Final answer:
The NFPA standard addressing the role of the Incident Safety Officer and when an Assistant Safety Officer should be requested is NFPA 1561. It provides guidelines for emergency service organizations on incident management and safety.
Step-by-step explanation:
When a single Incident Safety Officer (ISO) cannot perform all the safety functions at an incident, the ISO should request from the Incident Commander (IC) an Assistant Safety Officer (ASO). The NFPA standard that addresses this issue is NFPA 1561, which outlines the standard for emergency services incident management system and commands safety within emergency service organizations.
The NFPA, or National Fire Protection Agency, provides guidelines and standards for fire safety and related hazards, including the proper management of incident safety officers during an emergency. In cases where the scope of an incident exceeds the capability of the ISO, the NFPA 1561 standard supports the enhancement of the safety structure by adding ASOs to ensure comprehensive coverage of all safety considerations.