8.2 in 05 edition covers destructive testing as well. What they are refering to by Trepanning is a destructive test.
Trepanning is usually some form of boring. 8.2 "Destructive testing shall consist of the removal of completed welds, sectioning of the welds into specimens, and the examination of the specimens"
http://www.trepanningspec.com/index.htmlBy the prohibition of trepanning, they are clarifying their intent that the whole weld be cut out rather than a strap, or punch for testing.
It's been prohibited for a long time, but as I recall someone telling me many moons ago, people used to cut the strap, then weld up the hole rather than cut out the whole weld.
Regards,
Gerald