book 83 fire chemistry Flashcards Preview

Captain Prep Study Program > book 83 fire chemistry > Flashcards

Flashcards in book 83 fire chemistry Deck (44)
Loading flashcards...
1

Liquids having a flash point at or above 100 degrees F.

Combustible liquids

2

Rapid oxidation of a substance accompanied by the release of energy usually in the form of heat and light.

Fire

3

The lowest temperature of a liquid in an open container at which vapors evolve fast enough to support continuous combustion.

Fire Point

4

The term lower flammable limits (LFL) describes the minimum concentration of vapor -to -air below which propagation will not occur in the presence of an ignition source. The "upper flammable limit" (UFL) is the maximum vapor-to-air concentration above which propagation of flame will not occur.

Flammable limits

5

Liquids having a flash point below 100 degrees F.

Flammable liquids

6

The minimum temperature at which a liquid gives off vapors in sufficient concentrations to form an ignitable mixture with air near the surface of the liquid.

Flash point

7

A form, of energy associated with the motion of atoms and molecules.

Heat

8

The amount of heat released during the complete oxidation of a substance.

Heat of combustion

9

The minimum temperature to which a substance must be heated in air in order to initiate or cause combustion, independent of the heating element or source. The ignition temperature of ordinary combustibles is between 300 and 1000 degrees. F

Ignition temperature

10

As a substance burns, it mixes with oxygen and produces heat.

Oxidation

11

The ratio of the weight of a solid or liquid substance to the weight of an equal volume of water.

Specific gravity

12

The quantity of heat concentration. The intensity of heat is measured in degrees (Fahrenheit or Celsius).

Temperature

13

The weight per unit volume of a pure gas or vapor. In fire protection, vapor density is reported in terms of the ratio of the relative weight of a volume of vapor to the weight of an equal volume of air under the same conditions of temperature and pressure.

Vapor density

14

A vapor denisty less than 1.0 indicates a vapor is ____ than air.

lighter

15

A vapor density more than 1.0 indicates a vapor ______ than air.

heavier

16

Heat , fuel, oxygen equals?

The fire triangle

17

Heat , Fuel , Oxygen and Uninhibited chain reaction among all parts of the ________

Fire tetrahedron

18

The Chemical decomposition of matter through the action of heat.

Pyrolysis

19

The transfer of heat from one object to another through direct physical contact.

Conduction

20

The transfer of heat by some circulating medium (liquid or gas). This is the form of heat transfer most RESPONSIBLE for fire spread in structural fires.

convection

21

Example; The spreading of fire from lower to upper structural areas when upper areas become heated to their ignition temperature is ____.

Convection

22

The transfer of heat as energy traveling through space or materials as waves.

Radiation

example: exposure problems in large fires...

23

Although actual flame temperatures can reach 1000 degrees F. temperatures in the surrounding area are not greatly increased. There is free burning with open flame. Oxygen in the area remains new 21%. Thermal updrafts causes heat to accumulate at the higher portions of the area.

Incipient phase (growth)

24

Fully developed
air from surrounding atmosphere is drawn into the fire fire.
Mushrooming may take place and flame is present. Oxygen content of area is usually reduced to 16%-18% Fire gases which may be present are carbon, carbon monoxide, carbon dioxide, water, sulfur dioxide,
Flashover frequently occurs during this phase.

Free burning phase.

25

Decay:
Free burning may cease in the fire area. Area fills with dense smoke. Oxygen may drop below 15%. Temperature may reach 1000 degrees F. thought the area. Improper /uncontrolled air admission may result in "backdraft"

Smoldering phase

26

A ________ is defined as an explosion or rapid burning of heated fire gases resulting from the introduction of oxygen when air is admitted into a building heavily charged by smoke from a fire which has depleted the oxygen content of a building.

Backdraft

27

Backdraft indicators:

Heavy smoke conditions on arrival
Lack of Visible flame
Improper method of entering a structure may cause a backdraft
Movement of smoke prior to explosion
Structure may appear to breathe
Whistle, jet or train sound

28

_____ is the stage of the fire when all combustibles in an area have become heated to their ignition temperature, then ignite simultaneously.

Flashover

29

Fire resistive, structural elements in Type ___ fire resistive buildings shall be of steel, iron , concrete, or masonry. Walls and permanent partitions shall be of noncombustible fire-resistive construction except that permanent non-bearing partitions may have fire -retardant wood.

Type 1

30

Type ____ Noncombustible /fire-resistive , one-hour or no-hour construction.
construction in which walls, partitions, and structural members are of noncombustible material but do not qualify as type 1 fire-resistive

Type ll