Electricians, see current manufacturer's instructions for proper bonding and grounding of yellow CSST: 

1. 2011 National Electric Code, NFPA 70 Sec 250.104. See Informational Note #2.
   See most current adopted code at this  link.
   
   
2.  2009 National Fuel Gas Code, NFPA 54 Sec. 7.13.2  (This is identical to 2009 IFGC Sec. 310.1.1)
   See most current adopted code at this  link.
   
   
3. Direct Bonding of Standard (Yellow) CSST Technical Bulletin 
   

Additional information may also be found at CSST Safety.