Hydrostatic test of tubes

[Muhammad Ijaz]

Dear All,
We require A-179 tubes (OD 19.05 - 2.11mm MWT) to be hydrostatically tested at 250 bar (25MPa) as test pressure of tube side of heat exchanger is 250bar.
But manufacturer says that he shall perform hydrostatic test at 70 bar (7MPa).
Per Table 7 (para 23.2) of SA-450, Hydrostatic test pressure for OD 19.05 tubes come out as 7 MPa.
However, we understand that per para 23.2 and 23.3 of SA-450, Hydrostatic test can be performed at pressures higher than the values listed in table-7 or calculated by formula given in para 23.1 or both.

Please share your expert opinion.

Regards,
Ijaz

 

[EdStainless]

You are talking about two very different tests.
In order to show compliance with A179 7KPa is the max test pressure required.
Now if you want another test that is fine, and this can be done one of two ways.

You could have the higher pressure called out in you purchase documents.
And the manufacturer acknowledged those and agreed to test at the higher pressure.
And I hope that you had this highlighted since it is a deviation from the base specification.

Or it can be an additional test and cost and it will be done on tubes after you pay for them.
If tubes were to leak at the higher pressure that is your problem not the manufactures.

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P.E. Metallurgy, consulting work welcomed