Chapter 2.2: Understanding Fire Behavior - Fire Protection Engineering
Posted by Arowosegbe Olawale in General
Heat Transfer in Fires
Heat transfer is a fundamental aspect of fire behavior. There are three primary methods of heat transfer in fires:
- Conduction: Heat transfer through direct contact between materials. It occurs when heat moves through solid objects, heating adjacent materials.
- Convection: The transfer of heat through the movement of hot gases. Convection currents carry heat to other areas.
- Radiation: The emission of heat energy in the form of electromagnetic waves. Radiant heat can travel through a vacuum and does not require a medium.
Fire Plumes and Smoke
As a fire burns, it generates a plume of hot gases and smoke. Understanding the behavior of this plume is essential for designing effective smoke control and evacuation systems. The plume rises due to buoyancy and can influence fire spread and smoke movement within a structure.
Smoke: Smoke is a complex mixture of gasses and particulate matter produced during combustion. It is a significant fire hazard due to its toxicity, obscuration of vision, and potential for rapid spread.
Flame Spread and Flashover
Fire behavior is also influenced by flame spread and flashover:
- Flame Spread: This refers to the rate at which flames advance across a surface, such as a wall or ceiling. It can vary based on the type of fuel and the conditions.
- Flashover: Flashover is a critical event in fire development. It occurs when the contents of a room or space reach a high temperature, causing all flammable materials to ignite simultaneously. Flashovers lead to a rapid increase in fire size and intensity.