Dear all,

I have a discussion with a PED Inspector regarding my calculation and drawings for a pressure vessel.
In the calculation I do not have included the DIN flanges, because it is a standard part and must not be calculated (my understanding, hopefully correct).
The drawing of this pressure vessel shows the DIN flanges and the DIN material, the rest parts (pipe, plate) are from ASME material.

Is there a rule, that I am not allowed to work with this material mixture?

The PED Inspector forces me to change the DIN material to ASME material, but the calculation is without these flanges.
What can I do to recieve my PED stamp without this discussions?

Thanks to all for your help.

Main question is what is the design code?

regards,
malyl

""In the calculation I do not have included the DIN flanges, because it is a standard part and must not be calculated (my understanding, hopefully correct).
""

How above could be ?

Flanges are also pressure parts in no case any inspector will allow to use compliance of thickness .

Rest is you will have to provide calculation / compliance as per PED inspecotr insisted.

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Niraj

From the way you are placing your question, I understand the Code of construction is ASME VIII Div.1. If this is the case you have to use ASME material and standard flanges or calculate them per Appx.2
Mauro

Mauro, he HAS used standard flanges...
I know, I know, but this is a public forum, how do you know who reads it and how an ambiguous statement can be understood...

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Konrad Anikiel

Hi!

My understanding is:

1. You want to use standard DIN flanges, i presume these have been manufactured using applicable DIN or DIN EN material.

2. These are Weld Neck or some other suitable type.

Ideally, you should not have a need to perform separate design calculations, mainly due to the following:

A. Code allows the use of welded standard pressure parts for use other than shell or head under UW-11(c). If the pressure temperature ratings are duly catalogued and the appropriate marking applied, you need not make seperate calculations.

B. If you are using Weld Neck flange, the code boundry limit has already terminated at the first cir-seam joint i.e. joint between the weld neck flange and the nozzle neck. See U-1(e)(1) of the code. Hence, the question of addressing the design of component, which is part of the piping system should not ideally arise.

C. The material (DIN or DIN EN standard) can always be re-certified by you in accordance with UG-10 requirements of the code, hence assigning P nos for welding should also not be an issue.

Hope i have not complicated it further for you.

Mayur

Please see UG-11(d)