Restoration of vessel shell wall to nominal
Restoration of vessel shell wall to nominal
(OP)
As we know, some helpers are heavy handed and tend to grind the heck out of something when you instructed them to just blend it. Just bleeenndd it. Grrr
Anyways, I have a vessel made from SA-516-70, 2" in thickness with a minimum thickness of 1.8125". The helper ground it down below the minimum and now we are required to use weld metal buildup and follow that up with a MT/PT. I expected them to bring it back to the nominal thickness. They didn't. They built it up to just above the minimum and below the nominal thickness.
My thoughts were that this vessel was designed at a nominal thickness and being new construction, it should meet the designed minimal and nominal thickness. Now , of course im being asked to "Show me in code where it says that! My response is that code does not have the answer for everything. You designed it this way and that is where your answer comes from. Don't want to keep the animal in the tree if there is now reason to.
Any thoughts on this would be appreciated.
Jmann
Anyways, I have a vessel made from SA-516-70, 2" in thickness with a minimum thickness of 1.8125". The helper ground it down below the minimum and now we are required to use weld metal buildup and follow that up with a MT/PT. I expected them to bring it back to the nominal thickness. They didn't. They built it up to just above the minimum and below the nominal thickness.
My thoughts were that this vessel was designed at a nominal thickness and being new construction, it should meet the designed minimal and nominal thickness. Now , of course im being asked to "Show me in code where it says that! My response is that code does not have the answer for everything. You designed it this way and that is where your answer comes from. Don't want to keep the animal in the tree if there is now reason to.
Any thoughts on this would be appreciated.
Jmann





RE: Restoration of vessel shell wall to nominal
RE: Restoration of vessel shell wall to nominal
Weld toe grinding? Have a look at 6.2.5.7 in VIII-2. Something similar is in Annex C part C.4 of PD5500. Or was this grinding to blend out an LTA? See MA 32-5 in VIII-1 or 4.14 of VIII-2.
If the location is now above minimum thickness it will be satisfactory in the as-is condition but what about when you remove any corrosion allowance, will it still be compliant at it's end of life?
RE: Restoration of vessel shell wall to nominal
RE: Restoration of vessel shell wall to nominal
BenStewart, Code is Sec. VIII Div. 1 and will still be above minimum when the corrosion allowance is removed.
Jman
RE: Restoration of vessel shell wall to nominal
RE: Restoration of vessel shell wall to nominal
INTERPRETATION 13-07
Subject: Part 3, 3.3.3 s) and 3.3.4.3 a)
Edition: 2013
Question: When performing weld metal buildup of wasted areas of pressure retaining items, is the wall thickness required to be restored to the thickness listed on the Manufacturers Data Report?
Reply: No. The minimum thickness after build-up shall be the original thickness of the pressure retaining item minus the corrosion allowance.