For many centuries the most reliable method of suppressing an out of control fire is and has been the cooling or smothering the fire with water. For that reason alone, the need to find any alternatives have not produced any continued success.
In the 1800's the US density of population in many areas brought a risk of large fires in cities which are better known as conflagration fires. In the US, conflagration fires such as the great Chicago fire happened more than once to cities such as San Francisco, New York, Charleston and many others. Also major wars, such as WWII have caused more fire suppression equipment to be developed. Our own US Navy have been major innovators in the advancement of fire suppression, both in equipment design and tactical skills.
In response to these risk of mostly population density, these cities and towns organized a fire department and implemented codes or regulations to prevent the likelihood of such disasters. These cities and towns engineered water systems for _fire protection, bought equipment and pumps to deliver water in a moment's need. As these cities grew in density and in fire protection complexity, the answer is and was to provide more and quicker water to the flames of destruction. The city of Boston led the way for full time firefighters and the first fire code ordinance, while Ben Franklin is given credit for the development of the volunteer fire department in Philadelphia PA.
Until the early 20th century, most building and quality of life products were made from wood or cellulose or animal products such as horse hair etc. Then the polymer came and the race began. Now products were modifiable and could be shaped as desired. It became affordable and the general population could afford these products and they often provided a higher quality of life, especially in the home. Only one thing...... they burned completely different (much higher heat release and fire growth was factors faster) from the previous products.
The US fire service equipped itself and trained in a fashion that didn't see a major change after the conflagration times until World War II. The post war years marked a rapid growth and innovation period for the fire service as well as the entire economy.
What is Your Theory of Fire Suppression?
In the US, for many years, fire departments have focused on suppressing the fire by removing the heat in residential firefighting with larger amounts of water. More gallons per minutes, better Personal Protective Gear and vertical ventilation have been the main focuses to meet the increase fire loading in homes and businesses. This focus has not attempted to utilize the other elements of the fire tetrahedron. As the fires grew quicker and short cycle times to flashover, the focus on one side of the fire triangle has become very inadequate to firefighter safety.
So again our history will reflect another shift (this old geezer's crystal ball) in our theory of the best methods to control fire growth and restore the environment to the one we need to survive (normal). As the quality of life continues to demand new materials and conditions, the chemistry of what and where it burns in our fires continues to change the requirements to survive a fire with these new products and environments.
So what is the big deal? It is at its basics more risky, more liability and more frequent. The mishap or defect impact becomes so costly, we change the process to reduce the impact and enable our work to deal with the frequency of the tragedy conducting the firefight.
Just because we did, doesn't mean we should continue. Just because I don't care, doesn't mean you shouldn't care. Just because I am willing to sacrifice my life for a reason, doesn't mean everyone will. Mostly, just because the method you choose will kill you eventually, doesn't mean that we can't use another method and not die getting the same desired outcome.
You see, each of us are laymen at fire suppression theory. Some are more than others. It is theory. It is not fact. More importantly, it is a complex combination of many theories of several areas of different sciences. The context varies in some small or large amount on every fire we respond.
The amount of science needed is correlative to the amount of risk taken to suppress the fire and/or restore the environment. The amount of risk is correlative in most ways to the distance from the fire and / or the distance inside the structure on fire (both horizontally and vertically) not protected by an unmanned automatic protection system (i.e. sprinklers).
The distance from low risk to a position of higher risk requires an immediate control of the critical science variables for the duration of the exposure to manage that risk. This is better understood in our trade in the Hazardous Material Response arena. The extreme life risk engineering tradeoff should not be transferred from the occupant to the firefighter/rescuer (just this old man's opinion). In the interval, firefighters are called upon to not only attempt to rescue (sometimes successfully), but also to survive the attempt. To accept this challenge, the knowledge of fire growth must be our primary focus in fire suppression research and learning.
Not everyone on our teams/crews are or will be lifelong students, but I believe we should ensure that someone in our team is focused on the fire sciences. In that spirit, here are some areas that KTF is focus upon and maybe somewhat different than your fire science learnings:
A. Temperature of the space B. Velocity of the combustion flow/air track C. Moisture or ballast content in the space
The KTF Bar Stool is the model used to control / manage these critical areas of fire growth:
1. Tactical Thermal Data 2. Tactical Air Management 3. Enhanced Water Streams
The KTF model's functional areas of application are:
a. Detect (Detecting the thermals) b. Define (Defining the combustion growth) c. Access (Accessing the IDLH environment with a managed science risk tactic) d. Favorably Influence (Decaying fire growth with all tactics) e. Restore Environment (Fire out, environment restored to normal conditions)
This is a picture capture from KTF 2013 with demonstrating a very common attack tactic (non-KTF Suppression Theory) through the front door whileallowing the accessible flaming to continue as the crew pushes in the front door (no air control). The easy accessible flaming is not stopped, the door exhaust is not blocked, which increased the fire growth in the front room when the front door was opened and blocked open.
A Go / No Go is not performed with the TIC, while the crew gets low into the under-pressure and pushes the short distance in the hallway to access the room door in the fire compartment.
The stream is a 1 3/4 inch line which didn't flow until the crew accesses the fire compartment. The extremely hot over pressure flow is in excess of 800 degrees, which is approximately 250 degrees greater than the engineered high temperature specifications to prevent thermal injuries.
The under-pressure in the door is allowed to increase and is slowed as the crew unintentionally blocks the intake air with their bodies as they access the hallway.
Fire suppression theory should consider termperature, smoke / air velocity, and the amount of moisture available to decay fire growth of the fuels available.
KTF endeavors to learn the fire suppression sciences that impact the tactics we choose on the fire ground. This example obviously does not address these critical variables in this tactic. The KTF Fire Suppression Theory uses: 1. Tactical Thermal data 2. Tactical Air Management 3. Enhanced Water Streams to address the above critical components of the fire tetrahedron. Come learn with us and join the KTF Society at www.killtheflashover.com
Molecular movement in a fire compartment is nothing like I was taught, Steam/vapor/moisture/mist use the same highway (air track) as the molecules. Insufficient oxygen reduces flaming, reduced (decaying) flaming takes less moisture than growing flaming ( a lot less) , Current fire flow formulas are on the liberal side of fire growth, stop the fresh air to the flaming and the amount of moisture needed is significantly reduced. Add an agent (surfactant) to the water (Enhanced Stream) for surface cooling and even less water is needed.
Droplets of nozzle water only go in line, lose altitude and don't make turns. This is not true of steam. The impact of relative humidity in the fire space is significant.
There are at least 3 areas of suppression discussion to be understood. 1. Surface Cooling 2. Gas Cooling 3. Introduction of non flammable Ballast in the flammable space
I recommend listening to Lars Agerstrand from Sweden on the science of these phenomenons or chemistry. The power of (invisible) steam is underestimated in the US Fire Service
In addition, the use of an enhanced water stream especially as it relates to the effectiveness of surface cooling is tremendous. These streams are 3 to 4 times more efficient than un-enhanced water streams.
Also the traditional US Fire Service desire / requirement to ventilate for suppression purposes will negate much of the capability of the 3 areas mentioned above, in some cases almost completely.