Chpt 14 Flashcards
The national institute of standards and technology has determined that foam is ______ more effective than plain water in extinguishing fires, which can justify its use and added expense at an incident site
Three to five times
Is a device that mixes the foam concentrate into the fire stream in the proper percentage
Foam proportioner
The expansion of foam solution depends on good mechanical agitation and effective ______, the process of introducing air into the foam solution
Aeration
Foam tetrahedron includes four components
Water
Foam concentrate
Air
Mechanical agitation
Are produced when water and foam concentrate are mixed in the appropriate amounts
Mechanical foams
Hydrocarbon fuels, such as gasoline, jet fuel, and kerosene, have a lower _______ than water
Surface tension
Comprises the time required for a foam blanket to spread out across a fuel surface
Knockdown and speed flow
Are used on ordinary combustible materials such as wood, textiles, and paper; they are also effective on organic materials such as straw and hay.
Class A
Class A foams sometimes referred to as ______, are very effective because they improve the penetrating effect of water and allow for great heat absorption
Wetting agents
According to foam manufacturers, these wetting agents can extinguish fie involving class A materials as much as _____ faster than water
20 times
Is particularly useful for protecting buildings in rural areas during forest and brush fires when the water supply is limited
Class A foam
Many fire departments use ____ while performing initial attack and overhaul of fires
Class A foam
Class A foam increases the effectiveness of the water as an extinguishing agent by reducing the _____ of the water
Surface tension
Are used on hydrocarbon, combustible fuels, or polar solvent fires
Class B foams
A _____ reduces the surface tension of water and enhances penetration into fuel that is burning
Wetting agent
A ____ creates a stable mass of small, air filled bubbles with lower density than oil, gas, or water and will float on top of burning fuel, creating a blanket that separates the fuel from air, lowering the Temperature and suppressing the vapors
Foam
Are used to extinguish class B fires involving hydrocarbons
Protein foams
Contain naturally occurring proteins that is, animal by product as the foaming agent.
Protein foams
They produce highly stabilized mechanical foam with good expansion properties, excellent heat, and ______ and good drainage characteristics
Burn back resistance
Consists of hydrolyzed protein, stabilizers, preservatives, and synthetic fluorocarbon surfactants
Fluoroprotein foam
This type of foam is used for hydrocarbon vapor suppression and extinguishment of fuel in depth fires
Fluoroprotein foam
Have slower knockdown characteristics than other concentrates, but they provide a long lasting foam blanket after the fire is extinguished
Regular protein foams
Because they must be properly aspirated, these foams should not be used with non aspirating structural fog nozzles
Fluoroprotein foams
Is able to form a vapor sealing film on non polar solvents
Film forming fluoroprotein foam
Knockdown performance is improved because the foam releases an aqueous film on the surface of the hydrocarbon fuel
Film forming fluoroprotein foams
Can be used on both hydrocarbon and water soluble fuels
Alcohol resistant film forming fluoroprotein foam
AR-FFFP is basically FFFP with a _______ additive
Polysaccharide polymer additive
Is based on combination of flurochemical surfactants, hydrocarbon surfactants, mad solvents
AFFF aqueous film forming foam
Because of the versatility of ____; it is used by the majority of municipal and airport fire departments in North America
AFFF
It’s ability to flow quickly allows _____ to achieve a very fast knockdown of hydrocarbon fuels
AFFF
Aspirating foam nozzles Should be used to apply _____ to ensure maximum performance
AFFF
Comprises a combination of synthetic detergents, flurochemicals, and high molecular weight polymers
Alcohol resistant aqueous film forming foams
AR-AFFF
Is one of the most versatile type of foam.
AR -AFFF
Are highly effective in confined space firefighting operations and in areas where access is limited or entry is dangerous to fire fighters, such as basements, ship board compartments, warehouses, aircraft hangars, and mine shafts
High expansion foams
High expansion foams can be used on either ____ fires
Class a or class b fires
The foam concentrates are normally proportioned in rations between 1 to 3 percent for these uses
High expansion foams
Are designed to be mixed with water at specific ratios
Foam concentrates
Foam concentrate ratios vary from _____ for class a foams
0.1 to 1 percent
Foam concentrate ratio for class b
1 to 6 percent
Alcohol resistant foams can be used effectively on both hydrocarbon and polar solvent fuels. ______ is the most commonly used concentrate for this purpose; it is available in a variety of percentages
AR-AFFF
The _____ is the ratio of finished foam to foam solution after the concentrate is mixed with water, agitated, and aspirated through a foam making appliance
Foam expansion rate
Low expansion foam Has a foam expansion ratio of up to
20:1
This type of foam is primarily designed for use on flammable and combustible liquids
Low expansion foam
Low expansion foam is effective in controlling and extinguishing most
Class B fires
Medium expansion foam has a foam expansion ratio in the range of _______
20:1 to 200:1
This kind of foam is used primarily to suppress vapors from hazardous chemicals
Medium expansion foam
Foams with expansion ratios between ______ have been found to produce the optimal foam blanket for vapor mitigation of highly reactive chemicals and low boiling points
30:1 and 55:1 medium expansion foam
High expansion foams has a foam expansion ratio in the range of
200:1 to 1000:1
This type of foam is designed for confined space firefighting
High expansion foams
The foam concentrate consists of a synthetic, detergent type foam used in confined spaces such as basements, mines, ship board, and aircraft hangars
High expansion foams