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Golden Welds and Pressure Test
7

Golden Welds and Pressure Test

Golden Welds and Pressure Test

(OP)
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.

RE: Golden Welds and Pressure Test

Test the new section of pipe and any fittings welded to it first, then weld it in. Lastly, NDT the golden welds.

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

RE: Golden Welds and Pressure Test

(OP)
Thanks BigInch.... what if there are no fittings welded to it... just a straight run of pipe. Does it still require testing prior to welding it into the system?

RE: Golden Welds and Pressure Test

straight pipe can be hydro pressure tested.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Golden Welds and Pressure Test

It would still need to be hydrotested whether it has fittings or not

RE: Golden Welds and Pressure Test

(OP)
I know it "can" be tested. I am asking if it is "required" to be hydroed or pneumatically tested PRIOR to welding it into the system. It's just a straight 10' long piece of stainless, no fittings. It will be buttwelded into a system that cannot be pressure tested. So, it will have 2 closure (golden) welds that will be RT'd after welding it in. But, does the 10 foot long piece of new pipe need to be pressure tested in the shop PRIOR to welding it into the system? Is it a code requirement?

RE: Golden Welds and Pressure Test

It is REQUIRED.

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

RE: Golden Welds and Pressure Test

(OP)
Thank you Biginch.

RE: Golden Welds and Pressure Test

Big Inch,
Out of curiosity, where is the requirement stated ?
B31.3 Cl 345.9.1 states " Welds, including those used in the manufacture of welded pipe and fittings,which have not been subjected to hydrostatic or pneumatic leak tests in accordance with this Code,shall be examined as follows:"..... 100% RT or UT.

So, in accordance with B31.3 if you have ERW pipe you either hydrotest/pneumatic test the section of pipe or you perform 100% NDT on the longitudinal seam.
What if cadiehl has seamless pipe - what are you actually testing ?

IMHO it is a good idea to put caps on the end and pressure test if only to confirm the integrity of the pipe but again IMHO there is no code requirement for it to be performed,
Regards,
Kiwi

RE: Golden Welds and Pressure Test

345.1

But now that is unimportant, as codes represent the MINIMUM requirements, it is the engineer's opinion that sets the requirements. Your opinion has already superceeded code minimum requirements and now the system must be tested.... according to YOU, regardless of what is stated in the code, or anywhere else.

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

RE: Golden Welds and Pressure Test

Big Inch,
Your post has absolutely lost me ?
Your initial post stated "It is REQUIRED"
I asked for confirmation of where this requirement is ?
You came back with 345.1 which makes no reference at at all to piping, it talks about piping systems and ensuring "tightness".
Then you have a comment with YOU which completely lost me ?
Cheers,
Kiwi

RE: Golden Welds and Pressure Test

(OP)
Now I'm lost also. I just want to know if the CODE requires this 10 foot section of new piping to be pressure tested prior to welding it into the system. I don't care about good engineering practice, client requests, etc.... that is a totally different issue. Does the CODE require it? Or not? Now I see why no one in our office can come to a conclusion on this.

RE: Golden Welds and Pressure Test

Assuming that A312 is the product specification, you have the option to require a mill hydrostatic test. The thrust of the exchange above is that it would be prudent to exercise that option.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

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

RE: Golden Welds and Pressure Test

(OP)
Yes Steve. I just found that the A312 spec mandates a 30 second pressure test on all piping at the factory. However, the pipe segment would require a 10 minute pressure test to meet B31.3. That can done at the mill or on site, obviously. I think I have my answer. I think. Unless someone comes on here and throws a wrench in the gears.

Thank you, everyone.
CD

RE: Golden Welds and Pressure Test

why not contact the original engineer or any engineer that has worked this project.
flying blind is no excuse, someone there needs to be a qualified engineer.

Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.

RE: Golden Welds and Pressure Test

(OP)
Not flying blind MF... as you can see, opinions differ across the board on this subject. The same goes with the engineers I have spoken to around here.... even if this was a hypothetical situation, the answers would not be the same from every engineer you asked. Some say that pressure testing is for the welds, others say it is for the welds and fittings, others say it is for the welds, fittings, and pipe..... so, who is right? Those answers come from very experienced engineers. That is why I tried to pose the question here. Hoping to get some clarity.

RE: Golden Welds and Pressure Test

3
345.1 Each piping system shall be tested to endure tightness. The test shall be a hydrostatic leak test in accordance with 345.4 except as provided herein.

345.4.2 Test pressure in every point in a metallic piping system shall be as follows:
Not less than 1.5 x design pressure.

Is there any doubt that a piping system includes pipe, fittings and flanges?

