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39 Cards in this Set
- Front
- Back
Fuel exists in matter of three states ? |
Fuel. Liquid. Gas/vapor. |
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What is pyrolisis |
Heating solid fuels and chemically breaking them down by passing the liquid stage which emit toxic flammable gasses |
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Classes of fire |
A.comb solids B. Flam liquids C. Flam gasses D. Comb metals E. Electrically energized F. Fat/oils |
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Extinguishing methods x4 |
Smothering .cutting of o2 supply Starving . Removal of fuel Cooling. Removing temp Interrupting chemical chain reaction |
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What is the combustion process |
Self sustaining chemical reaction involving oxidation producing heat and light |
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What is the lfl |
Lowest amount of fuel in the air that supports combustion e.g too much air not enough fuel |
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What is ufl |
Fuel is above the maximum concentration above which combustion cannot take place. E.g too much fuel not enough air |
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What is ideal mixture |
Concentration of fuel and air that will burn with most intensity due to fuel and air at ideal mixtures |
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What does heat cause |
Causes pyrolisis/decomposition resulting in production of ignition vapors or gases Causes continuous production of ignition fuel vapours |
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What is spontaneous heating |
Known as self heating a chemical reaction between two materials without an external heat source |
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What is composition of smoke |
Gas vapours dispersed solid particles |
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Chemical reaction of combustion produces what |
Heat light smoke flammable vapours |
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What is a flash point |
Lowest temp at which a vapours is given off by a liquid to flash if ignited |
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What is fire point |
Lowest temp at which sufficient vapours is given off by a liquid to enable combustion if ignited |
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Ignition temp |
Lowest temp of which a substance can sustained combustion can be initiated |
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Auto ignition temp |
Minimum temperature at which a substance will ignite without a pilot flame |
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Spontaneous ignition temp |
Lowest temp at which a substance will ignite without an ignition source |
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Specific heat |
Amount of heat required to heat 1kg by 1degree |
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Latent heat of vaporization |
Amount of energy absorbed when 1kg of liquid is converted into gas at boiling point |
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What is the expansion ration of 1ltr of water at 100 degrees 1ltr of water at 500 |
1700 3400 |
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What is latent heat |
Heat energy required to change a substance from liquid gas and solid doesn't involve rise in temp just change of state |
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What are the fire development stages x4 |
Incipient Growth Fully developed Decay |
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What happens during incipient |
Ingredients of combustion come together. Fire may go out if triangle is split |
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What happens in growth phase |
Begins with self sustaining combustion Growth rate depends on ventilation |
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What is fully developed |
All fuel is consumed Fire burns with high release rate Duration depends on amount of fuel |
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Decay phase ? |
Starts once 80% of fuel is consumed Heat declines until all fuel is consumed Begins when fire passes back from ventilation controlled fire to fuel controlled |
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Factors that affect fire development x5 |
Size and number of ventilation openings Ceiling height Size volume of thermal properties Size of fuel Temperature |
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What is HRR |
Temperature that develop in a burning compartment are result of energy released |
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HRR HAS AN AFFECT ON X5 |
Flame height . Transition to flash over . Fixed safety design considerations . Smoke generation . Fire room temperature |
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Methods of fire transfer x5 |
Convection . Conduction . Radiation .ember transfer . Direct burning |
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What is a flash over |
Transition point between growth phase and fully developed phase of fire . Occurs when all fuel items in compartment ignite |
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What temp does flash over reach prior and during |
Prior 60sec 500-600 During 800-1000 |
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What are warning signs of flash over x4 |
Rapid increase in compartment temp . Dancing angels. Combustible fumes giving off pyrolisis . Smoke rapidly backing down to floor |
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Safety precautions for flash over x7 |
Always be aware of possible flash over . Ppe and ba. Additional branch covering entrance . Protect escape routes . Check doors for signs of heat . Stay low. Controlled bursts from branch directed at hot gases . Ventilate when safe to do so or OIC says |
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How to control a flash over x3 |
Briefed on tactics chosen by oic Ventilate compartment Cool over pressure zone |
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What is a backdraught |
Sudden eruption of fire in an under ventilated compartment due to the introduction of fresh air |
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Warning signs of a back draught x7 |
Smoke puffing around windows and doors. Black smoke and soot stained windows . Excessive heat. Windows rattling . Muffled sounds in compartment . Confinement of fire . Thick black smoke logging compartment . Sudden inrush of air |
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Safety precautions of backdraughtx6 |
Ppe. Doors closed and cover with charged branch . Stay out of room if possible. Cool compartment .keep clear of escaping steam and hot gases. Stay low and to side of door |
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How to prevent a backdraught |
Prevent o2 from entering and wait for compartment to cool. Cool environment . Remove flammable vapours |