HI everyone.

I have a question, and hope to receive your feedback-
We have some pressure vessels with natural gas
about 4 mts diameter and 6 meter height, elliptical heads
these include skirts, about 20 mm in thickness.
Normañlly we include a 24 " manhole in the skirt.

Recently someone told us wúld be recommended to add a second manhole
in the skirt as a security issue, For example for fast venting in case of
a gas leak in the bottom of the vessel.

what are your toughts

Are there goverments, laws or regulations in USA, ASME API,etc
which states something about this? more manholes?

Thanks

 

There are no rules against it in ASME BPVC other than placement (can't be too close together.) Having more than one is more of a process safety and maintenance issue. Whether its a "good idea" can be documented by an FMEA. If the manway is a safety device, then redundency may be needed.