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Pipe Pressure Test Failure
7

Pipe Pressure Test Failure

Pipe Pressure Test Failure

(OP)
A portion of 8" dia pipe failed a pressure test.  Failure was along the longitudinal welded seam.  It is my understanding that ASTM does not permit welding within an 1" of the seam.  Is this correct? and is it possible under some other regulation that the seam, with a proper welding procedure, can be rewelded to repair the damage.

Dik

RE: Pipe Pressure Test Failure

hmmmmmmmm.... more out of curiousity - what material? (carbon steel?)  What wall thickness/schedule?  What test pressure?

I have not heard of the 1" seam rule, but am aware of branch connections through seams, which are allowed - however there are also specific provisions in the ASTM (ASME) specifications that provide for repair welding for certification (approved by the purchaser, of course)  With general reference to A-530.

RE: Pipe Pressure Test Failure

I forgot,

Is this new pipe or has in been inservice?

RE: Pipe Pressure Test Failure

What nonsense.  Most of the time you can't see the seam.  Even when you can, a girth weld that can't approach the seam within 1-inch would actually leave a two inch hole in the pipe near each seam (call it a 4-inch gap 1/16 inch wide, pretty big hole).  

I have never heard of an ERW seam failing in a test (these seams are prone to MIC and other types of cathodic corrosion when they are standing in water, but that failure is always some time after the test).  I've had hydrotest failures, but never at the seam or at a girth weld.  I would get the mill data on the pipe and trace back to why a bullet proof weld failed.  This had to be a manufacturing defect that could have affected the entire mill run.

David

RE: Pipe Pressure Test Failure

(OP)
It is a new installation of offshore material and I think regular schedule 40 pipe.  All certificates were in place.  It was to be tested to 140 psi and the seam failed at less than 80.  According to the specs the original material was to be tested to 1400 psi...

Dik

RE: Pipe Pressure Test Failure

(OP)
Sorry... forgot to add the material... carbon steel...

RE: Pipe Pressure Test Failure

Hi dik

I would recommend that somebody check the design before re-testing and make sure the pipe wall is thick enough for the application.
Also I would be in contact with the pipe supplier particulary if the pipe failed at a pressure it should have withstood.
I know that in some pressure vessel specifications that some welds are restricted as to how close they can be to a main seam weld but I am not familiar with ASTM

desertfox

RE: Pipe Pressure Test Failure

80psi?? and then cracked.
You are sure it wasn't made of bubblegum?

Greetings

RE: Pipe Pressure Test Failure

What exactly does the failure look like? Is it a hairline crack or did the joint open up?

How long is the failure?

What is the ASTM designation of this pipe?
 

RE: Pipe Pressure Test Failure

dik...along the lines of the last post, but more on the face of the ERW failure face. Was there lack of fusion? Was there a cupping pullout from one side or the other?  Was there complete joint fusion?  I've seen ERW pipe "unzip" in pressure tests, due to poor weld.  Relatively rare, but it happens.

The 1"-rule makes no sense.  ERW pipe can and is routinely welded...wherever necessary for the connections.

There is a 1" proximity reduction in allowable stress for welded aluminum, but not carbon steel.

RE: Pipe Pressure Test Failure

In all likelyhood the failure was in the H.A.Z. and not directly at the seam which is probably stronger than the pipe material.

RE: Pipe Pressure Test Failure

(OP)
The pipe was 10" dia, sched 40 and the split was a few inches at the ERW joint.

ASTM A53, states:

12.2.2 Type S pipe and the parent metal of Type E pipe, except within 1⁄2 in. [13 mm] of the fusion line of the electric-resistance-weld seam, are permitted to be repaired in accordance with the welding provisions of 12.5. Repair welding of Type F pipe and the weld seam of Type E pipe is prohibited.

RE: Pipe Pressure Test Failure

(OP)
There were two failures, an 8" one that failed at 125 psi and the 10" one that failed at 80 psi.  Both from the same Chinese offshore manufacturer.

Dik

RE: Pipe Pressure Test Failure

To be frank - I wouldn't both repairing the pipe - I would flat out replace it and negotiate/demand restitution from the supplier - because that is not properly specified A53 pipe!!  The pipe, to meet specfication approval SHOULD have been already tested by THE MANUFACTURER to -

8" Sch. 40 Grade A: 1340 psi !!!!!!
           Grade B: 1570 psi !!!!!!

10" Sch 40 Grade A: 1220 psi !!!!!!
           Grade B: 1430 psi !!!!!2

I don't have access to the ASTM standards right now, but I am looking at the ASME SA-53, which is identical to the ASTM except for insertion of test practices in 11.1.1 and editorial correction to Table X4.1

And there is no mention of the clause you have stated , in fact - it states "14.5 Weld repair shall be permitted only subject to approval of the purchaser and in accordance with Specification A 530/A 530M."

