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Penciling?
Anyone practice penciling? I don't see the point, but I'm stoopid, so I figured I would get other people's opinions. If you think it has a place, please be specific.
Until recently, I never heard of it, but apparently it is used alot in Europe, and it is a tactic where you briefly blast rollover on the ceilings with a STRAIGHT stream to disrupt the thermal layer just enough to keep the flames from attaching to the ceiling - and you do this on your way to the seat of the fire. *IF* I'm understanding it correctly. I saw a video of it, but can't find one on the Internet to share with you guys.
The commonly held opinion here seems to be that there is no point to penciling, and it's better to not waste time getting to the seat of the fire.
Note: blasting rollover with a fog pattern can get someone killed, so don't do it.
Until recently, I never heard of it, but apparently it is used alot in Europe, and it is a tactic where you briefly blast rollover on the ceilings with a STRAIGHT stream to disrupt the thermal layer just enough to keep the flames from attaching to the ceiling - and you do this on your way to the seat of the fire. *IF* I'm understanding it correctly. I saw a video of it, but can't find one on the Internet to share with you guys.
The commonly held opinion here seems to be that there is no point to penciling, and it's better to not waste time getting to the seat of the fire.
Note: blasting rollover with a fog pattern can get someone killed, so don't do it.
Replies to This Discussion
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Permalink Reply by John on
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We were told that it is used for the rollover of the flame and to help cool the air above and to possibly prevent a fire from flashing over. We have done it during practise fires.
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Permalink Reply by Sarah Turner on
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We trained on it on a regular basis up north.
Likewise with what John says, it also keeps the fire from getting behind you
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Permalink Reply by Rescue601 on
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It is a tactic that is taught and used in all the rollover props that I have ever encountered and thus I have seen it in action and it works. You should never fog in a structure that isn't vented unless you want to be steamed.
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Permalink Reply by Dean on
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Penciling is a great thing to do when you got rollover( or sometimes referred to as flameover) coming at ya over your head.
Now lets start explaining this with NFPA 921 definition of flameover "The condition where unburned fuel (pyrolysate) from the originating fire has accumulated in the ceiling layer to a sufficient concentration (i.e., at or above the lower flammable limit) that it ignites and burns; can occur without ignition and prior to the ignition of other fuels separate from the origin."
What penciling does is that when the water you hit the ceiling with evaporates it converts to steam. When liquid water converts to steam it expands its volume by approximately 1700 times. This in turn adds to the hot gases and by products of combustion and hopefully is enough to take the atmosphere below their lower flammable limit.
It also does cool the atmosphere down. 5 gallons of water to be converted to steam from a liquid state that is already @ 100 degrees celcius takes 42747.5 Kilo Joules of heat energy to convert to steam. That is alot of heat energy your taking from the heated unburned combustion products and heated gases to convert that water to steam.
Now why do you want stop rollover/flameover from happening if it is only unburned byproducts of combustion in the atmosphere and not the structure itself?
Ok so flameover is actual flame in the atmosphere in the upper layer. Flame temps are approximately 1000 degrees Celsius. The smoke and gases in the upper layer are somewhere below 600 degrees Celsius (A technical indicator for a flashover to occur in a compartment is if the upper layer temperature reaches an average of 600 degrees Celsius so if your in there it's below 600 degrees if your in there and its over 600 degrees your prolly not gonna come out)
Now what would you rather have in that atmosphere radiating energy into the lower layer heating all the fuel (couches, tables, toys, tv's, carpet, and other furniture that is not yet on fire in the compartment, AND YOU if your in that compartment) in the lower layer and starting to cause it to pyrolyze (The destructive distillation of organic compounds in an oxygen-free environment that converts the organic matter into gases, liquids, and char. NFPA) into combustible gases? A 1000 degree Celsius flame puts out alot more radiant heat to heat up the fuels in the lower layer than the less than 600 degree layer(not gonna go over the whole calculation for calculating radiant heat unless you really want me to, but for now just take my word for it). Also when you introduce that water into the atmosphere and convert it to steam that layer is gonna cool down some. Penciling the flameover is a good way of giving yourself time to Vent the compartment of the heated gases and to extinguish the fire before the unburned fuels begin to pyrolyze and a flashover occurs but rollover/flameover is a real good indicator that the upper layer is getting near that 600 degrees Celsius where its radiating enough heat to cause a flashover.
NOTE: Too much water in the upper layer IS a BAD thing. Remember water expands 1700 times. That added volume to the upper layer is gonna expand the upper layers volume and the only place the upper layer has to go, is down. Too much water and you cause the upper layer to come right down on you and all that steam around you is like a lobster a Seafood Restaurant and we don't want any of that.
Questions? Comments? Stupid Remarks?
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Permalink Reply by Ben Waller on
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We use it occasionally. If you have either rollover or "Black Fire" over your head, a short "pencil" burst can inject enough moisture into the smoke/incipient flashover to prevent ignition. You don't want to cool the smoke enough to disrupt the thermal balance, thus the short bursts. You also don't want to move change the smoke movement, thus the use of straight or smooth-bore streams and not fog.
The reason that my department doesn't pencil much is due to three things...
1) We generally have short response times and catch the fires in the incipient stage, so we don't see a lot of rollover/Black Fire situations.
2) We have a lot of sprinklered buildings so the fire is often extinguished on arrival.
3) When we do have a working fire, it's often a well-involved delayed alarm in lightweight construction. When the fire is already flashed over, it's time for Big Water, not penciling.
If the fire hasn't progressed to the truss void, vertical ventilation directly over the fire can be at least as effective as penciling.
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P.S. Penciling can also be used to prevent autoignition of Black Fire if you're retreating or being driven out of the building.
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Permalink Reply by Jenny Holderby on
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I haven't heard it called "penciling" but I agree with the clockwise or Z pattern. Thanks Ted.
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Permalink Reply by PFC Harmon on
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Like everyone else has said I have used and it and trained on it but have never heard it reffered to as "penciling".
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Yeah, our community hates it when our local economy doesn't go up in smoke every few days :-)
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The term allegedly came from punching holes in a piece of paper with a pencil, then quickly removing the pencil. Supposedly, penciling a straight stream into overhead smoke and heat is a similar technique.
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Permalink Reply by Joey "BigShow" De Piano on
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I have heard of it but have no other info on it either , I can tell you in 91 in the academy we did learn a practice like that they called it peppering same principal it sounds like but it was dropped due to the fact once that ther balance came back you were 9 out of 10 times going to be killed. If memory serves right , it was thought of to help find the seat of fire with little water damage to home and prevent pushing the fire...don't quote me on that though
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Permalink Reply by Joe Stoltz on
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I have heard that one technique for using a smooth bore nozzle involves directing the stream at the ceiling and sweeping it back and forth. I can see this doing two things - first, cooling the upper layers to prevent or kill flameover action, and the second involves the water bouncing off of the ceiling to rain down on the seat of the fire.
I've personally not done this, since I'm a combination nozzle type myself. Anyone else heard of this?
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