Firefighting, Structural Firefighting

Today’s Evolving Fire Attack

By P.J. Norwood and Nick J. Salameh

When deployed properly, fire attack is the most important fireground function that will have the biggest impact on occupant survivability and firefighter safety. The old adage of “put the wet stuff on the red stuff” was taught, and it worked. When the fire service started to use that slogan, the fire environment was not what it is today. For many years, we taught and performed fire attack the same way with little variation and little precession. These teachings and practices were passed down from generation to generation, and much of yesterday’s training was experiential—not science—based. However, that’s changing thanks to science-based advances in modern fire dynamics and modern fire tactics.

In the past, like today, the fire environment was changing and becoming more volatile. The fire service looked at nozzles; nozzle movement; hose size; and all sorts of appliances, pressures, and so on to fight the changing environment. As well, our personal protective ensemble of turnout gear and self-contained breathing apparatus (SCBA) was improving and allowing us to push deeper and farther into the fire environment, which offered an increased sense of security. Although we focused on workarounds that allowed us to operate in a more hostile environment, we failed to understand the changing fire dynamics and to identify better tactics to more effectively combat modern day fires. Today’s fire science research is bridging the gap between the fire service and our understanding of modern fire dynamics—an understanding that is essential to firefighter success.

Over the years, the fire environment has been evolving. It has been influenced by the significant use of synthetics in building contents, new building construction, the use of lightweight and composite building components, less compartmentation, and more energy efficiency. Yet, despite this evolution, our understanding of fire dynamics and tactics had remained static. With the help of the Underwriter Laboratories—Firefighter Safety Research Institute (UL-FSRI) and the National Institute of Standards and Technology (NIST), recent and ongoing modern fire science research is adding to our previous experiential knowledge base through science-based findings. These findings have and continue to identify significant changes in fire dynamics, from the legacy period to the modern era. The studies confirm the effectiveness of what are often believed tried and true tactics, which are experiential based and have been identifying modern tactical options based in science to create tactical best practices. Today’s modern tactics focus on the best methods to apply effective water as quickly as possible, regardless of whether it comes from the interior or exterior of the structure.

In 1950, Chief Lloyd Layman presented a paper titled “Little Drops of Water” at the Fire Department Instructors Conference (FDIC). He introduced what he called the indirect method of attack to suppress interior building fires by using the heat-absorbing properties of expanding and condensing steam, produced in great quantities by fog streams. The conclusions were based on Coast Guard experiments that Layman was in charge of conducting at the Coast Guard Firefighting School at Fort McHenry in Baltimore, Maryland. Layman continued his experiments and applied his tactic in building fires after he returned to his position as fire chief in Parkersburg, West Virginia. This research had a very large impact on the fire service and suppression techniques to this day.

In 2012, during the UL-FSRI/NIST Governors Island experiments, UL Director Steve Kerber began looking at fire tactics and the use of exterior water application as part of the offensive attack mode, now referred to as the “transitional attack.” Most have become accustomed to recognizing exterior fire attack tactics as defensive actions, but the study findings were a pivotal moment in the fire service and proved that the transitional attack, when applicable, was an effective offensive attack mode tactic to quickly and initially take control of fire and to immediately improve interior conditions.

Although the debates over smooth-bore vs. fog nozzle have, for the time, slowed, the application of water from the exterior by transitional attack is debated furiously across the nation. During these debates, there seems to be some confusion on what transitional attack actually is and is not. So, rather than debate if transitional attack should or could be used, let’s take a closer look at what it actually is.

 

Fire Attack Modes

We have two basic fire attack modes: offensive and defensive. Attack modes can be easily defined as where the nozzle will end up. If the fire attack starts exterior and stays exterior, you’re in a defensive attack mode. If the fire attack mode ends on the interior, it’s an offensive attack mode.

Regardless of the fire attack mode used, how you apply water to the environment falls under the direct or indirect attack method. If you apply water directly onto the burning materials, you are conducting a direct attack. If you are applying water into the compartment to achieve cooling of the environment or to bank the stream into the area, you are using an indirect attack.

 

Definitions

Blitz attack is a fire attack where master streams are used to knock down a large body of fire. It can precede an offensive attack.

Defensive attack is an exterior fire suppression activity directed at protecting exposures.

Defensive operations are actions intended to control a fire by limiting its spread to a defined area, avoiding the commitment of personnel and equipment to dangerous areas.

Direct attack is a firefighting operation involving the application of extinguishing agents directly onto the burning fuel.

Extinguishment is a state of non-fire growth. To completely stop the combustion process.

