It sounds like you are welding a part to the web of a beam.
Technically, you are not supposed to weld in the "K-area". This is different than the "K" which is the raduis, The "K-area" is the zone that extends from the edge of the "K" for about 1 1/2" but check that, I don't have my book in front of me.
Now, let's say the piece to be welded is 10" long, but the drawing only calls for 5", then normally unless it's shown specifically on the drawing, the weld is put in the center of the piece. This would leave 2 1/2" unwelded on either side, and that might be your "k-area" zone and that's why it was called out that way.
Generally, most detailers aren't aware of the whole "k-area" issue and therefore don't know to not weld in that area. When that happens on my projects, as long as the drawings are approved, then the engineer should have picked up on it and either he doesn't know, or it doesn't matter. As long as the drawings are approved, do what they say, and you should be ok.
Hope this helps.
Chris