How lucky do you feel? Hydrotest is only as good as the day it is performed. Undiscovered defects may be growing. What does the plant mechanical integrity programme require in terms of inspection if one of the inputs to the risk assessment is: insufficient NDT during manufacture?

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

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

Hidrotest is usual done after the others anterior NDT done and just before start up. Considering that NDT was not fully completed or not compliant to Code requirement, and considering that happily the equipment/pressure vessel/piping/facility was successfully hydrotested and operated for almost 2 years now, it is mandatory that you make a risk assessement to your system with all NDT required. As SJones said hydrotest is only as good as the day it is performed.

luis

Allow me to be argumentative.

Hydrotesting is done to mimic the severest condition of operation. NDT in 99.99% of the time, does not in itself certify a facility.

There is no penalty by the Code if any NDT was not done or not done at all, unlike pressure testing which is compulsory and would entail numerous penalties and additional safeguards (“golden weld”) if pressure testing is not carried out.

An owner can choose to reduce to zero the cost on QA/QC by not carrying NDT and go straight to hydrotesting. This of course carries a huge risk of failing the pressure testing, but it is an option available to Owner.

Some may say “Not all defects can be found by hydrotesting” which I completely agree. However, the same can be said about NDT/RT, too. Not all defect can be found via 100% RT. Lack of fusion (at certain planar), lamination, fatigue potential, are not discoverable via RT.

Take care Hansac

Carry out the remaining NDTs and complete the paper-work. If you do not find any defects, close the chapter.

If there are defects, consult with the client's inspection team regarding the next scheduled shutdown. Share the NDT reports with them.

Plan the next shutdown / on-stream / external / internal inspection accordingly.

DHURJATI SEN
Kolkata, India

@Hansac,As suggested by others,this time you have been plain lucky. Do not try to wear the Devils Advocate hat!!. It is a losing proposition.

Make use of the earliest opportunity to complete the NDT requirements. Pray you do not encounter any surprises!

By all means you can be argumentative - it makes for a much better thread. The original post stated that the NDT was "not compliant to Code requirement." Of course, an operator can take the chance and opt to ignore that NDT is an integral part of "the Code", and supplementary to hydrotest. However, should there be an incident, then the operator has to justify why "the Code" was ignored which will get very ugly in the eyes of the regulator and the general public. One could also argue that, if hydrotesting is the be all and end all, why then are there such standards as API 510, or API 570. Which brings us to the point of my comment regarding the mechanical integrity programme. If it is known that pre-operation NDT was deficient, would that not trigger some sort of post operation fact finding just to check? Maybe, it could be another hydrotest if the operator can stand the disruption?

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

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

I will give you a luck star! But be careful

luis

Quote (There is no penalty by the Code if any NDT was not done or not done at all, unlike pressure testing which is compulsory and would entail numerous penalties and additional safeguards (“golden weld”) if pressure testing is not carried out.)

There is no penalty because the piping system is considered non-compliant with the relevant code.

Quote (An owner can choose to reduce to zero the cost on QA/QC by not carrying NDT and go straight to hydrotesting. This of course carries a huge risk of failing the pressure testing, but it is an option available to Owner. )

No, the owner cannot.
The owner can stipulate NDT in excess of code requirements but they cannot reduce code mandated NDT requirements.
The owner would then "own" a piping system that is non-compliant with the relevant code.

NDT and hydrotesting are done for a reason - predominantly safety.
Hypothetically, you had an incident tomorrow and someone was seriously injured or died and it was discovered you had knowingly operated a plant that didn't comply with the relevant code for 2 years.
The lawyers would be dancing for joy and rubbing their hands together.
And if you didn't know and it was only just discovered it is a very, very poor reflection on the Quality department associated with this facility.

Good luck !

For all intents and purpose, I was presenting a hypothetical case.

The point is this: which is more supreme. The NDT or the pressure testing?

Which act(s) actually certify, validate the integrity of a facility: the NDT or the pressure testing?

ASME B31.3 allows "closure weld" procedure for waiving of hydrotest, or more popularly known as "golden weld".

Now reverse that context.

The things must be done criteriously and complemented, for waiving of a hydrotest, sometimes we have a "golden weld" who is checked with complementar NDT tests such as UT or RX and others. And in your initial post it was not clear that your question was hypothetical again I hope my star would help you to be careful.

luis

You cannot say which is more "supreme".
The code requires both to be completed and you have not completed both.
Now, you seem to be " hypothetically" trying to find loopholes to achieve your end result.
There is only one way to resolve this, conduct the required NDT and if no issues you are home safe with a code compliant piping system.
If there are issues you will have to repair or remove welds and that then will require a new hydrotest.

It would be interesting to know what "code" is applicable. If the work is in accordance to the "Farm Code", all is good as long as you are off the premises and as long as you can't see it from your house when it goes boom.

Best regards - Al

In some services like severe cyclic and specific corrosive environments where initiating sites can lead to failure, the NDE is actually more important than the hydrotest, although both must be performed under B31.3. Only D service is exempt from NDE - hydro only.