Self reinforcement nozzle calculation by EN13445

[luike]

Dears Colleagues:

Does Anyone have any spreadsheet in excel to perform design using EN13445 or PD5500 for self-reinforcement nozzles in applications with high design pressure ( closer than 300 barg)?.

Your promptly help will be higly appreciated.

Best Regards
Luike

[luike]

Hi Sirs:

I understand that if we talk of european code or PD5500 it could be bored but two days ago, performing the calculations it is very strange that external diameter of reinforcement results in eurpean code (EN13445-3) higher than Asme code. Could anybody explain why?. The normal situation is that in ASME Code should be higher due to conservative way of calculation. I will thank you possible causes.

[luike]

Hi Sirs:

I understand that if we talk of european code or PD5500 it could be bored but two days ago, performing the calculations it is very strange that external diameter of reinforcement results in eurpean code (EN13445-3) higher than Asme code. Could anybody explain why?. The normal situation is that in ASME Code should be higher due to conservative way of calculation. I will thank you possible causes.

[marian_g]

As method, the first proposal of CEN/TC54 committee was to use 'Area Replacement Method' that is present in ASME VIII Div. 1 (based on method of replacement of cross sectional missing area of openings with cross sectional areas of material reinforcement of shell and nozzles), but during standardization works it was decided to adopt the 'Pressure-Area Method' because this one was well known and widely used in continental Europe.

The Pressure-area method is based on ensuring that the reactive force provided by the material is greater than, or equal to, the load from the pressure. The former is the sum of the product of the average membrane stress in each component and its stress loaded cross-sectional area; the latter is the sum of the product of the pressure and the pressure loaded cross-sectional areas.

You can conclude that it is not a matter of "factor of safety" (which, generally, it is more relaxed in EN than in VIII Div 1) but one of method (i.e. the method adopted by EN is more conservative).