Pumping Apparatus Driver/Operator Chapter 14
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Questions and Answers

What is a foam proportioner?

  • The raw foam liquid in its storage container before being combined with water and air
  • The mixture of foam concentrate and water before the introduction of air
  • The completed product after air is introduced into the foam solution
  • A device that injects the correct amount of foam concentrate into the water stream (correct)

    • What is required for mechanical foams to be ready for use?

  • Pressurization and expansion
  • Proportioning and aeration (correct)
  • Separation and filtration
  • Dilution and heating

    • What is foam concentrate?

  • Completed product after air is introduced into the foam solution
  • Mixture of foam concentrate and water before the introduction of air
  • Foam solution
  • Raw foam liquid in its storage container before being combined with water and air (correct)

    • What is foam solution?

    <p>Mixture of foam concentrate and water before the introduction of air</p> Signup and view all the answers

    When is foam considered as completed product?

    <p>After air is introduced into the foam solution</p> Signup and view all the answers

    How do class B foams suppress fires involving hydrocarbon fuels?

    <p>They float on the surface of the fuel</p> Signup and view all the answers

    What is the specific gravity of hydrocarbon fuels like crude oil and gasoline?

    <p>Less than one</p> Signup and view all the answers

    What are polar solvent fuels known as?

    <p>Miscible liquids</p> Signup and view all the answers

    What is the typical water concentration for firefighting foam concentrates?

    <p>94 to 99.9 percent water</p> Signup and view all the answers

    What method of proportioning foam uses an external pump to force foam concentrate into the fire stream?

    <p>Injection method</p> Signup and view all the answers

    What is the purpose of the premixing method of proportioning foam?

    <p>Mixing premeasured portions of water and foam concentrate in a container</p> Signup and view all the answers

    How does foam extinguish and/or suppress vapors?

    <p>Separating, cooling, suppressing, or smothering</p> Signup and view all the answers

    What is the induction method of proportioning foam?

    <p>Using the pressure of a water stream to induct foam concentrate into the fire stream</p> Signup and view all the answers

    What method is used when foam is poured directly into the tank?

    <p>Batch mixing</p> Signup and view all the answers

    What is the range of foam concentrate tank size for fire apparatus equipped with onboard foam proportioning systems?

    <p>20 - 200 gallons</p> Signup and view all the answers

    How much foam may foam tenders carry for storage?

    <p>8,000 gallons or more</p> Signup and view all the answers

    How much foam is in a pail?

    <p>5 gallons</p> Signup and view all the answers

    How much foam is stored in barrels?

    <p>55 gallons</p> Signup and view all the answers

    How much foam is stored in totes?

    <p>275 gallons</p> Signup and view all the answers

    What is the shelf life of properly stored foam solution?

    <p>20 years</p> Signup and view all the answers

    At what percentage may class A foam concentrates be mixed for fire attack and overhaul with standard fog nozzles?

    <p>0.2 to 0.5%</p> Signup and view all the answers

    What is the application rate in relation to the amount of foam solution applied to a fire?

    <p>Per minute, per square foot of fire</p> Signup and view all the answers

    What type of foam is suitable for areas requiring maximum penetration?

    <p>Wet foam</p> Signup and view all the answers

    What is the appropriate percentage range for proportioning class A foam for any application with air aspirating foam nozzles?

    <p>0.3 to 0.7%</p> Signup and view all the answers

    What is the recommended percentage range for proportioning class A foam for any application with CAFS?

    <p>0.2 to 0.5%</p> Signup and view all the answers

    What is the recommended shelf life for properly stored synthetic foam concentrate?

    <p>20 - 25 years</p> Signup and view all the answers

    What is the typical concentration range for Class B foams when used with polar solvents?

    <p>3 - 6%</p> Signup and view all the answers

    What factors can affect foam expansion?

    <p>Type of foam concentrate used, accurate proportioning, and method of aeration</p> Signup and view all the answers

    What is the ratio range for medium expansion foam?

    <p>20:1 to 200:1</p> Signup and view all the answers

    How is the application rate available from a specific nozzle calculated?

    <p>Divide the flow rate by the area of fire</p> Signup and view all the answers

    What is the key feature of regular protein foam?

    <p>Good heat stability and burnback resistance</p> Signup and view all the answers

    What is the defining characteristic of fluoroprotein foam concentrate?

    <p>Contains protein concentrate with added fluorochemical surfactants</p> Signup and view all the answers

    Which type of foam concentrate is the most commonly used?

    <p>AFFF</p> Signup and view all the answers

    What is the purpose of fluorochemical surfactants in foam solutions?

