EN 13445 (A weird clause for Lifting lugs) 1

[iTools]

Recently I have started working with EN 13445 for the design of pressure vessels and I have come across a clause in the section regarding lifting lugs, sec 16.7.3, which I do not quite understand. The clause is:
0.001 < en/Deq < 0.05, where en is nominal thickness and Deq in my case is the corroded internal diameter. What this clause says in plain English is that the thickness must be less than 20 times the diameter of the vessel and bigger that 1/1000 of the diameter. This last one is understandable but a maximum thickness over diameter.....well, weird!!!

Can anyone make me see clearly?

Regards,

iTools

 

[prex]

What you are referring to is a condition of applicability of the design rules that follow. Moreover e_n is the nominal thickness of shell. So you are told that you may use the provided design rules only if the shell is not too thin nor too thick.
This doesn't mean of course that lugs cannot be used outside those limits, but only that a different justification (not provided by code) need be used.

prex

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