1/3 Stress Increase has Disappeared or Moved again in 2013 CBC 1

[chorner26]

OK, so I'm doing a glass guardrail design and:
in the 2007-2010 CBC. (1607.7.1.3 on Pg. 10 . I can use a 1/3 Stress increase.
Now, for CBC 2013, it has disappeared. 1607.8.1 (pg.12)
My question is where did it go, is it buried in a handrail designer association manual or somewhere in the ASCE 7-10.
Or did the code official decide that handrails were failing all over the place, thus we can no longer use it.

 

[sandman21]

Stress increase is gone in 2010 CBC as well. Handrail Designer Association Manual is not listed in the CBC as a standard.

Modern Steel Construction article

Link