Position qualification as per API 1104

[Hang Suin]

Dear All,
Could you please let me know if a welder, who has been qualified using 6G position on butt weld pipe, could weld in branch connection? I have went through the API 1104 code but since I am not so familiar with this code, I was not able to clarify that issue. In this regard, the code does a reference at two different positions which are "roll" and "position welding". Could you please let me know what do those two positions stand for and how are they connected to the "common" positions (1G, 2G, 3G, etc) as specified by ASME IX?
Thanks
Hang

[Ballbearing]

Hang Suin,
The two positions you have noted - "roll" and "position" are actually "rolled" and "fixed".
Fixed as in "locked in position" and rolled as in rolled or rotated while welding is underway.

What was the diameter of the test coupon and what are the diameters of the intended branch welds. ?
Regards,
BB

[Hang Suin]

Thank you Ballbearing for the clarification,
Could you please explain how are the welding positions defined in API 1104 as for example in ASME IX are defined as 1G, 2G, 3G, etc since I am not pretty sure that I have understood this issue very well. Regarding the actual weldings, please note that they are 6" pipe branch welded on a 18" pipe as well as 4" pipe branch welded on 12" pipe.
Thanks

[Ballbearing]

Hang Suin,
API 1104 lists horizontal plane (the pipe, not the weld) = ASME IX 5G, vertical plane = ASME IX 2G and 45 degrees = ASME IX 6G.
The welder qualified in the 45 degree (6G) position is qualified for all positions (6.2.2 (f)).
If the diameter and thickness of the branch pipe falls within the qualification limits referenced in 6.2.2 (d) & (e) then the welders are qualified (irrespective of the diameter or thickness of the run pipe).
However, I am not 100% sure on 6.2.2 (g) - the change in joint design as you will be going from a single vee to a single bevel.

5.4.2.3 Joint Design
A major change in joint design (for example, from V
groove to U groove) constitutes an essential variable. Minor
changes in the angle of bevel or the land of the welding
groove are not essential variables.

I think with a Single qualification test (6.2) (as your welders have done) the welders are not qualified.
If they had performed Multiple qualification test (6.3) they would be qualified as that covers all joint designs.
Hope that helps,
Cheers,
BB

[mohd]

Dear Hang,

For Simple and layman understanding of Roll and Fixed, Roll is similar to 1G Rotated (as for example you see in SAW shell/head welding by rolling the shell/head), Fixed position can be 2G/5G/6G anythings but not rolling.

Regarding your question about branch welding, branch welder can be qualified as per API 1104/Figure-10/Page-16.

As far as API 1104 is concerned, for the WPS the diameter is non essential variable, you only have to qualify the welder for different diameter ranges as per 6.2.2 d.

But if the Project's requirements don't call for branch welder qualification (instead stress on very low rejection rate) then the welder can be used for branch welding as per his qualification range.

regards,
mohd.

[Hang Suin]

Thank you once again Ballbearing and Mohd for your valuable support,
Mohd, could you please let me know why shall the welder be qualified using branch connection only if it is specified by project's requirements? I am a little bit confused in this regard since It seems that Ballbearing is right saying that with a single qualification (butt weld) I can not qualify for branch connection because of the joint's change as per 6.2.2 (g).
Thanks

[Ballbearing]

Mohd,
Parent material thickness is not an essential variable for WPS but it is for welder qualification - see 6.2.2(e).

Figure 10 you have noted is listed in 6.3.1 which is multiple qualification - you have to do a branch weld to qualify for branch welding. A single qualification using two x pipe nipples does not qualify for branch welding.
Regards,
BB

[mawsamit]

Ballbearing and Mohd,

Please let me disagree with both of you,
Regarding Mohd's statement that "if the Project's requirements don't call for branch welder qualification (instead stress on very low rejection rate) then the welder can be used for branch welding as per his qualification range" please note that the API 1104 doesn't specify such a rule. The welder shall be qualified as defined by the code.

Regarding Ballbearing's comment that the qualification shall be done as multiple qualification and a branch welder shall be qualified by branch welding, I would like to clarify that the qualification could be done not only as multiple but also as single qualification as well as in case of full penetration welding a branch welder can be qualified by single qualification butt welding.

If the production joint calls for fillet weld, then please have a look at 6.2.1 "the weld shall be acceptable if it meets the requirements of 6.4 and either 6.5 or 6.6" that leads to 6.5.6 and that in turn leads to Figure 10 that is for welder qualification test for fillet weld. Instead, if the production branch connection is a full penetration welding then the 6.2.1 leads to 6.5.1 and this in turn leads to Figure 12 where the welder is qualified by welding butt weld with the same joint configuration as the production welding (6.2.2 g, for example if the production welding calls for "single bevel" joint then the qualification shall be done using such a joint). Either in fillet weld case or in full penetration weld case the essential variables of 6.2.2 shall apply.