3 Presentasi - Fire & Explosion

8/11/2019 3 Presentasi - Fire & Explosion

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KELOMPOK:

1. Cinthia Yunitha

2. Irwan Junawanto3. Ronald Sebastian

4. Anindhita Yuriska

5. Mengku Harjanti

6. Muh. Reza Pahlepi7. Gisda Irwanti


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ChainReaction

Fuel O2

Heat

All Elements are required to have afire

Ignition Temperature :Activation energy (heat)

which is needed to activatechain reaction.


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Class IA : Flash point < 22,8oC and boiling point < 37,8oC.

Class IB : Flash point < 22,8oC and boiling point 37,8oC.

Class IC : Flash point 22,8oC and boiling point < 37,8oC.

Class II : Flash point > 37o

C and boiling point < 60o

C. Class IIIA : Flash point 60oC and boiling point < 93,4oC.

Class IIIB : Flash point > 93,4oC.

Flash point :The lowest temperature that will allow a liquid to produce aflammable vapor.


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Classification from forensic standpoint

Natural Fires : Lightning strikes, Natural gasses escapefrom ground.

Accidental Fires : Malfunction of furnace, spontaneouscombustion (cloth+fuel chain reaction).

Deliberate Fires : burn trash, arson.

Classification from fire scene investigator

Direct Ignition : Flameor sparkfuel

Electrical Fires : spark

heat

fuel + O2 Weather-Related Fires : Lightning strikes or magnifying

glass effect.

Mechanical Fires : overheat machines.


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Fire scenes investigator must be aware of :1. Causes of fires.

2. Burning patterns.

3. How different materials react on fire.

4. The characteristic of points of fire origin.

5. How fires normally proceed through a structure.

6. Unusual fire characteristics.

7. The effects of fire suppresion on the scene.The investigator must proceed in an orderly, methodicalway and must make accurate, records of the investigation,examination from outside to inside or the point of origin.


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Arson Dogs:(+)Enable to search for accelerants

much faster and more efficiently.

(-)Cant discriminate between a real

accelerant and a hydrocarbon

that is part of some object and was released by the fire.

Point of Entry and Exit :

In the case of deliberate fire within building, there would be apoint where this person entered the building.

Physical evidence can be found includes fingerprints, shoeprints, hairs and fibers, and even blood.


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Low Burning : start in low area of a building.

V-Patterns : the point of origin near wall or corner of theroom.

Wood Charring : depend on intensitt of heat and time ofexposure.

Spalling of plaster or cencrete : destruction due to heat.

Material Distortion : metal and glass may melt or distort

owing to high heat. Soot and smoke staining : soot may indicate point of origin

and direction of travel of the fire.


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The presence of an accelerant : usually present at or nearthe point of origin.

Elimination of natural or accidental causes of fire.

Fire trails : normally would not be seen in acciedental ornatural fire.

Multiple points of origin.


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Airtight Container

Metal Container : paint cans, glass jar.

Bags :

- Paper bags : cant exposed to water- Polyethylene bags : may be reactive to some

hydrocarbon

- Polyvinylidine bags : impervious to solvents andflammable materials


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Consist of two major steps :1. Isolation of Accelerant Residue

Typical types of exhibits encountered :

Neat Ignitable liquid

Partially burned accelerants Nearly completely burned accelerants

Headspace Methods

The residue is put in a sealed metal

container. The vapor of accelerant can besampled on the headspace with a gastightsyringe.

Fire debris

headspace


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Adsorbtion Methods

Passive adsorption : charcoal or tenax placed inside thecontainer.

Active adsorption (adsorption-elution) : two tubescontaining charcoal or tenax inserted into the containerthrough holes in the top.

Air PumpVacuum

CS2


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Solvent Extraction

Small quantity of suitable solvent (carbon disulfide) added to thecontainer. The solvent is poured off and filtered and then evaporated toa small volume.

( - ) First, the solvent will dissolve unwanted pyrolysis products, matrixmaterials, and other substances. Second, the evaporation steps mayalso evaporate volatile components of accelerant residues.

