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21 Cards in this Set
- Front
- Back
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Four examples for fire causes |
1. natural 2. accidental 3.incindary 4.undeterimined |
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Definition of NFPA 921 |
A fire or explosion investigation is a complex endeavor involving both art and science. The compilation of factual data, as well as an anysis of those facts, should be accomplished objectively and truthfully. the basic methodology of the fire investigation should rely on the use of systematic approach. |
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characteristics of High explosives |
*detonates at a velocity above 3300Ft/s *Support a detonation wave *usually initiated with a detonator or booster *no confinement is required for detonation |
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Charactireristics of low explosives |
*Their Velocity is less than the speed of sound *Reactions are subsonic *They cannot support a detonation wave *the material is usually a mixture or a molecule propellant such as smokeless powder. *confinement is required for explosion |
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High explosive definition |
is an explosive compound or substance that supports a detonation wave, irrespective of the ambient condition of confinement.
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low explosive definition |
are usually solid mixtures of chemicals, which under no condition can support a detonation wave. |
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four Types of explosions ? |
*mechanical *Chemical *Nuclear *electrical |
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mechanical explosion example1 |
is characterized by a gradual buildup in pressure until that pressure overcomes the confinement vessel causing a mechanical rupture of the vessel. |
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Chemical explosion |
the rapid change of a solid, liquid, or gas to gases. |
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Nuclear explosion |
is induced by either fission (the splitting of an atom) or fusion (the joining of an atoms.) |
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Electrical Explosion |
is the result of a high energy electrical arch. |
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How are explosives accounted for ? |
1. Date-plant-shift-code- a code that is printed on all manufactured high explosives. 2. taggerts- indivudual disks with the a color to indicate the batch that it was from. like a id tag for taser deployment. 3. scent inbeded in material for detection of explosives.
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mechanical explosion example 2 |
Boiling - liquid expanding vapor explosion (BLEVE)
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Four types of explosion effects |
1.Blast pressure 2. Thermal 3. Fragmentation 4.ancillary |
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Blast pressure |
The first effect of an explosion is the expanding product gases rush out to produce a shock front. |
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Thermal heat effect |
positive blast pressure rising from the epicenter, and the of the blast pressure |
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Primary explosive characteriistics |
*undergo a DDT *they are the most sensitive type of explosive *they are classified as High explosive *they have less energy than secondary explosives *They are used in detonators and initiation systems. examples: Lead azide, Lead styphnate, mercury fulminate |
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Secondary explosive charatacteristics |
*They are more powerful then primary explosives. *They are less sensitive to intiation than primary explosives. *they require a booster, a detonator, or both to function. They are used in large quantities than primary explosives. examples: ANFO, Dynamite, water gel, Emulsion. |
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Types of low explosives |
1. Black powder 2. pyrodex 3. photoflash powder 4.smokeless powder
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Types of high explosives - Primary explosives |
1. Lead Azide 2. lead styphnate 3. Mercury Fulminate 4. DiaZodinitrophenol 5. Tetrazene |
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Types of explosives -secondary explosives |
1. ammonuium nitrate 2. Ammounium nitrate and Fuel oil (ANFO) 3.Nitroglyicerin 4. Dynamite
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