This website of MB Meletti presents resistance tests to pressure and temperature and burst tests to which the appliances manufactured by the company are subjected.
For burst tests the results were the following:
Tubular stainless steel tank (2012-0493 / 1) Pressure up to 54 Bar
Tank with a stainless steel plate (2012-0493 / 2) Pressure up to 38 Bar
In the test of resistance to temperature and pressure 2012-0493/1-2 samples were subjected to liquid penetrant examination to check for any defects or abnormal welds.
Then were filled with water to appropriately evacuate any air bubbles present in the tank. This was linked to a system that can increase the pressure inside the tank.
It was placed in the oven heated at 90°C and was maintained at ambient pressure for approximately 60 minutes. Then the pressure was increased up to 6 bar and maintained for 10 minutes.
It's been tested for leakage and/or deformation and then subjected to further examination of the penetrant (See RPP 2012-0493/PT).