Flash fire
Encyclopedia
A flash fire is a sudden, intense fire
caused by ignition of a mixture of air and a dispersed flammable substance such as a solid (including dust
), flammable or combustible liquid (such as an aerosol or fine mist), or a flammable gas. It is characterized by high temperature, short duration, and a rapidly moving
flame
front.
2113 as:
, typically flammable gas or dust, is mixed with air in concentrations suitable for combustion.
In a flash fire, the flame spreads at subsonic
velocity, so the overpressure
damage is usually negligible and the bulk of the damage comes from the thermal radiation
and secondary fires. When inhaled, the heated air resulting from a flash fire can cause serious damage to the tissue of the lung
s, possibly leading to death by asphyxiation. Flash fires can lead to smoke burn
s.
Flash fire is a particular danger in enclosed spaces, as even a relatively small fire can consume enough oxygen and produce enough smoke
to cause death of the persons present, whether by asphyxiation or by smoke inhalation
.
Protective clothing made of fire-retardant material
s (e.g. Nomex
) reduces or prevents thermal injury in the body areas that are covered by the fire-retardant material. Even normal clothing can provide partial protection.
where the presence of ignition sources such as electrical instruments or laser
s, an oxygen-rich environment, and flammable vapors (e.g. alcohol
-based disinfectants) may set the stage for such an accident. While apparently smaller fires go unreported, surgical flash fires have led to burn injuries and fatalities.
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
caused by ignition of a mixture of air and a dispersed flammable substance such as a solid (including dust
Dust
Dust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
), flammable or combustible liquid (such as an aerosol or fine mist), or a flammable gas. It is characterized by high temperature, short duration, and a rapidly moving
Flame speed
The flame speed is the measured rate of expansion of the flame front in a combustion reaction. Whereas flame speed is generally used for a fuel, a related term is explosive velocity, which is the same relationship measured for an explosive. Combustion engineers differentiate between the laminar...
flame
Flame
A flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...
front.
Definition
A flash fire is defined by CGSB 155.20-2000 and NFPANational Fire Protection Association
The National Fire Protection Association is a United States trade association that creates and maintains private, copywrited, standards and codes for usage and adoption by local governments...
2113 as:
- “A rapidly moving flame front which can be a combustion explosion. Flash fire may occur in an environment where fuel and air become mixed in adequate concentrations to combust...flash fire has a heat fluxHeat fluxHeat flux or thermal flux is the rate of heat energy transfer through a given surface. The SI derived unit of heat rate is joule per second, or watt. Heat flux is the heat rate per unit area. In SI units, heat flux is measured in W/m2]. Heat rate is a scalar quantity, while heat flux is a vectorial...
of approximately 84 kW/m2 for relatively short periods of time, typically less than 3 seconds.”
Characterization
Flash fires may occur in environments where fuelFuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
, typically flammable gas or dust, is mixed with air in concentrations suitable for combustion.
In a flash fire, the flame spreads at subsonic
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....
velocity, so the overpressure
Overpressure
The term Overpressure is applied to a pressure difference, relative to a "normal" or "ambient" pressure, in various circumstances:* In engineering: the pressure difference over the wall thickness of a pressure vessel...
damage is usually negligible and the bulk of the damage comes from the thermal radiation
Thermal radiation
Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation....
and secondary fires. When inhaled, the heated air resulting from a flash fire can cause serious damage to the tissue of the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s, possibly leading to death by asphyxiation. Flash fires can lead to smoke burn
Smoke burn
Smoke burns are burns that tend to be caused as a result of flash fires, both in house fires and in small chemical fires. These can be made to be more severe by a large presence of atmospheric humidity. These burns tend to occur at a temperature of about 121 °C / 250 °F...
s.
Flash fire is a particular danger in enclosed spaces, as even a relatively small fire can consume enough oxygen and produce enough smoke
Smoke
Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...
to cause death of the persons present, whether by asphyxiation or by smoke inhalation
Smoke inhalation
Smoke inhalation is the primary cause of death in victims of indoor fires.Smoke inhalation injury refers to injury due to inhalation or exposure to hot gaseous products of combustion. This can cause serious respiratory complications....
.
Protective clothing made of fire-retardant material
Fire-retardant material
A fire resistant material is one that is designed to resist burning and withstand heat. It is used in the bunker gear worn by firefighters to protect them from the flames in a burning building. Most auto racing drivers also wear fire-retardant materials in case their car catches fire...
s (e.g. Nomex
Nomex
Nomex is a registered trademark for flame resistant meta-aramid material developed in the early 1960s by DuPont and first marketed in 1967.- Properties:...
) reduces or prevents thermal injury in the body areas that are covered by the fire-retardant material. Even normal clothing can provide partial protection.
Surgical flash fire
Small flash fires can occur in the operating room during surgerySurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
where the presence of ignition sources such as electrical instruments or laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s, an oxygen-rich environment, and flammable vapors (e.g. alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
-based disinfectants) may set the stage for such an accident. While apparently smaller fires go unreported, surgical flash fires have led to burn injuries and fatalities.
See also
- Fuel-air explosiveFuel-air explosiveA fuel-air explosive device consists of a container of fuel and two separate explosive charges. After the munition is dropped or fired, the first explosive charge bursts open the container at a predetermined height and disperses the fuel in a cloud that mixes with atmospheric oxygen...
- FireballFireballA fireball is a somewhat spherical mass of fire, such that is caused by an explosion or a firestorm.It may also refer to:- Science and technology :* Ryan FR Fireball, an American aircraft* Fireball , a sailing boat...
- Trench effectTrench effectThe trench effect is a combination of circumstances that can rush a fire up an inclined surface. It depends on two well-understood but separate ideas: the Coandă effect from fluid dynamics and the flashover concept from fire dynamics....
- BLEVEBLEVEA boiling liquid expanding vapor explosion occurs when a vessel containing a pressurized liquid above its boiling point ruptures.-Mechanism:...
- Vapor cloud fire
- FlashoverFlashoverA flashover is the near simultaneous ignition of most of the directly exposed combustible material in an enclosed area. When certain organic materials are heated they undergo thermal decomposition and release flammable gases...
- ExplosionExplosionAn explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
- Flash floodFlash floodA flash flood is a rapid flooding of geomorphic low-lying areas—washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a storm, hurricane, or tropical storm or meltwater from ice or snow flowing over ice sheets or snowfields...
- Air Canada Flight 797Air Canada Flight 797Air Canada Flight 797 was a scheduled trans-border flight that flew on a Dallas/Fort Worth-Toronto-Montreal route. On , the aircraft developed an in-flight fire behind the washroom that spread between the outer skin and the inner decor panels, filling the plane with toxic smoke...
- The Station Nightclub FireThe Station nightclub fireThe Station nightclub fire was the fourth deadliest nightclub fire in American history, killing 100 people. The fire began at 11:07 PM EST, on Thursday, February 20, 2003, at The Station, a glam metal and rock n roll themed nightclub located at 211 Cowesett Avenue in West Warwick, Rhode Island.The...