PWHT of T-branch

[Pascal van Bon]

Can anybody help me on this??

We have this HP steam line on which we have to make an extra connection. Materialwise we need to do PWHT. Now i know there is some regulation about the percentage of circumference which states if you only need to do the PWHT only locally on the weld and HAZ, or the entire circumference of the main line? Can anyone help me where this is stated and what that percentage is??
Hope my question is clear enough. For any questions/remarks please contact me.

 

[XL83NL]

Hi Pascal. What design code are you using?
PS: Nederlands?

 

[Pascal van Bon]

ASME B31.3.2016

 

[Pascal van Bon]

Gaat erom bij welk percentage we alleen het lasgebied moeten gloeien en wanneer de gehele omtrek van de pijp.

 

[XL83NL]

Gaat erom bij welk percentage we alleen het lasgebied moeten gloeien en wanneer de gehele omtrek van de pijp.

As this forum is English (even though you and I speak the same language), I have translated your reply so other's may share their thoughts as well.

What Im after is the percentage at which we only need to PWHT locally, around the welds & welded zone, and when we have to PWHT the whole circumference of the pipe

Im not sure if such details are provided in B31.3. Also bear in mind B31.3 is for new construction. You mention you have a HP steam line in which an extra connection has to be made. Im not sure if thats covered by B31.3. Maybe it can, but from other forums I know the ASME codes (like VIII-1, B31.3) are only for new construction. Codes such as API 510 sometimes better handle modifications.

That being said, can you provide a sketch that shows the extra connection that is considered being made? Is it e.g. a weldolet, or just pipe-in-pipe? How is this 'main line circumference' affected by this extra connection?

 

[Pascal van Bon]

Just received a message that the percentage rule has been deleted in the 2016 verion. Thanks for any effort

 

[XL83NL]

You're welcome. Do you happen to know in which edition it was still present then?

 

[Pascal van Bon]

No, dont have an older edition. Did find the item in the B31.3-2016 artikel 331.2.6. '...and shall extend completely around the run pipe.