8.2 Initial Size-Up, Critical Factor Analysis, and Initial Radio Reports

Initial Size-Up, Critical Factor Analysis, and Initial Radio Reports

Quick Answer: Size-up is the continuous mental evaluation of all critical factors affecting an emergency incident. Originating in Chief Lloyd Layman's classic 5-step size-up model (Facts, Probabilities, Own Situation, Decision, Plan of Operation) and augmented by the COAL WAS WEALTH factor checklist, size-up dictates the entire Incident Action Plan. The first-arriving company officer must execute a mandatory 360-degree survey, transmit a standardized Brief Initial Report (BIR) / On-Scene Report, declare an operational strategy (Offensive, Defensive, Transitional), and establish one of three initial command modes: Investigation, Fast-Attack (Mobile Command), or Stationary Command Post.

The initial minutes of an emergency incident represent the period of highest risk and greatest opportunity. Decisions made by the first-arriving fire officer establish the foundation for all subsequent operations. Mastery of size-up theory, systematic exterior observation, and precise radio communications is a core requirement under NFPA 1021 and NFPA 1020.

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1. The Continuous Nature of Fireground Size-Up

Size-up is not a one-time event; it is an ongoing, cyclical cognitive process that begins before the alarm sounds and continues until the last unit leaves the scene:

+-----------------------------------------------------------------------------+
|                        THE THREE PHASES OF SIZE-UP                          |
+-----------------------------------------------------------------------------+
| PHASE 1: PRE-INCIDENT & EN ROUTE                                            |
| - Review pre-incident plans (building construction, occupancy, hazards).    |
| - Consider time of day, day of week, weather conditions, wind velocity.    |
| - Evaluate dispatch information, hydrant water availability, route hazards. |
+-----------------------------------------------------------------------------+
| PHASE 2: ON-SCENE ARRIVAL & 360-DEGREE SURVEY                               |
| - Visual assessment of smoke color, velocity, density, and volume (reading).|
| - Structural integrity, building size, occupancy status, life hazard.       |
| - Grade-level variations (walk-out basements), flow paths, exposure risks.  |
+-----------------------------------------------------------------------------+
| PHASE 3: ONGOING OPERATIONAL EVALUATION                                     |
| - Monitor benchmark achievements (water on fire, primary search all-clear). |
| - Re-evaluate structure under thermal attack; track air consumption/PAR.    |
| - Assess effectiveness of tactical assignments and adjust strategy.        |
+-----------------------------------------------------------------------------+

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2. Classical Size-Up Models: Lloyd Layman and COAL WAS WEALTH

Lloyd Layman's 5-Step Size-Up Process

Developed by Chief Lloyd Layman in the 1940s, this foundational 5-step sequence remains the recognized intellectual model for emergency incident decision-making:

1. Facts: What is actually known? (Building type, occupancy, time of day, location of smoke/fire, verified trapped occupants, available on-scene resources).
2. Probabilities: What is likely to happen? (Path of fire extension, potential for flashover/backdraft, roof/floor collapse risk, exposure ignition, occupant survivability).
3. Own Situation: What resources are available? (Current staffing on scene, apparatus arriving on 1st alarm, water supply adequacy, auxiliary systems).
4. Decision: What is the overarching strategy? (Offensive interior attack vs. defensive exterior containment vs. transitional cooling).
5. Plan of Operation: How will the strategy be executed? (Tactical assignments: stretching attack lines, establishing water supply, primary search, vertical/horizontal ventilation).

The COAL WAS WEALTH 13-Point Critical Factor Checklist

A widely utilized mnemonic for identifying critical structural fireground factors:

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3. The 360-Degree Survey (The Walk-Around)

The 360-degree survey is a mandatory, physical reconnaissance of all four sides of the structure performed by the first-arriving company officer prior to committing crews to interior structural attack.

                             Side Charlie (Rear)
                         +-------------------------+
                         |  [C/D]           [B/C]  |
                         |                         |
      Side Delta (Right) |                         |  Side Bravo (Left)
                         |                         |
                         |  [A/D]           [A/B]  |
                         +-------------------------+
                             Side Alpha (Front)
                                     ^
                                     |
                           [First-Arriving Unit]

Critical Discoveries During a 360-Degree Walk-Around:

1. Elevation and Grade Variations: A building appearing as a 1-story structure from Side Alpha may be 2 or 3 stories on Side Charlie (walk-out basement). Entering from Side Alpha could place firefighters directly above an active basement fire in a high-risk thermal chimney.
2. Seat and Extent of Fire: Direct visual identification of the fire room prevents blindly pushing into uninvolved compartments.
3. Victim Survivability & Egress Points: Identifying secondary doors, trapped occupants at rear windows, and security bars/gates.
4. Structural Degradation: Sagging roof lines, bowing brick veneer, burning structural trusses, or compromised decks on Side Charlie.
5. Utilities & Hazards: Overhead power drops, natural gas meters, liquid propane (LP) tanks, hazardous materials drums.

[!IMPORTANT] When a Full 360 is Physically Blocked: If physical barriers (fences, zero-lot-line commercial adjoining structures) prevent a complete walk-around, the first-arriving officer must complete a 270-degree survey and immediately assign the next-arriving company to verify Side Charlie conditions before interior benchmarks proceed.

