Fire Science Chapter 14 Quiz & Flashcards

Questions and Answers

What should not exceed the rated capacity in gallons per minute through the eductor?

The flow

Which kind of nozzle inducts air into foam solution by a Venturi action and is the only nozzle that should be used with protein and fluoroprotein concentrates?

Master stream foam nozzles

Smooth bore nozzles

Air-aspirating foam nozzles (correct)

Fog nozzles

Batch mixing is generally only used with which types of foam concentrates?

Class B and regular AFFF concentrates

Class B and alcohol resistant AFFF concentrates

Class A and alcohol resistant AFFF concentrates

Class A and regular AFFF concentrates (correct)

What is the percentage of Class A Foam?

1-1 Percent Signup and view all the answers

What is the percentage of Class B foam?

1-6 Percent Signup and view all the answers

The minimum amount of foam solution that must be used on a fire per minute per square foot (square meter) of fire is called the:

Application rate Signup and view all the answers

Which of the following BEST explains why fuel and fire might consume a portion or the entire foam blanket?

Inconsistent application time Signup and view all the answers

Installed in-line eductors are most commonly used to proportion which class of foam?

Class B Signup and view all the answers

Regardless of the type of tank, what is one characteristic that all foam storage containers share?

Airtight storage Signup and view all the answers

Driver/operators calculate the application rate available from a specific nozzle by:

Dividing the flow rate by the area of the fire Signup and view all the answers

For a portable foam application device, once foam concentrate and water have mixed to form a foam solution, the solution must be:

Aerated Signup and view all the answers

In which of the following situations is it acceptable to mix together different manufacturers' foam concentrates?

If they are mil-spec concentrates Signup and view all the answers

Which proportioning method uses premeasured portions of water and foam concentrate that are mixed in a container?

Premixing Signup and view all the answers

What is the smallest type of foam storage container?

Pails Signup and view all the answers

In order to produce fire fighting foam, what three items must be educted or injected in correct ratios?

Foam concentrate, water, and air Signup and view all the answers

Which of the following factors is MOST likely to affect the degree of expansion in a foam solution?

Method of aeration Signup and view all the answers

Which of the following has a pickup tube that is located in the center bore of the nozzle and uses a modified Venturi design to draw concentrate into its water stream?

Self-educting master stream foam nozzle Signup and view all the answers

What are Mil-Spec concentrates?

Foam concentrates manufactured to U.S. Military specifications Signup and view all the answers

Which of the following is the most common apparatus-mounted foam proportioner and consists of a small return (bypass) water line connected from the discharge side of the pump back to the intake side of the pump?

Around-the-pump proportioner Signup and view all the answers

Which of the following is a disadvantage of durable agents?

Once applied, surfaces coated with these products become very slippery for walking or driving Signup and view all the answers

The act of mixing water with foam concentrate to form a foam solution is called:

Proportioning Signup and view all the answers

Low energy foam systems impart pressure on the foam solution with the use of the:

Main fire pump Signup and view all the answers

Which of the following is true about the adequate and/or inadequate production of foam when an in-line proportioner is used?

A partially closed nozzle will result in a flow rate that will not allow the creation of a Venturi effect Signup and view all the answers

In some installed in-line eductor systems, a(an) ____ proportioner is installed to reduce the friction loss across the eductor.

Bypass Signup and view all the answers

Which method for Class B foam application involves directing the foam onto a vertical surface and allowing it to run down and spread across pooled fuel product?

Bank-down method Signup and view all the answers

Which kind of nozzle allows firefighters the option of operating fixed flow, selective flow, or automatic flow when applying a low expansion, short duration foam blanket?

Fog nozzles Signup and view all the answers

What is the commonly used guideline for proportioning Class A foam for exposure protection with standard fog nozzles?

0.5 to 1.0 percent concentrate Signup and view all the answers

Which of the following is determined by the rate at which natural bacteria can degrade foam?

Biodegradability Signup and view all the answers

What are the two basic types of medium- and high-expansion foam generators?

