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#49930 - 07/24/12 03:46 AM WRC CALCULATION FOR CODE STAMPED ITEM
ketan daraji Offline
Member

Registered: 10/18/09
Posts: 34
Loc: india
PLEASE REVERT ON WHICH PRESSURE (EITHER MAWP OR DESIGN PRESSURE) WRC CALCULATION FOR NOZZLES IS TO BE CARRIED OUT,IF EQUIPMENT IS CODE STAMPED ???? PLEASE NOTE THAT AS PER SPECIFICATION, EQUIPMENT IS TO BE DESIGNED FOR MAWP.NOZZLES REINFORCEMENT SHALL NOT GOVERN MAWP.
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#49988 - 07/27/12 02:39 AM Re: WRC CALCULATION FOR CODE STAMPED ITEM [Re: ketan daraji]
KunalShah Offline
Member

Registered: 12/07/11
Posts: 36
Loc: Delhi, India
WRC calculations should be at design pressure. Also, if the nozzle is already designed for MAWP + static head case, then it should not affect much the WRC calculations, since in this case the primary membrane stress due to pressure will be the stress at mawp pressure, and it should not affect much the local stresses.
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Kunal Shah
New Delhi

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#49996 - 07/28/12 04:24 AM Re: WRC CALCULATION FOR CODE STAMPED ITEM [Re: ketan daraji]
vishaltailor Offline
Member

Registered: 05/15/10
Posts: 56
Loc: Gujarat, india
Dear Kunal
I am not agreeing with said opinion. Let's take example, MAWP of vessel = 5 MPa. There is nozzle on bottom d'end. Now assume vessel is running at MAWP. During is running condition Piping loads are acting on this nozzle.

This means, to fulfill above case WRC has to be performed at MAWP; otherwise Nozzle would fail at MAWP + Piping loading.
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Thanking you & with regards
Vishal Tailor

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#50005 - 07/29/12 09:52 PM Re: WRC CALCULATION FOR CODE STAMPED ITEM [Re: ketan daraji]
KunalShah Offline
Member

Registered: 12/07/11
Posts: 36
Loc: Delhi, India
Hi Vishal,
1. I said that it will not affect much the local stresses, but you are talking about primary membrane stress (stress due to pressure).
2. Nozzle neck shall not govern the MAWP of the vessel, hence nozzle can not fail.
3. Most important is, MAWP is determined considering effect of static head and EXTERNAL LOADS (Refer definition of MAWP). Hence MAWP should be such that MAWP + external loads + static head causes the stresses less than or equal to allowable stress.


Edited by KunalShah (07/29/12 09:56 PM)
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Regards,
Kunal Shah
New Delhi

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#50015 - 07/30/12 07:10 AM Re: WRC CALCULATION FOR CODE STAMPED ITEM [Re: ketan daraji]
vishaltailor Offline
Member

Registered: 05/15/10
Posts: 56
Loc: Gujarat, india
Hello Kunal
Exactly, as you very well said "MAWP should be such that MAWP + external loads + static head causes the stresses less than or equal to allowable stress."
And this would only happen, when Nozzle is designed so. Hence, conclusion is that while performing WRC, MAWP to be considered as internal pressure.
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Thanking you & with regards
Vishal Tailor

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