A query related to DNV CN 2.6 - Offshore Mooring Chain. I'm reviewing a procedure for UT of chains. I'm not clear on the evaluation sensitivity and reference level for UT of the weld on the chain links.
Excerpt Scanning sensitivity DNV CN 2.6:
"Perform the testing...with the amplitude calibration increased by 6dB. ...indications equal or larger in amplitude to that of the reference notch, when properly corrected for distance, (are) subject to rejection..."
Sensitivity calibration requirements do not indicate a DAC, nor would the inspection appear to call for one. Is a DAC implied by "properly corrected for distance?"
Does the 6 dB remain for evaluation? The procedure I'm reviewing specifies that it be removed for evaluation. I see no reference to this in the CN.