Firehouse

JAN 2017

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reduced and the volume of steam is added to the hot gases, increasing the total volume. How much water is vaporized in the hot gas layer is dependent on many fac- tors including, droplet size and velocity as well as compartment geometry. Effective use of water fog for gas cooling can result in a contraction of hot gases, decrease the flammability of the fire gases by dilution and addition of thermal ballast. This is why I decided to say in the title that "sometimes less is more." What needs to be remem- bered is that this requires a conscious action, good selection of equipment and thorough training. In such conditions gas cooling is effective. We made some mistakes. Let us remember that fog should evaporate in gases (contracting them) and not on surfaces, only creating steam and adding to the volume. In our burn, we were not able to avoid that, and that is something we would like to correct the next time. Nevertheless, the graph shows that the technique worked quite nicely. If we look in literature, we will find that approximately 30 percent of water should evaporate in gases to maintain a relatively constant volume inside an enclosure. If the ratio is more, the volume will contract. If it is less, it will expand. I think it is a comfort- able value to keep in one's mind. While we always try for things to work as best as they can, if we are not always super precise, our goals should be achieved anyway. In sum There are many interesting solutions out there and all have their place in firefighting. We must never stop learning to be profes- sional and to serve our citizens to the best of our abilities, keeping in mind that our own safety should not be disregarded as well. To see the stunning effects of gas cooling with fog, please go to my You Tube channel (Szymon Kokot-Gora) and watch the video with a 110-psi (European standard) 50-gpm fog nozzle attached to a 2-inch handline. At 8:10, the effect of gas cooling pulls the door inside a room. While this deliberate effect was a result of testing and is not likely to be repeated exactly in real-life situations, it proves beyond any doubt that skillful gas cooling can, in some situations, bring amazing effects. You may think I am "one of those fog nozzle zeal- ots" who cannot be told otherwise. On that same YouTube channel, you will find us training with a stacked tip smoothbore noz- zle (50–80 psi, 210–416 gpm). I see abso- lute value in that because IT WORKS for me in some fireground situations, just like fog does in SOME OF THEM. I encourage you to examine my claims. Just like myself with the smoothbore, I think some of you will be surprised with the outcomes. I would like to thank Ed Hartin for his help with editing this article as well as his ongoing support. n References Grimwood, P., Hartin, E., McDonough, J., Raffel, S. "3D Fire Fighting: Training, Techniques & Tactics." 2005. Särdqvist, S. "Water and Other Extinguish- ing Agents." Swedish Rescue Services Agency. 2002. Lanca ganicza Mist-er Kiler: http://tinyurl. com/intl-exch-jan17. Request information at Firehouse.com e-inquiry CHECK OUT OUR NEWLY REDESIGNED WEBSITE Complete with Information, Products and Videos! marsars.com 866-426-2423 Modern Ice Rescue Sled While laying 6' from victim, empty sled becomes a self-rescue reaching device. With victim's forearms through sling, shore personnal gently pull patient aboard and back to safety. Request information at Firehouse.com e-inquiry OnSceneSolutions.com CARGO SLIDES Aluminum Cargo Slides from OnScene Solutions are built to withstand abuse in the most demanding environments and offer features not found anywhere else! The easy release latch designed for gloved hands along with smooth rolling urethane wheels allow effortless access to up to 1000 lbs. of equipment. All OnScene Cargo Slides include a Lifetime Warranty! January 2017 l Firehouse l 45

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