help needed for fibre-glass vessel 1

[jlmtl]

Hi,
we have contractor designing a vertical filbre glass vessel, the operating pressure will be up to 0.3kPag. random packing will be filled in the vessel. it will be used to strip the dissolved SO2 from the waste water by air bubbling from the the bottom the packing and the waste water entering from the top of the packing. Slight vaccum may be generated due to pumping out from the bottom.

In this case, is a breather (breathing in or breathing out) needed to protect the FRP vessel?
Is there any referential code?

Thanks.
Jlmtl

 

[gr2vessels]

If it is slight vacuum, why not design the vessel to withstand the 'slight' vacuum, instead of adding an expensive valve?
To answer your question, the is no code mandating a vacuum relief valve on the pressure vessel, but rather recommendation to design and manufacture the vessel for the vacuum condition.
However, if the vacuum condition exceeds the vessel capacity, then a vacuum relief valve set at the maximum allowed vacuum may be used. I only wonder how will you relieve the vacuum in the bottom part of the vessel when you are also introducing air to the bottom;- why don't you allow some extra air, to limit or exclude the vacuum??
Cheers,
gr2vessels