D1.1 UT

Date 02-13-2007 02:57

I am reviewing a UT procedure and find that the standard a-b-c = d. is being called for. the acceptance criteria is per table 6.3 cyclically loaded non tubular. Up until this point, it made sense. What I am seeing is the inclusion of a DAC curve, but using the A-B-C for acceptance. It's my understanding that Annex S could be used as an alternative procedure. It's further my understanding that the two cannot be mixed, your allowed either, but not a DAC curve using abc acceptance criteria. Contract documents only call for D1.1 2006.
with that said, I am looking for opinions preferably ones that are code based as to if I am properly interpreting the following.
A) Can you or can you not mix a DAC curve with the A B C formula
B) With no other specific contract document other than the call for D1.1 2006, should the requirements or should they not of section 6 apply?

Thanks in advance for any responses.

By dmilesdot (**)

Date 02-13-2007 14:42

After establishing a DAC curve, most procedures give a percentage of DAC as the "recordable" indication level. I dont understand how you would then apply A-B-C to determine an indication level and then apply it to table 6.3. The DAC curve has already taken into consideration the attenuation factor and to then subtract out the "C" value would reduce the indication size even further. It seems to be an "ether or situation"and not a "both" situation.

By hogan

Date 02-13-2007 16:13

i tlooks like you'll need to use a-b-c=d and table 6.3. annexs a thru j are normative ( part of the code), while annexes k thru v are informative ( extra info).

By CWI555

Date 02-13-2007 17:23

My interpretation as mentioned is 1-b-c=d and table 6.3. However; the provided procedure mixed in a DAC. Which didn't make any sense to me. I just wanted to make sure there wasn't something I was missing here before I turn down this procedure.

By hogan

Date 02-13-2007 22:55

i've only seen the two mixed in ut of tyk connections. it sound like a little different set up then your dealing with

By thirdeye (***)

Date 02-13-2007 23:03

Of course it would be better to see the written procedure in the event there is some intent for the DAC curve .... but it does appear that they are mixing apples and oranges. Are you positive they were not somehow referring to using the IIW block for initial calibration, then without changing the gain setting, comparing and recording the height of another reflector on a smaller block which would be easier to carry and used during the inspection?

Just curious, for plotting the DAC curve, what type of calibration block was proposed for use and what were the sizes of the side drilled holes?

~thirdeye~

By CWI555

Date 02-14-2007 03:37 Edited 02-14-2007 03:41

the number and size of the SDH for the DAC curve didn't make any sense. the maximum material thickness is 5/8". It's a standard moment connection. The SDH is 1.5mm with 4 holes required for calibration. However; I have since made sense of it all. This procedure was designed for use to A. Euro standards, and B. thicknesses in excess of 50mm tky connections according to the information I was given today. This procedure was cut and pasted in an attempt to make it work for the scope at hand and therefore the appearance of of the DAC plus A-B-C=D reference. The contractor is currently revising the procedure. Using 4 1.5mm holes made absolutely no sense for a 5/8" moment connection. Simply setting up and scanning per section 6 requirements is sufficient for our application in my opinion. However; I am fallible, and as said, wanted to make sure there wasn't something I was missing. Thanks for all the replies everyone.