FIRE BEHAVIOR AND THE FIRE TRIANGLE

Kurt Kamm

August 18, 2008

OXYGEN, HEAT and FUEL are referred to at the "Fire Triangle" Take any one of these things away, and you will not have a fire, or it will be extinguished.

Fuel characteristics will determine the fire intensity and rate of spread

FUEL TYPE- grass leaves, brush with high oil content will result in fast burning rapid rates of spread. Heavy fuels like timber have slower rate of spread. Fuels will oil in them burn hotter. Certain brush in California and Australia contains oils which burn at 1400 degrees farenheit.

FUEL MOISTURE – the amount of moisture in the fuels will affect how easily a fuel will ignite and burn. Moisture in dead fuels is obviously lower than in live fuels.

FUEL TEMPERATURE – fuel temperature is changed by solar radiation. There can be as much as a 50 – 80 degree difference between surface temperature of a fuel in the sun and in the shade.

As the sun moves through the sky, the temperature of fuel will change based on which aspect of the land is getting direct sunlight. South and west facing slopes heat up the most because they receive the most direct sunlight during the day. The fuels on these slopes are warmer and drier.

Fire burns faster going uphill because of preheating and the fact that the flames are closer to the fuel. This is how many firefighters are trapped. The steeper the slope, the faster the rate of spread.

WEATHER – Wind, humidity and temperature will affect fire behavior.

Wind is the primary factor. It brings additional oxygen to the fire, flattens flames to bring them closer to the fuel, and causes spot fires by blowing embers ahead of the fire. In times of high winds, (Santa Ana conditions) fire danger is at its highest.

Humidity is the amount of moisture in the air, which affects the moisture in the fuel. At relative humidity of 30% or below – fires are active. At relative humidity of 10% or below, fire danger is CRITICAL

Air temperature has a direct effect on how a fire burns. The hotter the air, the lower the humidity.

EXTREME FIRE BEHAVIOR – Rapid increase in intensity and rate of spread, crown fires (fire in the tops of trees) long distance spotting (fires set by blowing embers well ahead of the main fire), fire whirlwinds.

Fire fighters are warned – "When the fire wants to get up and go, there´s nothing you can do about it, so get out of the way!!"

Kurt Kamm

I have written a novel about wildland firefighters, One Foot in the Black and am currently working on a second novel about an arsonist, Red Flag Warning (More information at http://www.kurtkamm.com)

I am a graduate of Brown University and Columbia Law School and have retired from Wall Street. I spent five years as a masters (55 -60) bicycle racer. I moved to Malibu 5 years ago. The first thing you realize about Malibu, after its beauty, is the fire danger. Every year Malibu has fires. Every 10 years, Malibu has devastating fires. In October and November 2007, we had two terrible fires which destroyed 60 homes. The October fire was driven by 60 m ph winds. It literally burned to my front door. My closest neighbor lost his house and a church nearby was destroyed. I saved my house as a result of the things about firefighting, which I learned while writing my book.

Malibu is full of fire stations and fire camps. Camp 13, a female inmate camp trains women to work on wildland fires. Camp 8, is a helitak camp, where crews train to fight fires using modified Blackhawk helicopters. One day when I was riding my bike home, I passed Pepperdine University and saw an LA County Fire helicopter on the lawn, with several firefighters standing around it. I wondered what their lives were like and thought I would write a book about it.

I have been fortunate to have access to all the fire stations, camps and training academies of LA County as well as CalFire (CA state fire agency). My book tells the story of a boy from Michigan who is forced out of his home by an abusive father. He comes to California and becomes a firefighter. His role model and mentor is killed in a wildfire burnover. He struggles to cope with his father's influence on his life and the loss of his mentor. While the book is complete fiction, it is based on real situations and people involved in firefighting in California. One foot in the black is a wildland firefighter's phrase. It refers to a position on the fireline, which is next to an area already burned ("the black"). It is at once the most dangerous place, usually close to the flames, and the safest place, near a zone into which escape is possible.

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