COAL WAS WEALTH Size-Up Explained (How To Actually Use It On The Fireground)

Most firefighters first hear COAL WAS WEALTH in a fire academy classroom, write the thirteen letters down, get tested on what each one stands for, and then never use it again. That is a waste, because COAL WAS WEALTH is one of the few size-up frameworks that actually works at three in the morning when you are pulling up to a working fire and have about twenty seconds to make decisions that will shape the next hour.

The problem is not the acronym. The problem is how it gets taught. Most instructors hand it over as a checklist to memorize, when what it really is, is a mental scaffold. You are not supposed to recite all thirteen letters out loud on scene. You are supposed to have them so well wired into your brain that your eyes automatically pick up the inputs that matter and ignore the noise, before you ever pick up the radio.

I learned this the hard way at Kansas City Kansas Fire Department early in my career. I had the acronym memorized cold. I could write it on a napkin. I could not actually use it on a fire, because I had never built the connection between the letters and the things I was looking at through the windshield on the way in. This post is the version of COAL WAS WEALTH I wish someone had taught me when I was a probie.

COAL WAS WEALTH did not come from a textbook. It came out of FDNY tradition, written down most famously by Chief Vincent Dunn in his work on collapse and command, and reinforced by Chief John Norman in the Fire Officer's Handbook of Tactics. Frank Brannigan's Building Construction for the Fire Service does not use the acronym directly but covers most of the same inputs because the size-up factors and the building factors overlap heavily.

That heritage matters because it tells you what the acronym was designed for. It was built for the urban first-due officer arriving on a fire where the building, the occupancy, and the time of day were going to drive the entire incident. It maps cleanly onto residential and commercial structure fires. It is less useful as a checklist for wildland, hazmat, or technical rescue, where other frameworks fit better. Know your acronym and know its lane.

The standard version of COAL WAS WEALTH covers thirteen size-up factors. Some instructors swap the last letter between Height and Hazardous Materials. I will give you the most common version and flag where the variants live.

Construction. Type one through type five, plus the era of the building. Modern lightweight wood construction collapses faster than legacy balloon frame, which collapses faster than ordinary brick and joist, which collapses slower than fire-resistive concrete and steel. You read this off the building in seconds: brick veneer over wood frame is a clue, a peaked roof on a single-story commercial is a clue, exposed steel I-beams in a strip mall are a clue. Construction tells you how long you have before the building starts working against you.

Occupancy. What is the building used for, and who is in it right now? A residential occupancy at 0300 has a high life hazard with low awareness. A commercial occupancy at 0300 likely has a low life hazard. A nightclub at 2300 has a different problem entirely. Occupancy drives life safety priorities, search priorities, and the kind of contents you are going to find burning.

Apparatus and personnel. What is on scene, what is coming, and how fast? This is honest math. Two engines and a truck with three-person staffing is not the same response as two engines and a truck with four-person staffing. The first due officer has to know what is realistic with what is rolling, not what would be possible with a metropolitan response. If your staffing requires you to delay an interior attack until the second engine arrives, that is a tactical decision you make in the size-up, not a problem you discover after committing.

Life hazard. Who is in danger, where are they, and how do you reach them? Life hazard is not just civilians. Your crew is a life hazard exposure to you the moment you commit them. Trapped occupants drive your search priorities. Visible victims drive your rescue decision. An empty building at 0300 may still have an unhoused occupant inside, so empty does not mean unoccupied.

Water supply. Where is your water coming from, how much do you have, and how long will it last? Hydrant on the corner with adequate pressure is one situation. Tanker shuttle from two miles out is another. Water supply has to be solved before you commit to an attack, not during it. The number of probies who have run out of tank water on a working fire because nobody confirmed the supply is uncomfortable to think about.

Auxiliary appliances. Sprinklers, standpipes, fire pumps, smoke control systems, alarm panels. Most residential fires do not have these. Most commercial fires do. Knowing they exist and knowing whether they are working is a different question than knowing whether you can rely on them. A standpipe that you have not supplied from the FDC is just decorative.

Street conditions. Can the apparatus get there, can it set up where it needs to, and can additional units get past you? Hydrant locations, road width, dead-end streets, gated communities, downtown one-ways, snow conditions in winter. The size-up starts on the way in, not on arrival. If you cannot get the aerial within reach of the building, your tactics changed before you stepped off the rig.

Weather. Wind direction and speed, temperature, humidity, precipitation. Wind drives smoke and flame path on the fireground and is the single biggest factor in wind-driven fire risk in residential and high-rise occupancies. Cold weather drives equipment performance, hose freezing, and rehab cycles. Heat drives crew exhaustion. Weather is a variable that changes throughout the incident, not a one-time check.

Exposures. What is the fire threatening if you do nothing? Exposures are usually thought of as adjacent buildings or vehicles, but they also include attached structures, common attics, void spaces, and combustible materials stored near the fire building. A row of vinyl-sided townhomes shares an attic. A strip mall shares a roof deck. Exposures determine where you put your second hose line, if you have one.

Area and height of the building. Square footage and stories. A 1,400 square foot ranch is one fire. A 4,000 square foot McMansion with three above-grade floors and a finished basement is a different fire that requires different tactics, different staffing, and different command structure. Big buildings eat hose, eat air, and eat crew faster than small ones.

