In the US, it would be considered ASME pressure piping, as it is under 6", but does operate above one atmosphere pressure, and is intended for LPG. As such it would be required to be certified to 350 psi.
It would also be required to have a pressure relief valve, because it will be flooded and then valved off, where thermal expansion can produce not vapor pressures, but hydraulic pressures. For that reason LPG pressure vessels may not be filled beyond 80% capacity, and of course a column is near 100%.
In short, even if your overall arrangement could pass International Building Codes and International Electrical codes, it couldn't pass ASME because it is potentially a bomb.
Having said that, our experiments with a simple closed tube and soaking, is that we extracted a lot of non targeted C-30 size molecules, so the yield was higher but the quality lower.