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Up Topic Welding Industry / Inspection & Qualification / What is better?
- - By cremx (*) Date 05-21-2009 07:33
I would like to know your opinion on below two cases and/or what is your suggestion for welds examination of a piping system which is normal service, the product is pressurized air or nitrogen, maximum operating pressure 190 psi.

Case 1: The project specification requires 5% RT and 100% MT for CS piping; the contractor wants to deviate from project specification to delete 100% MT and to perform 10% RT only

Case 2: The project specification requires 5% RT and 100% PT for SS piping; the contractor wants to deviate from project specification to delete 100% PT and to perform 10% RT only
Parent - - By Ke1thk (**) Date 05-21-2009 10:44
I'd be concerned about my liability.  Point out the section in the Code directly to him.  I'd have his purchase order read exactly what he wants done.  My document would state what I did.  Not to the Code.

Good Luck,

Keith
Parent - By Shane Feder (****) Date 05-21-2009 11:38
cremx,
There is no requirement in B31.3 for MT or PT, it is purely an additional form of inspection required by the piping designers.
The request by the contractor should be dealt with by your engineering department.
Most projects I have ever worked on required 5% RT for NFS and 100% MT/PT only on weldolets/sockolets or other pressure retaining socket welds.
Generally the only time you would do 100% MT/PT is if you were doing 100% RT on hazardous liquids or high pressure piping.
Send it back to the people who actually nominated the 100% for their decision,
Regards,
Shane
Parent - - By Joey (***) Date 05-21-2009 11:50
opinion is to issue NCR and dont issue release notice / clearance if NCR is not closed out

suggestion on weld examination : to follow the project specification unless otherwise approved by the owner-user.

5% RT requirement is a minimum, tracer shots may be required when there are rejection.

Regards
Joey
Parent - By 803056 (*****) Date 05-21-2009 16:25 Edited 05-21-2009 16:49
There are details of the project that we are not privy to.

The engineer and the owner developed the project specification with full knowledge of the project details.

The contractor is interested in a few things: (A) Get the job done, (B) get paid,  and (C) get the hell out of Dodge before anything goes boom in the middle of the night.

The cost of the additional MT and PT is a fraction of the cost of repairs if something does fail while in service. In-service failures can cost lives, millions of dollars due to environmental clean-up, and lost production.

I hope the owner invoked progressive inspection should any of the radiographs fail to pass muster, i.e., two additional radiographs for each radiograph failed. I also hope the owner knows enough to require random radiography and does not permit the contractor to select the joints to be tested.

I had a tank job where the contractor told the radiographer (not associated with me) where to test the joints. Every radiograph passed. The owner, smelling a rotting fish, asked me (as an independent third party) to select random joints for radiography and invoked progressive testing as per the project specification. Every joint I selected was rejected for slag inclusions in the root (the contractor didn't back gouging the majority of the weld joints). The tank had to be completely rewelded and all back gouged joints were MT'd before back welding. It passed all radiographic testing after rewelding.

Best regards - Al
Parent - - By cremx (*) Date 05-23-2009 04:49
In this case the owner is approving the deviation....
Parent - By Joey (***) Date 05-25-2009 08:07
cremx

You wrote : "In this case the owner is approving the deviation...."

In this case.....the owner realized that this MT / PT requirement is an error in project specification. Ironicaly, the contractor did not clarify this requirement during the time of tendering process. They waited for the owner to award the project and thereafter negotiate for waiver of NDT requirement.

Regards
Joey
Parent - - By CWI555 (*****) Date 05-21-2009 16:41
You haven't identified what year code your building to. However, if your still on the same project I think you are, this may apply.

Interpretation 21-37 date issued Oct, 2, 2007.

paraphrased it's asking if additional RT can increase the joint quality factor. The answer is no.
Therefore, additional 5% RT does you no good from the codes standpoint. The group wishing to do away with the surface methods specified by engineering cannot use the RT for that justification for that reason.

Under the same interpretation, visual examination of fabrication is required, but the PT and MT are not mentioned.
If you got to 2008 addenda B31.3 it would be another story, and may be worth some researching to you.

In 08 para 341.4.1 (extent of examination) subpara 341.4.1 paraphrased states:
piping in normal service shall be examined to the extent specified herein or to "any greater extent specified in the engineering design".

engineering design therefore will have to be careful what they write for a specification as will contractors bidding a job. That statement just made any engineering examination above and beyond the code mandatory if they have been specified by design engineering.
Under that, only DE could relieve it.

