IT’S EARLY AFTERNOON on a bright spring day. We cleaned the firehouse and equipment during morning chores and now it is after lunch. The engine crew went “in service” on the air to do a couple of building inspections in their district. The firehouse activity has been average—nothing big or exciting for the time being.
Suddenly, the fire phone rings and the man on watch writes down information and announces over the house speaker, “An alarm of fire. Supposed to be a house on fire!”
- The Impact of Ventilation at Structural Fires: Breaking Down the Fire Triangle
- The Two-Inch Hose in the Modern Era
- The Two-Inch Attack Hose: The Middle Child (Always Misunderstood)
- Fire Attack: Experience-Based Principles and Practices
In an instant, the easygoing atmosphere in the firehouse shifts as personnel rush to their apparatus, quickly put on their turnout gear, and climb into the cabs and their seats. In a few more seconds, the squad and ladder trucks move slowly out of the station with lights flashing into the narrow, congested street where the station is located. There are always vehicles parked on both sides. Each truck makes a left as the sirens scream and then another left onto the main avenue that they will follow until arriving at the street with the reported fire.
Traffic is moving as the apparatus weave through the five-lane thoroughfare. This is an old neighborhood in an old city; the age and condition of many structures are notable. Most buildings were constructed around the beginning of the 20th century and the homes were mostly built of wood-frame construction using balloon framing methods. Houses and other buildings are situated on small urban lots and are close to each other.
The squad truck slows down as it nears the street where the alarm is located. As it makes a right turn, all eyes begin looking for a working incident. There, about halfway down the block, is a large woodframe residential structure with smoke rising from the third floor, indicating a working fire. The third floor is an attic, but it is full height with a complete living area. Interestingly, there is not a lot of excitement on the fire department’s arrival.
The house was originally constructed as a single-family dwelling and has a gable roof running from front to rear. Over time, economic and demographic changes have caused this structure and many like it to be remodeled into a two- or three-family structure. Occupancy changes along with remodeling of rooms, stairways, structural framework, electrical, plumbing, and a multitude of other factors have changed the fuel load and, in some cases, the stability of these buildings and their internal systems.
First-due firefighters enter the structure to find the best access to the fire area-it is an internal wooden stairway from the living room to the second floor. Looking up to the third floor, they see thick smoke banking down to the floor and hear popping and snapping sounds-but no visible flame. There is nothing to do at this point but recon the fire because there is no engine on the scene yet. The expected first-due engine was performing in-service building inspections in the far corner of its district when the alarm came.
Another minute or two goes by and the first-due engine arrives on the scene. The firefighters stretch, charge, and bleed off a 1½-inch handline to the second floor. The firefighter with the nozzle moves up the stairway and cannot find an entrance to the fire area-again, the smoke is thick as gravy. No water is being played into the heavy smoke condition at this point. After a short time, the line is backed down to the second floor. We are thinking about another way to investigate the fire area. For sure, this is a fire where roof and horizontal ventilation in the rear of this structure are a necessity. However, it, too, is delayed as initial operations are focused on the interior only.
Another push is made up the stairway. As the young firefighter with the nozzle gets on the floor, he is on his knees but unable to move because of the severe heat condition that is now banked down to the floor with nowhere to go—no ventilation and no water! What happens next seems like it happens over a long period but only a matter of seconds go by as everything goes from black to orange as the fire flashes over at the top of the stairway. Even after the nozzle is opened fully, there seems to be no reduction in heat because the volume of flowing water is nowhere near the amount needed to take control of this flashover.
A short time later, the young firefighter is laying on a gurney in a nearby hospital emergency room. Injuries are minor. Slight burns and a twisted ankle will heal quickly. The young firefighter now has a new respect for learning to read fire conditions, water volume, and nozzle mechanics and the importance and understanding of ventilation!
This fire occurred in the mid-1970s. Many elements of the fire service were different back then, including protective gear, self-contained breathing apparatus (SCBA), and fire attack capabilities-especially regarding hoseline sizes, nozzles, and fire streams. Since then, the U.S. fire service has made great gains and improvements in apparatus, equipment, and training and educating its personnel. However, nothing speaks louder than real-life fire experience (photo 1)!
