I don't have a direct answer for you, I don't recall seeing a table such as you describe, but you shoukld look at the commentary for 5.14.
The intent is to minimize the possibility of cracking by assuring there is enough heat input from welding.
But the requirement does not limit the maximum weld sizes that can be used. Those would be decided by an engineer.
However it is interesting to note that if a multiple pass weld is required, each pass must meet the minimum heat input for the minimum fillet sizes listed.
Chet Guilford
By jciras
Date 12-08-2005 18:08
The reference is in both Design of Welded Structures, by Blodgett and in Mark's Standard Handbook for Mechanical Engineers - Table 13.3.1 in Mark's.
AWS D1.1 : 2004 2.3.2.8 just states that the fillet weld has to be large enough to transmit the applied load and also references 5.14.
John Wright
You won't find a table to tell you what you need. As jwright said, you need both to meet the absolute minimum size requirements to avoid cracking a small fillet with a large base metal heat sink, and to be able to transfer whatever load it is you need to transfer, which as you rightly suspect is likely to be far more than 5/16". The tables will only give you the first requirement; you need to calculate the second.
Depending on what load it is you need to transfer, you may find that the fillet weld size calculated is so large that it is more economical to use a groove weld.
Hg
I think you might have seen it in section 3 of the D1.1-2004 code book. Look at table 3.4 for minimun prequalified PJP weld size, but it's not for fillet welds.