Several common factors have been identified in the analysis of firefighter fatalities and injuries during interior operations at structure fires where rapid fire progression took place. The firefighters and fire officers involved failed to a) recognize critical fire behavior indicators; b) understand the dynamics and potential for rapid fire development; and c) use effective tactics or techniques to mitigate these hazards.
Reports by the National Fire Protection Association (NFPA) and U.S. Fire Administration (USFA) show that there’s an increasing trend in the number of firefighter fatalities due to traumatic causes during interior operations on the fireground, including rapid fire progress.(1,2) Reversal of this trend will likely require improving both operational and training practices in structural firefighting.
“3D Firefighting”
Paul Grimwood coined the term “3D firefighting” to emphasize the three-dimensional nature of the compartment fire environment and threats to firefighter safety. 3D concepts focus in particular on the hazard presented by unburned pyrolysate (the product when solid fuels, such as wood and plastic, undergo pyrolysis, decomposing into flammable gas phase fuel) and flammable products of incomplete combustion present in smoke.
As described in “3D Firefighting: Training, Techniques, and Tactics,” 3D firefighting is grounded in an understanding of fire behavior and taking a proactive approach to controlling hazards in the fire environment.(3) This process includes:
- Increased situational awareness through ongoing size-up of key fire behavior indicators from both the exterior and interior of the building;
- Dynamic assessment of the risk associated with specific strategies and tactics on an ongoing basis;
- Proactive control of hazards presented by unburned pyrolysate and flammable products of incomplete combustion present in smoke; and
- Control of both smoke and air through effective ventilation strategies integrated with fire control.
In some respects, these elements are firefighting fundamentals. So what makes the concept of 3D firefighting different?
In the United States, fire control tactics focus largely on direct attack and often neglect to address the hazard presented by the hot gas layer. Similarly, ventilation strategies often focus on removal of thermal energy and smoke, without considering the influence of air provided by openings created for entry or ventilation. This is not to say that direct attack is not effective (it is critical to most fire control operations) or that removal of smoke is not an essential part of ventilation operations (it can, and does, provide a more tenable environment when performed correctly). The important point is that this is only part of the picture!
As synthetic materials have become more prevalent in building construction, the energy contained in fuel loads has increased substantially. At the same time, buildings have become more energy efficient, retaining heat and limiting air and smoke movement under fire conditions. As a result of changing fuel and building design characteristics, fires develop and become ventilation-controlled more quickly, with increased unburned gas phase fuel present in smoke. These conditions all result in shorter time to flashover and increased risk due to extreme fire behavior as a result of unplanned changes in the ventilation profile. Operating safely in this dynamic environment requires that firefighters and officers take the changing nature of the building environment into account in their strategic and tactical decision making.
Integrating Research into Firefighting
Massey Shaw (the first fire chief of the London Fire Brigade) observed that it’s unusual for two cities to approach firefighting in exactly the same way and even more unusual for two countries to do so.(4) However, fire is a physical and chemical phenomenon that behaves consistently under the same conditions regardless of where it’s encountered.
3D firefighting concepts are based on the integration of scientific research and firefighting best practices from across the world. These best practices include the excellent work done by the Swedish fire service on fire behavior training and control of the hazards presented by gas phase fuel in smoke, dynamic risk assessment as developed by the British fire service, and an integrated blend of European and American ventilation strategies.
Tactics & Techniques
Many people who have heard of 3D firefighting focus on the use of pulsed application of water fog to control the hazards presented by the hot gas layer. However, this is only one tool in the 3D toolbox. Fire control methods include direct attack, indirect attack and gas cooling.
Gas cooling is not an extinguishment method. It’s simply a way to reduce the hazard presented by the hot gas layer over the heads of firefighters operating inside a structure fire, allowing them to more safely gain access to the seat of the fire. Short pulses of water fog are applied into the hot gas layer, to cool the gases and reduce the likelihood of ignition. Contrary to many firefighters’ experience with water fog, this does not produce a large amount of steam and untenable conditions.
When performed skillfully, gas cooling will cause the hot gas layer to actually rise (the fire gases reduce in volume to a greater extent than the expansion of steam from the water used), providing improved operational conditions. Note: Gas cooling is not a “silver bullet”; it must be appropriately and effectively integrated with direct and indirect attack as well as tactical ventilation for safe and effective firefighting operations.
3D ventilation strategies include both tactical ventilation and tactical “anti-ventilation.” Tactical ventilation is simply the planned, systematic and coordinated removal of heat, smoke and fire gases, and their replacement with fresh air. This sounds quite similar to our old definition of ventilation, which indeed it is (with the addition of the word coordinated). However, the emphasis is on both removal of smoke and introduction of air–an often neglected part of the ventilation equation. Not making an entry opening until a charged line is in place, and closing doors to prevent fire spread or to keep additional air from reaching the fire are not new tactics. However, thinking of these actions in terms of their impact on ventilation might be. The term “anti-ventilation” was taken from the Swedish fire service, which places as strong an emphasis on the impact of inlet openings as exhaust openings as they relate to fire ventilation. The key in applying 3D concepts to ventilation strategies and tactics is to deliberately base decisions on what impact both inlets and exhaust openings will have on the fire and the fire environment.
Summary
3D firefighting is a bit like what the bride brings to a wedding: something old, something new, something borrowed and something blue. 3D firefighting is not entirely new; many of these ideas have been around since the 1800s. However, what is new: the unprecedented integration of time-tested firefighting practices with state-of-the-art understanding of the chemistry and physics of fire behavior and fire dynamics. Borrowing and integrating best practices from fire services around the world is at the core of 3D firefighting; we can, and should, continue to learn from one another. All that is left is something blue …
References
- Fahy, R. (2002). “U.S. fire service fatalities in structure fires, 1977—2000.” Quincy, MA: National Fire Protection Association.
- United States Fire Administration. (2002). “Firefighter fatality retrospective study (Report Number FA-220).” Retrieved Nov. 6, 2003, from www.usfa.fema.gov/downloads/pdf/publications/tr-100.pdf.
- Grimwood, P., Hartin, E., McDonough, J., & Raffel, S. (2005). “3D Firefighting: Training, Techniques and Tactics.” Stillwater, OK: Fire Protection Publications.
- Shaw, E. (1876). “Fire Protection.” London: Charles and Edwin Layton.