The U.S. fire service has worked hard over time on strategic and tactical improvements to achieve today’s tactical successes. We need to know where we have come from to know how we got here today.
In May 1976, an organization called PROJECT F.I.R.E.S. was started for the U.S. fire service. Made up of several professional organizations, its purpose was to update and upgrade firefighting for everyone. This was a very busy time for many on the job. It was also a time when the fire service was seeing differences in fires mostly because of the growing use of materials containing synthetics and oils and hydrocarbon-based contents. Back then, many older firefighters sensed the changes and likened the materials to solid Class B fires. As time went on and more man-made materials were involved in fires, the witnessed results were quicker, heavier, more dense smoke conditions and greater toxicity with an accompanying increased heat production with fast heat release. The realization and bottom line were that more water and better ventilation were necessary for fire attack.
Protective Turnout Gear and Clothing
During the 1970s, standards for protective firefighter turnout gear were being worked on but weren’t yet on the table. This was also a time when many fire departments were seeing themselves going into their “War Years” or “Battle Years.” Firefighters in many cases were performing the impossible with the personal gear and firefighting equipment they had (photo 2).
It was not unusual to see some firefighters wearing hunting jackets or military field jackets while working a fire. Some fire departments issued rubber coats to their engine firefighters because the idea was that the rubber would shed water (and other liquids) before getting to the wearer! Coincidentally, firefighters would put a field jacket or other coat inside their rubber coat to help insulate them from heat and steam. Firefighters assigned to trucks or squad companies sometimes wore turnout coats made of cotton or Hypalon. Turnout pants were available but not used much, as firefighters wore ¾-length hip boots in most cases. Again, if you worked an engine, you likely wore rubber boots while other firefighters were wearing heavy, leather work boots or shoes.
Turnout boots, gloves, and helmets were being researched at the same time. PROJECT F.I.R.E.S. members realized that an entire head-to-toe protective envelope was the goal. However, many firefighters felt the encapsulation kept in body heat and that they could not vent or cool off easily. It took some departments many years to “sell the idea” of total protection to their members. Another part of the study and research was station wear clothing, too. There were several different kinds of materials used to construct work clothing. Hoods were not thought of at that time!
The last piece of the firefighter protective envelope was SCBA, thanks to the late Leo Stapelton, former chief and commissioner of the Boston (MA) Fire Department, for his spearheading the work to develop the high- pressure breathing system that firefighters use today. Smoke inhalation injuries were common everywhere. As synthetic and other man-made materials were becoming prevalent in fires, it was clear that a greater toxicity level existed for firefighters and civilians in a structural fire. For example, in the fall of 1980, many occupants got sick and died later from the smoke aftereffects of the MGM Grand Hotel fire in Las Vegas.
If you were a firefighter from those times and you compare the protective gear (or lack of it) worn then to the full protective envelope, including SCBA, worn by today’s firefighters, it is clear we have the best protection in the history of the fire service. Of course, there is ongoing research for the continued improvement of all turnout gear.
Fire Attack Then and Now
A new, young firefighter entering the fire service back in the 1970s, or earlier, most likely learned about three sizes of attack hoselines (14-inch and 1-inch booster line, 1½ inch hose, and 2½-inch hose) and, though there weren’t a lot of fire departments using solid bore nozzles, there were plenty of fog nozzles, as the theory of fog use was advancing. But without proper understanding of water volume, stream application, steam production, and ventilation, many firefighters incurred burn injuries from steam and fires were lost because of low flows and poor/no ventilation.
