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#7335 - 10/06/05 01:54 AM EN material in ASME calculation
Gabor Szabados Offline
Member

Registered: 06/03/04
Posts: 7
Loc: Hungary
What is the correct method in ASME calculation.
The rectangular header calculation is useful for me, because in the AD 2000 isn't calculation formula for rect. header.

If I Use EN material for ex. P355 NH the allowable
stress higher as I use ASME naterial SA 516 Gr 70.
In AD 2000 the allowable stress is the Yield stress / 1.5. In the ASME the allowable stress is the Yield strenght / 1.5 or the Tensile strenght / 3.5, the less. On 100 Celsius the Tensile/3.5. This value more less. The two material is very similar, the tensile strenght is same,

What is the correct method, when I use EN material in ASME header calculation?
Calculating allow.stress according to AD 2000, (Yield Str/1.5) or calculating according to ASME (Tensile Str/3.5).
When I calculating with the latter the wall thk. is significantly thicker.

In EU I mustn't use ASME material in construction with CE mark.

Other question: What is the hydropress value: pdesign*1.43 acc. to AD2000 or pdesign*1.3 acc to ASME?
Regards Gabor Szabados
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Gabor SZABADOS

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#7336 - 10/10/05 07:37 AM Re: EN material in ASME calculation
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
Hello Gabor

It is true that in Europe design stress is base upon the yield stress (yield/1.5 in most cases). You are presumably using AD 2000. It is my opinion that the stress value to use is as stated in AD 2000. As I understand it, the safety factor for hydrotesting is 1.1, in AD 2000, making the test pressure about 1,36 x design pressure. The European code EN 13445 employs a safety factor of 1,05 for the hydrotest which would mean the hydrotest pressure is 1.428 x design pressure.

If you are using AD 2000, or EN 13445, you would use the rules for that code, and not the rules for ASME Section VIII, Division 1. ASME is a very conservative code. That is my opinion.
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Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#7337 - 10/10/05 10:43 AM Re: EN material in ASME calculation
Gabor Szabados Offline
Member

Registered: 06/03/04
Posts: 7
Loc: Hungary
Dear Ray,
Its True, but the the safety factor in AD2000 and EN 13445 is same, 1.05.
My problem is: In the AD2000 isn't calculation formula for rect. header, so I have to use only the ASME Rectangular Header Calculation App. 13.
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Gabor SZABADOS

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#7338 - 10/11/05 06:58 AM Re: EN material in ASME calculation
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
Hello Gabor

I apologise, I have an earlier edition of AD Merblatter and my information is dated. It seems appropriate to use the AD 2000 data for the materials, and compute the hydrotest per AD also.

You can of course compute the stresses using the lower stress value. As I understand matters, the PED says the maximum allowable stress is Yield/1,5 (in most cases). However for the hydrotest, I believe you have to use 1,43 times the design pressure.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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