Final answer:
NFPA 1403 is the standard that necessitates a dedicated Safety Officer, separate from the Incident Commander, during firefighter live fire training drills.
Step-by-step explanation:
The standard that requires a dedicated Safety Officer (SO), separate from the Incident Commander (IC), for firefighter live fire training drills is NFPA 1403. This standard is specifically designed to ensure that firefighter training exercises are conducted in a safe manner. The Safety Officer is responsible for monitoring the safety of all personnel on the training ground and has the authority to intervene and stop any operations deemed unsafe.