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Fire Technology and Investigation

Fire - exothermic reaction involving the oxidation of some substance (fuel) resulting in the

release of energy in the form of light and heat.

Fire Quadrangle

1. Fuel2. Oxygen3. Heat4. Ignition energy

Triangles of Fire

1. Fuel2. Oxygen3. Heat- removal of any of these results in the suppression of the fire.

Some major products of combustion

1. water2. carbon dioxide3. carbon monoxide4. oxides of sulfur

Definition of terms

1. Vapor Density - the density of the vapor relative to the density of air and is calculated bydividing the molecular weight of the gas by that of air.

2. Flash point - the lowest temperature at whichliquid fuel produces a flammable vapor.

3. Fire point/flame point - the lowest

temperature at which liquid fuel produces aflammable vapor in sufficient quantity such that

if a source of ignition is introduced, the vapor

will ignite and is usually a few degrees abovethe flash point

4. Ignition/auto-ignition temperature - the temperature at which a fuel will

ignite on its own with out any additional source ignition.5. Thermal inertia - the ease at which a material can be ignited.

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6. Heat release rate - is a measure of the amount of energy a specific type offuel can contribute to the heat flux in a fire.

7. Heat transfer - the mechanism in which fire can spread from its origin to

other sources of fuel.

Methods of heat transfer

1. Conductive/conduction heat transfer - heat is transferred by direct contact and the rateof transfer is dependent on factors such as the thermal conductivity of the material and

the temperature difference between the cooler and warmer areas.

2. Convective/convection heat transfer - transfer of heat through physical movement ofmaterials and occurs only in liquids and gases. Hot gases rise and spread heat to nearby

ceilings and walls.

3. Radiative/radiation heat transfer - heat is transferred if the form of electromagneticenergy directly from one object to another. ex. infrared radiation from the sun.

8. Combustion - or burning - is the sequence of exothermic chemical reactionbetween fuel and an oxidant accompanied by the production of heat andconversion of chemical species. The result of the heat can result in the

form of either glowing or flame.

Glowing combustion - occurs when solid fuels are not capable of producing sufficientquantities of gas during pyrolysis to sustain a flame. If access to the oxidant (air) is

limited, glowing combustion may result.

Flaming combustion -commonly recognized type of fire and occurs with gaseous fuelsources only. The color of the flame can give some indication of the composition of the

fuel.

Spontaneous combustion - the ignition of organic matter with out apparent cause,typically through heat generated internally by rapid oxidation.A process whereby a

material self heats.

Explosive combustion - can occur when vapors, dust of gases, premixed withappropriate amount of air are ignited.

Definition of Terms:

Arson - intentional or malicious destruction of property by fire.

Fire analysis - the process of determining the origin, cause and responsibility as well as thefailure analysis of fire or explosion.

Fire cause - the circumstances or agencies that bring a fuel and an ignition source together with

proper air or oxygen.

Fire spread - the movement of fire from one place to another.

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Flash fire - a fire that spreads with extreme rapidity such as the one that races over dust, over thesurface of flammable liquids or through gases.

Fuel load - the total quantity of combustible contents of the building, spaces or fire area,

including interior finish and trim expressed in heat units or the equivalent weight in wood.

Point of origin - the exact physical location where a heat source and fuel comes in contact with

each other and a fire begins.

Rekindle - a return to flaming combustion after incomplete extinguishment susc as a fire

reigning at some time after being put out.

Spalling - chipping or pitting of concrete or masonry surfaces.

Definition of terms - (RA no.9514)

Abatement - any act that would remove or neutralize fire hazard.

Administrator - any person who acts as agent of the owner and manages the use of a buildingfor him.

Blasting Agent - any material or mixture consisting of a fuel and oxidizer used to set off

explosives.

Cellulose nitrate or Nitro cellulose - a highly combustible and explosive compound produced

by the reaction of nitric acid with a cellulose material.

Cellulose nitrate plastic (Pyroxylin) - any plastic substance,materials or compound havingcellulose nitrate as base.

Combustible/Flammable or Inflammable - Descriptive of materials that are easily set on fire.

Combustible fiber - any readily ignitable and free burning fiber such ascotton,oakum,rags,waste cloth,waste paper,kapok,hay,straw,Spanish moss,excelsior,and other

similar materials commonly used in commerce.

Combustible liquid - any liquid having a flash point at or above 37.8 degrees Celsius or 100

degrees Fahrenheit.

Corrosive liquid - any liquid which causes fire when in contact with organic matter or withcertain chemicals.

Curtain board - a vertical panel of non-combustible or fire resistive materials attached to and

extending below the bottom chord of the roof trusses, to divide the underside of the roof intoseparate compartments so that heat and smoke will be directed upwards to a roof vent.