Definition & Operational Usage of Incident Size-Up
What Is Incident Size-Up?
Incident size-up is the rapid, continuous evaluation of scene factors — building construction, weather, fire size, smoke conditions, life safety hazard, water supply, and available resources — conducted to formulate, execute, and revise the Incident Action Plan.
Why Incident Size-Up Matters on the Fireground
Size-up starts at dispatch and never stops until the scene is cleared. Failing to recognize a lightweight truss roof or a basement fire during size-up leads to sending firefighters into structural collapse traps.
Relevant NFPA Standards
- NFPA 1010: Standard on Professional Qualifications for Firefighters
- NFPA 1550: Standard for Emergency Responder Health and Safety
Field Procedures & Tactical Steps
- Evaluate dispatch information (time of day, occupancy, caller report) while en route to anticipate scene needs.
- Deliver initial arrival radio report: apparatus location, structure type, visible conditions, initial strategy, command mode.
- Perform 360-degree walk-around: check all four sides (Alpha, Bravo, Charlie, Delta), basement access, and utility status.
- Update Command radio report with 360 findings and declare final tactical assignments.
- Re-assess size-up factors continuously throughout the incident as fire conditions change or resources arrive.
Common Context & Application
Performed continuously on all fire, EMS, hazmat, and rescue calls, with major reports delivered upon arrival and after 360-degree checks.
Frequently Asked Questions about Incident Size-Up
What are the three main phases of size-up?
What key information must be included in an initial arrival report?
Other Names for Incident Size-Up
Incident Size-Up may also appear in training materials, NFPA standards, or department SOPs as: size-up, initial assessment, scene evaluation.
Relevant Tools
Operational calculators related to Incident Size-Up: