Chapter 13 - Foam Types and Systems

What is the key ingredient in AFFF foam that is harmful to health and the environment?

Fluorosurfactants

The primary concern with finished foam after application to a fire or spill is:

The environmental impact

Which statement describes how the biodegradability of a foam impacts the environment?

The less O₂ required to degrade a particular foam, the more environmentally friendly the foam is when it enters a body of water

Mixing the proper % of foam concentrate and water is known as:

Proportioning

How is mechanical foam created?

Introducing air into a foam solution

A higher introduction of air causes a ___ in the finished foam:

Greater expansion ratio

Class A foams may be mixed with percentages as low as:

0.1%

Foam expansion is the increase in the volume of foam solution after:

Aeration

Class B foams mix in proportions from:

1% - 6%

The foam concentration for polar solvents compared to the foam concentration for hydrocarbon fuels is typically:

Higher (3% hydrocarbon, 6% polar solvents)

Some foam concentrates that are UL Solutions listed as a combination foam can be used:

On Class A, B, D, and K fires

In a foam eductor, water flowing across an orifice at a right angle to the flow inducts (drafts) foam into the water stream due to the ___ effect

Venturi

A self-educting master stream foam nozzle uses a pickup tube located:

In the center bore of the nozzle

How does an installed in-line eductor compare to a portable in-line eductor?

The same operating principles apply

Variable-flow variable-rate direct injection systems proportion foam concentrates up to 6% in increments of:

0.1%

With a variable-flow demand-type balanced pressure proportioner, the:

Flow of foam concentrate matches the pressure demand

When batch mixing foams, Class A foam solutions do not retain their foaming properties after:

24 hours

When batch mixing foam, regular AFF concentrate mixes readily with water and remains suspended in the solutions for:

An extended time

When batch mixing foam, the D/O should slowly circulate the water in the tanke to prevent:

Frothing

After a water tank is used for batch mixing, and it has been thoroughly flushed, the D/O should:

Check seals for proper lubrication

A compressed air foam system works as a:

High-energy foam system

Compressed air foam system (CAFS) supplies foam to the fire stream at a rate of:

0.1% - 1%

In foam operations, a smooth bore nozzle is effective when used in the application of:

Class A foams from a CAFS

Personnel may use fog nozzles when applying a ___ foam blanket

Low-expansion, short-duration

Expansion ratios for fog nozzles range from:

2:1 to 4:1

The air content for medium-expansion foams ranges from:

20:1 to 200:1

Foam expansion is developed by use of:

Air-aspirating equipment

High-expansion foam generators work as ___ that produce foam containing high air content

Mechanical Blowers

The expansion ratio for high-expansion foam ranges from:

200:1 to 1000:1

Placing a foam line into operation using an ___ achieves a basic foam delivery system

In-line proportioner

Proper pressure at the eductor is generally:

150 to 200 psi (1035 to 1380 kPa)

The pressure at the discharge side of the eductor must not exceed ___ of the eductor inlet pressure

70%

When operating an in-line eductor system, too low inlet pressures will not create the ___ effect necessary to pick up the foam concentrate

Venturi

What is the maximum height of the eductor above the liquid surface of the foam concentrate?

6ft (2m)

Foam concentrates are generally considered:

Corrosive on equipment