"P" numbers vs. "S" numbers in weld procedures 1

[dcb2]

"P" numbers group different materials together in the ASME code to minimize weld procedures. A vendor is quoting API material that per the ASME code should use a "S" material number. Am I correct in interpreting the ASME code that "P" numbers can be used for welding "S" material or should the "S" material have its own weld procedure?


Thanks in advance

 

[metengr]

dcb2;
Please refer to QW-420.2 in Section IX of the ASME B&PV code (2001 Edition, 2003 Addendum). Qualifications for S-number materials do NOT qualify corresponding P-number materials. In your case, the PQR must be qualified specifically with the S-number material.

 

[dcb2]

Thanks for your help.

 

[bmoorthy]

I am welding a pipe line (In a plant, Designed to ANSI/ASME B 31.3) with material API 5 L Gr B, due to non availability of material our manger has decided to get A 106 Gr B and A 333 gr 6. I have a weld procedure with API 5 L Gr B. Will Using A 333 Gr 6 warrant additional procedure qualification. I do not have sec IX at my disposal and our welding engineer is on emergency leave. Can some oone look up Sec IX and let me know any such S number P number problems exists or is it OK to use same Procedure (With API 5 L Gr B).

Thanks in advance.

 

[metengr]

The welding procedure that was qualified using the API 5L Grade B base material cannot be used for the SA 106 Grade B or SA 333 Grade 6 base materials because the SA grades are assigned a P-No1 Group 1 designation, per QW 422. From my understanding, you will need to qualify a separate procedure using either of the SA 333 Grade 6 or SA 106 Grade B pipe materials.

If you had originally qualified the procedure with the P-No1 Group 1 assigned base materials this procedure could be used for S-No 1 Group 1 base materials, however per QW-420.2.

 

[bmoorthy]

On a relook i see there are A 105 Flanges welded already to the API 5L Gr B pipe and A 216 and A 234 items welded to API 5L gr B pipes, then is it not automatically implied (Assuming that our welding inspector and engineers have done their job properly in the past by having suitable qualifications for welding API 5L gr B with A 105, A 216, A 234 etc) that A 333 Gr 6 and or A 106 Gr B can be welded to API 5L gr B.

Due to the non availability of codes and standards at my immediate disposal at site and having to take a decision (Already permitted our welder to go ahead with welding (Due to exegency)), i am trying to muster enough technical back up to supprt my decision to have gone ahead with welding and i do not want to cut any of the welds and or perform additional NDT/NDE or additional tests(In the event of objection from the client and or our welding engineer)by the vertiue of opposition that may araise for having gone ahead.

More over i see the chemical and physical properties of A 333 Gr 6 and API 5L gr B are almost identical (Except of course A 333 Gr 6 is impact tested)

 

[GRoberts]

Bmoorthy,
You say that you have a procedure for welding S1 material. Just to clarify, are you talking about the procedure (WPS) or PQR. The essential place to check is the PQR. Make sure if it was qualified with S1 or P1 materail. If it turns out S1 material was used on the PQR, it is clear that the P1 to S1 joint is not currently qualified. At this late point in the game, it would seem to me that the easiest route to just have you welder make 1 extra (or multiple of the pipe is too small) pipe weld, welding P1 to P1 material. Record the parameters and test the joint. If it passes you will be set.

 

[sayee1]

Additional twists to the tale
1. SA 106 Gr B material is P1 but A106 Gr B is S1 as per QW420.2 (See para 3)
2. QW 420.2 is a not a mandatory requirement (see heading of QW 420.2).
3. P no qualifies same S No but not vice versa.
============================================================You have stated that the joints welded are are A 105 Flanges welded already to the API 5L Gr B pipe and A 216 and A 234 items welded to API 5L gr B pipes which are all S 1 materials.
Unless there is impact testing (in which case Grp no becomes essential), the materials you are welding/have welded are ASTM materials (A xxx-Xx)or API 5l Gr B and not ASME Section IIC materials(SA xxx-Xx), and hence you are safe, whether the PQR is qualified using P1 or S1 materials.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!

 

[bmoorthy]

That was a good insight. I was always under the impression that A and SA material have same P numbers. Having A material in PQR is a certainly disadvantageous choice. This is a real shocker.

Personally i feel this is very complicated situation created by ASME.


Good Luck
B.Moorthy
moorthykar@yahoo.com

 

[metengr]

sayeeprasadr;
I am not sure that I understand your explanation. The nonmandatory statement in the heading of QW 420.2 refers to the assignment of S-No designation to P-No base material designation for procedure qualification purposes. In other words, if you are using P-No base material you do not have to assign an S-No for qualification purposes (non-mandatory). So, any weld procedure qualified using a P-No base material is qualified for use on similar S-No base material, but not vice versa.


QW420.2 applies to the use and qualification of base materials that are not endorsed by ASME Section II.

 

[sayee1]

Metengr
QW420.2 is non mandatory because if you are fabricating a coded pressure vessel to ASME Section VIII Div 1, all the materials are bound to be SA materials i.e. listed in II A. Section IX was basically designed for qualification of ASME vessels. However additional codes like ASME B31.3 refer to ASME section IX for qualifications as well. Hence if you see clause 328.2.1 F last sentence of ASME B31.3, it is clearly mentioned that S Nos are mandatory for piping fabricated to B31.3. Hence my interpretation is that it is the fabrication code which decides whether S no is mandatory or not.
BMoorthy had mentioned that they had already welded on site A 105 Flanges to the API 5L Gr B pipe and A 216 and A 234 items welded to API 5L gr B pipes. Note that these are alle all S 1 materials. So what I am saying is that if the WPS has already been used for welding S1 materials, I would assume that the welding engineer has already checked appropriateness of the WPS for S1, and thus it should be ok for the A 333 Gr 6 and or A 106 Gr B to be welded to API 5L gr B.
BMoorthy,
Note that ASTM has listed materials as Axxx. However ASME has only derived materials from these that are going to be used in pressure vessels and added to the A specifications to come up with SA as in ASME Section II A. In most cases you will find that A and SA classifications are almost the same. Piping on the other hand is generally fabricated to B31.3/1 which allow for the use of ASTM classified materials and API grades as well.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
email: sayee_prasad@yahoo.com
If it moves, train it...if it doesn't move, calibrate it...if it isn't written down, it never happened!