Back in the 1950s, Iowa State University and Akron Brass Fire Fighting Equipment Corporation of Wooster, Ohio, did a lot of work regarding nozzles, flows, and streams. The research led to the creation of a flow formula that was used throughout the fire service for many years known as the Iowa State Rate of Flow formula, developed by Keith Royer and Floyd Nelson, and was created with fog application in mind. The idea was to give the attacking firefighters an idea of how much water would be needed to take into battle. This quick calculation formula gave the nozzle team an idea of the approximate gallons per minute (gpm) their attack line should flow and, from there, pump operators would adjust pump discharge pressures to accommodate the flows in the various size hoselines. Here’s an example:
- One bedroom on fire.
- Room dimensions: 12 ft. L x 10 ft. W x 8 H = 960 cu. ft.
- Divide by 100 = 9.6 gpm. This is the recommended flow from your nozzle.
A booster line could easily flow this low volume. This made it easy to understand the belief and reliance on small attack hoselines and small supply lines.
Of course, there were still strong feelings about preventing water damage through figuring out how much water to flow. Flow meters were not readily available then, but as they became more accessible, firefighters were able to understand attack line flows and necessary nozzle pressures, pump pressures, and hoseline control.
Imagine this example with today’s fuel loads. A good fire inside the bedroom that has flashed over into the hallway, reaching into other rooms, and about to extend into the walls and ceilings/attic space above will most likely produce smoke and heat down to the floor and probably bank down the steps.
The earlier, historic flows of around 9 to 10 gpm isn’t enough water for extinguishment to absorb the heat produced, especially after flashover. Eventually, many fire departments, with good reason, outlawed booster lines for any interior structural firefighting, and some fire departments bought engines without booster line equipment.
Ventilation tactics for many fire departments in the 1950s, 1960s, and 1970s were not used for fear of causing unnecessary damage, due to lack of knowledge about how ventilation helps with victim searches and fire movement and attack. There is still much to learn regarding this extremely important fireground job.
Strategic and Tactical Fire Attack Then and Now
For more than 50 years, the fire service has witnessed changing structural fire environments and associated conditions.
Historically, firefighters would quickly and offensively attack fires with low-flow hoselines and without SCBA, generally Class A fires with a lot of wood, cotton,paper, or similar materials that were easily extinguished with that kind of flow. Then came Naugahyde, foam insulation, and other plastics, and the challenge was on.
Many older remodeled buildings have had insulation added to them or have had voids and other openings filled with foam insulation, so the heat and smoke can stay in buildings longer and build a very toxic, deadly atmosphere with a high heat condition.
Currently, we now have a better understanding of fire dynamics and ventilationand realize that we must design and, in some cases, redesign our fire attack systems if we are going to keep up with the changing fire environment and still be effective and offensive. Attack fires offensively whenever possible. Kill the fire and stop the combustion process. “Take as much water into battle as we can” for the anticipated fight-even if the fire does not appear to be that much on arrival.
Newer structures-houses, apartments, offices, and many other kinds of occu- pancies-have plastic and manufactured wood along with flammable insulation. The building and contents can create a sizeable, solid fuel fire load that, when burning, gives off tremendous amounts of heat, smoke, and toxic gases, so the attack must be substantial to stop the production as quickly as possible.
As importantly, ventilation can be as significant as fire attack. If getting close to the fire is not possible, then stretch other hoselines to support attack operations or use heavier streams. More ventilation may also be needed.
Critical Flow Rate, Target Flow Rate, Offensive Firefighting, and Overwhelming Force
In today’s structural firefighting environment, you need to understand the importance of taking as much water with you as you can based on the size of the attack hoseline you are stretching. Here’s what you need to know:
1. Critical Flow Rate
According to William Clark’s Fighting Principles and Practices, Second Edition (Fire Engineering Books): “Critical flow rate is the minimum flow in gallons per minute (gpm) needed to extinguish a given fire. A flow greater than the critical flow rate will extinguish a fire, but a flow less than the critical flow rate will not.”
2. Target Flow Rate
Target flow rate is the minimum number of gpm flow of a particular size of handheld attack hoseline, especially in serious structural situations or other serious fire conditions.
