I agree with the pressure retaining part (after I looked it up :) but I don't think "load carrying" is addresses.

from sub para (c) of QW202.2

........."Nonpressure-retaining fillet welds, as defined
in other Sections of the Code, may as an alternate be
qualified with fillet welds only. Tests shall be made in
accordance with QW-180. Limits of qualification"

I love this place. I have read through the code on various occasions and its amazing some of the things I overlook because I never had a need for them. I have always just done groove welds and therefore only neede to remember the 1st part of  the paragraph.

I don't have any codes of construction handy so that may be where your getting the "load carrying" part. Let me know.

Have a good day and thanks for your comments here and elsewhere.
Gerald Austin

The "load carrying" is my interpretation of the intent of the referencing paragraph.

If the fillet weld is expected to transmit a force, i.e., load, the engineer needs to know what mechanical properties the weld has. That can only be ascertained if mechanical testing, such as a reduced section tensile test, is performed.

A case in point:
I have a client that welds carbon steel support rings to copper alloy vessels. The welds are brittle as one would image, but they do develop certain mechanical properties that can only be determined by performing tensile and bend tests. Only then was the client able to assign the weld sizes necessary to transmit the design loads expected when the vessel was installed and filled.  A procedure qualified using only a fillet break test or macro etching several samples would not have provided the necessary information.

Best regards - Al