Mini blazes show Eastside students how fire behaves
Author: Tammy L. Lane • First Posted: Tuesday, March 05, 2013
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For safety's sake, the students took turns with the firefighting gear.
When the fire truck pulled up outside Eastside Technical Center, it was only a precaution as students did indeed set a dozen small, wooden structures ablaze – all in the name of science and exploration. They safely extinguished the fires themselves.
“In the past couple of weeks my class has been studying fire behavior, which covers the many aspects of how and why fire starts and continues the combustion process,” said Tim Marshall, a homeland security and fire science instructor. “In order to help the students better understand fire in its physical state, we built miniature houses to burn so they could observe and study the effects of how fire responds in different environments and with different materials.”
The houses, also known as burn boxes, were made of 3/8-inch plywood. Some students added individual features such as a sofa fashioned from Popsicle sticks and a tiny cardboard staircase. One was a traditional family home; another was staged as a crime scene; still another was dubbed a “safe house” in Iraq.
“Once we burn them, we’ll take the tops off and look at how the fire spread and see if they can tell where it was set in different rooms. It will be hotter in the room of origin than other rooms throughout the house,” Marshall explained beforehand.
Students had shredded paper and cut scraps of material to add as accelerants.
“Heat, oxygen and fuel make up the fire triangle,” noted sophomore Blake Darland, whose team was among the first to torch their house. “We used acetone, sawdust and fabric, and the smoke spread really quickly.”
Before heading outside amid the snow showers, Marshall recapped the four stages of a fire – incipient (barely starting to burn), growth, fully developed and decay – and reminded students about the threat of flashover and backdraft.
“Once it starts consuming and heating things up, the paralysis of a solid material creates gaseous fumes that then become ignitable,” he said. “Everything has to be the right temperature, right oxygen and right amount of heat, and then a chemical reaction must take place.”
Materials such as couches, flooring and wallpaper ignite at different temperatures and put off heat at different rates.
“Once everything reaches its ignition temperature, the room heats up to 1,000 to 2,000 degrees and then it ignites,” said Marshall, who has 20 years of firefighting experience.
Aaron Sawyers, a junior, expected the heat and the fire to rise inside the house, and that’s what happened in the experiment. “You see how fast it can spread from one room to another,” he said, recognizing the immediate danger not only from flames but also from toxic smoke.
Marshall considered the exercise a useful supplement to his classroom instruction, saying, “Since they can’t go into an actual structure, it allows them to see fire and how it moves on a smaller scale.”