Penciling is for Drawing a Nozzle Fully Open
When recruit firefighters are told one thing and then shown something different they end up applying what they were shown. I have witnessed numerous occasions in which new firefighters would open the nozzle on an interior attack for about 2 seconds and the then shut it off. This was followed by a couple more short blast also known as penciling. The lack of flow on the fire had very little effect. I could hear these small penciling techniques being applied while watching fire continue to rage from a window or out a roof opening. I would sometimes radio to the interior crew, “Open the nozzle and leave it open!”
This scene played out over and over and I couldn’t justify or understands its origins. Then one day I attended a class in our new flashover container and there I discovered the source. In an attempt to teach the recruits fire behavior using the flashover chamber, the instructors talked about and then demonstrated penciling in the chamber. Some of the instructors even told the students that this was just used in the container but as I started off, we remember what we see and it sticks. Without any previous experiences the new firefighters relate the dangerous flashover situation with what they saw inside in the heat of the moment…..penciling. They take this experience and apply it as soon as they see flames. It is also common in Class A burn buildings for the instructor to only let the student flow water in a quick burst and shut it off so the water will not extinguish the bed of coals we have built up. Once again in our attempt to teach extinguishment we say and practice not extinguishing....go figure.
It takes gallons per minute to put out the fire and get the most bang for the buck. Big fire big water is still true. Do your own research by starting a small fire with 5-6 pieces of paper in a 1-3 gallon metal bucket (follow all NFPA and local safety protocols. Make sure you have a water source, RIT, risk management profile, notify the FAA and make sure not to breathe any of the smoke). Have another 1 gallon bucket full of water ready. First wet your fingers in the water and sling or thump the water off your hands at the fire. As you will see the fire continues to burn. Next try dumping the bucket of water on the burning material and see which one works best.
Sometimes our best intentions can backfire on us if we don’t consider the experience level of the student and understand the impact of the mental slide that is built during our demonstration. Without getting too technical let’s just say that every tactic is situational. Based on my own experiences penciling the nozzle in a typical modern structure fire is sketchy. If you are going to pencil make sure to draw the nozzle fully open and attempt to display between 150-200 gallons per minute.