Classifications of Fires
Determining the cause of a fire is the principal task of a fire investigator during the conduct of a post-fire examination of a fire scene.
To do this, an investigator will want to locate the point of origin of a fire. If the point of origin of a fire cannot be identified or if it is determined that it started over a larger area, the term area of origin is used.
From there, a detailed inspection of the area can lead the investigator to the exact cause of the fire. This inspection is done by examining the charred debris and other residues found at the point of origin.
Fires can be classified in two ways: according to cause and according to burning fuel.
Based on Cause
These can be used to classify both causes of fires and fires themselves.
Natural
These fires involve events that are sometimes called "Acts of God". The most famous example of natural fires are wildfires.
BBC Earth Unplugged | What Causes Wildfires? (Note: In addition to natural fires, video shows other causes of wildfires.)
As discussed in the video, wildfires can be caused by lightning, lava, or earthquakes. These are natural events that occur with no human intervention.
Accidental
- Electrical Accidents
- Short Circuit
Interesting Engineering | Short Circuits - when electricity goes wrong
- Arcing
Northwest Lineman College | Anatomy of an Arc
- Sparking
Slow Motion | Electrical Wires Sparking ( Slow Motion )
- Induced Current Sudden release of electrical current
- Overheating Rising temperatures in an electric circuit beyond that which is tolerable by the device
NITE Official | 【nite-ps】Electric fan:4.A fire starting from an electric fan during sleep
- Pure Accidents
- Negligence and other forms of human error
Intentional (Incendiary)
Fires can be identified as intentional if the following are found at the scene:
- accelerants highly flammable chemicals that are used to facilitate flame propagation
- plants combustible materials gathered or prepared at the scene that are utilized to start a fire
- trailers prepared flammable substances that are used to spread fires
Based on Burning Fuels
These types of fires are based on the types of fuels that were discussed in a previous lesson.
- Class A Fire Ordinary Fires
- Class B Fire Liquid Fires
- Class C Fire Electrical Fires
- Class D Fire Metallic Fires
- Class K Fire Kitchen Fires