rman487-
As SnTMan pointed out, Section VIII won't get into helical insert issues - after all, Section VIII is a new construction code (only) and one would not be expected to use helical inserts in the controlled environment (hah!) of new construction.
You'll find a single three-sentence paragraph which addresss helical inserts in ASME PCC-2 Repair of Pressure Equipment and Piping. Specifically, Article 3.3, paragraph 3.5 of the 2011 edition. I do not believe that this article is being changed in the 2013 2014 edition.