Fabrication Tolerance - Rectangular Tank Top plat flatness

[pnrngv]

Hi,
What is the recommended fabrication tolerances for the top plate flatness of the rectangular tank?

There is no limitations or guidance in any of the standards. As a good practice +/- 5.0mm tolerance measured between the distance is < 500 MM should be ok ?

Any expert opinion and references. Please share.

Regards
pnrngv

 

[kingnero]

If there's really no guidelines, ISO 13920 is always a good reference. You'll find lots of tables online.
Standard values are row C and G.

 

[Compositepro]

You may want to avoid ponding on top of the tank by dishing it slightly, but too slight a dish can result in oil canning, where the dish can invert.