Students’ Corner – Fighting Flashover: Is “Penciling” the Best Technique?

Posted: June 11, 2015 in Fire Protection, Fire Science
Tags: , , , , , ,

by: Peter Raia

The fire service is a traditional, paramilitary brotherhood that is one of the most long standing professions in the world. I had the privilege of joining this brotherhood in 2007, at the age of 15. I quickly gained a large interest in firefighting and wanted to learn what goes on “behind the flame,” for a lack of a better phrase. Shortly after joining the fire service, I stumbled upon the Fire Protection Engineering Program at the University of Maryland and gained an entry level understanding of fire dynamics and computer fire modeling. Unfortunately, some of what I learned with my degree did not correspond to my knowledge of basic firefighting.

“Penciling” is a technique taught in fire academy classes as, “short blasts of water, aimed at the ceiling, to provide enough cooling to stop or slow a flashover.” I was taught that three, one second long bursts at the ceiling are enough to cool the ceiling temperatures to fight back the onset of flashover and allow the fire attack crew to push on to the seat of the fire for final extinguishment.

As a fire protection engineer, this practice did not make sense. Why would you only provide three short bursts of water at the ceiling when you have a “relatively infinite” amount of water to cool the surrounding atmosphere? And, why just at the ceiling? The ceiling only accounts for one of the sides of the room that are affected by the high temperatures of the upper smoke layer. The temperature of these surfaces can be near, and sometimes over, 1000 degrees Fahrenheit immediately before flashover. Three short shots of water at the ceiling will only decrease the temperature slightly and for a short amount of time before the upper smoke layer overwhelms the cooling and heat displacement created from the water application. In my mind, it made more sense to apply water to multiple sides of the compartment, hopefully causing a rapid decrease in the compartment temperature and the conversion of liquid water to steam.

I took this question to my fire academy instructor, who I am very friendly with and currently work alongside with as a firefighter. The response I received was not as grounded in science as I expected. My friend stated, “Pete, that amount of water would cause extreme steam burns to your body (i.e., rapid steam expansion due to the water phase change), and it is the way it has always been taught.”

I partially agreed with his first point. Steam burns are atrocious. They resemble and feel like severe sunburns, but occur all over the body in some cases. However, these burns have become rarer with improvements in protective gear standards and new and improved practices in fire ground ventilation.

His second argument was more problematic. The standard rebuttal, “because that’s the way it has always been done…,” is just not in line with modern fire dynamics and fire fighting tactics. This answer simply is not good enough to warrant the practice of a technique that is performed in as hazardous a job as fighting fire.

With the help of online resources, I began to research the direct application of a continuous water stream to the upper layer in an effort to rapidly cool and decrease the flashover temperature of the fire room. Kill the Flashover is one example of a group that is working on this type of research (NIST has also conducted research in this area). As a group of firefighters/engineers, they are dedicated to examining the ins and outs of attacking and preventing flashover. In addition to many other live fire burns, they have performed a comparison test of the penciling technique and the full-flow technique. In their experiment, Penciling demonstrated improvement in the fire compartment, but these improvements were temporary and still fostered high temperatures and dangerous operating conditions for the interior firefighting crews. The full-flow technique performed much more consistently, and in some instances resulted in the full extinguishment of the fire in the compartment.

A question to now pose to ourselves is, “do we get firefighters to use this method?” More research is certainly needed, and once completed and analyzed, the next step is to get this information out to the fire service community. In my experience on the fire ground, practice is the best form of education. The more you practice a proven technique, the more convinced you will be of its validity. In modern firefighting practice, it is imperative to question the old “because that is how it has always been done” attitude and embrace the idea of more adaptive and scientifically-based techniques.

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Comments
  1. Dave Snyder says:

    Pete –
    You note your entry into the fire service in 2007. By now I’m sure you have come across the phrase, “Two hundred years of tradition unimpeded by progress”. In some instances this really rings true when dealing with many folks in the service. Trying to change an ingrained culture of empirically-based “expertise” with a reasoned or scientific-based approach will cause you to bang your head against the wall more than a few times.

    My personal favorite; go back to about 1985 or so and take a look at the idea – published by IFSTA – that there are (were) 4 methods of heat transfer; convection, conduction, radiation, and direct flame contact. Many new F/F’s were blindly taught that one and it stuck. It didn’t help when NFPA picked it up in one of their publications.

    Best of luck in changing the culture.

    Dave Snyder
    FPE (MD’78) / P.E.
    Lt. Balto. Co. FD .

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  2. Doug F says:

    This is a conversation that needs to take place. I have had the opportunity to teach the flashover program for several years. People are not teaching the reason behind the pencilling technique to the students. It is used in the flashover trailer as a reset technique to cool the fuel to produce more products of combustion and fire gases for the trailer only. People continue to teach it as a method of killing the flashover on the foreground. It is not a fire ground technique. If you want a real life example read the NIOSH report on the LODD of the firefighter in Peabody Ma. It clearly states that Lt was taught this technique (pencilling) at the state academy flashover program. We tell the students with no exception they must flow water full bail for an extended time to prevent flashover. Maybe we need to rethink the way we are teaching the flashover program by using a full bail open technique at the end of our scenario work to show how to actually do real world flashover prevention.

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  3. PerOla Malmquist says:

    Peter-
    Interesting thaughts. One more reason for not using more water than necessary is to avoid water damage to the construction and other, not fire and smoke affected areas. I think we all can think of fires we´ve been to where the cost of damage from fire fighting is greater than the cost from fire damage. That is of course acceptable when saving lifes but is not the optimal outcome when trying to save property. I have been to a couple of fires, as a chief, where the fire fighters used just enough water to put the fire out and every drop of water evaporated and could be ventilated as steam. That was a very good feeling knowing that no other apartments was affected by fire that with a more aggressive water usage would mean property damage to many more people. I think that is one part of being a good fire fighter. To know when to use much water and when not to do that. This of course takes a lot of training.

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