RE: Pipe Pressure Test Failure

Both from the same Chinese offshore manufacturer... say no more. I have never seen new pipe fail at such a low pressure, 80 psi, that is ridiculous. I have seen some ERW failures during hydrotest in the weld, most are due to lack of fusion, others porosity if the weld was really poor. I have also seen hook cracks fail. I don't know if your pipeline is liquid and will cycle, but if it does, defects like this in welds can grow from fatigue and fail later. I would be very weary considering these failed at such a low pressure, they must be very large defects.
I would not attempt to repair the weld but put in a new spool piece where the failures were.
I would seek some compensation from manufacturer.

RE: Pipe Pressure Test Failure

dik...

Can you get pictures and post them...???

They might be very informative and enable you ( and us) to learn more...

"brimmer" is spot on...... you have been sold un-inspected Chinese "crap pipe" and deserve compensation.

Now ... lets all repeat that new millenia business mantra:

"freemarkets....freemarkets....freemarkets...freemarkets.."

This fine forum has many other previous posts about defective Chinese piping, pressure vessels and components.

-MJC

   

RE: Pipe Pressure Test Failure

(OP)
Chicopee:

I don't know where the actual failure was, but was in the same line as the ERW joint. See note to MJC

MJC:

No pix... the pipe was re-welded prior to us being informed.

AllHandlesTaken:

My quote from A53 was a direct 'cut and paste'; if you cannot locate this, has this been changed?

RE: Pipe Pressure Test Failure

I will have to check the ASTM standard later for that clause (or just take your word for it).

Like I mentioned I was looking at the ASME SA-53; 2007 ed.

What year is the ASTM spec that you are looking at?

RE: Pipe Pressure Test Failure

Whoops - I just noted that the clause you specified is in fact in the 2007 ASME SA-53; under 14.2.2 (I guess I should have looked a little harder :(

Regardless, I would still replace it all with different QUALITY pipe and take it up with your purchaser's/supplier.

RE: Pipe Pressure Test Failure

(OP)
AllHandlesTaken...

I will have to check the ASTM standard later for that clause (or just take your word for it).

I see you've caught my posts before... if I don't like a standard... I make one up and give it a number <G>.

Dik

RE: Pipe Pressure Test Failure

(OP)
Is there any non-destructive testing that can be done? Can they be proofed to the capacity of any of the fittings?

There are several runs of several hundred feet of the material already installed.  The work was almost finished and failed the pressure testing part of the specification.  The structure is enclosed and it would be difficult (not impossible) for the pipes to be removed and replaced.

RE: Pipe Pressure Test Failure

dik...if the thickness is 1/4 or greater, you could use ultrasonic flaw detection.  Magnetic particle would work as well, unless the defect is on the inside of the pipe.

Radiography would work, but would be expensive.

RE: Pipe Pressure Test Failure

(OP)
Thanks, Ron, I hadn't considered ultrasonic for this app... Because there's so much of it, I was hoping for an easier method.

Dik

RE: Pipe Pressure Test Failure

dik,

you might be able to test with internal ultrasonic tool, should detect these types of defects, I don't know what your scenario is

RE: Pipe Pressure Test Failure

3
You don't want ANY of that manufactor's pipe in your project carrying anything more important than gutter water as a downspout.

Rip it out - DEMAND your money back.

Look - pipe that is failing at 80 psi is tissue paper.

On an offshore rig, are YOU going to live UNDER it 24/7 for 30 years with anything "important" or flamable inside?   Tell that rig's crew what happened: See how of them stay on board.

RE: Pipe Pressure Test Failure

(OP)
racookpe1978:

That was my original thought, but there is a lot of it installed and it is difficult to remove and re-install and I was wondering if there was another solution.

Dik

RE: Pipe Pressure Test Failure

Dik,I have heard of this type of failure but never witnessed it. From recollection it was attributed to  welding process start up. This might allay some of your doublts but it would be worthwhile completing some random UT and possibly RT if the UT techniques available are limited.

Regards BrianC

RE: Pipe Pressure Test Failure

(OP)
by UT and RT you are referring to Ultrasonic and Radiographic?

Dik

RE: Pipe Pressure Test Failure

No - R/T won't be an effective answer.

Consider that a single R/T of a circum. weld takes 1 hr setup (in a powerplant at least) and an exclusion area of around 100 ft radius.  45-75 some-odd minutes per weld (36 inch circle) then 1/2 hour take down time.  Move to the next weld, repeat.

Now image that much time for a linear distance of "several hundred feet".   The R/T might work if it (the souorce) were dragged down the inside of the pipe with the film tapes continuously to the outside over the weld.  But you'd need calibration points on the pipe and film to track down defect locations.  Add thousands more dollars for exam time, rip out and replacement of the bad/suspect pipe anyway.   Scaffolding.  Insulation takeut, hangers in the way of the exams.

