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Incorrect Hole on the ASME Head
5

Incorrect Hole on the ASME Head

Incorrect Hole on the ASME Head

(OP)
Hello Everybody:
I have 5/16" THK Stainless Head. I need to patch a 6" hole in the head? Does ASME Sec VIII Div 1 allows to do this? If yes, what NDE methods should I use after patching.
Please help

Thank You
Dave

RE: Incorrect Hole on the ASME Head

Are you fabricating it now, or is this an existing vessel that's already been hydrotested/U-stamped?


-Christine

RE: Incorrect Hole on the ASME Head

(OP)
Christine74 Thanks. It is under construction right now. New Vessel

RE: Incorrect Hole on the ASME Head

I'm not aware of any restrictions against flush patches in ASME Section VIII Div. 1. If the vessel is RT'ed the flush patch would have to meet the RT requirements for a Category A weld, but it's possible that your client might have additional NDE requirements.

If this is a seamless head you may have to do 100% RT for your E=1.0 head calculations to still be valid (I may be wrong about this, not sure really).

Also depending on the size of the opening your client may prefer you to use a flush patch that has been dished in order to match the head dish radius, otherwise the head would have a flat spot.


-Christine.

RE: Incorrect Hole on the ASME Head

Always keep your drops :)

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

RE: Incorrect Hole on the ASME Head

Any weld in a formed head is considered a Cat. A weld, so the efficiency of UW-12(d) (.85) for seamless heads with no RT is no longer valid. If E=1 is required, full RT is necessary. As stated above, your customer may want Full RT anyhow. And tell your customer...this will be obvious with a stainless head.

RE: Incorrect Hole on the ASME Head

(OP)
Thank you Everybody
This is a two piece head with 100% RT came with partial data report. The E used in the calcs is 85%
I was thinking it will come under spin hole category where you can plug the hole & perform a PT inspection. But there is a restriction on diameter for doing this. I think the best bet here is Patch with Full Penetration & 100% RT to maintain 85% efficiency.
Please comment your suggestions. thank you

RE: Incorrect Hole on the ASME Head

Standard Designation: BPV Section VIII Div 1
Edition/Addenda: 2013 Eidtion
Para./Fig./Table No: UW-34
Subject Description: Spin-Holes
Date Issued: 09/16/2015
Record Number: 15-1429
Interpretation Number :
Question(s) and Reply(ies):
Question 1: Does paragraph UW-34 prohibit the use of spin holes that are greater than 2 3/8 inches (60 mm) diameter in formed heads?

Reply 1: No.

Question 2: If a spin hole larger than 2 3/8 inches (60 mm) is closed using a butt welded plug, is it required to apply the applicable joint efficiency of Table UW-12 to this weld for the design of the head or head-to-shell joint?

Reply 2: Yes.

Standard Designation: BPV Section VIII Div 1
Edition/Addenda: 2015 Edition
Para./Fig./Table No: Paragraph UW-34
Subject Description: Section VIII, Division 1; UW-34 - Spin Hole Plug Configuration
Date Issued: 12/08/2017
Record Number: 17-1867
Interpretation Number : BPV VIII-1-17-77
Question(s) and Reply(ies):
Question: May an opening in a head be closed with a welded plug categorized as a Category A weld joint, and the head thickness calculated following the current code rules for weld type and extent of examination?

Reply: Yes.

RE: Incorrect Hole on the ASME Head

Type of head?..Diameter?.

Regards

RE: Incorrect Hole on the ASME Head

(OP)
r6155. Thanks. It is ASME F & D head, Thk 5/16" & Diameter 72" ID

RE: Incorrect Hole on the ASME Head

An inspection opening can be installed and avoid RT.

Regards

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