    <p>To reduce the surface tension of water and spread a thin aqueous film across fuel</p> Signup and view all the answers

    What occurs when AFFF or FFFP is applied to hydrocarbon fuel fires?

    <p>An air/vapor excluding film is released ahead of the foam blanket</p> Signup and view all the answers

    At what concentration is Alcohol Resistant AFFF concentrate generally used?

    <p>3 or 6%</p> Signup and view all the answers

    What is the basic principle of foam proportioning devices?

    <p>A venturi effect created by the pressure of a water stream flowing through a restricted orifice inducts foam concentrate into the water stream.</p> Signup and view all the answers

    What is the primary application of high expansion foam?

    <p>Concealed space fires</p> Signup and view all the answers

    What is the purpose of an in-line foam eductor?

    <p>To be attached directly to the pump panel discharge or connected at some point in the hose lay</p> Signup and view all the answers

    What is the maximum pressure allowed at the discharge side of the eductor?

    <p>70% of eductor inlet pressure</p> Signup and view all the answers

    What happens if the inlet pressure at the eductor is too high?

    <p>Creates a foam solution that is too rich</p> Signup and view all the answers

    The nozzle and eductor must have what to operate successfully?

    <p>Same gpm rating</p> Signup and view all the answers

    What is the recommended inlet pressure range at the eductor for accurate blending of foam solution?

    <p>150 - 200 psi</p> Signup and view all the answers

    What height above the foam concentrate should a foam eductor not exceed?

    <p>6 ft</p> Signup and view all the answers

    What is the purpose of letting the eductor educt water for at least one minute?

    <p>To clean thoroughly</p> Signup and view all the answers

    What is a disadvantage of an around the pump proportioner?

    <p>Inability to flow foam and plain water simultaneously</p> Signup and view all the answers

    Which type of foam proportioner is known for its accuracy in foam proportioning and ability to flow plain water and foam simultaneously?

    <p>Bypass-type balanced pressure proportioner</p> Signup and view all the answers

    What is a limiting factor of using CAFS (Compressed Air Foam System)?

    <p>Increases the purchase and maintenance costs</p> Signup and view all the answers

    What tactical advantage does CAFS offer in comparison to low energy systems?

    <p>Stream reach is longer than low energy systems</p> Signup and view all the answers

    What is the typical airflow rate of foam solution used in most structural and wildland operations with CAFS?

    <p>0.5 to 1 cubic feet per minute</p> Signup and view all the answers

    How are smooth bore nozzles utilized in relation to foam usage?

    <p>Limited to class A foam from a CAFS system</p> Signup and view all the answers

    What is the primary function of air aspirating foam nozzles?

    <p>Induct air into the foam solution by a venturi effect</p> Signup and view all the answers

    Which method is used for class B application when a vertical surface is near or within a pool of ignitable liquid?

    <p>Bank-down method</p> Signup and view all the answers

    How is the biodegradability of foam determined?

    <p>By the rate at which natural bacteria can degrade the foam</p> Signup and view all the answers

    What did studies by U.S. Forest Service reveal about class A foam in bodies of water?

    <p>It can be lethal to fish</p> Signup and view all the answers

    What is the standard application ratio when using durable agents as an extinguishing agent?

    <p>1:100</p> Signup and view all the answers

    What is the chemical composition of durable agents compared to class A foam?

    <p>Water absorbent polymers vs. hydrocarbon based surfactants</p> Signup and view all the answers

    For structure protection, what is the recommended application ratio for durable agents?

    <p>2 to 3%</p> Signup and view all the answers

    Study Notes

    Foam Proportioning Overview

    • A foam proportioner is a device used to mix foam concentrate with water to create foam solution for firefighting.
    • Mechanical foams need water, foam concentrate, and air to be ready for use.

    Foam Concentrates and Solutions

    • Foam concentrate is a concentrated liquid that, when mixed with water, generates foam.
    • Foam solution is the mixture of foam concentrate and water before it is dispensed.

    Foam Completion and Fuel Types

    • Foam is considered a completed product once the foam solution is properly mixed and ready for discharge.
    • Class B foams effectively suppress fires involving hydrocarbon fuels by forming a barrier that prevents oxygen from reaching the fuel.

    Specific Gravity and Fuel Classification

    • Hydrocarbon fuels like crude oil and gasoline typically have a specific gravity of around 0.6 to 0.8.
    • Polar solvent fuels are known as water-miscible fuels.

    Concentration and Storage

    • Typical water concentration for firefighting foam concentrates ranges from 3% to 6%.
    • An external pump method of proportioning foam uses a pump to force foam concentrate into the fire stream.

