Essentials Ch 16

Question 1

The primary way that water extinguishes fire is by:

Answer 1

Absorbing heat which creates a cooling effect

Pg 944

Question 2

_______ _____ is the amount of energy required to increase the temperature of a substance by one degree.

Answer 2

Specific Heat

Pg 944

Question 3

_______ ____ ____ ______ is the amount of heat required to convert unit mass of a liquid into a vapor without a temperature change.

Answer 3

Latent heat of vaporization, water has a latent heat of vaporization of 970 Btu/lb
Pg 944

Question 4

Does a solid stream evaporate quicker than a fog stream?

Answer 4

No, solid stream of water has a smaller surface area (similar to a log)and absorbs heat less efficiently.
Pg 946

Question 5

When flowing a stream into an upper heated layer, the water ________, the hot gases are _____ and the upper layer ______.

Answer 5

Evaporates / cooled / contracts

Pg 947

Question 6

What’s the most common example of loss of pressure in a hoseline?

Answer 6

Friction loss between the pumper and the nozzle (friction loss).
Pg 947

Question 7

A _____ ______ is a stream of water or other extinguishing agent after it leaves a fire hose nozzle until it reaches the desired target.

Answer 7

Fire stream

Pg 949

Question 8

Fire streams are classified into one of three sizes:

Answer 8

Low volume streams (less than 40 gpm)
Handline streams (40 - 350 gpm, 1 1/2” - 3” size)
Master streams (more than 350 gpm - nozzle pressures of 80 to 100 psi)
Pg 950-951

Question 9

The volume of water discharged is determined by the design of the _____ and the _____ ______ at the nozzle.

Answer 9

Nozzle / water pressure

Pg 951

Question 10

To be effective, a fire stream must deliver a ______ of water sufficient to ____ ____ _____ than the fire generates it.

Answer 10

Volume / absorb heat faster

Pg 951

Question 11

The minimum flow rate at which extinguishment can be achieved is:

Answer 11

Critical flow rate

Pg 951

Question 12

The major types of fire stream patterns are:

Answer 12

Solid
Fog
Straight
Broken

Question 13

A stream that stays together is a _______, produced from a ______ _____ nozzle.

Answer 13

Solid stream / smooth bore nozzle

Pg 951

Question 14

Characteristics of solid streams include:

Answer 14

Good reach and stream penetration
Stream produced at low nozzle pressure
Produces less steam conversion
Provides less heat absorption per gallon
More likely to conduct electricity
Pg 951

Question 15

Four critical elements of a fire stream:

Answer 15

Agent (water)
Pressurized device (pump)
Means of delivery (hoseline)
Dish charge device (nozzle)
Pg 953

Question 16

The ____ _____ point of a stream can be observed as the distance where it begins to lose its forward velocity.

Answer 16

Break over point

Pg 953

Question 17

A ____ _____ is a fine spray composed of tiny water droplets. ____ ____ are used to produce fog streams and designed to permit adjustment of the top to produce different fog stream patterns.

Answer 17

Fog stream / fog nozzle

Pg 954

Question 18

The desired performance of a fog stream is characterized by the amount of:

Answer 18

Heat that it absorbs and the rate by which the water is converted into steam or vapor
Pg 954

Question 19

Fog streams have the following characteristics:

Answer 19

Fog stream patterns can be adjusted
Used for hydraulic ventilation
Used for vapor dispersion
Used for crew protection
Reduce heat by exposing the max water surface for heat absorption
Cool the hot gases
Shorter reach than solid/straight streams
More affected by wind
May disturb thermal layering
May intensify fire by pushing fresh air into the fire area
Pg 955

Question 20

A _____ _____ pattern is a semi solid stream that is produced by a fog nozzle.

Answer 20

Straight stream

Pg 955

Question 21

A _____ ____ is a fire stream that has been broken into coarse lay divided water droplets by specialized nozzles (cellar nozzles, piercing nozzles and chimney nozzles

Answer 21

Broken stream

Pg 955

Question 22

Where will you use a broken stream?

Answer 22

Attics, cocklofts, basements, and other confined spaces

Pg 955

Question 23

There are five limiting factors that affect the reach of a fire stream:

Answer 23

Gravity
Water velocity (60 - 120 ft/second at 25-100psi)
Fire stream Pattern
Water droplet friction with air
Wind
Pg 956

Question 24

Ideal angle for greatest horizontal reach for a fire stream is:

Answer 24

45º angle, 30-34º provide the maximum effective horizontal reach
Pg 956

Question 25

Both categories of nozzles (straight tip - smooth bore and spray nozzles - fog nozzles) perform three main functions:

Answer 25

``` Controlling water flow Creating reach Shaping the fire stream NFPA 1963 - Standard for Fire Hose Connections Pg 957 ```

Question 26

Characteristics of smooth bore nozzles:

Answer 26

Operate at low nozzle pressures Are less prone to clogging with debris Can be used to apply compressed air foam May allow hose lines to kink due to pressure loss Do not allow for deletion of different stream patterns Pg 958

Question 27

Characteristics of fog nozzles are:

Answer 27

``` Discharge pattern can be adjusted Provide protection to firefighters with wide pattern Used for a variety of applications Offer a variety of nozzle choices Used to apply certain types of foam Pg 959 ```

Question 28

There are four basic types of fog nozzles:

Answer 28

``` Basic fog nozzle Constant gallonage fog nozzle Constant pressure (automatic fog nozzle) Constant/select gallonage fog nozzle Pg 961 ```

Question 29

What are the three type of nozzle control valves?

Answer 29

Ball Slide Rotary control Pg 962

Question 30

The counter force directed against a person holding a nozzle by the velocity of water being discharged:

Answer 30

Nozzle reaction - caused by velocity, flow rate and discharge pattern of stream Pg 964

Question 31

In general, fire fighting foam works by forming a:

Answer 31

Blanket of foam on the surface of burning fuels - both liquid and solid Pg 967

Question 32

Foam extinguishes and/or prevents ignition in several ways:

Answer 32

Separating - creates a barrier between the fuel and the fire Cooling - lowers the temperature of the fuel and adjacent surfaces Smothering - prevents air from reaching the fuel and mixing with the vapors and prevents the release of flammable vapors reducing the possibility of ignition (reignition) Penetrating - lowers the surface tension of water and allows it to penetrate fires in Class A materials Pg 967

Question 33

Class B foams is especially effective on the two basic categories of flammable liquids:

Answer 33

Hydrocarbon fuels and polar solvents | Pg 968

Question 34

Class B foams are used on hydrocarbon fuels such as:

Answer 34

``` Petroleum based combustible/flammable liquids that float on water: Crude oil Fuel oil Gasoline Benzene Naptha Jet fuel Kerosene Pg 972 ```

Question 35

Class B foams are used on polar solvents such as:

Answer 35

``` Flammable liquids that mix readily with water: Alcohols Acetone Lacquer thinner ketones Esters Acids Pg 972 ```

Question 36

The mixing of water with an appropriate amount of foam concentrate to form a foam solution:

Answer 36

Proportioning | Pg 974

Question 37

There are four basic methods by which foam may be proportioned:

Answer 37

``` Eduction Injection Batch mixing Premixing Pg 975 ```

Question 38

Foam application techniques:

Answer 38

Roll On Method Bank Down Method Rain-Down Method Pg 984

Question 39

What are qualities of water that makes it the primary extinguishing agent to extinguish fires?

Answer 39

Readily available Inexpensive Extinguishes by cooling and smothering the fire Pg 943