For example, a 1¾-inch attack hoseline can flow a little or flow a lot! It can comfortably flow 140 gpm or less or 185 gpm to 195 gpm. The target flow for this size hoseline should be at least 150 gpm. This flow difference is attributed to different sizes and types of nozzles as well as different styles and materials used in hoseline construction. The flow uses less pressure pumping less water into the nozzle or by more pressure pumping to the nozzle, which will create a higher reaction force. It’s preferable to pump nozzles at their designed pressure for maximum fire attack efficiency and safety. Underpumped hoselines (especially older hoses with rubber linings) will flow less than acceptable volumes, and one serious kink can cost you 25% of the remaining volume, which may leave the crew with an extremely low volume for attack.
The two-inch attack hose has been in the fire service since the 1970s and was originally paired with automatic nozzles (photo 5). The belief was that a nozzle with a variable flow range could flow amounts of water (like a 2½- inch handline). It didn’t work as planned.
Currently, low pressure nozzles and newer hoses are gaining popularity. Two-inch hoselines should have a target flow rate of 230 gpm. However, they can flow from 240 gpm to 260 gpm and give the attack crew the ability to make a big hit on a fast-moving fire but also have maneuverability—68 lbs. of water weight per 50-foot length. They can also be used for exterior or interior operations depending on the circumstances. Perhaps more consideration needs to be given to the two-inch hoseline as an initial attack line. Interestingly, there is only a .3 lbs./ft. difference in water weight compared to a 1¾-inch hoseline.
The 2½-inch hoseline is still the “king of hoselines” because of its power and versatility. In past decades, it was expected to flow around 265 gpm, with a solid bore 1 ⅛-inch nozzle. If a stacked tip with 1¼-inch base tip was used, it could flow around 325 gpm.
Modern fire hose with liners constructed of synthetic or polymer liners and a 1⅛-inch tip pumped at 50-psi nozzle pressure will flow around 285 gpm to 300 gpm, while the 1¼-inch tip can flow 345 gpm without increasing pump pressure! This creates a new “bomb” or heavy-hitting line for us.
However, it’s not a mobile attack line, weighing in at around 106 lbs./50-ft.
NOTE: Fire departments can now use a single line of 2½-inch hoseline to supply master stream devices with an expected flow of around 400 gpm.
NOTE: These numbers are approximating, as time and materials have changed the quality of hose and equipment for the better and the fire service has benefitted from the ability to throw more water at a fire during attack.
Newer fire hoses are built using materials that allow for higher flows and less friction losses. Some hose is designed for higher-pressure nozzles while some styles are built for low-pressure fire attack systems. Fire departments can now purchase fog nozzles that are of the low-pressure family. There are also break-apart nozzles that need only one pressure for the type of stream used.
Data from FSRI
FSRI has developed data and visual materials from test fires to verify much of what we’ve learned from actual firefighting over time. Here are key takeaways:
- FSRI data has confirmed that it doesn’t take a lot of water to control a fire if it is applied quickly and from the right location.
- Apply water at the first opportunity. If a fire is of such volume that an outside hit is warranted, do it. This is called a transitional attack. Please note that many fire departments that have experienced heavy fire conditions in their past histories have likely used transitional attack with success. It was just never called anything other than an outside hit.
- Don’t delay fire attack while a water supply is being established. Use the water in your engine tanks. Our protective gear, along with hoselines and nozzles with greater fire flows, allows us to approach a well-involved area and attack it there.
- Door control is important for firefighters to know and understand, especially when confronted within a narrow or tightly confined area or hallway. Having everyone in place with a hoseline and tools can be effective in controlling a fire or confining it.
- Delayed alarms and responses. Expect greater fire volume and problems. It is just that simple.
NOTE: Be mindful that the test fires conducted by FSRI were in compartmented residential type fires, under controlled conditions. Always remember that firefighting is circumstantial, especially where there are variables like the environment, hoarding conditions, increased fire loading, and heavy fire on arrival with extension within and without.