Water aspirating and mechanical blower Signup and view all the answers

Which of the following are examples of polar solvent fuels requiring the use of special polymeric fire fighting foam?

Alcohol and ketones Signup and view all the answers

The formula of Class A foam includes ____ that reduce the surface tension of water in the foam solution.

Hydrocarbon surfactants Signup and view all the answers

Which foam is MOST likely to be used to combat concealed space fires in cellars or other subterranean spaces?

High-expansion foam Signup and view all the answers

Which of the following is an element that affects the breakdown process of Class A foam?

Ambient air temperature Signup and view all the answers

Due to the low eduction rates on a CAFS apparatus, what is required to supply the fire stream at the rate of 0.1 to 1.0 percent?

A variable flow rate sensing proportioner Signup and view all the answers

Which of the following is released as fire fighting foam breaks down, providing a cooling effect on the fuel and suppressing the process of heat-producing oxidation?

Water Signup and view all the answers

Both of the basic types of medium- and high-expansion foam generators produce foam containing:

High air content Signup and view all the answers

In order to eliminate using pails or barrels to supply a foam eductor, fire apparatus equipped with onboard foam proportioning systems usually have ____ piped directly to the delivery system.

Foam concentrate tanks Signup and view all the answers

Class A foam solutions do not retain their foaming properties when mixed in water for more than:

24 hours Signup and view all the answers

Which of the following is a variable that affects a foam's rate of application?

Whether the fuel is contained or uncontained Signup and view all the answers

Direct application is a method of attack that is BEST used with:

Class A foam Signup and view all the answers

Class B synthetic foam concentrate is made from:

A mixture of fluorosurfactants Signup and view all the answers

Which of the following are designed to work in conjunction with proportioners to produce the best possible foam?

Foam nozzles Signup and view all the answers

Which of the following statements about variable-flow demand-type balanced pressure proportioners is MOST accurate?

It features the ability to monitor the demand for foam concentrate and adjust the amount of concentrate supplied Signup and view all the answers

A type of in-line eductor that may be used to supply foam concentrate to a self-educting master stream foam nozzle is called a:

Jet ratio controller Signup and view all the answers

The process of foam decomposition results in the consumption of:

Oxygen Signup and view all the answers

Which of the following is a common handline nozzle used for foam application?

Fog nozzle Signup and view all the answers

Because it forms a rigid coating that adheres well and is slow to drain, the best consistency of Class A foam for vertical surfaces is:

Dry foam Signup and view all the answers

When using the batch mixing proportioning method, frothing can be avoided by:

Slowly circulating water in the tank Signup and view all the answers

Which of the following statements about regular protein foams is MOST accurate?

They degrade more quickly and are becoming increasingly rare Signup and view all the answers

Which proportioning method uses an external pump to force foam concentrate into the fire stream at the proper ratio in comparison to the flow?

Injection Signup and view all the answers

Which foam consists of fluorochemical and hydrocarbon surfactants combined with solvents to create a high boiling point?

Aqueous film forming foam (AFFF) Signup and view all the answers

Which of the following is a proportioner used on large mobile apparatus installations, such as ARFF vehicles, and is one of the most accurate methods of foam proportioning?

Bypass-type balanced pressure proportioner Signup and view all the answers

Viscosity, or the thickness and ability of a liquid to flow freely, is MOST likely to be affected by:

Temperature Signup and view all the answers

Which of the following is BEST described as the device that injects the correct amount of foam concentrate into the water stream to make the foam solution?

Foam proportioner Signup and view all the answers

In which of the following ways are durable agents similar to Class A foam?

Both products are used in a similar fashion Signup and view all the answers

Which of the following is a limitation of CAFS?

In the event of a hose burst, compressed air will intensify the reaction of the hoseline Signup and view all the answers

High-energy foam generating systems/CAFS differ from other methods because:

They introduce compressed air into the foam solution prior to discharge into the hoseline Signup and view all the answers

Which of the following is a basic foam proportioner that is designed to be attached directly to the pump panel discharge or connected at some point in the hose lay?

