Understanding fire behavior across different building types and ventilation conditions is essential for making informed tactical decisions that help to save lives and protect property. Given the risks that members face and the complexity of today’s fireground, fire dynamics training must become a vital part of our professional development.
Evolving fireground
In 2020, I had the opportunity to attend a fire dynamics boot camp that was led by instructors from UL’s Fire Safety Research Institute (FSRI). This training was urged in the federal after-action report that was issued following the tragic loss of Lt. Joyce Craig, who made the ultimate sacrifice while battling a house fire in the West Oak Lane section of Philadelphia in 2014. It also honors the memory of Capt. Matthew LeTourneau, who collaborated on this critical research with FSRI prior to his line-of-duty death at a rowhouse fire in Philadelphia in 2018.
The training was funded through a FEMA Assistance to Firefighters Grant, highlighting a national commitment to firefighter safety and operational excellence. As we work to implement this training across my department, it not only provides our members with essential, life-saving knowledge but also stands as a tribute to Craig, LeTourneau, and all who serve with courage and dedication.
The fireground is evolving constantly. With construction methods, materials and furnishings changing, so must our approach. Yet, the foundational concept of locate-confine-extinguish remains a tactical staple. What has changed is how we apply it, now guided by a more precise understanding of fire dynamics and flow path control and of how locate-confine-extinguish intersects with real-world tactics and firefighter safety.
Locate
Fire dynamics. Because of synthetic materials and higher fuel loads, modern fires grow faster and burn hotter. Within minutes, a room can flash over. Identifying where the fire is and, more importantly, where it is going is critical.
Flow path considerations. A flow path is the movement of heat and smoke from high pressure (fire origin) to low pressure (exit points, usually open doors/windows). If firefighters unknowingly create a new flow path by opening a front door or breaking a window, hot gases and fire can move toward them or trapped occupants rapidly.
Tactical implications. Use thermal imaging early to scan behind doors, down hallways and overhead. Take note of smoke movement and pressure indicators (e.g., color, density, volume and velocity).
A deliberate size-up should assess not just the seat of the fire but the entire structure’s ventilation profile. A poor evaluation—and, thus, a poor response to conditions, which can be difficult to recover from—often yields a negative outcome for the entire operation.
Simply opening a door creates a flow path, which, in some cases, makes matters worse without the presence of water.
Confine
Fire dynamics. Fires spread via conduction, convection, radiation and direct flame contact. Of these, convection—the movement of superheated gases and smoke—is the fastest, and it’s heavily influenced by flow paths. Remember, convection can equal direction. Pay attention to the flow path; it will tell you a lot. A ventilation-limited fire must remain so until a hoseline is properly positioned to begin extinguishment (i.e., cooling).
Flow path considerations. If the fire has access to oxygen and an open flow path, it will grow and spread rapidly. Our job is to interrupt that flow path, limit air entry and keep the fire in the room of origin.
Tactical implications. Close doors behind you. This is a simple tactic that dramatically slows the spread.
If conducting VEIS (ventilate, enter, isolate, search), ensure that it’s communicated. If possible, locate the door to protect you and occupants from flow path.
If the fire room is located and can be isolated, control ventilation until suppression is ready.
Use coordinated ventilation. Don’t open up unless water is on the way to the seat of the fire.
Water makes everything better.
Extinguish
Fire dynamics. Water doesn’t just put out flames; it absorbs heat, reduces compartment temperatures and prevents flashover. It could give sleeping occupants who are wearing only pajamas a better chance of surviving by changing the environment in which they’re located. Effectively using water isn’t just about direct fire knockdown; it’s about changing conditions throughout the space to assist us in completing our task safely and efficiently. Firefighters must own the environment. Cool the environment and beat the heat.
Flow path considerations. Rapid water application—even from the exterior—can “reset the fire” and slow fire growth. When done appropriately, timing is everything. If done too early or without coordination, rapid water application can drive fire toward other openings or occupants.
Tactical implications. When it’s done correctly, transitional attack (hit it from the outside, then move in) is a legitimate tactic. Quick water application to upper smoke layers during entry can reduce flashover potential and protect advancing crews and trapped occupants.
Don’t delay water to wait for a “perfect interior push.” Early water makes everything safer.
Decisions based on realities
The principles of locate-confine-extinguish remain vital, but their success hinges on our ability to apply them through the lens of modern fire dynamics and flow path recognition and control. The fire service must combine tactical discipline with a deep understanding of how heat, air and water interact. When we make smart, timely decisions that are based on these realities, we don’t just fight fire; we take control of the environment, increase survivability and increase our chances of returning home safely. The fireground has changed. We must change, too.