That is new to 08, and I don't have time to dig into which interpretation or code case drove it, but I would sure be looking into it if I where you given your situation.

Tomar cuidado mi amigo,
Gerald
Parent - - By Shane Feder (****) Date 05-21-2009 22:09
Hi Gerald,
That clause is actually in my B31.3 2002 edition. I was just being lazy by not typing it out in my original answer.
Regards,
Shane
Parent - - By CWI555 (*****) Date 05-22-2009 01:24
It's listed as a change in the 08. May be the wording.
Parent - - By Shane Feder (****) Date 05-22-2009 04:08
Hi again Gerald,
Not sure what is going on.
My 2002 edition has 341.4.1 " Piping in Normal Fluid Service shall be examined to the extent specified herein or to any greater extent specified in the engineering design."
Regards,
Shane
Parent - By Richman (**) Date 05-22-2009 08:49
If I were the representative of the owner and the contractor suggest that ; my answer is better they comply to approved project specs requirements or approved Welding plan for NDT as per line Class base on reference codes of the project not because they experience that in other project.
Parent - - By CWI555 (*****) Date 05-22-2009 11:12
When I get back to town, I'll have to look into that one. Either way, the message is the same. Inclusion of engineering design mandates it.
Parent - - By cremx (*) Date 05-23-2009 04:17
Thanks to everyone for you input, in fact there is a interest conflict in this case; please let me explain you more in detail: Company A delevoped a FEED (basically the project specifications) for the Owner; the Owner assigned to company B a EPC contract to built the plant; now the company B wants to deviate from projects specifications going to code bottom line (10% RT); the code B31.3 doest not requires MT or PT for normal fluid service; the owner is accepting the change based on B31.3 requirements only;  of course VT is not in question has to be done period.

In my opinion the company A may be selected 5% RT, 100% MT or PT (for SS) for certain reasons that we do not know. Probably to provide more reliable piping system? here is the way of my question What is better? Examination on 100% of the welds wiht MT + 5% RT or examinaion on 10% of the welds with RT only.

I will check B31.3 may be that paragraph help us, thatk a lot for your feedback
Parent - - By Shane Feder (****) Date 05-23-2009 06:48
cremx,
Take 100 welds for example.
5% RT = 5 welds
10% RT = 10 welds
100% MT = 100 welds

With 5% RT and 100% MT you have 95 welds that may have volumetric defects and 100 welds that do not have surface defects.
With 10% RT only you have 90 welds that may have volumetric defects and 100 welds that may have surface defects.

I think it is pretty easy to see which method would give you more confidence in the completed piping systems.
Regards,
Shane
Parent - - By 3.2 Inspector (***) Date 05-23-2009 06:58
Lets say that the amount of welds you described was welded by 3 different welders, how many welds would need to be examined?

3.2
Parent - - By Shane Feder (****) Date 05-23-2009 08:14
3.2,
Still only 5 or 10 welds.
2/2/1 or 3/3/4 or any combination as long as all three welders are radiographed.
Clause 341.4.1 only states "The welds to be examined shall be selected to ensure that the work product of each welder or welding operator doing the production welding is included."
Regards,
Shane
Parent - - By 3.2 Inspector (***) Date 05-23-2009 08:36
That is what I also usually go by when working to ASME
According to EN codes, the required % apply to each welder within the "control group"

3.2
Parent - By cremx (*) Date 05-24-2009 16:57
Look at B31.1 344.1.3 ..... The following terms apply to any type of examination:

100% examination: complete examination of all of a specified kind of item in a designated lot of piping

random examination: complete examination of a percentage of a specified kind of item in a designated lot of piping

spot examination: a specified partial examination of each of a specified kind of item in a designated lot of piping, e.g., of part of the length of all shop-fabricated
welds in a lot of jacketed piping

random spot examination: a specified partial examination of a percentage of a specified kind of item in a designated lot of piping
Parent - By cremx (*) Date 05-23-2009 04:38
B31.3 2004 has the same paragraph
341.4.1 Examination Normally Required. Piping in
Normal Fluid Service shall be examined to the extent
specified herein or to any greater extent specified in the
engineering design. Acceptance criteria are as stated in
para. 341.3.2 and in Table 341.3.2, for Normal Fluid Service
unless otherwise specified.

