Fire Behavior: Flashover and Backdraft

Convection is the transfer of heat by direct contact between two bodies.

Good heat conductors include wood and fibrous materials.

Radiation is the transmission of energy with an intervening medium.

Conduction speed is not dependent on the conductivity of the material.

Convection heat currents are generally the cause of heat movement from wall to wall.

Radiated heat is not a major source of fire spread.

Flashover can occur spontaneously and slowly with a release of dangerous amounts of heat.

During the fully developed phase of a fire, oxygen is consumed slowly and the heat produced is minimum.

Once the decay phase of a fire is reached, the room will be filled with fresh air and clear gases.

Rollover occurs when burned combustible gases accumulate at the ceiling.

Flashover is the transition from the growth phase to the decay phase of a fire.

Flame breaks out over the surface of contents involved in the fire during rollover.

Positive Pressure Ventilation (PPV) fans can only be used in horizontal positions.

Negative Pressure Ventilation (NPV) uses smoke injectors to remove smoke from a structure.

Hydraulic Water fog spray is typically applied in a 30 degree fog pattern.

Ventilation helps in speeding up the spread of fire.

Equipment fires in mines should always be fought by mine rescuers, regardless of their competence level.

Being aware of fuel and lubricant volumes is important when dealing with hazards in equipment fires.

Dense black smoke is a sign of flashover.

Backdraft usually occurs during the growth phase of a fire.

Impending backdraft is signaled by visible flames and clear smoke.

Thermal layering is caused by conduction and is known as heat stratification.

The hottest gases in thermal layering accumulate at lower levels.

Proper ventilation disrupts thermal layering when water is applied directly into the layer.

The handle of an extinguisher is used to expel the agent.

All cartridge extinguishers have a pin that indicates pressurization.

Poorly timed or located ventilation can make a fire easier to control.

Proper ventilation can help mine rescuers find trapped individuals more safely during a fire.

The pressure indicator on stored-pressure extinguishers shows the pressure of the extinguishing agent stored.

Label on an extinguisher indicates only the classification of the agent but not the maintenance instructions.