Indirect attack is a firefighting operation involving the application of extinguishing agents to reduce the buildup of heat released from a fire without applying the agent directly onto the burning fuel (P. 1830, NFPA Glossary of Terms, 2018 Edition.) This form of fire attack involves directing fire streams toward the ceiling of a compartment to generate a large amount of steam to cool the compartment. Converting the water to steam displaces oxygen, absorbs the heat of the fire, and cools the hot gas layer sufficiently enough for firefighters to safely enter and make a direct attack on the fire.

Interior attack. For fire attack, water application occurs on the interior using a hoseline to cool adjoining spaces and extinguish the fire.

Knock back is a state of partial fire extinguishment allows for fire regrowth in a short period of time without additional intervention.

Knock down.is a state of partial fire extinguishment that is close to full extinguishment and where regrowth is unlikely.

Offensive attack is an advance into the fire building by the firefighters with hoselines or other extinguishing agents that are intended to overpower the fire.

Offensive operations are generally performed in the interior of involved structures that involve a direct attack on a fire to directly control and extinguish the fire.

Transitional attack is a fire attack where the application of water starts on the exterior to cool the fire area for a period and then repositioned to the interior for final suppression.

It’s important to note that the definitions of terms used in this article come from various sources and, in some cases, differ. The UL Impact of Fire Attack report, cited in this article, listed multiple definitions for some terms but did not cite the specific source (i.e. NFPA, various fire service training manuals, and so on) for each definition. For the purposes of this article, we provide the sources as best we can. Keep in mind that just because the term is cited in the UL report does not necessarily mean the definition originates from UL.

A noteworthy observation is the acknowledgement that some definitions were originally derived based on the knowledge available at the time. In some cases, we can see where definitions are more accurate for the times. For instance, the term “indirect attack” has been defined generally as an exterior attack method used to generate large quantities of steam to cool and extinguish. This suggests this action can only be done with a fog nozzle. However, the indirect attack can also be generally defined as an action of using water (extinguishing agent) to reduce the buildup of heat without actually applying to the burning fuel, suggesting we can accomplish the action of cooling with a solid stream nozzle.

No longer are fire operations limited to narrow definitions written years ago from dated knowledge. The research-based information that is being identified from modern studies is increasing our knowledge and understanding to the point where new terms are created for context and original definitions are being revised to keep up with the times and to remain accurate.

Where we once saw an indirect attack limited to a fog stream and steam production, we now see straight streams and solid streams being used to cool the environment without the need to create large volumes of steam because our understanding that water cools and gases contract is better understood today. As well, the offensive attack mode is no longer limited solely to interior attack. By understanding that fire does not know where the water is coming from or by what stream pattern, our tactical arsenal broadens and allows for exterior and interior water application during offensive attack modes.

 

What is a Transitional Attack?

Transitional attack is an offensive attack mode tactic. By definition, it’s an indirect attack method. Many think of the indirect attack as the action of using an exterior fog stream into a window to generate high volumes of steam to cool and smother fire. Although this is still an option, the transitional attack achieves the same goal of cooling with a solid or straight stream to cool surfaces and the gas layer without producing large volumes of steam. It is not designed to achieve knock back through steam production. In fact, the cooling action causes gases to contract.

Remember, we define the attack modes by where you end up; not where you start. When you choose a transitional attack (the most effective method of initial water application) to coat the most surfaces and provide the most cooling, use as steep an angle as possible off the ceiling and keep the nozzle as steady as possible to reduce air entrainment. The nozzle firefighter should constantly evaluate the effectiveness of the water application, looking for indications that it is having a positive effect such as knocking back flames in the gas layer within seconds. If he sees no effect, he should direct the nozzle in a different location (i.e., alternate window or door to the fire compartment) or possibly off the top of the window to coat surfaces. Once the gases have been cooled enough to no longer have fire venting out the window (knock back), he can shut down the nozzle to evaluate conditions.

There is no specific time limit or suggested flow time; base the time required for cooling on conditions. If the water application is no longer showing signs of effective cooling, adjust the application angle.

Failure to move quickly from the transitional attack following effective exterior flame knock back to the interior to complete extinguishment will allow for flame regrowth. An efficient transition is essential to success, whether repositioning the first attack line or simultaneously coordinating to have the second attack line advance to the interior.


(1) Photos courtesy of P.J. Norwood.

 

The images above show an example of improved conditions from the initial water application during a transitional attack using a smooth-bore nozzle at a steep angle and directed off the ceiling. The sequence of images represents the first three seconds after initial water application. The moment suppression starts (top left), one second after suppression starts (top right), two seconds after suppression starts (bottom left), and three seconds after suppression starts (bottom right). 

