Reinforcemet pad ASME VIII div 1 vs div2

[olatz]

Hi,

I´ve the complete design of one tank acc ASME VIII div 1.
The reinforcement pads I´ve used are acc UW-16.1 (h) with no "hole" between plate and pipe (full penetration).
Now, my customer ask me calculate the reinforcement pads acc ASME VIII div 2 5.5 too.
My question is:
-The results will be more or less the same?
If usually div2 needs more diameter for the reinforcemet pad isn´t a problem but if needs more thickness maybe.
I´m going to buy nozzlepro but I´ve to give an answer to my customer about the impact on price.
So, as general rule what is the diference of the reinforcement pads calculated acc Div2 vs Div1?
Is necessary self-reinforcemet acc UW-16 (f-1), (f-2) (f-3), (f.4) or (g) to meet Div2?
Thanks for your answers,

Best Regards,

Olatz

 

[Crompto29]

Olatz,

As I understand it Div 1 contains simple rules for designing pressure vessels relatively quickly.

Div 2 contains advanced rules for designing pressure vessels. i.e. FEA, fatigue analysis etc.

It also contains alternative methods of designing pressure vessels. These methods typically reduce the size of components such as nozzle reinforcement slighly. They are in Div 2 to test them before moving them to Div 1. The calculations for nozzle reinforcement appear to me to be quite long and I expect will never make it into Div 1.

This is how I interpret it. I hope the above is some help.

Both methods let you choose thickness and diameter.

The extra hours needed to design a single opening on a single vessel using Div 2 may cost multiples of the material you will save.

Why don't you get your customer to decide what code they want the vessel to be designed to or next they may be asking you for a design to some other code as well.

 

[vesselfab]

In simplified terms

Div 2 brings reinforcement in closer to opening by using different limits.

 

[jte]

Olatz-

Have you READ VIII-2 part 5.5? At least the title?

You are literally talking apples and oranges. Part 5.5 does not relate specifically to opening reinforcement. Your client is asking for something altogether different, and probably with good reason. It is likely that you will be moving from a re-pad design to an integrally reinforced design.

Although you could design reinforcement using a Part 5 approach, the design by rule approach as provided in 4.5 would be more directly comparable to Div. 1 UG-37. Note that 4.5 is a rapidly changing (read “minor to moderate tweaks”) part of Div. 2.

Given the “common rules” philosophy that the code committee is working to, I’d expect to see the opening rules made more similar in Div. 1 and Div. 2 – with the current Div. 2 Part 4.5 approach (once the bugs are worked out) being the model.

jt

 

[StaticPressure]

I always avoid mixing two different codes. Div. I and II have different theoretical basis (two different failure theories), and different design factors, however the formulas/methods look similar, and results are very close. I have not hearted design with Div. II is safer, or even always more economical. When Div. I vessel does not include some requirements, like Fatigue assessment for vessel in cyclic condition, using Div. II method for Div. I vessel is recommended.
Div. I has all the required proven tools for design of opening, even for the local stresses analysis due to the external piping loads. Whatever is the geometry of the nozzle, with re-pad or with self reinforcement, nozzle must meet the requirements of UG-37.