Calculation for change Weldolet with pipe to pipe

[jafary64]

Hello everyone, I wanted to know where the branching from the line is in the form of a weldolet, if we want to implement it as a reinforced pipe, with or without a pad, how can we do it, is this change in the branching method possible or not? In ASME B 31.3, there is a reference to calculations for the need or not for a pad, but whether the branching is with an olet or another type is mentioned in the standard or not? I know that in PMS and the Branch Table sections, the branching method is specified for each class, but if we want to do it differently, how should the calculations be done? Thank you.

 

[NovaStark]

I can't rememeber the exact paragraph in B31.3, but those integrally reinforced branch welded fittings are typically expempted from the calculatons once they adhere to some additional criteria.

If you wish to change the type, then you'd need to redo the branch reinforcement calculations and show the area is sufficient with or without a re-pad. Depending on the pressure/temperature, the stresses on the line may change significantly due to the stress intensification factors associated with the different branch types.

 

[LittleInch]

Look at B31.3 - Branched fittings. There are calculations there which tell you. Basically its a replacement metal theory which within a certain distance of the branch if there is enough metal in the main pipe which isn't "used" fr pressure retaining or bending, then as long as it is the same volume as the amount of metal you've removed from the pipe by cutting a hole in it then you might not need a repad.

Integrally reinforced branched fittings (aka weldolets - which are a brand name) don't need this calculation as its already been done by the vendor. It does need a lot of weld metal though.

 

[jafary64]

Look at B31.3 - Branched fittings. There are calculations there which tell you. Basically its a replacement metal theory which within a certain distance of the branch if there is enough metal in the main pipe which isn't "used" fr pressure retaining or bending, then as long as it is the same volume as the amount of metal you've removed from the pipe by cutting a hole in it then you might not need a repad.

Integrally reinforced branched fittings (aka weldolets - which are a brand name) don't need this calculation as its already been done by the vendor. It does need a lot of weld metal though.

Thanks for your respond
Is there a sample example for convert weldoet to pipe to pipe at ASME

 

[LittleInch]

Look at B31.3 or search "B31.3 branch connection"

I'm not really sure what your question is though.

 

[jafary64]

I want to know when can I replace weldoet with pipe to pipe on branches
Thanks

 

[LittleInch]

Whenever you want.

Each pipe branch needs to have its own calculation or set of calcs for each header size and branch size and wall thickness. You might need a re-pad depending on pressure, size, wall thickness etc.

A weldolet you just order.