PUMP OPS Chap 14 Flashcards
What caused the foam eductor to become plugged during the overturned tanker truck incident?
Different types of foam concentrate were substituted for the original supply, causing blockages.
What should agencies coordinate to avoid eduction problems during mutual aid operations?
Agencies should coordinate the specifications of the foam concentrate they intend to use.
What are major reasons for the increased use of foam agents in firefighting?
Magnitude of hazardous material incidents, easier foam use, improved systems, and water conservation.
What is mechanical foam?
Produced by physical agitation of foam concentrate, water, and air.
What is proportioning in foam firefighting?
Mixing water with an appropriate amount of foam concentrate to form a foam solution.
What is aeration in foam production?
Introduction of air into a foam solution to create bubbles.
Define eduction in relation to foam systems.
Process used to mix foam concentrate with water using the Venturi method.
What is a foam concentrate?
Raw chemical compound solution mixed with water and air to produce finished foam.
What is a foam proportioner?
Device injecting correct amount of foam concentrate into the water stream.
What is a foam solution?
Result of mixing foam concentrate with water before adding air.
What is finished foam?
Extinguishing agent formed by mixing foam concentrate, water, and air.
What are the three elements needed to produce quality foam?
Foam concentrate, water, and air.
What happens if any foam-making element is missing or misapplied?
Poor quality foam or no foam production.
What type of fuels require alcohol-resistant foams?
Polar solvent fuels like alcohol, acetone, and esters.
What category do crude oil and gasoline fall under?
Hydrocarbon fuels.
How do hydrocarbon fuels behave in water?
They float on water (specific gravity less than 1).
What is the specific gravity of hydrocarbon fuels compared to water?
Specific gravity less than 1.
What foam types can be effective against polar solvents?
Alcohol-resistant foam may be effective if used per manufacturer’s instructions.
What are the three main ways foam works to extinguish fires?
Separating, cooling, and suppressing/smothering.
What is the definition of a polar solvent?
Liquids with positive and negative charges that ionize in solution.
What is the typical proportioning percentage for Class A foam?
0.1% to 1%, depending on manufacturer and local SOP.
What are the four methods of foam proportioning?
Induction, Injection, Batch Mixing, Premixing.
Describe the induction method of foam proportioning.
Water stream pressure drafts foam concentrate into the stream via Venturi effect.
What is injection method of foam proportioning?
External pump injects foam concentrate into the stream at the proper ratio.
Explain batch mixing.
Pouring concentrate directly into a tank of water.
What is premixing in foam systems?
Premeasured portions of water and foam mixed in a container.
List two examples of portable foam storage containers.
Pails and barrels.
What is the standard size of a foam pail?
5-gallon plastic pail.
What is the capacity of a foam barrel?
55-gallon barrel.
Where are totes typically used for foam storage?
ARFF, wildland, and industrial fire operations.
How large can foam tanks on foam tenders be?
Up to 8,000 gallons or more.
What principle does an in-line eductor use?
Uses Venturi principle to draft foam into the water stream.
What happens if back pressure exceeds 70% of inlet pressure at an eductor?
Foam production will be inadequate or fail completely.
What is a foam nozzle eductor?
Nozzle with built-in eductor introducing foam at the nozzle.
What is the function of a self-educting master stream nozzle?
Draws foam concentrate through built-in pickup tube or metering valve.
What is a balanced pressure proportioner?
Foam and water supplied at equal pressures using pressure control devices.
How does a pressure proportioning tank system operate?
Tank pressure forces foam concentrate into venturi-type proportioner.
What is an around-the-pump proportioner?
Introduces foam concentrate at pump intake side using small impeller or venturi.
What is a direct injection system?
Electronic system controlling foam concentrate pump speed.
What does CAFS stand for?
Compressed Air Foam System.
What are two advantages of CAFS foam?
High-quality foam with excellent penetration and long drainage time.
What is a medium-expansion foam generator typically used for?
Confined spaces, basements, shipboard fires, tunnels, and mines.
What fuels can non-aspirating foam nozzles be used on?
Hydrocarbon fuels like gasoline and crude oil.
What is the typical expansion ratio range for medium-expansion foam?
20:1 to 200:1 expansion ratio.
