oversea no USA or Canada. No jurisdiction is in that country.
And the accident is not exposed to heat.
Anyway, this matter is almost finalized. I proposed the conditinal hydrotest as followings to the client.
They seem to be satisfied with my proposal, though the offical letter has not been issued yet.

1. The most impacted vessel will be hydrotested.
2. Hydrotest will be conducted without stripping the coating.

And I would like to appreciate your writtings on my issue.