Golden Welds and Pressure Test 8

[cadiehl]

So I understand the application of Golden Welds. Let's say I am replacing a 10' long damaged segment of 3" ips piping in a 600 psi Liquefied Natural Gas system. There is no feasible way to pressure test the 2 buttwelds required to perform this task. Am I required to separately pressure test the new 10' long piping segment prior to welding into the system? This has been a topic of discussion around the office for the last couple of days, and needs to be put to rest. We have ourselves in a situation similar to the above.

 

[Kiwi2671]

Guys,
Just to throw a spanner in the works.
Excerpt below from Dr Becht's commentary states that

"Closure welds are not used in the Code in the context of a con-nection to an existing pipe, since that weld is considered to be outside of the scope of ASME B31.3 (although you could look to the closure weld requirements for guidance). Rather, it is a con-nection between new components."

As cadiehls piping is new connecting to existing it is outside the scope of B31.3 - see also Clause 300 (2).

So what code would it fall under ?
Cheers,
Kiwi

 

[BigInch]

If you read it, changing it to a positively framed statement ...
IMO ... it is saying that "golden" welds are considered as a connection between two new components, so that even though one component is actually old and would not otherwise be included under the code, a golden weld is.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[dcasto]

It is only required to hydrotest a piece of pipe for strenght under B31.8 Under B31.3, the test is to assure that all mechanical fittings are secure. B31.3 has all material strenghts qualified by proceedure. the weld proceedure, the pipe manufacturing proceedures all assure that the pipe is fit for use. If anyone thinks they are testing a piece of pipe for strengh under B31.3, they are sadly mistaken.

In the example above, pretesting the pipe is meaningless if you have documentation on the pipes process of manufacturing. The weld is the weakest link and a 100% inspection is where the integrety of the piping system is assured. If you apply B31.3 you would only have to xray 10% of the total weld lenght, why do 100%?

 

[cadiehl]

Dcasto, The pipe is NOT tested by the pipe manufacturer to a level that meets B31.3. Nor is it required unless you request and pay for it to be done. It must be tested in accordance with B31.3 prior to installing in the field. In this case it's a 10 minute pressure test. The pipe manufacturer does a simple 30 second test. And that is in accordance with the pipe spec.

 

[BigInch]

That's the typical mill test. I don't know what it's good for.
Pipeline tests are 4 hours minimum and many companies specify 24.
It's not like pipe itself (away from joints) hasn't ever burst during a real hydrotest.


"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[cadiehl]

Little sarcasm there BigInch? LOL.... I think the test is just to ensure there are no blatant fab screw-ups. Other than that, useless, I agree.

 

[BigInch]

Humm, ya. I can't tell if I'm being sarcastic or not. Guess it's built in now.
If it's welded pipe, they do check the joint, so they are reasonably sure that the welds are OK before testing, so it seems that it is to try to catch those occasional laminations and inclusions that get into the pipe walls... somehow.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[cadiehl]

I have the same problem, says my wife. This has been a pretty enlightening discussion. Surely appreciate your input.

 

[dcasto]

TESTING
The B31.3 Code requires leak testing for all components. This test does not assess the structural integrity of the components. The Code leak test is performed at pressure levels that do not challenge the ultimate strength required by the Code. In most cases the component is subjected to the leak test after being installed in the field. All components should be reviewed to insure that their pressure/temperature rating is acceptable for the test conditions.

EXAMINATION FOR LEAKS
1) Test personnel shall ensure the hydrostatic pressure is maintained for sufficient time to determine if there are any leaks. A minimum time of 10 minutes is required by Code. After the hydrostatic pressure time has been satisfied, all joints shall examined visually for leaks.

where does it say the pipe must be strenght tested?

 

[BigInch]

B31.3 does not say pipe must be strength tested, only leak tested. I said it was required initially, before knowing that it was a B31.3 build .. maybe the only code that does not mandate strength testing. B31.3 strength test is not required, but leak testing is, at every point. The entire thread above read in the context of B31.3, only states the supposed benefits, which could include more than just simply proving the pipe, of strength testing. B31.3 actually says, its the owner's responsibility to determine what the testing requirements shall include, or not include. Where, when, or if there are other concerns, or regulations that may enter into that decision, CFRs, OSHA, etc. I do not know. If it were me, I'd stop arguing about it, hydrotest it, it's good practice anyway, and get along with start up.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[Kiwi2671]

Big Inch,
Was waiting to see if you could help me out with an earlier question.

"As cadiehls piping is new connecting to existing it is outside the scope of B31.3 - see also Clause 300 (2).
So what code would it fall under ?

Not trying to be argumentative - even at 51 I still like to learn.
Cl 300 (2) (b) states the code is not intended to be used for piping that has been put in service - so what code would cadiehls piping fall under ?
Regards,
Kiwi

 

[BigInch]

I thought I caught that question above,
... "If you read it (Becht's wording), changing it to a positively framed statement ...
IMO ... it is saying that "golden" welds are considered as a connection between two new components, so that even though one component is actually old and would not otherwise be included under the code, a golden weld is."
----------------
In other words, as I read all of this, his pipe plus the two connecting joint welds are new. He is connecting new pipe to old pipe.
--------
What I would do personally in this situation is, not worry about the technical details of if only one joint of pipe really needs to be leak tested, or hydrotested, or not. I've seen pipe bust at the center, so I'd just agree with Dr Becht, there's benefits to doing it, there's safety in doing it, so I'd just do it, wash my hands and be done with it, but I'm a die-hard pipeliner and that's what we do ... To paraphrase Robert Frost, "There's (1000) miles to go before I sleep."

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[KevinNZ]

Glad we use B31.1 and with owners permission only service leak test. no hydros. (and VT only)

Kevin