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4. The Brief Initial Report (BIR) / On-Scene Radio Report

The first-arriving unit must transmit a standardized, structured Brief Initial Report (BIR) (also termed an On-Scene Report or Arrival Report) to establish command and paint an operational picture for all responding units and dispatch.

+-----------------------------------------------------------------------------+
|                     SIX CORE ELEMENTS OF A COMPLETE BIR                     |
+-----------------------------------------------------------------------------+
| 1. UNIT IDENTIFICATION       | "Engine 1 is on scene..."                    |
| 2. INCIDENT ADDRESS          | "...at 1424 West Elm Street."                |
| 3. STRUCTURE DESCRIPTION     | "...we have a two-story, wood-frame multi-   |
|                              | family dwelling..."                          |
| 4. CONDITIONS / SMOKE & FIRE | "...with heavy black pressurized smoke and   |
|                              | fire showing from Side Alpha, second floor." |
| 5. OPERATIONAL STRATEGY      | "Engine 1 is in the Offensive Mode..."       |
| 6. INITIAL ACTIONS & COMMAND | "...stretching a 1.75-inch attack line to the|
|    DECLARATION               | front door. Engine 1 is establishing Elm     |
|                              | Street Command on Side Alpha."               |
+-----------------------------------------------------------------------------+

Following the BIR and 360 survey, the officer transmits a 360-Degree Follow-Up Report providing updates: confirmation of basement presence, fire location, life hazards, and specific tactical assignments for incoming units (e.g., "Elm Street Command: 360 complete, confirmed two-story on Alpha, three-story on Charlie walk-out. Fire is on the second floor. Ladder 1 take primary search, Engine 2 secure water supply").

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5. Establishing the Initial Command Mode

Depending on scene conditions, occupancy risk, and immediate tactical needs, the first-arriving company officer must select one of three operational command modes:

+-----------------------------------------------------------------------------+
|                         THE THREE INITIAL COMMAND MODES                     |
+-----------------------------------------------------------------------------+
| 1. INVESTIGATION MODE ("Nothing Showing")                                   |
|    - On-scene conditions show no visible smoke, flame, or obvious hazards.  |
|    - The company officer investigates with the crew, carrying portable      |
|      radios, thermal imaging cameras, and forcible entry tools.             |
|    - Command is maintained by the officer while moving with the crew.       |
+-----------------------------------------------------------------------------+
| 2. FAST-ATTACK MODE / MOBILE COMMAND ("Action Required")                   |
|    - Critical, immediate action is required to save a life or stop rapid    |
|      fire progression (e.g., immediate rescue, rapid interior knock-down).  |
|    - The officer enters with the crew to supervise and direct the attack,   |
|      maintaining command via portable radio.                                |
|    - STRICT DURATION LIMIT: Fast-Attack mode must terminate when:           |
|      a) The fire is controlled / tactical benchmark achieved,               |
|      b) A higher-ranking officer arrives and assumes command, or            |
|      c) The officer withdraws to establish a fixed Command Post.            |
+-----------------------------------------------------------------------------+
| 3. STATIONARY COMMAND POST MODE ("Fixed Command")                           |
|    - Complex, large-scale, high-risk incidents (commercial fires, multi-    |
|      family dwellings, hazardous materials) requiring immediate broad       |
|      coordination, multi-company control, and resource staging.             |
|    - The company officer remains outside at the apparatus or a stationary   |
|      command vehicle, directing the crew via a designated crew leader       |
|      (senior firefighter) while maintaining full strategic command.         |
+-----------------------------------------------------------------------------+

Comparison of Command Modes

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Real-World Fire Service Scenario: Split-Level Basement Fire

Scenario: Engine 3 arrives at a residential structure fire. From Side Alpha, the structure appears to be a single-story ranch home with light gray smoke emitting from the front door. The Lieutenant performs a 360-degree survey around to Side Charlie and discovers a full daylight walk-out basement with heavy, turbulent, dark brown smoke and rolling fire pushing under pressure from the basement patio door.

Tactical Decision: If the officer had failed to perform a 360-degree survey and ordered an immediate interior attack through the front door (Side Alpha), the crew would have walked directly onto a burning, compromised floor assembly directly into the exhaust flow path of a basement inferno. Because the 360 was conducted, the Lieutenant immediately updates dispatch, transmits a 360 follow-up report, re-routes the initial 1.75-inch line to Side Charlie for a direct basement exterior knockdown, and prevents a catastrophic line-of-duty tragedy.

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Common Officer Traps & Exam Watch

• Trap 1: Fast-Attack Mode Abuse: Fast-Attack mode is temporary (lasting only a few minutes). It is an operational failure to remain in fast-attack mode indefinitely while multi-alarm companies arrive with no exterior command coordination.
• Trap 2: Omitting Building Description in BIR: A BIR that states "Engine 1 is on scene with a working fire, going interior" is critically deficient. It must include building size, construction type, occupancy, conditions, mode, and command location.
• Trap 3: Layman Size-Up Sequence: Remember the exact sequential order of Layman's 5 steps: Facts -> Probabilities -> Own Situation -> Decision -> Plan of Operation.