Since B31.3 places responsibility for performing examination on the Fabricator or Contractor who is doing the welding, lot selection is the prerogative of the Fabricator or Contractor in the absence of arrangements in which a lot is established by contract. B31.3 recognizes that lot selection can be a source of dispute and suggests that the quantity or extent of a designated lot should be established by agreement between the contracting parties before the start of work. (for e.g. welds in each piping class may be designated as a lot by agreement)
More than one kind of designated lot may be established for different kinds of piping work. Refer Pipe Fabrication Institute Standard ES-48, Random Examination, for examples of lot selection. The welds to be examined must include the work product of each welder
However, irrespective of how the lot sizes are established, it is important to note that "Random NDE" can not be taken to pre-qualify work that has not yet been performed. refer Information Bulletin No. IB13-006 in the link below.
http://www.absa.ca/newsletter/2013-V18-Iss2.pdf
More than one kind of designated lot may be established for different kinds of piping work. Refer Pipe Fabrication Institute Standard ES-48, Random Examination, for examples of lot selection. The welds to be examined must include the work product of each welder
However, irrespective of how the lot sizes are established, it is important to note that "Random NDE" can not be taken to pre-qualify work that has not yet been performed. refer Information Bulletin No. IB13-006 in the link below.
http://www.absa.ca/newsletter/2013-V18-Iss2.pdf
On 3 October 2015 at 04:29, Anban <gane2478@hotmail.sg> wrote:
Dear Sirs
341.3.3 Defective Components and Workmanship
341.3.4 Progressive Sampling for Examination.
When required spot or random examination reveals a defect, then
(a) two additional samples of the same kind (if welded or bonded joints, by the same welder, bonder, or operator) from the original designated lot shall be
given the same type of examination
What does it exactly means by stating " two additional samples of the same kind"
My understanding is
1- Can be 2 additional joints-100% NDT( same type of examination ) OR
2- 2 additional films on another joint welded by same welder/operatot.
Pls advise
Thanks
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