The knock down strategy is employed when firefighters decide that a certain hotspot needs to be suppressed immediately. To diminish the section of a fire deemed to have grown too hot, too active, or too large, fighters directly apply some combination of dirt, water, or retardant to that section.
What does throwing dirt on a fire do?
Water or dirt should be directly applied on the fuels being consumed to reduce fuel temperature. Flames are actually the burning gases liberated by the heated fuels. Water, dirt, foam and retardants will reduce the supply of oxygen for the combustion process.
What do firefighters use to put out forest fires?
Firefighters control a fire’s spread (or put it out) by removing one of the three ingredients fire needs to burn: heat, oxygen, or fuel. They remove heat by applying water or fire retardant on the ground (using pumps or special wildland fire engines) or by air (using helicopters/airplanes).
Why do firefighters dig trenches?
Why we dig lines
We do that by digging line — essentially a trench several feet wide — around the perimeter of the fire. “We’re supposed to remove any fuel that could burn within the fireline,” Washington wildland firefighter Ryan Dahl explained during a training exercise earlier this year.
How do you fight a fire?
In order to fight a fire, you must take out any one of the fire elements. The most common method is to use water to put out the fire. The water takes away heat by cooling the fire. Water also smothers the fire, taking away oxygen.
How is fire containment calculated?
Containment, normally expressed as a percentage, indicates how much of the fire has been enclosed by a control line. A wildfire with 25 percent containment means control lines have been completed around 25 percent of the fire’s perimeter.
What does 100 contained fire mean?
When officials say a fire is 100 percent contained, that doesn’t mean it has been extinguished. It means only that firefighters have it fully surrounded by a perimeter.