Filter Accelerant residue


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Steam DistillationThis method is not very sensitive and relatively needed largequantity of matrix and also complicated to run.

2. Determine the type of ignitable liquid

This process involves gas chromatography. The basic analysis ofgas chromatography is the pattern of peaks that is characteristicof the accelerant type.

Mass spectrometry

It provides features in identifying ignitable liqueds presence ofcontaminants or in mixture of multiple ignitable liquids.

Selective ion monitoring

Target compund analysis


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Explosion The Process of internal burning

Rapid oxidation reaction

Production of large quantities of gases

Heat expands gases Sudden build up of gas pressure

Explosive Chemical composition ( solid, liquid, gas)

unstable

Initiated by friction, shock or heat


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Velocity of detonation below 3,280 fps

Produces greater propellant effect and few

blasting effectdisrupts surroundings

Generally sensitive to fire, impact and

friction and are easily initiated


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Black powder Potassium or sodium nitrate Charcoal Sulfur

Pipe bombs Potassium chlorate Fuels

Sugar Carbon Sulfur Starch Magnesium filings


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Smokeless powder

Most powerful

Single base powder

Nitrated cotton or

nitrocellulose

Double base powder

Nitroglycerin and

nitrocellulose


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Ammonium nitrate soaked in fuel oil

Inexpensive

Safe to handle

Ammonium nitrate

fertilizer used

in home-madeexplosives


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Velocity of detonation above 3,280 fps

Extremely rapid oxidation

Accompanied by violent disruptive shock

Disrupts surroundings


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Very powerful dan very sensitive

Provide major ingredients found in blastingcaps or primers used to detonate otherexplosives


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Relatively insensitive to heat, shock, or friction

Normally burn rather than detonate if ignited insmall quantities in the open air

Majority of commercial and military blasting Dynamite

TNT - trinitrotoluene

PETN pentaerythritol tetranitrate

RDX cyclotrimethylenetrinitramine Tetryl 2, 4, 6-trinitrophenylmethylnitramine


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Dynamite: Nobel Nitroglycerine

Kieselguhr(diatomacious earth)

Modern

Nitroglycerine

Wood pulp

Sodium nitrate (oxygen) Stabilizer (calcium carbonate


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Replaced by ammonium nitrate-basedexplosives

Water gels

EmulsionsANFO explosives

Low cost

Very stable


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Set gelatin or gel toothpaste

Water resistant: underwater blasting

Composition

Ammonium nitrate

Sodium nitrate

Gelled with guar gum

Aluminum as fuel


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Oil phase

Water phase

Droplet of supersaturated ammonium nitrate

solution Surrounded by hydrocarbon fuel

Typical Water

One or more inorganic nitrate oxidizers

Oil

Emulsifying agents


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Microspheres/microballoons Micron-sized glass

Resin

Ceramic spheres Control

Sensitivity

Detonation velocity


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Triacetone triperoxideAcetone

Hydrogen peroxide

Catalyst (HCl) Terrorist explosives

Friction sensitive

Impact sensitive Potent in confined container


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Accessible outside US

RDX

Composition

C-4 (US military) Pliable plastic

Dough-like

consistency


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Most important military bursting charge explosive Wide application

Shells Bombs

Grenaqdes Demolition explosives Propellant compositions

Military dynamite No nitroglycerin RDX and TNT

Rarely encountered in US


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Used with TNT

Small caliber projectiles and grenades

Detonating cord/primacord

Connect explosive charges

Detonate immediately


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BOM


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Fragmentation Effect

Thermal Effect


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Undetonated residues at site

Samples taken from

appropriate locations


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Terkena luka, deskripsi lukanya jika jari tangannyahancur?

Cara screening area sekitar ledakan, screening residu

Pmx forensik bekas terkena petir

Proses perubahan2 kulit pada kebakaran

Tanda intravital korban kebakaran msh hidup

Documents

3 Presentasi - Fire & Explosion