What are the two foam types produced by mechanical blowers?
Medium and high expansion foams.
What is the roll-on method of foam application?
Aim foam stream at ground near burning fuel’s edge to roll across surface.
What is the rain-down method of foam application?
Spray foam above the fire allowing it to fall gently onto the fuel surface.
Why must foam application be continuous once started?
Foam blanket must not be interrupted to maintain vapor suppression and extinguishment.
What can happen if different brands of foam concentrates are mixed?
They may be chemically incompatible, reducing foam effectiveness.
What is the purpose of a Safety Data Sheet (SDS)?
Provides chemical composition, hazards, and safety handling procedures.
What is a surfactant?
Chemical that lowers the surface tension of water.
What is the shelf life of synthetic-based Class B foam?
20 to 25 years under proper storage conditions.
What are characteristics of regular protein foam?
Good heat stability and burnback resistance but lower fluidity.
What is the main purpose of alcohol-resistant AFFF (AR-AFFF)?
Forms a membrane over polar solvents, allowing effective suppression.
What are the characteristics of fluoroprotein foam?
Flows readily and offers longer vapor suppression compared to protein foams.
What should be done after using foam equipment to ensure readiness?
Thoroughly flush all foam equipment with clean water after use.
What is the correct proportioning range for Class A foam used with standard fog nozzles?
0.2% to 0.5% for fire attack and overhaul.
What effect does Class A foam have on water surface tension?
Reduces surface tension allowing better fuel penetration.
Why should foam not be discharged into bodies of water?
It reduces oxygen levels and can harm aquatic life.
What happens when finished foam decomposes in water?
Oxygen consumption and harm to aquatic life.
What are durable agents used for?
Extinguishing fires, structure pretreatment, and fire line construction.
What is the standard size of a foam pail in gallons?
5 gallons.
What is the capacity of a standard foam barrel in gallons?
55 gallons.
What is the capacity of a foam tote in gallons?
275 gallons.
What is the foam tank capacity range for municipal fire apparatus in gallons?
20 to 200 gallons.
What is the maximum acceptable height for a foam pickup tube above concentrate surface?
No more than 6 feet (2 meters).
What should back pressure NOT exceed in relation to inlet pressure at an eductor?
70% of inlet pressure.
What is the typical inlet pressure required for an in-line foam eductor in psi?
150–200 psi (1,050–1,400 kPa).
What is the proportioning percentage range for Class A foam?
0.1% to 1%.
What is the typical Class A foam proportion for exposure protection with fog nozzles?
0.5% to 1.0%.
What percent foam solution is typical for fire attack and overhaul with standard fog nozzles?
0.2% to 0.5%.
What percentage concentration is used for portable Class A foam applications with CAFS?
0.2% to 0.5%.
What is the recommended Class B foam application proportion for hydrocarbon fuels?
1% or 3%.
What proportion percentage is recommended for polar solvent fuels using Class B foam?
3% or 6%.
What is the foam expansion ratio for low-expansion foam according to NFPA 11?
Up to 20:1 air to solution ratio.
What is the expansion ratio range for medium-expansion foam?
20:1 to 200:1.
What is the expansion ratio range for high-expansion foam?
200:1 to 1000:1.
What is the shelf life of properly stored synthetic-based Class B foam in years?
20 to 25 years.
How many gallons of foam concentrate are needed to make 100 gallons of 3% foam solution?
3 gallons of concentrate and 97 gallons of water.
How many gallons of foam concentrate are needed to make 1000 gallons of 3% foam solution?
30 gallons of concentrate and 970 gallons of water.
What is the flow rate from a handline nozzle typically below in gpm?
Less than 350 gpm.
What is the maximum flow rate for a handline nozzle before being considered a master stream?
Greater than 350 gpm.
At what rate must the flow through an eductor match its rated gpm capacity to produce proper foam?
Must match rated gpm flow exactly.
What percentage overproportioned solution does a Jet Ratio Controller (JRC) produce?
66.5 percent.
How far away can a Jet Ratio Controller supply foam concentrate from the nozzle?
Up to 3,000 feet (900 meters).
What is the air-to-solution ratio for low-expansion foam?
Up to 20:1 ratio.
