Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fire Everything > Chapter 5 Fire Behaviour > Flashcards

Chapter 5 Fire Behaviour Flashcards

1
Q

Combustion

A

Chemical process of oxidation that occurs fast enough to produce heat and usually light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fire definition

A

Rapid oxidation, which is a chemical process resulting in heat and light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Heat

A

Form of energy characterized by vibration of molecules and capable of initiating and supporting chemical change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Temperature

A

Measure of a materials ability to transfer heat energy to other objects.
Measure of average kinetic energy of particles in a sample of matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Fuel

A

A material that will maintain combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Oxidizer

A

Any material that readily yields oxygen or other oxidizing gas or that readily reacts to promote or initiate combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Matter

A

Anything that takes up space and has mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

All fire

A

Involves a heat producing chemical reaction between some type of fuel and oxidizer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Oxidation

A

Can be rapid like methane combusting or slow like rust.

Chem process when a substance combines with oxygen in air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Energy

A

Capacity to perform work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Joules

A

A force of one newton through a distance of one meter.
For ffers, the energy required to increase temp. 4.2joules to raise one gram of water one degree.
1055 J = 1 btu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pyrolysis

A

Chemical decomposition of a solid material by heating. Pyrolysis often precedes combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Vaporization

A

Liquid into a gaseous state. Rate depends on heat, substances, pressure and surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ignition

A

The process of initiating self sustained combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Piloted ignition

A

Moment when mix of fuel and oxygen encounter external heat sufficient to start combustion reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Auto ignition

A

Initiation of combustion by heat without spark or flame. NFPA 921
Always a higher temp for a given substance than its piloted temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Fire triangle

A

Heat oxygen fuel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Fire tetrahedron

A

Fuel heat oxygen and self sustaining chemical reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Passive agent

A

Material that absorbs heat but does not participate actively in combustion process. E g drywall.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Nonflaming combustion

A

Burning is localized on or near the fuels surface where it is in contact with oxygent
Eg burning charcoal or smouldering wood or fabric
Flaming is when substance is vaporized and the vapours are ignited forming the flame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

CO

A

Colourless odourless

0.2 percent unconscious in 30 minute. High concentration immediate collapse and unconscious

22
Q

Formaldehyde

A

Colourless gas. Pungent odor. 50-100ppm can cause severe irritation to respiratory track and serious injury. Can injure skin in high concentrations. Suspected carcinogen

23
Q

Nitrogen dioxide

A

Reddish brown gas or yellowish brown liquid which is highly toxic and corrosive

24
Q

Sulfur dioxide

A

Colourless gas with a choking or suffocating odor. Toxic and corrosive. Irritates mucus membranes

25
Q

Hydrogen cyanide

A

Colourless toxic and flammable liquid below 26C. Produced by combustion of nitrogen containing products. Lower smoke concentrations than CO. Common from polyurethane furniture and bedding

26
Q

Carbon dioxide

A

Colourless odourless heavier than air. Neither burns nor supports combustion. Used to extinguish class B or C fires by displacing oxygen

27
Q

Irritants in smoke

A

Hydrogen chloride
Formaldehyde
Acrolein

28
Q

Flame brightness

A

Luminosity will decrease with more complete combustion

29
Q

Thermal energy

A

Heat. Kinetic energy transferred from high to low temp substance
Heat is the thermal kinetic energy needed to release the potential chemical energy in a fuel
Molecules vibrate. Release vapours which can ignite and release thermal energy

30
Q

Temperature

A

Measurement of heat, more specifically measure of average kinetic energy in particles in a sample of matter

31
Q

Sources of thermal energy

A

Chemical mechanical electrical (most common the result in ignition of fuel) but also light nuclear and sound

32
Q

Chemical energy

A

Most common source of heat
Self heating is a form of oxidation, normally lost to surroundings nearly as fast as generated. More heat means faster reaction means more heat

33
Q

Common self heating materials

A

Charcoal linseed oil soaked rags straw and manure

34
Q

4 types of electrical heating

A

Resistance heating
Overcurrent (a type of resistance heating; too much electricity for design)
Arcing
Sparking

35
Q

Mechanical heating

A

Friction or compression

36
Q

Heat flux

A

Measure of rate of heat transfer to a surface expressed in kilowatts/m2, kJ/m2 x sec or btu/ft2 x sec
* squared not doubled

37
Q

Heat transfer is based on

A

Temp differential and thermal conductivity

38
Q

Conduction

A 
More dense molecules will more readily it will conduct heat
Based on 3 factors:
Area being heated
Temp difference 
Thermal conductivity
39
Q

Thermal conductivity of common objects in W/mK

A

Copper 386
Steel 36-54
Concrete 0.8-1.2
Wood 0.13

40
Q

Radiation transfer factors

A

Nature of exposed surface - dark emits and absorbs heat better. Smooth or polished reflect more than rough surfaces
Distance
Temp difference - as temp increases radiant energy increases by a factor to the fourth power.
Radiant heat travels in straight line at speed of light

41
Q

Reducing agent

A

Fuel that is being oxidized or burned during combustion

42
Q

Heat of combustion

A

Total amount of thermal energy by combustion reaction if a fuel were completely burned. Measured in btu per lb or mJ per kg

43
Q

Heat release rate

A

Total amount of heat released per unit time

44
Q

Power

A

Measured in watts. 1 watt = one J per second
Defined as energy transferred over time or rate at which energy is converted from one form to another.
In terms of fire power is described as hrr

45
Q

Common flammable gases

A

Methane - vapour density 0.55, ignition temp 540C
Propane 1.52 450C
CO 0.96, 609C

46
Q

Vapour density

A

1.0 is air. Under one rises

47
Q

Specific gravity

A

Density compared to water. Less than one floats

48
Q

Flammable liquid

A

Flash point below 37.8C (100F) and vapour pressure less than 40 psi absolute

49
Q

Vapour pressure

A

Measure of the tendency of a substance to evaporate. The pressure at which a vapour is in equilibrium with its liquid phase for a given temp.
High VP is more likely to evaporate

50
Q

Flash and fire point

A

Flash is minimum temp for a liquid to ignite but not sustain
Fire point is enough for a liquid to support combustion (for 5 seconds). Usually a few degrees higher for fire point
Flash point is used to indicate flammability

51
Q

Solubility

A

Degree to which a substance dissolves in a solvent (usually water)
May be qualitative like slightly, completely or a percentage

52
Q

Miscible

A

Will mix with water in any proportion

Fire Everything (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions