Chp 14

Question 1

Foam used more because

Answer 1

Bigger hazmats
New foam is easier to use by structure and wildland
Proportioners are better, easier to put in pumpers
Helps reduce water if water is limited

Question 2

Mechanical foam

Answer 2

Produced by physical agitation of concentrate, water and air

Most common

Question 3

Aeration

Answer 3

Put air into foam solution to create bubbles that give finished foam

Question 4

Foam concentrate

Answer 4

Starting point

Can be protein, synthetic, aqueous film forming, high expansion or alcohol

Question 5

Foam proportioner

Answer 5

Second step
Injects correct amount of foam concentrate into the water stream
Makes foam solution

Question 6

Foam

Answer 6

Completed product after air is introduced
Foam solution + air
For use on Class A or B
Protein,

Question 7

Class B fuels

Answer 7

Hydrocarbons: crude oil, benzene, kerosene, specific gravity <1
Polar Solvents: alcohol, acetone, ketones, esters, miscible and conduct electricity
Modern fuels with 15% solvent additives treat as polar solvents
Class B foam only works on hydrocarbons

Question 8

Foam works by

Answer 8

Separating: fuel and fire
Cooling: the fuel and adjacent surfaces
Smothering: vapors
Initial blanket excludes oxygen then as it breaks down into water it cools and runs off, taking product with it

Question 9

Proportioning

Answer 9

Can mix with fresh or salt water
Mix per mfg
Mix from 0.1 - 6%
Class A 0.1 - 1%

Question 10

Proportioning Methods

Answer 10

Induction: Pressure of water to draft concentrate by passing through a venturi device called an eductor, through a pickup tube
Injection: External pump forces concentrate into firestream at correct amount (fixed systems)
Batch mixing: Dumping concentrate (usually A) into a tank. Inaccurate and shuts down lines when tank is empty. B has to be stirred
Premixing: mixed in the container, portable and wheeled extinguishers, can use with CAFS

Question 11

Foam storage

Answer 11

Pails: 5 gal, non corrosive, airtight, easy to store
Barrels: 55 gal, usually just for storage, can put on a trailer
Totes: 275 gal, storage for ARFF or wildland, can be on a trailer
Apparatus tanks: 20-200 gal, tender up to 8000 gal and no water

Question 12

Foam concentrates

Answer 12

Some are A and B but most are one or the other

Question 13

Class A foam

Answer 13

Hydrocarbon based surfactants or wetting agents that reduce surface tension
Used on structure, wildland, coal, tire storage and others
When used with CAFS (entrains lots of air) makes excellent insulation
20 yr shelf life, buy in bulk
Don’t flow directly into lakes
Corrosive on skin
0.1 - 1.0 %

Question 14

Class A foam nozzles

Answer 14

Fog
Aerating foam
Medium and high expansion devises
CAFS with most nozzles including solid stream
Produce more stable foam at 1.0% than 0.5%

Question 15

Class A proportioning

Answer 15

Fire attack and overhaul with fog: 0.2 to 0.5
Exposure protection with fog: 0.5 to 1.0
All with air aspirating foam nozzle: 0.3 to 0.7
All with CAFS: 0.2 to 0.5

Question 16

Application rate definition

Answer 16

Minimum amount of foam solution applied to unignited fire, spill, or spill fire to control vapor emission or extinguish the fire
Take GPM/square ft to calculate
Determine in pre incident planning

Question 17

Application of class A

Answer 17

Areas needing max penetration
Vertical surfaces: dry foam clings well
Surface of fuel: cling and penetrate

Question 18

Foam breakdown affected by

Answer 18

Heat of fire
Size of flames
Ambient temp
Prevailing winds

Question 19

Class B Foam

Answer 19

Made of synthetic (Fluorosurfactants) or protein (animal) base
Store in cool place, 10 yr life protein, 20-25 for synthetic
Usually cant mix but AFFF and fluoroprotein can be mixed immediately before use, mil spec mixed anytime

Question 20

Class B proportioning

Answer 20

1 to 6 %

Can depend on fuel hydrocarbon 1 to 3%, polar solvents 3 to 6%

Question 21

Foam expansion

Answer 21

Low medium or high depends on
Type of concentrate
Accurate proportioning
Qualify of concentrate
Method of aeration
NFPA 11 finished foam to solution, low: 20:1, medium 20:1 to 200:1, high 200:1 to 1000:1

Question 22

Rate of class B application

Answer 22

Set by NFPA 11, Depends on:
Type of concentrate
If the fuel is on fire (requires more)
Hydrocarbon or polar solvent
If fuel is contained or not
Once you start, mus apply continuously from uphill upwind so make sure at the beginning that you have enough, or fire may consume a portion of the blanket
Apply uphill upwind

Question 23

1-Regular protein foams

Answer 23

Protein hydrosolate plus additives to prevent freezing
From hooves, horns and feathers
Good heat stability and burnback resisitance
Not as fluid
Shorter shelf life
More rare