The transitional attack is not a one-size-fits-all tactic. A company officer who indiscriminately uses the transitional attack on every fire ground is destined to fail. Like all strategies and tactics, it has a time and place. An effective engine company officer will understand and have a variety of tactical fire attack options, and he will choose the best tactic for each given fire. Failure to apply the right tactics from the start will allow fire—rather than the firefighters—to maintain control; this puts firefighters in a reactive rather than a proactive stance. For instance, if it is determined the transitional attack is the proper tactic, failure to transition the first attack line or simultaneously coordinate the second attack line to interior attack immediately following the transitional attack will allow for fire regrowth. You will not achieve a knock down and extinguishment unless crews move quickly to the interior to completely stop combustion.

Some would argue flowing water from the outside of the structure, to push in, is, in essence, using a transitional attack. Although it may not meet the specifics of the proper angle it is still a transitional attack based on the definition of this fire attack method.

 

The Blitz Attack

The blitz attack confuses some members. Created in Chicago, it is an offensive attack that is used in the same manner as a transitional attack. Some have called the transitional attack the modern blitz attack. Although a traditional blitz attack may not meet the defining criteria of a transitional attack, the goal is the same: flow quick, effective water from the exterior to overtake or slow the growth of fire and to create a more habitable interior environment, allowing for a rapid aggressive interior attack to complete extinguishment.

 

Applying it on the Fireground

One of the most profound statements found in the technical report Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival, as it relates to fire attack, is found on page 184, Sect. 7.7: (Water in the Fire Compartment Matters, and so does Timing):

“Effective application of water, whether from the interior doorway or from the exterior window, into the fire compartment has a positive impact. The heat release rate of the fire is reduced, temperatures both near and remote from the fire are reduced, and the rate at which toxic gases are produced slows making tactical ventilation effective. With all else being equal, the tactical choice on where to apply water from should be based more on the time it takes to knock back the fire and less on the position the water is being applied from.”

The time has come to stop arguing over what we call something and put our energy into learning the “when” and “how” to effectively apply water to our firegrounds in the quickest way possible. If it’s truly about our members, we need to analyze how we deploy our attack lines, use available personnel and resources, and perform fire attack at each and every fire. There is no one-size-fits-all tactic for every fire. Although every fire burns in a predictable manner, the fire environment and what each of our departments faces on arrival will be different. Therefore, each department must quickly analyze each fire and deploy the best strategy and tactics for each situation.

The primary goal to save lives remains unchanged. However, we must effectively apply sufficient water into the fire area as quickly as possible to immediately improve interior conditions for savable trapped occupants and for firefighter effectiveness, efficiency, and improved safety. Do what’s right for the fire you’re on, not necessarily what you’ve always done.

 

References

Impact of Fire Attack Utilizing Interior and Exterior Streams on Firefighter Safety and Occupant Survival: Full Scale Experiments. https://ulfirefightersafety.org/docs/DHS2013_Part_III_Full_Scale.pdf.

Fredricks, A. Little drops of water: 50 years later, part 1. 2 2000.

Layman, L. “Attacking and Extinguishing Interior Fires.” National Fire Protection Association.

NFPA Glossary of Terms 2018 Edition. https://www.nfpa.org/-/media/Files/Codes-and-standards/Glossary-of-terms/glossary_of_terms_2018.ashx?la=en.

Fundamentals of Fire Fighter Skills, Enhanced Third Edition. IAFC and NFPA. Jones and Bartlett, 2014.

Smith, J.P. Strategic and Tactical Considerations on the Fireground, Second Edition. Pearson. 

 

P.J. NORWOOD is a deputy chief training officer for the East Haven (CT) Fire Department and has served four years with the Connecticut Army National Guard. He is an FDIC classroom, workshop, and H.O.T. instructor; a Fire Engineering educational advisory board member, and a Fire Engineering book and video author. He was a member of the UL Technical Panel for the Study of Residential Attic Fire Mitigation Tactics and Exterior Fire Spread Hazards on Fire Fighter Safety. He has lectured across the United States and overseas. Norwood is certified to the Instructor II, Officer III, Fire Marshal and Paramedic levels.

 

NICK J. SALAMEH is a 36-year veteran of the fire service. He was a Fire/Emergency Medical Services Captain II and previous Training Program Manager for the Arlington County (VA) Fire Department, with which he served 31 years. He is a former Chair of the Northern Virginia Fire Departments Training Committee.  Nick is a contributor to Fire Engineering maagazine, www.fireengineering.com, and Stop Believing Start Knowing (SBSK) (https://www.facebook.com/StopBelievingStartKnowing.)

Originally ran September 21, 2018.