Pipe wall thickness sizing 3

The only good use of the burst pressure I´d recommend is to compare the safety factor of the code you are using and the safety factor of the manufacturer (commonly based on cold water pressure tests not on code comitee criteria).

If your case is "special" and no public user can be related if something happens you may take the risk.

I think the manufacturer states the bursting pressure in order to have a reference for quality or in case of a claim or incident.

I remember a case where a PE pipe bursted on site several times. On a factory burst test it resisted a very high pressure (above stated bursting pressure). The manufacturer proved that the pipe was not deffective and the problem was not his fault (abnormal conditions or bad selection/design).

2" sch 160
3" Sch XXS

Per ASME B31.3, the design pressure must account for the highest pressure the system could experience, including transient conditions or safety valve settings. The safety valve setting of 290 bar represents the maximum pressure the system is designed to handle before the safety valve activates.
It’s common practice to add a margin to the safety valve setting to ensure the pipe can withstand pressures slightly above the relief point, especially for dynamic systems like high-pressure water with plunger pumps, where pressure spikes can occur.
Your choice of 300 bar as the design pressure is reasonable and conservative, as it provides a small margin (approximately 3.4%) above the safety valve setting of 290 bar. This accounts for potential pressure surges or tolerances in the safety valve operation.
Use 300 bar (4350 psi) as the design pressure, as you’ve done, to ensure the steel piping system can handle the maximum system pressure with a safety margin. If you want to be less conservative, you could use 290 bar (4205 psi), but the 300 bar choice is safer for dynamic systems with potential pressure transients.
This page introduces the technical indicators and compressive strength values of stainless steel pipes: https://www.pipeun.com/astm-a312-stainless-steel-pipe/ Tensile Strength: Minimum 515 MPa (75 ksi) Yield Strength: Minimum 205 MPa (30 ksi) Elongation: Minimum 35% in 2 inches