Under what conditions can defensive operations be initiated?

Defensive operations are typically initiated when the scenario presents risks that make it unsafe for interior operations, such as when the structure is under construction. In this phase, there are often hazards like incomplete structures, exposed materials, and a higher likelihood of structural collapse due to the absence of finished support systems. Therefore, initiating defensive operations in this context allows responders to protect surrounding areas and prevent fire spread while minimizing risks to personnel.

The other scenarios generally involve conditions that do not warrant a defensive approach or suggest a different threat level, like occupied buildings where life safety is a priority or fully engulfed structures where interior engagement may not be feasible.