How To Give A Clear Size-Up Radio Report (The Sentence Structure Chiefs Want To Hear)

Listen to a hundred size up reports on a working incident channel and you can hear which crews have rehearsed and which have not within the first ten seconds. The ones who rehearse sound like they are reading from a clean template. The ones who have not sound like they are narrating a movie. Building, smoke, action, command. Four pieces. In that order. Every time.

The size up is the moment your radio voice either earns you credibility or costs you the rest of the incident. Get it wrong on the first transmission and the chief will be calling you back for clarifications for the next twenty minutes. Get it right and the rest of the assignment hums along while you do the actual work of being first due.

This post breaks down the size up report into the four sentence structure that aligns with NFPA 1561 incident management practice. It then walks through the most common rookie mistakes and gives you a way to rehearse the cadence until it sounds the same every single time you key the mic.

Almost every clean size up report on the fireground fits a four sentence structure. The sentences can be combined or split based on what is happening, but the four pieces are always there. Building. Conditions. Action. Command.

Sentence one is the building. What is in front of you. Type of occupancy, number of stories, approximate size, construction type if relevant. Be observational. Do not editorialize. If you are not sure of the square footage say "approximately 1,500 square feet." Do not guess at construction details you cannot verify in the first 30 seconds.

Sentence two is the conditions. What you see. Smoke and fire. Where it is showing, what color it is, what volume, what pressure, and any specific side or floor. This is not the place to draw conclusions about the fire location inside the building. Stick to what is visible from your viewpoint.

Sentence three is the action. What your unit is going to do. Pull what line, deploy to what side, with what objective, in what mode. This sentence tells the rest of the responding units what your tactical decision is so they can plan their assignments.

Sentence four is command. Whether you are taking command, passing command, or assuming a fast attack position. This sentence resolves any ambiguity about who is running the incident. The next due units need to know.

Put it together and a working fire size up sounds like this.

"Engine 12 on scene. Two story single family residential, approximately 2,000 square feet, ordinary construction. Heavy black smoke showing from a Side Alpha second floor window and light smoke from the Charlie side eaves. Engine 12 stretching a 1 and 3 quarter inch attack line for an offensive interior attack through the Alpha side front door. Engine 12 has command, Main Street Command."

Eight to ten seconds of radio time. Every responding unit now has a clear mental picture, knows the strategy, and knows who is running the show.

The four sentence structure is the spine. Some incidents call for additional information after the spine is delivered. The pattern is to finish the spine first, then add the additional information, not to mix it in.

If you have a working fire and immediate resource needs, add a resource request after the command declaration. "Engine 12 has command, Main Street Command. Requesting a working fire assignment, second alarm." Notice the resource request is its own clean sentence.

If you have life safety concerns visible from your position, add them as a separate sentence. "We have a confirmed victim at the Bravo side second floor window." That gets transmitted before the action sentence in some cases because it changes the action.

If you have utility concerns visible, such as a down power line across the driveway or a propane tank against the Charlie side, add them right after the conditions sentence. "There is a 500 gallon propane tank on the Charlie side approximately 15 feet from the structure."

The discipline is to keep each addition to one sentence, and to keep the additions structured rather than narrative.

There are five common patterns that turn a clean size up into a problem for the rest of the incident.

Burying the building description. Probies sometimes start with what they see happening, not what they see standing. "We have heavy smoke and fire" with no building description leaves command guessing what they are looking at. The building always comes first.

Editorializing the smoke. "We have nasty smoke" or "really bad smoke showing" are not size up phrases. Volume, color, pressure, location. Light, moderate, or heavy. White, gray, brown, or black. Low pressure or pushing hard. Side and floor. Stick to descriptors that paint a picture for someone who is not standing where you are.

Combining sentences into a run on. "We are on scene with a two story house with heavy smoke and we are going to pull a 1 and 3 quarter and have command at this time." That is one breath, four pieces of information, and almost impossible to copy for a chief listening from the command post. Slow down. Period. Period. Period. Period.

Forgetting to declare command. The single most common ambiguity. If you do not say "Engine 12 has command" or "Engine 12 is passing command" or "Engine 12 is in a fast attack mode," the next due officer does not know what to do when they pull up. Always declare.

Calling for resources before the spine is delivered. "Engine 12 on scene, we need a second alarm, this thing is huge." Now the responding chief has a resource request but no picture. The chief cannot make a smart decision about apparatus and staffing without knowing what you are looking at. Spine first. Resources second.

The cadence has to live in your mouth, not in your head. Reading the four sentence structure on a screen does not put the words there. The way to rehearse is to do reps out loud, against varied building types, on a clock.

A useful drill takes 15 minutes. Pull up images of structure fires online, set a 30 second timer per image, look at the image for 5 seconds, then deliver a full size up report out loud while the clock runs. Do 10 images per session. Vary the building types. Single family residential. Two story. Garden apartment. Strip mall. Warehouse. Commercial. Each one trains a different vocabulary set.

If you want graded reps, StruckBox includes a tactical fire simulator that puts you in front of a real first due scenario and grades your size up report. You speak the report out loud, the AI scores the spine for structure, conditions vocabulary, tactical priority, and command declaration, and you get written feedback on what the chief would have heard. It is the closest thing to standing in front of a working fire and getting graded by a captain without leaving your kitchen. Run 30 of those scenarios across different building types and your radio voice will sound completely different the next time the bell hits.

The probies who sound calm on the radio are not naturally calmer. They have done the reps. Do the reps and the voice follows.