Size up refers to which concept?

• A. Initial measurement of the area by the first arriving company.
• B. Ongoing evaluation of influential factors at the scene of an incident.
• C. A formal risk assessment performed before arrival.
• D. A final report summarizing the incident.

Answer: (B)

Size up is an ongoing evaluation of influential factors at the scene of an incident. It begins with the first arriving unit’s initial assessment and continues to evolve as new information comes in. You’re looking at conditions that affect safety and tactics, such as building construction and stability, occupancy and life hazards, location and behavior of the fire, potential for victims, exposures, water supply, staffing, and available resources. This continual assessment shapes the incident action plan and guides decisions about attack or defense, ventilation, position of crews and apparatus, and when to shift priorities. It’s not a one-time measurement or a pre-arrival risk assessment, and it isn’t something that ends with a final report—it's a dynamic process that continuously informs how you respond and adapt to changing conditions.