Annex P Figures P.2a-l

[sajk14]

Hello all,

I am going through the sample problem in Annex P and familiarising myself with the formulas, methodology etc...

I noticed that Figures P.2(a-l) are applicable if L/2a = 1.0 or L/2a = 1.5

My query is that if you have an L/2a value greater than 1.5 ( lets say 4.0 for e.g ) would you just use the graphs for L/2a = 1.5?

Also i'm sure this topic has been approached numerous times before but....

if we have a tank less than 36m diameter am I correct in saying that we can still use the methodology outlined P.2.7 for allowable nozzle loads if agreed by the purchaser, or do we specifically have to use Finite Element Analysis software to do this?

Your comments and feed back are much appreciated.

 

[JStephen]

If I remember right, where the 100'/36m limitation came from is that in the derivation of the method, in order to simplify it, it was assumed that shell thickness was proportional to pressure. On tanks where the thickness is governed by minimum thickness, that is not true. You might look up the two technical papers referenced. If the tank in question is large enough to fit this assumption, then consider using the method shown.

 

[sajk14]

Thanks JStephen,

The tanks are approx 75 ft Diameter and 60ft high and the calculated thicknesses for the lower 3 shell tiers are above the code governing minimum thicknesses ....so im hoping I should be ok using the formulas and nomograms per Annex P.

Did you have any thoughts on how to use Figures P.2(a-l ) for an L/2a value greater than 1.5?

Thanks again for your comments.