Dear all,

Note in PVElite:

For ASME Division 1, the hydrotest allowable stress is 1.3 times the ambient allowable stress for the material. When the vessel is tested, the largest circumferential stress should not exceed this value. If you wish to use 90 percent of the ambient yield stress instead of 1.3 the ambient allowable, then you can check this box.

If i take 90 percent of yield as allowable during hydrotest,what considerations regarding deformation?

Regards
ASD23789

The reference to 90% of the yield stress is reasonable but it is not a Sect.VIII Div.1 requirement.
MG

I agree with MG, the reference of 90% of yield strength can be seen in PG-99 of Section I , however.

_________________
Thanks & Regards,
Nasir
Welding Engineer
DESCON Engineering Limited.
Lahore, Pakistan.
Mobile # 0092-336-4145402

Come on, it's UG-99(c), although it's not clear what material is the vessel made of. If it has a G-5 note, then it is designed to 90% of yield strength anyway...

_________________
Konrad Anikiel

Hello all,

Thanks for the reply.

I was talking about SA 240 TYPE 304 material.
for one of its occurences it has the G5 note.

Thanks for clearing the Doubt.
Regards
ASD23789

Dear all
1. For the case of material with G5 note ( example of SA240 304 material discussed in this post), the calculated test pressure as per appendix 3-2 definition will produce hoop stress (maximum principle stress) equal to the allowable stress given in Table:Ia of Sec II Part D. i.e 90% of yield stress if claculations are based on G5 note line.

2. But hydrotest pressure as per UG-99 (C) is equal to 1.3 times the calculated test pressure which means the stress in that element will reach 1.17 times yield (1.3 x 0.9 yield) which is permitted by code for austenitic material with warning or caution on deformation by foot note G.

3. Now coming to start of this post if we check the box in PV Elite then the intention is to limit the stress to 0.9 times yield under hydrotest (instead of 1.17 times permitted by UG-99C).

This means PV Elite will allow lesser hydrotest pressure than UG-99(C) if we check this box.

For valauble comments please

_________________
R.SRINIVASAN
Sr. VICE PRESIDENT
Head, Design and Engineering
PED,ISGEC,
YAMUNANAGAR
HARYANA -135001
INDIA

Right, I haven't read the pvelite message from the original post carefully. I don't use pvelite. I wonder what does it do when testing at 0.9 yield isn't enough to satisfy UG-99. Overdesign?

_________________
Konrad Anikiel

UG 99(c) uses Calculated Test Pressure which is 1.3 times MAWP .
From Appendix 1, Section II D we find :
Maximum Allowable stress = 2/3 of Yield stress .
Hence the stress is 1.3 x Maximum Allowable Stress or 0.867 x Yield stress.
Pvelite has an option to do the calculation at 0.90 x Yield stress.