Worse: he has had catastrophic failure at low pressure in one pipe.   How many other pipes from that supplier has he got installed?   The supplier is overseas, behind a protective (and corrupt) local and national government.  Replacement pipe is expensive, but imagine trying to collect billions to pay for the burned out rig PLUS medical liability claims for the killed workers.   

Faced with that bill, the Chinese company will likely simply "disappear" - nobody will be be there to be liable.

1)  UT/MT might show extent of what pipe needs to be replaced.  

2)  Get the repair records of what was re-welded.  DON'T trust the re-welded pipe.

RE: Pipe Pressure Test Failure

Dik/Racookpe  I did mean Ultrasonics and radiography though I would limit it to  % inspection.

Whatever you decide to do further inspection will be required and the results past up the chain to ensure root cause and corrective action.

Regards Brian

RE: Pipe Pressure Test Failure

(OP)
In view of

ASTM A53, states:

12.2.2 Type S pipe and the parent metal of Type E pipe, except within 1⁄2 in. [13 mm] of the fusion line of the electric-resistance-weld seam, are permitted to be repaired in accordance with the welding provisions of 12.5. Repair welding of Type F pipe and the weld seam of Type E pipe is prohibited.  

is there any means of re-welding to effect a repair? 'Prohibited' seems to be a pretty strong word.

Dik

RE: Pipe Pressure Test Failure

You could take the view/argue that the A53 specification does not apply to you because you are not a manufacturer and have already purchased the specified pipe.  Then you could work with, perhaps, ASME B31.3, PCC-2, API 570 ...., all of which (MUST) allow welding near the fusion line or you would never even weld on a flange.

RE: Pipe Pressure Test Failure

May I suggest you pose your question to a metallugist/welding engineer, or technical area of supplier (actual or otherwise). This might give you confidence in pursuing your line of action.

It might well be that a repair can be justified pwht.


I take it you have found no more defective pipe on your or other projects and the supplier has had no other reports of similar failures?

Regards Brian

RE: Pipe Pressure Test Failure

A separate problems lies in ambush for you:  

One run of pipe was tested during one hydro test: That run failed at only 80 psig.  

"Somebody" weld-repaired that (one run) of pipe at that failed location: so he had to heat up the failed (burst out and deformed) section and beat it back into a "sort of round" shape in order to get the original edges back near enough together to weld them manually.  So now you have a heat-affected (low strength) zone around the weld, a low strength (yellow-or-dull red-heat) "manually forged" section and an out-of-round (stress -induced failure) section AND a retest-required weld that must be itself tested at full  hydro pressure.  

BUT, the rest of the pipe has NEVER been tested to anything past 80 psig: the original failure point of the first pressure test.    Why do you assume that the rest of the pipe will even get up to 100 psig, much less 120, 140, or full hydro pressure.  (As noted above it "should" have passed the 1250 pressure test at the factory - but we know that it could not have.)       

RE: Pipe Pressure Test Failure

There are a number of manufacturing reasons why the ERW weld could fail at such a low pressure; however, the high pressure test at the mill should have opened it. You should assume that it was not so tested and expect that additional partially fused locations are present. You need to examine the pipe seams for their full length (all installed 8" and 10" pipe from that Chinese manufacturer) to assure freedom from future failure assuming that you think the material can be salvaged.

As a minimum, I recommend removal and replacement of the burst pipes and perform the A-53 required tests thereon. Welds should additionally be examined using magnetic flux leakage and UT methods.

RE: Pipe Pressure Test Failure

Try this: You're obviously facing short-sighted (economically driven) pressure to get the rig built, and to NOT replace the piping.

So,

1) Remove the pipe that has burst.   Unbolt the flanges and fittings (it will be less expensive than rebiulding the pieces).  Pull it  out of the racks and overheads and put the pieces 9each spool) on the deck.   Put blanks on each section - leave the long welded sections in the rack only if you have too.  Hydro each section.   As more and more break - if they break - demand your money back plus damages plus cost of testing plus delay time.  

2)  Use the separated spools as templates for the replacement sections:  Weld brackets (dead or dummy flanges temporarily attached to the deck or brackets) at each flanged end of each spool.  From each of these dead flanges, rebuild the replacement spools back towards the template at the other end - that way, the replacement spools will fit the original location with little problem.   

As you find out how many spool sections are breaking, you can begin to identify the limits of your problem.  Use NDE properly: to verify the fabrication welds at fittings and flanges, not to check the full length resistance welds down every length of pipe.   Field NDE isn't accurate enough to do that job.  Field welding isn't accurate enough (economical enough and fast enough) to rebuild pipe lengthwise welds.

