What are the implications of having piping fixed /attached to the tank during the hydro test? Is this at all acceptable?

Answer

As new tanks can settle, it would be risky to attach the piping before the hydrostatic test. The tank can go down, that way introducing stresses in the nozzles and surrounding equipment if it exists (pumps, for example).

It is not acceptable. Maybe in an older tank where you already know if the tank will go down or not. But it is not recommended neither.

Let’s make decisions according to risk .

If a tank starts to tilt or settle, we are talking of thousands of liters of water you need to take out before you can remove the piping. That’s one day or two of reprocesses and cost of water transport.

There is also the risk of damaging the tank. Tank shells can be deformed. Fillet welds can crack. The risk is real.

On the other hand, the cost of putting some blinds in the nozzles is minimal.
The blinds can even be made by the contractor.

That’s one case where a big risk can be eliminated with cheap actions. It is better for everyone to have peace of mind.

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