Vacuum distilation Column under external pressure made in flanged sections

[plantprowler]

I have a SS304 distillation column that's supposed to operate under a full vacuum and is fabricated in flanged sections 1600 mm dia each 3500 mm in length and 6 mm wall thickness.

The sections are flanged to each other by bolted flanges 1800 mm dia and 40 mm thick.

My question is, can I take credit for the flanges themselves as stiffening rings (assuming their moment of inertia is high enough which I think it is in this case) in which case the max unsupported length for a buckling calculation would become the section length of 3500 mm.

Of course, this calculation will be verified by a PE later but I am only trying to get a rough estimate of suitability for now.

 

[SnTMan]

plantprowler, you don't state a Code of construction, but under Sec VIII, Div 1 bolted flanges are considered as lines of support, so that your section length is 3500 mm as you state. See Fig UG-28.

At a quick read, there do not appear to be any particular MOI requirements for these flanges.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand