Dunn’s Dispatch: Conflagrations

By Vincent Dunn

Do you really know what the word “conflagration” means? The traditional, historical, and academic definition of conflagration states it is a “major building-to-building fire involving many structures and/or spreading flame over a large area.” Another term, “group fire,” describes a major fire that requires multiple alarms of firefighters to extinguish. A group fire, which is not as large as a conflagration, is defined by fire protection engineers as a “major building-to-building fire involving many structures, spreading flame over a large area.” However, a group fire is limited within the boundaries of an industrial complex, within one city block, or some man-made boundary. The difference between a conflagration and a group fire is the area of fire spread.

The conflagration spreads over a larger area and jumps fence boundaries, goes beyond a city block of buildings or across streets, waterways, and any man-made fire breaks such as large avenues and open design spaces. The group fire is a large fire that spreads from building to building; however, it is limited by a man-made boundary. An entire industrial park could burn down; including several building in a fenced-off area, and it would be considered a group fire, not a conflagration.

A third classification of a major fire is a “large-loss fire,” which is neither a conflagration nor a group fire. A large-loss fire is defined by the insurance industry as a fire that causes $5 million or more of direct property loss. This dollar amount increases with inflation. The definition of a large-loss fire used to be considered a fire creating more than $250,000 of direct fire loss–structure or content. This definition changes and may soon change to $10 million of direct fire loss. It fluctuates and is adjusted for inflation.

Today’s most common conflagration is a wildfire. The classic conflagration of the last century, in which flames spread across narrow city streets to closely packed manufacturing buildings, is rare. This is because today fire departments protect large cities and sprinkler systems protect most large commercial buildings. Today’s conflagration is a forest or woodland fire, also called an urban/wildland interface fire. This strange term is fire service jargon used to describe a “conflagration in a forest, or woods which spreads to houses, mobile homes, camp grounds, and parked vehicles for miles.” The last conflagration in New York City was an urban/wildland interface fire. On April 23, 1963, a wildfire spread over four square miles and destroyed 100 houses in the borough of Staten Island.

For more information on this subject, go to vincentdunn.com or Google search “conflagrations.” Chief Dunn can be reached at 1-800-231-3388 or via e-mail at vincentdunn@earthlink.net.

Deputy Chief Dunn (Ret., Fire Department of New York) is the author of a number of textbooks, including the new Strategy of Firefighting (Fire Engineering, 2007), Collapse of Burning Buildings (Fire Engineering, 1988), Safety and Survival on the Fireground (Fire Engineering, 1992), and Command and Control of Fires and Emergencies (Fire Engineering, 1999).

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