API Standard 1104, Section 5.4.2.2 and Welding Dual-Stencilled Pipe

Already on the cards

4206 5L Dual/Triple Grade Marked Pipe

(TG LP) (Approved work item-2008)

Standards Category : ISO 3183/API 5L

Charge:

WG Chair: Jim Cox

Members:

A summary of the item was given by Joe Majkrzak. End users have identified an issue with welding qualification when dual or triple stenciled pipe are used. Dual stencil pipe has been in the industry for such a long time that eliminating these products would cause issues within the trade. A recommendation was given to limit manufacture to dual stencil and to only PSL-1 products. It was reported that the work group had passed a recommendation onto the API 1104 committee requesting they modify the requirements within 1104 to broaden their classifications. The API 1104 committee agreed to work on the issue.

or

http://napca.com/webfiles/2009_Workshop/NAPCA_-_Workshop_-_2009_-_Bob_Wise_Presentation.pdf

Also API clarification

http://committees.api.org/standards/tech/docs/1104ti.xls (row 42)

Does this mean that a WPB (35,000 psi yield) fitting can be welded to X-52 Grade pipe as long as a qualified procedure for welding X-52 pipe is being used (Please answer assuming all pressure, wall thickness and all other design requirements are met)?

Or, does it mean that when welding pipe, which has been double or triple stenciled, such as a double stencil of X-42/X-52, that a procedure qualified to weld X-52 or the higher yield rating must be used.

We are trying to understand whether fittings and/or pipe from different groups in section 5.4.2.2 can be welded together utilizing the procedure for the higher yield material of the two or if this statement is trying to cover the procedure by which the pipe mills will stencil pipe to qualify for several grades.

It means that fittings and/or pipe from different groups(as defined in 5.4.2.2) can be welded together, provided that the welding procedure specification to be used has been qualified for welding the higher of the two yield strengths involved in the specific pipeline design, regardless of the number of grades that a specific pipe may have been qualified to by the pipe mill.

Also as per API 1104, 5.4.2.2 the X42 and X52 are in same category

b) "specified min yield strength > 42,000 PSI but less than 65,000 PSI"

I respectfully disagree. Group "A" is for materials with a SMYS less than or EQUAL To 42,000. Group "B" is for materials with a SMYS greater than 42000 but less than 65000. Group C is for materials with a SMYS greater than or equal to 65000 psi. And that is the delimma and basis for my question. Dual stencilled API 5L X42/52 crosses two "material groups" in API 1104 section 5.4.2.2.

You are right. X42 is just below border .

and then you still have the foot note to take care of after the (c)

However again it is vioalating the clause.

But the X52/X42 means the pipe meets the criterion for the both grades.

Then next point is what it is getting welded to ? X42 grade or X52 Grade?

I vaguely remember that in similar cases, the code calls for the qualification acceptance criterion based on the higher grade (ie X52 for you).

Still remember the note (final decision will be depending on the composition).

Main problem is not the technical aspect here. It is convincing the auditor (we frequently get into this type of problems, and difiicult to convince, even when you know it is correct, but the code is ambiguous. You can decipher it the way you want.

I heard that the next edtion of API 1104 due out in 2010? will address this issue. I was hoping for a sneak preview to show the naysayers. The current edition is silent

Can you help me understand why a welding procedure for X60 would not allow dual grades X60/X65 ? API has certain specification criteria that must be followed and tested to allow pipe to be certified to Grade X60 and Grade X65, and under API, if that specification criteria happens to meet both, then you are allowed to certify both grades. This does not mean anything other than it meets Grade X60 and Grade X65 - I am confused how this would affect anything to do with welding procudure. If the line is X60 but the weld test pipe is X60/X65 - so what? In order to certify Grade X60 and X65 under API, The testing results and Chemistries will fall under both results that constitute X60 and X65. , Why would API allow dual certification of grades such as X60/X65 and not be 100% compatable with Grade X60 alone or X65 alone -

. In fact, I work for a distributor - often times, distributors will make the choice after mill production and testing, the mill will ask us if we want to dual grade. Yes or no, our choice... We can have pipe with the same OD wall Grade and Heat number stenciled X60, - X60/X65 or just X65 - There is no difference in chemistry - So I do not understand when someone tells me they can only accept X60 but not X60/X65 or for that matter X65 and cant accept X60/X65 for Weld testing procedures.,.... Why make it difficult, its the same pipe guys

I've had several discussions with the federal regulators in the US over the past few months pertaining to this topic. The following is the consensus we came to:

"For pipe that meets the requirements of more than one pipe grade (i.e., pipe that is 'multi-graded' or 'dual or triple stenciled'), it is not necessary to use a welding procedure that is qualified for the highest grade to which the pipe is certified. It is only necessary to use a welding procedure qualified for use on the grade for which the material will be used. For example, for pipe certified to both API 5L X42 and X52, a welding procedure qualified for use on X42 is acceptable provided that the material is being used as X42. However, for some applications (e.g., high longitudinal strains), it is good practice to at least match the actual yield strength of the pipe. The use of filler metal with yield strength that matches or overmatches the actual yield strength of the pipe material prevents longitudinal strains from accumulating in the weld region, which is more likely to contain imperfections than the pipe material."

Regarding the requirement in 5.4.2.2 for a separate qualification test for materials with a SMYS of 65,000 psi (448 MPa) and above, this is my position:

"For welding procedure qualification tests conducted on multi-graded or dual or triple stenciled pipe (e.g., pipe certified to both API 5L-X65 and X70) the test results can be used to support WPSs pertaining to any of the grades to which the pipe is certified. Using the example of pipe certified to both X65 and X70, a successful procedure qualification test qualifies the procedure for use in welding X70 to X70, X65 to X65, and X65 to X70. Even though 5.4.2.2 requires a separate qualification test for materials with a SMYS of 65,000 psi (448 MPa) and above, it would make little sense to perform two identical qualification tests (i.e., one considering it to be X65 and the other considering it to be X70) on the exact same material."

Here's another bit of guidance pertaining to this topic that has been discussed at recent API 1104 committee meetings, which may be useful:

"The strength level grouping listed in 5.4.2.2 should be based on 'nominal' strength levels. The actual strength levels that are now specified in API Spec 5L (Forty-fourth Edition) as the result of normalization need not be considered (i.e., it is not necessary to consider that API 5L-X42 now has an actual specified minimum yield strength, expressed in US Customary units, of 42,100 psi)."

All of this guidance will appear in a report to Pipeline Research Council International titled 'Guidelines for Interpretation and Application of API 1104', which should be published in the near future.

Bill Bruce - DNV Columbus, Inc.

Thanks for sharing valuable information.