Right now, all you have is a deathtrap of unknown pressure rating.

RE: Pipe Pressure Test Failure

(OP)
This thread has whiskers... but, an update from Testing Co report (names have been changed to obscure those involved but the text is almost verbatum):

----------- Start of Quote -----------

"...Joint 001 welded by 'Welder A' failed the radiograph.  Joints 002 and 003 the (sic) films were not able to be used.  These joints are required to be re-tested.

Testing Co has reviewed all of the three pipes that, the weld seam has cracked (6" pipe that had visually bad seam - V groove; this one also offshore but from India).  It is our recommendation that samples of these pipes be sent for Chemical and Mechanical testing to verify that they meet the requirements of ASTM A53 standard for pipe grade B.

The Client has requested that Testing Co perform ultrasonic inspection to the piping throughout the Project, to insure the pipe weld joint is sound.  Testing Co has requested pipe samples several times from the contractor, for calibration purposes.

Once we have these samples from the different nominal pipe diameters we can begin the random spot checks of the heat numbers that have failed the hydrostatic testing as will (sic) as some additional testing of other piping that has passed the hydrostatic testing..."

----------- End of Quote -----------

It seems to be moving slowly... and will keep you posted on the end results. I haven't been involved with this, but it seems that there is some difficulty in obtaining samples from the contractor.  Some of the pipes carry water at about 160F while others have cold water.
 

RE: Pipe Pressure Test Failure

I'm not convinced UT will show fundamental flaws in the longitudinal weld in the bad pipes: You're looking for flaws and cracks and lack of penetration in that weld better discovered by MT across the joint rather than UT into the joint (no penetration, partial penetration, no weld continuity, no weld at all.)  

UT could show "depth" problems inside a deep piece of metal, but not across a seam that thin.  (Pipe wall is less than 1/2 thick.)

RE: Pipe Pressure Test Failure

(OP)
racookpe:  By MT you mean?

Dik

RE: Pipe Pressure Test Failure

I believe by MT he means Magnetic Particle Testing.

I know ive come to this late, but yeah id have gottent eh lawyers involved a long time ago, replace all the pipe that came from that supplier.

Ive worked in Offshore and i know the kind of service life that is expected in alot of this stuff, and the usual quality standrds, this pipe ahs failed miserably. the sad thing is no matter how this works out its a lose lose situation, your losing fab time, its going to cost you money to rebuild it all and to source new pipe, things are bad all around really.

RE: Pipe Pressure Test Failure

dik,

This is an interesting thread, and I think everyone here can empathize with your situation. One encounters such ethical-economic dilemmas in the supposedly objective world of engineering with surprising frequency.

That being said, I find myself agreeing to most of the statements made by racookpe1978. Would like to hear more as the situation evolves, and wish you the best.  

RE: Pipe Pressure Test Failure

Hi Dik

What was the outcome of the pipe in question

RE: Pipe Pressure Test Failure

(OP)
Last I heard, they still don't have resolution on this...

Dik

RE: Pipe Pressure Test Failure

Something I've learned the hard way is that you as an end user can not inspect integrity into a product. Despite all the codes, standards, and guarantees you still have to depend on the integrity of the manufacturer to produce the very best product needed to meet your specified requirements.  Unless there an accident or injury your best bet is get rid of the problem to cut the losses.

We have had several hydrotest failures in CS piping over the years and If I recall correctly all were of the ERW variety slated for use in non hazardous service. We did have inservice failure of 10" Sch 80 welded pipe from fatigue, thermal, in 75 psig steam service. The origin of the failure was an area of LOF and LOP in the seam weld. All our failures were in domestic made pipe.

The same problem is found in SS piping. Take a look at the following thread to see what you can run into with such a failure. Since this thread was posted two other sticks of SS pipe, one SCH 40 and one SCH 80 have been found to contain LOF defects by the pipe fitters while prepping for welding. These pipe were by two different manufacturers.  I don't have the spec for the pipe.  This has resulted in the requirement that all end preps on SS pipe are to be PT tested..  

thread378-70822: Stainless Steel Pipe

The reference URL  in the above thread has changed to the one below.

http://www.uscfc.uscourts.gov/sites/default/files/Mortenson.pdf

In my previous post I mentioned that the same problem had occurred at Vandenberg Air Force Base and I have sense learned that the same problem was found at the NASA Site in Mississippi except on a larger scale.  I have heard that NASA wasn't very happy about the problem.     

RE: Pipe Pressure Test Failure

MT will only show external or surface breaking indications, we would not know if the failed indication broke the surface until it actually ruptured which is why there is a need for UT here as well. MT won't show tight LoF indications in the weld even though material is only 1/4 inch thick. You are definitely on the right track with the material testing, good luck.

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