Hydrostatic testing is commonly used to test pressure vessels when required by ASME code, PED or standards such as API 620 or API 650.  It proves the design and shows that there are no leaks while under pressure.  The following criteria must be met for the hydro test to be accepted.

  • Tank tested in its normal operating position (if possible). 
  • Tank filled with water and pressurized per Code or Standard.
  • Pressure is held for the time period specified by Code or Standard.
  • Test acceptance (such as “no leaks”) per Code or Standard. 

Much of tank fabrication is done with the vessel laying on its side in tank rolls.  This allows the tank to be rolled over as needed for welding, grinding, installation of fittings, etc.  Larger tanks can be a challenge to get into operating position in the shop for hydro test.

The tank pictured was too large to be lifted to a vertical position indoors and it had to be taken outside for hydro. Because it weighed over 40,000 pounds, it was pushed outside on rails so two cranes, working together, could set it on its feet.  After hydro, the tank was taken back in the shop to be completed.

For more info, go to https://www.stainlessfab.com/shop-fabricated-tanks-vessels.html

Moving a large tank outside the shop for hydro

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