In Figures 3.50 and 3.51, all the terms are self explanatory. The term “Effective Throat” is the shortest
distance measured from the root of the weld to its face, less any reinforcement. Also, it should be
noted that the root penetration is only considered as part of the effective throat for fillet welds made by
the submerged arc welding process. This is stated in the CSA W59 Standard (Clause 4.3.2.4). In
some standards or codes, the root penetration is not considered.