Post by SOL Owner on Nov 28, 2013 8:15:03 GMT -6
HOW FIRE WORKS
The Basic Elements of Fire
The Fire Triangle
The Fire Triangle is a simple way of understanding the factors of fire. Each side of the triangle represents one of the three ingredients needed to have a fire – oxygen, heat, and fuel – demonstrating the interdependence of these ingredients in creating and sustaining fire. When there is not enough heat generated to sustain the process, when the fuel is exhausted, removed, or isolated, or when oxygen supply is limited, then a side of the triangle is broken and the fire will die.
Heat
A heat source is responsible for the initial ignition of fire, and heat is also needed to maintain the fire and permit it to spread. Heat allows fire to spread by removing the moisture from nearby fuel, warming surrounding air, and preheating the fuel in its path, enabling it to travel with greater ease.
Fuel
Fuel is any kind of combustible material, and is characterized by its moisture content (how wet the fuel is), size and shape, quantity, and the arrangement in which it is spread over the landscape. The moisture content determines how easily that fuel will burn.
Oxygen
Air contains about 21% oxygen, and most fires require at least 16% oxygen content to burn. Oxygen supports the chemical processes that occur during a wildland fire. When fuel burns, it reacts with oxygen from the surrounding air releasing heat and generating combustion products (i.e. gases, smoke,embers). This process is known as oxidation.
11 facts about wildfires
•A wildfires (AKA forest or peat fires) are uncontrolled fires. Often wildfires occur in wild, unpopulated areas, but they can occur anywhere and destroy homes, agriculture, humans, and animals in their path.
•Firefighters refer to these disasters as surface fires, dependent crown fires, running crown fires, spot fires, and ground fires.
•“Running crown fires” are a firefighter’s worst nightmare because they burn extremely hot, travel rapidly, and can change direction quickly.
•The most dangerous aspect of running crown fires are the convection currents which produce massive fire storms and tornadoes. These subsequent storms can send embers well ahead of the main fire front, causing spot fires that in turn can start new fires in other directions.
•Weather conditions can directly contribute to the occurrence of wildfires through lightning strikes or indirectly by an extended dry spell or drought.
•Wildfires can be caused by an accumulation of dead matter (leaves, twigs, and trees) that can create enough heat in some instances to spontaneously combust and ignite the surrounding area.
•Lightning strikes the earth over 100,000 times a day. 10 to 20 percent of these lightning strikes can cause fire.
•The number one reason for wildfires in the U.S. is mankind. Man-made combustions from arson, human carelessness, or lack of fire safety cause wildfire disasters every year.
•More than 80 percent of all wildfires are started by humans.
•An average of 1.2 million acres of U.S. woodland burn every year.
•A large wildfire — or conflagration — is capable of modifying the local weather conditions (AKA producing it’s own weather).
more info about wildfires
environment.nationalgeographic.com/environment/natural-disasters/wildfires/