Branch Reinforcement Calculation

It is better to have and not need, than to need and not have.

The language to describe all of this is perhaps too fine-tuned to give in a brief Web post. Basically, the cross-sectional area you cut out of the main pipe must be replaced somehow. This can be done by surplus thicknesses of header and/or branch, addition of a reinforcement pad, some extension of the branch (or vessel nozzle) into the main pipe (or vessel shell), and weld cross-sections. There are five areas involved.

An easy, but sometimes too conservative, way to address this is to provide a reinforcement pad of thickness equal to the vessel wall or main pipe, with outside diameter 2x the branch or nozzle diameter.

Do you have a copy of B31.3? If so, this is pretty much cookbook. If not, get it.

Ed.: but I'm guessing reinforcement will be required. Post back when you calculate the answer.

My own guess might (not necessarily would) go the other way. On quick glance, the pipes seem to be well thicker than needed; this could give some surplus cross-sections that might be adequate without reinforcement. I don't have the B31.3 standard to hand, and don't know how closely it matches the pressure vessel code.

As the saying goes, don't try this at home. Find out and follow the correct calculations.