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Up Topic Welding Industry / ASME Codes / Impact Test Customer Specification versus ASME Code
- - By stef33000 (*) Date 11-09-2019 13:18 Edited 11-09-2019 15:02
Good day everyone,

I am a Welder Engineer in French Oil and Gas Company and there is a Question that everybody in Europe would like to have the answer.

I make you an actual Example:

An UNS 32750 Super Duplex Steel is to be qualified Ø168.3 x 18.26mm.

The COMPANY specification request to perform a charpy test @-20°C in WM/FL/FL2/FL5. Minimimum Design Temperature is -20°C.

Case A - Pressure Vessel ASME IX (No Piping)

Accoding to ASME IX the Semi Essential Variable are activated and then the thickness range is 15.875 to 36.52mm. I speak about 15.875mm and not 16mm because 5/8Inch is a actual Value = 15.875mm.

Do you confirm that Semi Essental Applies for ASME IX as mentioned above as the "COMPANY requests charpy".
Semi Essential is based on COMPANY requirement only for CHARPY?

The Semi-Essential are activated from ASME VIII or from COMPANY spec?

Case B - Pressure Piping ASME B31.3 (my case)

This case interest particually me as I work always wiith B31.3. and oil and Gas COMPANIES make to much confusion with ASME IX and B31.3 (always mixing)

The UNS S32750 is referenced as -51°C Impact Test exemption as per ASME B31.3 therfore

The Table 323.3.1 says that as the -29°C is not reached WM/HAZ is not requested. Therfore Impact Test is not requested.

However as my COMPAPNY requests to perform the charpy @-20°C whatever the table Table 323.2.2. WHat is the range that the PQR covers?

Answer:

1 - As COMPANY spec prevalence and ASME B31.3 is the Code
Therfore T/2 to T+6.35,  here 9.13 to  24.61mm  is to be used even the design température is >-29°C (here-20°C)

2 - Impact Test is performed @-20°C as per COMPANY spec but have no consequence of the Range of thickness Qualified but only on Temperature qualified for COMPANY spec. ASME IX semi essential Variable is not activated as ASME B31.3 does not request Impact Test normally.
Therfore the range covered is 5 to 2T, here 5 to 36.52

3 - Impact Test is performed @-20°C as per COMPANY spec but as ASME B31.3 does not request impact Test therefore ASME IX takes prevalence for Impact Test as "COMPANAY request impact Test"
ASME IX semi essential Variable is activated
Therfore the range covered is T (or 16) to 2T, here 15.875 to 36.52mm.

--

Now Same Question be with Impact Testing @-46°C of UNS 32750 requested by COMPANY

1 - As COMPANY spec prevalence and ASME B31.3 is the Code
Therfore T/2 to T+6.35,  here 9.13 to  24.61mm  because <-29°C and therfore the range of ASME B31.3 must be respected

2 - ASME IX is to be used therfore 15.875 to 36.52mm.

--

One of the thing is that for <-29°C (-46°C) there is no problem that the ASME B31.3 is to be respected (T/2 T+6.35) but when >-29°C (= - 20°C) the case is wird as the Code will considere the Pipe as "Pressure Vessel" if ASME IX takes place.

Therefore two range would applied:

9.13 to 24.31 mm for -20°C
15.875 to 36.52mm for -46°C

As you see the ASME B31.3 limites the Maximum thickness to avoid over-heat and here @-46°C the range is more open to the high thickness that is non-sense for ASME B31.3 philosophy. (less stringeant than @-20°C)

---

This Question is a very blocking point for most of the Europeen Welding Engineer that work with very stringent COMPANY specification and ASME B31.3 code. At the end the quesiton is Does the costomer spec take prevalence to the CODE?

Therefore please can you answer without using only Yes or NO and explain where you answer come from? Code Cases...?

Thank you a lot for your answers
Parent - - By Shane Feder (****) Date 11-10-2019 13:01
The Customer Specification always takes precedence over the code/standard if it is more stringent than the code/standard.
Codes/Standards provide minimum requirements - Clients / Customers can add anything they like to the specification as long as it is listed in the contract documentation.
Parent - By 803056 (*****) Date 11-10-2019 15:49
I concur with Shane's position.

A;
Parent - - By stef33000 (*) Date 11-10-2019 19:51
Ok thanks

Therefore if a COMPANY asks for Charpy Test @0°C while SuperDuplex is ok for -29°C without Impact Testing according to the Code B31.3.

Do you confirm that the Range of the WPS is T/2 to T+6.35 @0°C and above and Semi essential Variables of ASME IX appliy?

Actually my position would be to perform the Charpy yes ok of course as per specfication, but the Semi essential Variable are lead by the Code and therefore range is 5 to 2T.

Do you confirm this last sentense is wrong for you?
Parent - - By Shane Feder (****) Date 11-10-2019 23:04
ASME IX
The toughness supplementary essential variables do not apply unless referenced by the construction codes.

When toughness testing is required for Welding Procedure Specification (WPS) qualification by the construction code, the supplementary essential variables become additional essential variables, and a change in these variables requires requalification
of the procedure specification.

IF B31.3 does not require impact testing then ASME IX supplementary essential variables are not applicable.
Nor is the B31.3 thickness range (T/2 to T+6.35) applicable.
The range of the WPS is as you have noted - 5 to 2T.

