Chapter # 15 Foam Equipment and Systems Flashcards
Name three reason that foam and durable agents has increased dramatically in municipal and wild land firefighting.
Increase in HAZ MAT incidents that require foam.
New advancements in foam concentrates have made is easier to use.
Improvements in foam proportioning that have made there inclusion in the construction of a new pump or a addition to a existing pump feasible.
The majority of foams in use today are of this type. they must be proportioned and aerated before they can be used.
Mechanical type
The raw foam.
Foam concentrate.
The device that introduces foam concentrate into the water stream.
Foam Proportioner.
Mixture of foam concentrate and water.
Foam Solution.
The completed product after air is introduced into the foam solution.
Foam (finished foam)
Should produce uniformed sized bubbles to provide a long lasting blanket.
Proper Aeration
What type of fuel should modern fuels with additives be considered?
Polar solvents.
T or F Some polar solvent foams can extinguish a hydrocarbon fire, but hydrocarbon fuels can never extinguish a polar solvent fire?
True
Creates a barrier between the fuel and the fire.
Seperating
Lowers the temp of the fuel and adjacent surfaces.
Cooling
Prevents the release of vapors.
Suppressing (smothering)
The three ways foam extinguishes a fire or prevents a fire.
Separating. Cooling. Suppressing.
Most foam concentrates are intended to be mixed with what type of water?
Fresh or salt water.
Most fire fighting foam concentrates are intended to be mix with …….. to ….. water.
94% to 99.9%
Can be adjusted within limits recommended by the manufacturer. (usually 0.1 to 1.0%), to achieve a specific objective.
Class A foam
Name the four ways foam is proportioned.
Induction. Injection. Batch mixing. Premixing.
Uses the pressure energy in a water stream to educate the foam concentrate through a venturi device.
Induction
Uses a external pump of head pressure to force foam concentrate into the fire stream at the correct ratio in comparison to the fire stream.
Injection
The simplest method of mixing foam concentrate and water. Foam concentrate is poured directly into the water tank. Common for class A foam, but should only be used as a last resort for class B foam. If Class B is used it must be circulate (mixed) in the pump before use. Not effective on large incidents.
Batch Mixing
One of the more commonly used methods of proportioning. Used with portable extinguishers, wheeled, skid mount twin agent units, and vehicle mounted tank. Typically discharged from a compressed air or a inert gas like nitrogen. One time application.
Premixing
Name the four common ways that foam concentrate is stored.
Pails. Barrels (drums). 275 gallon tote tanks. Apparatus tank.
Most common container used by municipal fire service to receive and store foam concentrate. Must be a air tight container.
Pail (5 gallons)
More common foam concentrate storage container in industrial applications. Can transfer from this storage devices to another one.
Barrels or drums. 55 gallon plastic or plastic lined.
May be a good choice and money saving if large amounts of foam concentrate are expected to be used.
Totes (275 gallons).
Found on municipal and industrial pumpers, foam tenders, and ARFF apparatus. May also be mounted on a trailer. Has to be airtight, standard vented atmospheric storage tanks are not acceptable. Tank should also be equipped with a pressure vacuum vent. Size on municipal pumpers range from 20-200 gallons. Foam pumpers and tenders may carry 8,000 gallons or more of foam concentrate.
Apparatus tanks.
Proven effective in fires in structures, wildland, coal mines, tires storage, and other deep seated fires.
Class A foam
A formulation of hydrocarbon surfactants that reduce the surface tension of the water in the foam solution.
Class A foam
When Class A foam is used with a CAFS system it has what?
Excellent insulating properties.
What can the shelf life of class A foam be?
20 years.
Common class A foam proportioning for specific types of incidents.
Fire attack and overhaul w/ a standard fog nozzle = 0.2-0.5 %.
Exposure protection with standard for nozzle = 0.5 - 1.0%.
Any application with a air aspirating foam nozzle. = 0.3-0.7%.
Any application with a CAFS = 0.2-0.5%.
Refers to the minimum amount of foam solution that must be applied to a fire, per minute, per square foot of fire.
Application rate.
What is the application rate of class A foam?
The same as the minimum critical flow rate for water.
Elements that affect the breakdown time of finished foam.
Heat of the fire. Height of flames. Ambient air temp and wind.
Used to extinguish fire involving flammable and combustible LIQUIDS.
Class B foam.
What type of class B foam can be applied with a standard for nozzle?
AFFF and FFFP
T or F Class B foam concentrates are made from either a synthetic or protein base. Protein base are derived from animal protein. synthetic is made from a mixture of flurosurfactants.. Some foam is a combination of the two.
True