Question 24

2-Fluoroprotein Foam

Answer 24

Protien foam with synthetic fluorchemical surfactant added
Makes it flow better and has longer lasting vapor suppression
Popular
Add Ammonia salts to work with alcohol for 15 min

Question 25

3-Film forming fluoroprotein foam

Answer 25

Combines 2-fluroprtein foam's long heat resistance with 5- AFFF's for quick knockdown Can be alcohol resistant

Question 26

4-Aqueous film forming foam

Answer 26

Most common synthetic Fluorochemical and hydrocarbon surfactants for high boiling point Creates thin film over fuel specifically: Vapor suppression film is released before the blanket Fast Moving blanked spreads across fuel for insulation Drains and fill in holes where blanket was disturbed

Question 27

4.5-Alcohol resistant AFFF

Answer 27

For use on polar solvents Creates a membrane over the fuel, separates water in the foam from alcohol in the product 3 to 6% concentrate Also used on hydrocarbons at 1 to 6% Aspirating nozzles are best to create and preserve membrane Put on gently to help membrane form first

Question 28

High expansion foam

Answer 28

``` Detergent base, low water content Less runoff, less water damage Used in cellars and coal mines Class A Industrial hazards ```

Question 29

Two types of proportioners

Answer 29

Venturi | Pressurized injects set ratio into water

Question 30

In line foam eductor

Answer 30

Low energy proportioner Mfg for pressure and distance Gpm must not exceed rated capacity Pressure at discharge side can't exceed 70% of inlet pressure (back pressure) Too high or too low pressure makes lean or rich mixture Flush for 1 minute Eductor inlet within 6" Nozzle and eductor must have same gpm rating

Question 31

1-Foam nozzle eductor

Answer 31

Low energy proportioner Nozzle with an eductor Foam must be at the nozzle

Question 32

2-Self educting master stream foam nozzle

Answer 32

Low energy proportioner For flows >350 gpm up to 14000 gpm Lower pressure drop Jet ratio controller can locate 3000' from nozzle and elevation of 50', proportions at 66.5% then in line eductor from MS drops it to 3%

Question 33

3-App mounted in line eductor

Answer 33

Same as portable Foam can come from bucket or onboard tank Bypass proportioner can reduce FL across eductor when just flowing water Usually for class B

Question 34

4-Around the pump proportioner

Answer 34

App mounted, Most common 10-40 gpm of water from the tank flows through an inline proportioner to create venturi to get foam then dumped back to pump inlet Old ones can only work off tank water

Question 35

5-Bypass type balanced pressure proportioner

Answer 35

Large mobile app like ARFF Monitors demand for foam and adjusts concentrate supplied by a separate foam pump for each discharge Most accurate

Question 36

6-Variable flow variable rate direct injection system

Answer 36

Positive displacement foam pump injects concentrate into the water flow so supplies all discharges with foam Monitors hoselines to maintain consistent quality of foam 0.1 to 3% Class A or B, not alcohol resistant Atmospheric pressure fed foam tanks

Question 37

7-Variable flow demand type balanced pressure proportioner

Answer 37

Both fixed and mobile Variable speed drives foam pump and monitors the flow of foam Ready to pump, no flushing and can go to any number of discharges

Question 38

Batch mixing

Answer 38

Only done with Class A Not good 24 hrs after mixing Foam can remove lube Last resort

Question 39

CAFS

Answer 39

``` High energy Stream reaches farther Small, uniform, durable bubbles Good adherence good heat resistance More expensive, maint, training 0.1 to 1% 10:1 expansion ratio ```

Question 40

Smooth bore nozzles

Answer 40

Only work with CAFS | Good reach

Question 41

Fog nozzles

Answer 41

Apply low expansion short duration foam blanket 2:1 to 4:1 expansion Best for AFFF and Class A not fluoroprotein or polar solvents

Question 42

Air aspirating foam nozzle

Answer 42

Induct air into the foam solution Good for Class A and only ones for protein and fluoroprotien concentrates Max expansion, worst reach

Question 43

Medium and high expansion foam generators

Answer 43

Water aspirating: same as other foam nozzles just bigger with screens Mechanical Blower: uses a fan instead of water, good for total flooding Create high air content from 20:1 to 200:1 For high expansion foam 200:1 to 1000:1

Question 44

Problems with foam fire streams

Answer 44

``` Not matching eductor and nozzle flow Air leaks, lack of suction Clogged proportioning equipment Attack line too long Too much elevation to nozzle Mixed concentrates ```

Question 45

Foam application techniques

Answer 45

``` Direct application: class A Roll on: Class B Bank down: Class B Rain down: Above ground storage tanks ```

Question 46

Durable agents

Answer 46

gelling agents: superabsorbent liquid polymers absorb 100x their weight in water Slippery Expensive Trap water instead of air in the bubbles Non toxic Can stick to walls for 24 hrs and be rehydrated with a fine mist

Question 47

Class A application rate

Answer 47

Same minimum required flow rate for water