Transcript Types of Concentrates (Water Additives)
Types of Concentrates (Water Additives)
Foam Concentrate - Water Additives
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Wetting agents Not to be mistaken for Class A concentrate
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Class A foam concentrate
– Class A Foam •
Class B foam concentrate
– Protein & Film Forming Fluoroprotein (FFFP) – – Aqueous Film Forming Foams (AFFF) Alcohol Resistant-AFFF (AR-AFFF) •
Emulsifiers / Spill response agents
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Gels
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• • • •
Concentrate Usage Class A foam
(Proportioned 0.1-1.0%) – Wood, paper, tires, any Class A combustible – Effective in initial attack, overhaul, mop-up and exposure protection – Does NOT affect application rates or manpower requirements
Class B foam
(Proportioned 1.0-6.0%) – Hydrocarbons and polar solvents
Emulsifier/Spill response agent
(Various rates) – “Fuel neutralizer” and hydrocarbon recovery
Gel
(Various rates) – Exposure protection 14
Class A Foam
Class A Foam Characteristics Finished foam
adjusted by concentrate percentage
using the proportioner
Wet 0.2% Fluid 0.5% Dry 1.0% Overhaul Initial Attack Exposure 16
Wet Foam At 0.2% - Overhaul
Small bubble structure and quick drain time 17
Fluid Foam At 0.5% - Initial Attack
Medium bubble structure and slower drain time 18
Dry Foam At 1.0% Exposure Protection - Long Lasting
Produces a dry foam blanket with a very slow drain time 19
Foam Properties
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Expansion ratio
– Volume of
finished foam solution
to volume of
foam
– Hose-end appliance dictates expansion ratio –
Based on amount of air introduced
– – – Low Expansion Medium Expansion High Expansion 1:1 - 20:1 20:1 - 200:1 200:1 + 20
Exterior Low Expansion Application
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Medium Expansion Foam
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High Expansion Foam
High expansion generator Flowing down a hillside 23
The Value Of Using Class A Foam Improves Fire Fighting Effectiveness By 2 To 4 Times
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Salem Tests Fire Engineering, February 1993 Temperature drop from 1,000 ° F to 212 ° F, at a four foot level
250 200 150 100 50 0
Water Water:
223 Seconds
Foam:
103 Seconds
CAFS:
39 Seconds
Foam CAFS
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Dr. Holger de Vries (Germany) Fire Chief Magazine, August 1999
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Crib burn - controlled test conditions
– Class A foam vs. plain water – 40% less solution than plain water – 43% less
extinguishing effort
than with plain water (extinguishing agent volume x time to extinguish) •
Conclusion
– Reduced exposure to hostile environments and
improved fire fighter safety
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Palmdale Study Fire Chief Magazine, August 2001
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Palmdale Study
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L.A. County Fire Dept. scientifically conducted tests to compare effectiveness of:
– – – Plain water Foam solution Compressed air foam •
Temperature readings obtained via wall and ceiling mounted thermocouples at one foot increments
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Palmdale Study
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Three identical 1100 sq./ft. homes and contents
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Critical Application Rate
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The IOWA formula was used to calculate flow rate
Cubic Feet Involved 100 = GPM 9,075 100 = 91 30
0:57 0:50 0:43 0:36 0:28 0:21 0:14 0:07 0:00
Knockdown Time Results Water Foam CAFS Extinguishment Medium
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Water:
50 seconds
Foam:
25 seconds 50% better than water
CAFS:
11 seconds 78% better than water 66% better than foam
Gallons Required To Knockdown
40 30 20 10 80 70 60 50 0
Water Foam Water:
73 gallons
Foam:
44 gallons 40% better than water
CAFS:
16 gallons 79% better than water 64% better than foam
CAFS Extinguishment Medium
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350 300 250 200 150 100 50 0
Total Gallons Used Water
After 225 gallons, IC ordered foam to aid overhaul
Water:
320 gallons
Foam:
95 gallons 71% better than water
CAFS:
45 gallons 86% better than water 53% better than foam
Foam CAFS Extinguishment Medium
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Time To Cool: 600°F To 200°F
7:12 6:00 4:48 3:36 2:24 1:12 0:00
Water Water:
6:03 min
Foam:
1:45 min 71% better than water
CAFS:
1:28 min 76% better than water 17% better than foam
Foam CAFS Extinguishment Medium
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Total Foam Concentrate Used
35 30 25 20 15 10 5 0
Foam CAFS Concentrate Cost:
$15/gal
Foam Solution:
31 oz = $3.63
CAFS:
5.8 oz = $0.68
Extinguishment Medium
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What These Tests Prove
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Naturally aspirated foam (NAF) beats water
– – – – Time to knockdown Gallons to knockdown Total water used Cooling
Compressed Air Foam beats NAF - in all categories
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Why Does Foam Work?
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Smaller droplets – faster heat absorbtion
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Reduces surface tension – penetrates and wets fuel
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Foam blanket – provides protection
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Water And Class A Concentrate
Surface tension causes water to bead up on fuel…
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Water And Class A Concentrate
Add Class A foam to plain water… solution spreads and penetrates the fuel…
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Water And Class A Concentrate
Chance of rekindle lessens with Class A solution
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Give It A Try
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Place a small drop of plain water on piece of corrugated cardboard (Note: it maintains beaded shape, caused by surface tension) Place a small drop of soapy water next to it (soap is a surfactant similar to Class A) Which would provide better extinguishment and have less runoff?