Lessons Learned
Firefighters now have the best access to ex- perience/education, equipment, and personal protection in the history of our profession. History and the experiences learned from the past cannot be denied. But it must be acknowledged that efforts to move the fire service forward have always been happening. Here’s what we’ve learned throughout fire service history:
You might think that just because you have a big stream working, everything will get better shortly. Maybe it will, but positioning the big guns to cut off fire spread should be one of the prime considerations rather than flowing water on charcoal from the areas that have already been burned.
- Delayed response for most structure fires is going to result in a larger fire loss to the contents and the building. It will create extra work demands for initial firefighters and then the rest of the assignment, especially when there is a piecemeal response and water application is delayed. More water and personnel will be needed.
- Many decades ago, smaller attack hoselines and less water volumes were common. Much of it was based on theories that a quick response would allow firefighters to attack a fire quickly with a low to moderate water volume, which would turn to steam and expand in volume, snuffing the fire out and, therefore, resulting in extinguishment with less water damage. That has changed over time.
- Fires today can easily create heat that can quickly eat up small volumes of water, leaving firefighters in a tough position.
- Proper nozzle pressure, nozzle mechanics, and hoseline management are critical factors when attacking fires with handlines.
- Proper nozzle pressure is simple. If a nozzle has a design operating pressure of 50 psi, then that’s what the nozzle pressure should be. The idea of underpumping for comfort results in less water volume, and overpumping for a few extra gallons creates more back pressure (a possible control issue), which many people don’t want to, or can’t, handle. If your hose does not match your nozzle type, you may have a management problem.
- Nozzle mechanics are the “art” of how a nozzle firefighter controls the nozzle during an attack to get the greatest knockdown power and then shuts the line down and moves to the next vantage point. Coincidentally, many firefighters have never been given instructions on nozzles and their uses.
- Hoseline management is a discipline issue. Don’t crowd the person “on the nozzle,” but do support the hoseline and relieve any back pressure. Lighten up on the line when the nozzle firefighter calls for more and don’t force the hose to him. Keep the line straight behind the nozzle for about five to 10 feet and keep the hoseline on the floor during attack.
- Position the nozzle where the stream can do the most good from one location and as close to the fire as possible first. Hit the fire with the nozzle fully opened and don’t be concerned with water damage right now! Remember, water is meant to kill the fire and take control of the area as well as provide a better condition for you.
- It seems heavy streams can be misunderstood, especially when and how to use them. Where to place them for the best advantage is sometimes another misunderstanding.
- When comparing hose diameters and gpm of expected discharge, it has been mistakenly thought that two smaller hoselines can flow the volume and have the same impact and extinguishment capability of one larger handline. This is simply not true. A good example is two 1¾-inch handlines stretched at a heavy fire operation vs. one 2½-inch handline. The larger line will have greater reach and penetration power than two smaller lines, even though their total volume exceeds the 2½-inch handline. This relates to extinguishment and “kill power.” Use the big line (or heavy stream appliance) when it is needed!
Today’s offensive tactical operations are based on past experiences. As time goes on, much of our history is disappearing. However, we need to be aware of how we got to our current fire attack strategies. Reviewing the successes and lessons learned from the past 50 years is useful to pave the way for future success on the fireground.
REFERENCES
- ISU Films. “The Nozzleman.” YouTube, uploaded by ISU Library. SCUA. AV Collection. 12 June 2018, bit.ly/3ARDuoc.
- Clark, William. Firefighting Principles & Practices, Second Edition, Fire Engineering Books, 1991. bit.ly/3MCgyf2.
JEFF SHUPE began his career in 1974 and retired from the Cleveland (OH) Fire Department in 2011. He then served as a division chief in North Myrtle Beach (SC) Fire and Rescue. He has also served as a volunteer firefighter. He is an Ohio certified fire instructor. He was a field training officer for the State of Ohio Fire Academy for 24 years and taught for many years in basic and advanced firefighter training programs. Shupe has authored numerous fire service articles over the years for Fire Engineering and FireNuggets.com. He instructs and consults on engine company and fireground operations, procedures, and practices. He has an associate degree in fire technology from a community college and attended the University of Cincinnati Fire Protection Engineering program.