The project specifications (FEED) were developed by a engineering company (Company A) for the owner; Company B (is an engineering company also) was assigned with a EPC contract to build the plant; now Company B request to owner to deviate from project specifications which specify the NDE requirements (5% RT+100% MT)

What is greater extent?

      Code        or Project Specification

(10% RT only) or (5% RT + 100% MT)

What is better?

I think depends how many reliability you wants, but how to measure it?
Parent - - By cremx (*) Date 05-23-2009 04:47
Hey brother!!!
Nothing to do with the joint factor, the actual contractor says: "It is not necessary MT 100% if we are in compliance with the code"; the owner concurs with them!!!!

The owner it self approve to remove the greater extent specified in the engineering design (..... well, the project specification) the engineering design is being done by the actual contractor....who is who?

Warm regards chief,
Parent - By Shane Feder (****) Date 05-23-2009 06:38 Edited 05-23-2009 06:49
cremx,
The project specification always takes precedence over the code when the specification is more stringent than the code.
The statement above from B31.3 341.4.1 clearly states " ...or to any greater extent specified in the engineering design."
The specification states 5% RT and 100% MT so if the contractor does not do this amount they do not comply with ASME B31.3 Clause 341.4.1.
Regards,
Shane
Parent - - By CWI555 (*****) Date 05-23-2009 08:33
I feel your pain jerarca. What the "owner" apparently has yet to realize they are held to other standards and not just the code and spec.
While inspectors are typically focused on code and spec. Example CSA Z276-01. While API 620 covers most of it and is heavily referenced and in many parts required, the Canadian "law" is above and beyond API 620.

Another example is ASME Section III. Specific parts of it are exempted, modified, or not allowed by the U.S. NRC by law. Even down to what edition is valid. 10CFR part50.55a.
Example:
http://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-0055a.html
"
(1) As used in this section, references to Section III of the ASME Boiler and Pressure Vessel Code refer to Section III, and include the 1963 Edition through 1973 Winter Addenda, and the 1974 Edition (Division 1) through the 2004 Edition (Division 1), subject to the following limitations and modifications:

(i) Section III Materials. When applying the 1992 Edition of Section III, applicants or licensees must apply the 1992 Edition with the 1992 Addenda of Section II of the ASME Boiler and Pressure Vessel Code.

(ii) Weld leg dimensions. When applying the 1989 Addenda through the latest edition, and addenda incorporated by reference in paragraph (b)(1) of this section, applicants or licensees may not apply paragraph NB–3683.4(c)(1), Footnote 11 to Figure NC–3673.2(b)–1, and Figure ND–3673.2(b)–1."

Not only is the specific code year edition specified, but they go so far as disqualifying specific paragraphs even though it is the "code".

The rules are different in your part of the world, the law of the land applies to them.

In that lies the conflict. The 'owner' has over ridden the previously accepted (by the government) FEED.

At any time an owner can over ride a code or spec which relieves the EPC/contractor of that particular responsibility. However; it does not relieve the owner of permit and governmental requirements. That particular relief can only come from the appropriate governmental authorities.

Example: If I use a sledge hammer to knock the tail lights out of my truck, I own it, I can do that if I wish. However, the State department of transportation and the US government have specific laws requiring those tail lights to be in working order before I can use that truck on the highways.

I hope all that helps. Even withstanding that, as mentioned by Shane and others, they are technically in violation of the code by ignoring the specs in the manner in which they have. That loops back to the governmental sign off's and the code both.

Owning something doesn't relieve a person, group, or company of responsible use.

pequeño jefe y la esposa decir hola.
Tomar cuidado mi amigo,
Gerald
Parent - By Richman (**) Date 05-23-2009 10:42
If the owner/representative agrees on the proposal of the contractor to change the requirements it’s the owner prerogative and need to respect. The codes respects the owner decisions to over ride what is written in the code or specs which reduce the specific responsibility of the EPC/contractor. But they shall have written documents that everybody agreed and signed by all parties involve otherwise it is very difficult to implement at site the revise requirements of the project. As inspector we always need a written and signed documentation so we can implement fully requirements at site not only by verbal information or instruction to avoid any discussions in all parties involved. However the owner shall always needs to follow the requirements of the government (law), because the LAWS applies to everybody and can only change by proper /higher government authorities.
Up Topic Welding Industry / Inspection & Qualification / What is better?

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