I don't think there is any more experienced engineer than Dr. Becht.
Dr. Charles Becht's opinions;

Pressure Testing

ASME B31.3 requires leak testing of all piping systems other than Category D systems. For piping in Category D fluid service, the piping may (at the owner’s option) be put in service without a leak test and examined for leakage during the initial operation of
the system. This is an initial service leak test. For all other piping, the following options are available:

(1) hydrostatic test,
(2) pneumatic test,
(3) hydropneumatic test, and
(4) alternative leak test.

An alternative leak test is only permitted by ASME B31.3 when:
(1) exposure of the piping to water via a hydrostatic test would damage the linings or internal insulation, or contaminate a process that would be hazardous, corrosive, or inoperative
in the presence of moisture; and
(2) a pneumatic test is considered by the owner to entail an unacceptable risk due to the potential release of stored energy in the system (the danger of a pneumatic test ncreases with the pressure and contained volume); or
(3) a hydrostatic test or pneumatic test would present the dan-ger of brittle fracture due to low metal temperature during the test.

Hydrostatic Test

"A hydrostatic test is generally the preferred alternative because it is conducted at a higher pressure, which has beneficial effects such as crack blunting and warm prestressing, and entails sub-stantially less risk than the pneumatic test (alernative). These reduce the risk of crack growth and brittle fracture after the hydrotest when the pipe is placed in service. The test is generally conducted at a pressure of 1.5 times the design pressure times a temperature correction factor.

Closure Welds

In the 1996 edition, addenda c (1998), closure welds were added [para. 345.2.3(c)] as an acceptable exemption from leak testing. A closure weld is a final weld connecting piping system or component that has been successfully leak tested. The closure weld does not require leak testing if it passes 100% radiographic or ultrasonic examination and is in-process examined. 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. For example, consider a large diameter vapor line, for which providing additional support for the fluid weight in a hydrotest is impractical, and for which a pneumatic test would entail undue hazard. The line could be pres-sure tested, as a subassembly, at grade, erected, and connected to equipment with a closure weld. "


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

RE: Golden Welds and Pressure Test

(OP)
Gots me some clarity... thanks BigInch.

RE: Golden Welds and Pressure Test

Now some mud in the water.
The above said, with B31.3 the decision ultimately resides with the OWNER of the installation, but at least now WE know how to advise him and that if he thinks differently, he should contact his insurance company and his lawyer.

Note that the pipeline codes B31.4 & 8 differ. Code & USA regulated pipelines must be pressure tested. Fortunately the pipeline codes B31.4 & 8 are specific. The applicable CFRs are law. The owner has no options.

Quote:

B31.4
437.1 General
(a) In order to meet requirements of this Code, it is necessary that tests be made upon the completed system and upon component parts of the finished system.
437.1.4
(2) Systems to be operated at a hoop stress of more than 20% (in 35 years I've never designed a pipeline for < 20%) of the specified minimum yield strength of the pipe shall be hydrostatically tested in accordance with para. 437.4.1.

437.1.4 (5)-b Testing Tie-Ins. Because it is sometimes necessary to divide a pipeline into test sections and install test heads, connecting piping, and other necessary appurte-nances for testing, or to install a pretested replacement section, it is not required that tie-in welds be tested; however, tie-in welds and girth welds joining lengths of pretested pipe shall be inspected by radiographic or other accepted nondestructive methods...

437.4 Test Pressure
437.4.1 Hydrostatic Testing of Internal Pressure Piping
(a) Portions of piping systems to be operated at a hoop stress of more than 20% of the specified minimum yield strength of the pipe shall be subjected at any point to a hydrostatic proof test equivalent to not less than 1.25 times the internal design pressure at that point (see para. 401.2.2) for not less than 4 hr.

B31.8

841.3 Testing After Construction

841.3.1 General Provisions. All piping systems shall be tested after construction to the requirements of this Code except for pre-tested fabricated assemblies and welded tie-in connections where post construction tie-in testing is not practical. Additionally, single lengths or multiple welded lengths of pipe previously tested in accordance with this Code
for the purposes of repair or replacement do not require a post construction retest.
(a) The circumferential welds associated with con-necting pretested assemblies, pretested repair pipe lengths or sections and welded tie-in connections not pressure tested after construction shall be inspected by radiographic or other accepted nondestructive methods
in accordance with para. 826.2.

(b) Nonwelded tie-in connections not pressure tested after construction shall be leak tested at not less than the pressure available when the tie-in is placed into service.

Furthermore, the pipeline codes/CFRs define maximum allowed operating pressure as test_pressure / test_pressure_multiplier, so if not pressure tested, pipelines will not have an operating pressure ... and therefore cannot be operated. A pipeline designed for 1460 psig, but only tested to 1250 psig can only be operated to a maximum pressure of 1250/1.25 = 1000 psig.

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

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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%?

RE: Golden Welds and Pressure Test

(OP)
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.

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

(OP)
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.

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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?

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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

RE: Golden Welds and Pressure Test

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

Kevin

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