In-line foam eductors Signup and view all the answers

A smooth bore nozzle is limited to the application of which classification of foam?

Class A foam from a CAFS Signup and view all the answers

Which of the following statements about batch mixing is MOST accurate?

It is potentially inaccurate Signup and view all the answers

Why is it important to avoid direct application of Class A foam to natural bodies of water?

It can harm aquatic life Signup and view all the answers

When operating an in-line foam eductor, which of the following operating guidelines must be followed to achieve properly proportioned finished foam?

The pressure at the discharge side of the eductor must not be less than 70 percent of the eductor inlet pressure Signup and view all the answers

Study Notes

Foam Application and Properties

Application Rate: Minimum foam solution required is referred to as the application rate, which is determined per minute and per square foot (or meter) of fire area.
Foam Blanket Consumption: Inconsistent application time can lead to consumption of a portion or all of the foam blanket by fuel and fire.
Mixing with Water: Class A foam solutions lose foaming properties if mixed with water for over 24 hours.

Foam Proportioning and Storage

Installed In-line Eductors: Primarily used for Class B foam.
Foam Storage Containers: All foam storage tanks share the characteristic of being airtight to prevent contamination and degradation.
Foam Concentrate: Essential components for producing firefighting foam include foam concentrate, water, and air.

Mixing Methods

Premixing: Involves premeasured portions of foam concentrate and water mixed in a container.
Batch Mixing: Can lead to frothing unless water is slowly circulated in the tank.
Injection Method: Uses an external pump to accurately introduce foam concentrate into the water stream.

Foam Generators and Nozzles

Foam Generators: Two basic types are water aspirating and mechanical blower generators, both producing foam with high-air content.
Foam Nozzles: Fog nozzles offer flexibility for operating fixed, selective, or automatic flow, while air-aspirating nozzles are designed for use with protein and fluoroprotein concentrates.

Specific Foam Characteristics

Biodegradability: Refers to the rate at which natural bacteria can degrade foam.
Durable Agents: Although effective, they create slippery surfaces post-application, which may pose safety risks.
Polar Solvent Fuels: Examples include alcohol and ketones, requiring specialized polymeric firefighting foam.

Class A and Class B Foams

Class A Properties: Foam concentrate percentage for exposure protection typically ranges from 0.5 to 1.0 percent.
Class B Properties: Made from fluorosurfactants; application rates can range from 1 to 6 percent based on the specific foam type and fire scenario.

System Limitations and Considerations

CAFS Limitations: The system's hoses can exacerbate burst reactions due to compressed air while being effective at low eduction rates.
Temperature Effects: Ambient air temperature affects the breakdown process of Class A foam and the viscosity of foam solutions.

Application Techniques and Situations

Direct Application: Class A foam is best used with direct application methods for combating specific scenarios.
Bank-down Method: Involves directing foam onto vertical surfaces for spreading across pooled fuel.
Colloquial Feed Systems: Systems like the around-the-pump proportioner use small return water lines to balance water and foam concentrate.

Foam Types and Uses

High-Expansion Foam: Preferred for concealed space fires due to its volume and ability to fill spaces effectively.
Film Forming Fluoroprotein Foam (FFFP): Often used in situations requiring high efficiency and effectiveness.

Key Equipment and Performance

Self-Educting Master Stream Foam Nozzle: Utilizes a modified Venturi design for concentrate integration.
Variable-Flow Demand-Type Proportioners: Adjust foam concentrate based on demand while maintaining effective flow.
Foam Proportioner: Essential device for injecting the correct amount of foam concentrate into the water stream.

Best Practices

Quality Control: Ensure nozzle pressure is maintained for effective foam generation and delivery.
Avoiding Environmental Harm: Direct application of Class A foam to natural water bodies should be carefully monitored to prevent ecological damage.

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Test your knowledge with these flashcards covering crucial concepts from Chapter 14 about Foam Equipment and Systems. This quiz includes key terms like application rate and factors affecting foam effectiveness in fire suppression. Perfect for fire science students or professionals looking to refresh their understanding.

Fire Science Chapter 14 Flashcards