Location and extent of fire. Where is the fire in the building, and how much of the building is involved? Light smoke from a single window is not the same as fire showing from three floors. Basement fire is not the same as attic fire. Location drives where you commit your attack line, and extent drives whether you can commit at all. This is the input that most often pushes the size-up from offensive to defensive.

Time. Time of day, day of week, season, and elapsed burn time before your arrival. 0300 on a Tuesday has fewer people awake to call. Sunday afternoon has more occupants home. A fire that has been burning for ten minutes before you got the call is a different fire than one that started two minutes before dispatch. You estimate burn time from smoke conditions, structural cues, and what the caller said.

Height or Hazardous materials. The two common variants for the final H. Height matters because aerial reach, standpipe operations, and stairwell logistics change above the second floor and change again above the seventh. Hazardous materials matter because residential garages, agricultural buildings, and small commercial occupancies hide chemicals that change the fire behavior and the decon profile. Some officers carry both Hs in their head and let the building tell them which one matters more.

You do not stand on the front lawn reciting the thirteen letters. If you do, the IC after you will assume you are overwhelmed. What you do is run the acronym while you are still in the rig, before you step off, and then again during your 360 walk. By the time you are giving your on-scene report, the relevant factors have already filtered to the top of your attention and the irrelevant ones have fallen away.

For most residential fires the size-up that matters out of COAL WAS WEALTH compresses to four or five factors: construction type, occupancy and life hazard, location and extent of fire, water supply, and exposures. The other letters are still there in the background, but those five are the ones that drive the initial attack line, the initial assignment, and the offensive versus defensive call. Train the compression. Reciting all thirteen on every call is a sign that you have not internalized the framework.

For commercial fires the compression shifts. Construction and auxiliary appliances move to the front. Occupancy at the time of the fire becomes more important than the listed occupancy on the pre-plan. Area and height drive whether your initial assignment can even cover the building.

For high-rise fires the compression shifts again. Height, auxiliary appliances, and life hazard become the dominant factors. Standpipe operations replace water supply as the controlling water question.

The skill you are building over the first few years of your career is pattern recognition. New officers run the full thirteen letters slowly and miss the urgent ones. Experienced officers see the building and the smoke and immediately know which three or four letters matter most, then check the others as a sanity pass.

Treating it as a reporting structure. The acronym is for your decision-making process, not your radio report. Your on-scene report should be tight, three to four sentences, building and conditions and actions and command. Do not give COAL WAS WEALTH on the radio. Use it to shape what you put on the radio.

Skipping the 360. The 360-degree walk is where most of the inputs get verified. If you skip the 360 you are size-ing up half the building. Some fires make a 360 impossible, on attached structures or contiguous occupancies. In those cases say so on the radio and assign someone to gather the missing sides.

Ignoring the negative space. A house at 0200 with no cars in the driveway and no lights on does not mean unoccupied. Read both what is there and what should be there but is not. A commercial building during business hours with no one in the parking lot is a different anomaly. The absences are inputs.

Locking in too early. Size-up is continuous. The fire you arrived on changes every five minutes. Crews ventilate, conditions shift, occupants emerge, additional units arrive, and the framework has to re-run on each major change. Officers who lock in their tactics at minute one and stay locked in at minute fifteen lose buildings and sometimes lose crews.

Treating it as the only framework. COAL WAS WEALTH is excellent for structure fires. For other incident types use the framework that fits. RECEO-VS covers fireground priorities. SLICERS covers modern fire dynamics attack sequencing. Wildland uses LCES and the 10s and 18s. Hazmat uses APIE. Knowing which acronym to pull is part of being a competent first-due officer.

The fastest way to wire COAL WAS WEALTH into your reflexes is repetitions on real-world building photos. Pull up Google Street View, pick a random residential neighborhood, freeze the image, and run the thirteen letters out loud against the building you see. Construction type. Likely occupancy. Likely life hazard at this time of day. Where would the hydrant be. Where would the exposures be. Do this for five buildings in a row. Then switch to commercial buildings. Then switch to strip malls.

Once you can run the acronym out loud against a static image, the next progression is timed reps. Look at the building for ten seconds, then close your eyes and produce the size-up from memory. Then look again and check what you missed. The goal is for the relevant inputs to filter to the top of your attention in under thirty seconds.

The hardest reps to get on your own are the ones where smoke conditions and fire location are visible. That is the situation that actually matters on a real fire, and that is the input you cannot replicate from Street View. StruckBox Tactical Fire Sim is a free AI-scored scenario tool that runs you through realistic working-fire photos with smoke and flame visible from Side Alpha, prompts you for your on-scene report, and grades your response against the size-up factors and the radio communication standards a real chief would expect. It is the closest thing to first-due reps I have found short of running real calls, and the reps stack on your own time without burning anyone else's schedule.

The badge does not come from memorizing thirteen letters. It comes from training your eyes and your gut to read the building before you step off the rig. COAL WAS WEALTH is just the scaffold the reps hang on. Do the reps, get the scaffold wired, and the size-up stops feeling like a checklist and starts feeling like the way you naturally see a fire scene.