Hold point require the review of the testing and inspection documentation up to date by both the Vendor and Purchaser and approval to proceed further. It could be also linked to a particular inspection or test activity during the fabrication, the outcome of which could condition the progress of the work or generate re-work, repair or even rejection.
The witness point is a rutine activity which is offered to the Purchser to observe the fabrication process or inspection / testing development. The witness person(s) may or may not comment, request additional activities or if has been agreed in advance, could stop the activity if is not in accordance with the requisition requirements or to the satisfaction of the witness, considered competent representative of the Purchaser.
Please note that the hold and witness point in a ITP do not exclude each other, they can also overlap on the same activity if agreed between the Vendor and Purchaser prior to signing the contract.
cheers,
gr2vessels