    Proportioning Methods

    • Premixing method of proportioning foam mixes foam concentrate with water prior to application.
    • Induction method involves drawing foam concentrate into the water stream using a venturi effect.
    • Pouring foam directly into the tank is known as the pour-in method.

    Foam Storage Capacities

    • Foam concentrate tank sizes on fire apparatus can range from 20 to 500 gallons.
    • Foam tenders can carry up to 1,000 gallons or more for storage.
    • A pail typically contains 5 gallons of foam concentrate.
    • Barrels usually hold 55 gallons of foam.
    • Totes can store 275 gallons or more of foam.

    Foam Solution Shelf Life and Application

    • Properly stored foam solution has a shelf life of 10 years or more.
    • Class A foam concentrates can typically be mixed at 0.1% to 1% for fire attack and overhaul with standard fog nozzles.

    Application Rate and Types of Foam

    • Application rate refers to the amount of foam solution applied per unit area of the fire.
    • High expansion foam is suitable for maximum penetration in confined spaces.
    • The appropriate percentage range for proportioning Class A foam with air aspirating nozzles is 0.1% to 1%.

    Specific Foam Recommendations

    • Recommended percentage range for Class A foam when using CAFS (Compressed Air Foam Systems) is typically 0.3% to 1%.
    • Properly stored synthetic foam concentrate usually has a shelf life of around 10 years.

    Class B Foam Concentrations

    • Typical concentration range for Class B foams when used with polar solvents is 3% to 6%.

    Foam Expansion Factors

    • Factors affecting foam expansion include the type of proportioner, water quality, and concentrate formulation.
    • Medium expansion foam typically has a ratio range of 10:1 to 100:1.

    Application Calculations and Foam Types

    • Application rate calculations from nozzles depend on flow rate and nozzle size.
    • Regular protein foam features a protein base, while fluoroprotein foam concentrate contains additional fluorochemical additives.

    Foam Behavior and Application Techniques

    • AFFF (Aqueous Film Forming Foam) or FFFP (Film Forming Fluoroprotein) applied to hydrocarbon fires displaces oxygen and cools the fuel.
    • Alcohol Resistant AFFF concentrate is generally used at a concentration of 3% to 6%.

    Foam Proportioning Devices

    • Foam proportioning devices work on the principle of mixing foam concentrate with water to achieve desired ratios.
    • High expansion foam is primarily used in confined space situations to displace air.
    • An in-line foam eductor allows for continuous mixing and application of foam solution.

    Eductor Specifications

    • Maximum pressure allowed at the discharge side of the eductor is typically around 100 psi.
    • If inlet pressure is too high at the eductor, it may reduce foam effectiveness or damage the unit.

    Eductor Requirements

    • Successful operation of the nozzle and eductor requires proper matching of flow rates and pressures.
    • Recommended inlet pressure range for accurate blending of foam solution is 50 to 70 psi.
    • Height above the foam concentrate for the eductor should not exceed 10 feet to maintain suction.

    Eductor Operation

    • Letting the eductor educt water for one minute allows for proper priming and mixing of foam solution.

    Proportioner Disadvantages and Advantages

    • Around the pump proportioners may lead to inaccurate mixing ratios, especially at low flow rates.
    • Accurate foam proportioners can flow plain water and foam simultaneously for effective dispensing.

    CAFS Considerations

    • A significant limiting factor of using CAFS is the need for a high airflow rate, which may require a larger apparatus.
    • CAFS offers tactical advantages such as faster application rates and better coverage compared to low energy systems.

    Structural and Wildfire Applications

    • Typical airflow rates of foam solution with CAFS in structural and wildland operations can vary but are often around 20 to 40 CFM.
    • Smooth bore nozzles are utilized to deliver a solid stream of foam solution effectively.

    Nozzle Functions and Application Methods

    • The primary function of air aspirating foam nozzles is to create an expanded foam through aeration.
    • For class B foam applications, particularly near ignitable liquid pools, specific techniques must be used to mitigate the flames.

    Foam Biodegradability and Environmental Considerations

    • Biodegradability of foam is usually determined through laboratory testing and environmental impact assessments.
    • Studies by the U.S. Forest Service indicated that Class A foam has minimal long-term environmental effects in bodies of water.

    Durable Agents and Ratios

    • The standard application ratio for durable agents as extinguishing agents typically ranges from 0.3:1 to 0.5:1.
    • Durable agents have a chemical composition that differs from Class A foam, offering unique benefits for structure protection.
    • For structure protection, the recommended application ratio for durable agents ranges from 0.5:1 to 1:1.

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