The Science Behind: Extinguishing Flames
When people usually imagine firefighters putting out fires, most of them think about a bulky, devilishly handsome, young male with a fiery desire to help people, someone barging into the flames and rescuing people, grabbing a hose, wildly watering the inferno, and in the process, saving all of humanity.
Though our image of firefighters might be of very passionate men and women who tackle everything head-on with strength and power, the case, in reality, is actually quite different. Firefighters have to use both brain and brawn in order to defeat the wildfires that take place in our communities. They have to think through everything smartly and then take action. Today, in honor of all the firefighters of California, I will be explaining how these heroes battle these wildfires, what processes they have to undergo, how they take action, and much more. Read on to learn more!
The first step to the process is detecting the fire. Firefighters might get an alert from a fire detector or a call from wherever the fire is happening. As soon as they are informed of this, fire crews and helicopters with fire suppression supplies are immediately transported to the location. The fire crew usually consists of about 5-10 people who are accompanied by the IC, or the Incident Commander. The Incident Commander first has to assess the fire and determine whether it should be, “monitored, addressed to protect values at risk, or suppressed” (Environment and Natural Resources). Other than this, the IC has to look at many different factors before coming to a decision. Some of these factors include weather, topography, and fuels, better known as the “three sides of the fire behaviour.” By evaluating these three factors, the IC can determine whether the firefighters should attack indirectly or directly and which supplies they will need in order to diffuse the flames.
Once they have come to a decision, they call their home fire department, inform them of the status, and order the materials.
But how do these firefighters extinguish the flames and what techniques do they use? When I first started researching how firefighters put out fires, I was expecting to read about the use of supplies such as hoses or fire extinguishers that immediately eliminate the fires. But to my surprise, I was wrong! Though this technique might be showcased in shows and books, in reality, firefighters take a much smarter approach to beating these wildfires. Instead of wasting time and resources to extinguish the entirety of the flames, they get rid of the fuels that incite the fires and cause them to spread. Most fires would die down in a couple of days if they weren’t given any fuel, however, more fuel progressively builds up as the fires burn. Firefighters simply get rid of the fuels and restrict other fuels from coming in, which eventually stops the fires. The methods used to remove the fuels differ though, depending on which type of attack the IC suggests to follow.
In indirect attacks, control lines or boundaries for the fire are created first. Once they’ve contained the fire inside the boundaries, they remove any flammable objects around the site. Lastly, they spray the fires with chemicals that help to deflammablize the fuels.
Direct attacks are a lot more dangerous as they involve firefighters entering the fires. The firefighters enter the site when helicopters first spray water/retardant to the flanks of the flames. This cools the sides down enough that the firefighters can enter. Once in the fires, firefighters use specialized hand tools to help dissect and then remove the fuels. If available, water pumps/hoses can also be used to diffuse.
There’s more to come, however! Even after the firefighters have supposedly removed all fuels and flammable objects, there might be some left over that can later evoke more wildfires. To make sure this doesn’t happen, firefighters have to recheck the site again and dispose of any fuels they might find. They first start mopping up by “extinguishing all smoldering material along the fire's edge, ensuring logs/debris cannot roll across the fire line, making sure all burning fuel is burnt out or is spread or buried to stop sparks traveling, clearing both sides of the fire line of snags, rotten logs, stumps, singed brush and low hanging limbs of trees, searching for underground burning roots near the line.” After mopping up, they have to make sure that there aren’t any fuels left. They usually survey the site with an infrared scan, or in extreme cases, use “cold trailing” (carefully inspect all of the premises for heat).
And that is how flames are extinguished! I hope you had fun reading this article and learned something new in the process!