If there is a groove weld with no specified dimension, it is CJP however if the depth of preparation is detailed but weld size is not, the the weld size is equal to the groove depth, so based upon the example written the effective size is equal to the depth of groove. Looking in an old standard (98) there is no reference to the depth of penetration of the backing weld be it dimensions or not dimensioned. There is a statement in the commentary that seems to indicate using a backing symbol means CJP.
If I was to come across this and had any questions as an inspector, I would refer to the design authority for clarification. It seems to be difficult to tie down based upon the content of the standard.
Trying this for the third time, I'm really too tired to be doing this right now.
Milt,
As inspectors, especially TPI's, we don't guess. 'Just the facts please'. This really does need an RFI for official opinion from the engineer.
But, Blaster,
First, just for clarification to the discussion: is the 3/8" in parentheses?
Second, Is there a joint designation from Clause 3? A root opening?
So, the discussion assumption is that this 5/8" material with a supposed 3/8" depth of groove/bevel has no weld size dimension and no CJP or PJP in the tail.
If all the above is true:
1) A2.4 does not say it is a CJP. It says it "requires a groove weld that extends through the thickness of the joint". That is not the same thing. And that is if it is missing BOTH size and depth.
2) Both A2.4 and D1.1:2010 say that a PJP shall show dimensions enclosed in parentheses above and/or below the reference line..."
3) A2.4 also says that it 'may be used to specify a groove weld size not less than the depth of groove."
No weld size? NOT a PJP. Not without further clarification. 'Shall' takes precedence over 'may'.
He Is In Control, Have a Great Day, Brent
We have glossed over the fact that the weld shall receive UT.
Is the UT inspection criteria looking for a 1/16" line of non fusion between the filled bevel and the back/backing weld? Of course not.. It's a CJP
This is why symbols with order of operations are best... So we can define whether we have a back weld or a backing weld... And what about "GTSM" ?
Fill groove, gouge to sound metal, back weld, UT.
This is what is wanted, and this is what you will end up doing... I bet :)
By jwright650 
Date 03-08-2016 13:09
Edited 03-08-2016 13:19
The depth of bevel for this CJP was most likely reduced to 3/8" simply to reduce the chance of blowing through the joint, then like stated back gouge the second side to cut out the line of non-fusion and get down to sound material, then weld it back up flush.
If the welder follows these steps it should pass UT with no problems.
edit:
Well, seeing as how a good many job specs are now specifying UT on PJP's I don't believe that can be a dogmatic stand. All they want is to prove depth but they are also giving us acceptance/rejection criteria.
I will hang my hat only on an RFI in order to determine what is being asked.
Brent
You are right of course... The joint as explained is not adequate and should be made clear by the detailer or engineer.
I am a UT infant, but still "bet" a CJP was what they were after.... Hopefully we will find out.
You and Al always bring me back to earth when I start making assumptions.
By Blaster 
Date 03-08-2016 20:33
Edited 03-08-2016 20:42
Thanks for the discussion guys.
Brent, no, the 3/8" is not in parentheses and there is no root opening. Also it is a butt joint. No tail notes - so not clear if it was a back weld or a backing welding that was intended.
I have not checked, but this job may be in inspection by now. It was a case where this aspect of a project "has to be done today" and the appropriate engineer was not reachable for questioning at the time. For apparent access and convenience reasons the guys doing the work were not keen on backgouging for CJP.