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Why Use Water Additives?
CAFS Foam Water Typical Fire Curve Time
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Class A Foam Applications
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Fire Reported!
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1890’s brick schoolhouse
– 4 miles outside of town – No hydrants
First pumper on scene
– 6 minute response – 750 gallons of water – FoamPro 2001 44
Fire Knocked Down!
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Initial attack
– – – 2 1/2” line 328 gpm 0.5% Class A foam
Knockdown
– – 6 seconds 33 gallons of water – 0.17 gallons of Class A foam concentrate 45
Effectiveness On Tire Fires Tire Fire Plain Water
Class A foam: – 60 gpm @ 0.5% – Medium expansion – 20 minute knockdown
Tire Fire Class A Foam
Water: – 750 gpm supplied by: – Two 2 1/2” – Two 1 3/4” – No effect 46
Fully Involved Garage!
Class A foam attack - 125 gpm at 0.5% 47
Garage After 35 Second Attack
NOTE: Lack of smoke; ability of Class A foam to bond with carbon 48
• • •
Structural – Exterior Attack
200
'
x 24
'
x 35
'
wood frame structure Attack with single 1 ½
"
CAFS line with 1
"
Approximately 50 gpm, 20 cfm at 0.5% tip
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Structural – Exterior Attack
Exposure on left protected with foam CAFS attack begins 50
Structural – Exterior Attack
CAFS attack continues 51
Exterior Structure Attack with Low Expansion CAFS stream
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Benefits Of Class A Foam To The Department
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Improves firefighter safety Increases efficiency of plain water 2 to 4 times Faster fire knockdown Reduces heat rapidly Reduces property damage
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Reduces overhaul Fewer rekindles Exposure protection Preserves evidence Faster cleanup Reduces on scene time
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Points To Ponder
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Immediately reduce your fire losses by 50 to 75% … just by implementing Class A foam or CAFS.
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What other initiative would have as significant an impact for your department?
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If this is not a top priority for your department, why not?
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Class B Foam & Emulsifiers
Class B Foam
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Designed to form a film and seal vapors Applied at 1%, 3%, or 6% per foam manufacturer Polar solvents require alcohol resistant (AR) foam Multi-use foam can be used on both
– Concentration ratios are 1%x3%, 3%x3%, and 3%x6% (second percentage for polar solvents) 56
Class B Foam
Fuel must be contained to form film 57
Containment Challenges
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Training
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Real life
– If no containment: – No film forming seal – Then alternatives are: – Class A foam – Emulsifiers 58
Types Of Class B Concentrate
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Film Forming FluoroProtein (FFFP) Aqueous Film Forming Foam (AFFF) Alcohol Resistant-Aqueous Film Forming Foam (AR-AFFF)
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Film Forming FluoroProtein (FFFP)
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Capabilities:
– Biodegradable – Excellent fuel shedding – Long lasting foam blanket and high burn-back resistance
Limitations:
– Requires aspiration – Used at ratios 3% or 6% – Poor at flowing and wetting (messy and smelly) 60
Aqueous Film Forming Foam (AFFF)
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Capabilities:
– Does not require specialized delivery equipment – Fluid foam that spreads across the fuel surface – – Quick knockdown Long shelf life in original sealed container (unopened)
Limitations
: – Fast drain time – – – – Limited burn-back resistance May be hazardous Storage and shelf-life once original container is opened Use only on hydrocarbons at 1%, 3% or 6% ratios 61
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Alcohol Resistant-Aqueous Film Forming Foam (AR-AFFF) Capabilities:
– Multi-use fuels (Hydrocarbons/Polar Solvents) – – Excellent burn-back resistance and stable foam blanket Long shelf life in original sealed container (unopened)
Limitations:
– – – – – Does not require aeration delivery equipment Viscous liquid difficult to premix May be hazardous Storage and shelf-life once original container is opened Used at 3% and 6% ratios (Multi-use 1%x3%, 3%x3% or 3%x6%) 62
What To Consider -“B” Concentrates
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Cost of solution vs. concentrate
– Your application – hydrocarbon or polar solvent
Shipping, storage and handling
– – Significant logistics improvement with lower ratios Given storage capacity - added protection
Mutual aid Proportioning system
– Higher concentration ratios require larger systems – Lower concentration ratios require high accuracy 63
Do Not Mix Class A & B Foam
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Result of mixed foam (in strainer)
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Emulsifiers / Spill Response Agents
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Capabilities:
– – – Non-toxic and biodegradable Long term vapor suppression Aids in hydrocarbon recovery
Limitations:
– – Limited extinguishing potential Application rates vary with products-high cost – – – Application by volume not by percentage Not compatible with Polar Solvents No approval process or recognized performance standard 65
Gel
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Capabilities
– – Excellent insulator Long term exposure protection
Limitations
– Limited extinguishing potential – – – High cost May cause slippery work areas Solution viscosity very high-most products require hose end eductor – No approval process or recognized performance standard 66
Extinguishing Agent Synopsis Extinguishing Agent Water Wet Water Class A Foam AFFF AR-AFFF FFFP & AR-FFFP Emulsifier Gel CHARACTERISTICS Fuel Class Usage A A A B B B A A Ability to Wet Ability to Foam Ability to Insulate Affinity to Carbon Indifferent to Carbon Reacts with Fuel
Poor Average Excellent 67