The specification may note additional impact testing is required but that will not affect code mandated thickness requirements.

When I get a chance I will check my interpretations for you
Parent - - By stef33000 (*) Date 11-11-2019 09:55
Hello

Thank for your support

Actually I see on ASME IX 2018 §Introduction Page xl

"In addition, special consideration is given when toughness testing is required by other Sections of the Code. The toughness supplementary
essential variables do not apply unless referenced by the construction codes."


&

When toughness testing is required for Welding Procedure Specification (WPS) qualification by the construction code, the supplementary
essential variables become additional essential variables, and a change in these variables requires requalification
of the procedure specification.


On ASME B31.3:

Table 323.3.1 Impact Testing Requirements for Metals:

Column A -Materials Tested by the Manufacturer [Note (1)] or Those in Table 323.2.2 Requiring Impact Tests Only on Welds

The mandatory fact that T/2 to T+6.35 is to be used is only when Table 323.2.2 is used. (My understanding)

However when cutstomer specification requests charpy whatever the Code it is not linked to Table 323.2.2 because § is not used.

I would very appreciate if you can check your interpretation

When I get a chance I will check my interpretations for you

So the Final Question is:

1 - Is the Charpy customer specification superseed the input of the Table 323.2.2 and therfire is the Table 323.2.2 application if the customer specification request Charpy?

For me my interpretation is that:
if the customer speficiation wants to use T/2 to T+6.35 of the Table 323.2.2 therefore he shall it notifity on his document in the paragraph if "Thickness Range" ans cleary states the Semi Essential Variables of ASME IX Apply.

The problem is that : they put "Design Code as per B31.3" & " Welding Qualification as per ASME IX" and 10 § later "charpy is requested @-20°C for example.
Parent - - By Shane Feder (****) Date 11-11-2019 10:32
The customer gets what they ask for and what they pay for.

"Design Code as per B31.3" & " Welding Qualification as per ASME IX" and 10 § later "charpy is requested @-20°C for example.

They can request impact testing at minus 100 degrees C and that is what you will need to do.
That additional temperature requirement has nothing to do with the WPS thickness requirements of B31.3 or ASME IX.

Just FYI the B31.3 thickness requirements will " soon" be bought in to line with ASME IX so there will be no difference between the two codes for impact tested applications.
Parent - - By stef33000 (*) Date 11-11-2019 15:45 Edited 11-11-2019 16:22
Ok

Does someone  have a Code Case or whatever the relevant document that I can use to inform my COMPANY about that?

Because I quite sure they will me

"It is not our understanding, use T+6.35 and not 2T." as they want to take 0 risk. (This is not them that wrote the specs)
Parent - - By Shane Feder (****) Date 11-11-2019 22:54 Edited 11-11-2019 22:57
(This is not them that wrote the specs)
Your last sentence is very important.
If the specification was written by the designers then my answer is different.

323.3.1 General. When impact testing is required by
Table 323.2.2, provisions elsewhere in this Code, or
the engineering design,
it shall be done in accordance
with Table 323.3.1 using the testing methods and acceptance
criteria described in paras. 323.3.2 through 323.3.5.

You will be required to follow the T/2 to T + 6.35 mm thickness requirements.
Parent - - By stef33000 (*) Date 11-12-2019 12:33
OK in that case I see better. I thin you have a good point.

Yes actually the spec is written by "Welder Expert of COMPANY"

"The designer" requests only to follow the advices of the "Expert". They even don't know that impact test can be requested for Duplex. that they want is "MPa" and corrosion Properties...

Therfore as the "Engineering design == COMPANY == Welding Expert who wrote the spec" it is obvious now that T/2 to T+6.35 is to be applied when Impact Test is needed whatever the Impact Temperature.

Therefore almost all my Piping WPSs will be T/2 T+6.35 as Table  323.2.2 is completly superseed by the Impact Test requirement.

I see that on B31.3 Rev 2018 that it is Still T/2 T+6.35 and not T to 2T as ASME IX. Therfore still not changed.

Thank for you support! i appreciate.
Parent - - By Shane Feder (****) Date 11-12-2019 12:41
I have asked for clarification on this issue from other members of the B31.3 committee.
I personally do not think that a 3rd party writing a specification falls under the " Engineering design" classification.
The change from B31.3 thickness requirements to ASME IX requirements is still going through the code ballot process - nothing happens quickly (unfortunately).
Parent - - By stef33000 (*) Date 11-28-2019 12:36
Do you have some new about the ASME B31.3 Committee?
Parent - - By Shane Feder (****) Date 11-28-2019 12:47
Sorry for not replying sooner.
I had an informal response via e-mail from the former chairman of the ASME IX committee (who is also on the B31.3 committee) and he disagreed with my thoughts.
His opinion was if it was included in the contract documents then it is deemed as part of the " design" - (unless formally agreed as not required by the Design Engineer).
Sorry I couldn't be more help,
Cheers,
Shane
Parent - By stef33000 (*) Date 11-29-2019 14:47
ok very thanks you for you answer.

Ok if he think like that i will consider the range will be always T/2 to T+6.35 as quite all my customer specs say "Charpy @-20°C whatever the steel".

This clarification would deserve a Code Case :)
Up Topic Welding Industry / ASME Codes / Impact Test Customer Specification versus ASME Code

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