PDO Questions 501-1000 Flashcards
In fire hose, the following cause friction loss: (6 things)
- Movement of water molecules against each other 2. Linings in the fire hose 3. Couplings 4. Sharp bends 5. Change in hose size or orifice by adapters 6. Improper gasket size
What are the causes of friction loss in piping? (4)
Movement of water molecules against each other, inside surface of piping, pipe fittings, valves
The friction loss in old hose can be as much as ____ greater than the friction loss of new hose.
50 percent
First principle of friction loss
If all other conditions are the same, Friction loss varies directly with the length of pipe.
Second principle of friction loss
When hoses are the same size, friction loss varies approximately with the square of the increase in velocity of flow.
Third principle of friction loss
For the same discharge, Friction loss varies inversely as the fifth power of the diameter of the hose
Fourth principle of friction loss
For a given flow velocity, friction loss is approximately the same, regardless of the pressure on the water.
A pressure of _____ is required to reduce a given volume of water by _____.
30,000 psi; one percent (this is why water is considered incompressible)
The velocity where water velocity is so great that the agitation from friction causes a degree of turbulence.
Critical velocity
Who are considered experts in water supply issues?
Water department officials
T/F In cities the domestic/industrial water demand exceed that required for fire protection.
True. The opposite is true for small or rural towns.
List of ways water can be treated. (6 things)
- Coagulation 2. Sedimentation 3. Filtration 4. Chemicals 5. Bacteria 6. Other organisms
Valves in the water system should be operated _____ to keep them in good condition.
Once a year
Valves in private fire protection systems are usually the _____ type.
Indicating
Public water distribution systems usually are equipped with ____ type valves.
Non-indicating
Common materials for underground pipes (6 things)
- Cast Iron 2. Ductile iron 3. Asbestos cement 4. Steel 5. Plastic 6. Concrete
Unstable or corrosive soils usually get which type of pipe?
Steel or reinforced concrete
How is maximum daily consumption (MDC) calculated when designing a water system?
Max total water used during any 24 hour interval within a 3 year period
Most commonly, private water supply systems receive their water from?
Municipal systems
Use a ____ to measure the forward velocity of flow pressure.
pitot tube
What is used to classify fire apparatus
Primary Function
How should the lug nut tightness be tested on the rear wheels
by hand
What are the steps to clean the interior of the apparatus?
- Park in an appropriat location, 2. chock the wheels, 3. set up work area and equipment, 4. sweep or vacuum large particles, 5. whipe interior surfaces, 6. clean glass, 7. wash exterior
Within what amount of time should pressure rebuild in the braking system after the pressure has been run down and the engine restarted?
60 seconds
What will shut down less important electrical equipment to prevent an overload?
monitor
What is the maximum that the pressure should drop after 1 minute in the straight-chassis vehicle when testing the air brake system?
3 psi
On apparatus after which year is it especially important to check for signs of cracks or leaks in the exhaust system?
2007, due to def
What must be true to check the steering for free play if the apparatus has power steering during an in cab inspection?
Engine must be running
Since what year have most commercial and private vehicles been built with antilock braking systems?
1990
What are the steps to perform daily inspections of apparatus?
- Set up area, 2. check the underside of the apparatus and inside compartments for evidence of water or foam leaks, 3. inspect water and foam tanks for level, 4. check suppression systems on board for damage, 5. all auxiliary fuel is filled, 6. oil tanks are full, 7. check winterization systems
Where is the brake fluid checked in the hydraulic brake system?
Master brake cylinder
Where are the gauge limits typically found that should be used during an in cab operational inspection?
face of the gauge
What are 3 things you should be aware of when jump starting a battery?
Ensure that the vehicle being used as the power source has the same voltage electrical system as the apparatus being jump-started. check manufacturers operations manual before jumping or charching, it will specify which cables should be connected. Make sure that the jumper cables are connected to the specified battery in the recommended manner. Wear ppe
Who should operate all rear running and emergency light switches in the cab one at a time during a routine walk-around maintencance inspection?
Second Firefighter
At full engine RPM, within what amount of time should the air pressure build to 85-100 psi in the air brake system during the in cab operational inspection?
45 seconds
What reading should be seen on the DPF indicatior lamp during an in-cab operational inspection?
OFF
How should the air system be checked for leaks?
The system should be at normal operating pressure and the engine shut off, walk around the apparatus and listen for leaks.
What should be done if any faults are found during the hard intake hose service test?
Mark them
Before what pressure should the air tank pressure warning light and buzzer activate on the air brake system during the in cab operational inspection?
60 psi
What should the dry chemical system be checked for during the daily inspection of an apparatus with a fire pump?
Signs of lumping
What is the maximum amount of vacuum that can be lost in 10 minutes during the hard intake hose service test once the engine has been shut off?
10 inches
What can result if the clutch has excessive free play?
Harsh shifting
What are the steps to stop flowing water during a daily inspection, in order?
Throttle down the engine, closse the discharge valve, replace discharge cap
Where will the correct tire type be listed?
on the sidewall of the tire
Up to how many times greater distance may it take to stop an appparatus on snow and ice than on dry pavement?
15 times
How many points of contact must always be maintained when working on top of an apparatus?
Three
What means that the driver acted while ignoring any potential consequenches of his actions?
reckless disregard
What must be moved by the spotter when backing straight is approved?
forearms
Which type of retarders provide the highest level of braking torque?
transmission output
Where is the braking torque created with the electromagnetic retarder?
rear wheels
Up to how many times the equipment’s weight must the bracked or cabinet be able to restrain the equipment against a force?
ten times
How many underpasses should be driven under during a road test in the fire apparatus?
one
How much hose is pulled out each second when driving 5 mph?
7 feet
Which is the least capable of the four auxiliary braking devices?
Exhaust brake
what is the first thing that the driver should do when entering into a skid without ABS?
Release the brakes then turn the steering wheel in the direction the vehicle should be traveling
What can be used to control engine speed downhill?
Use the service brake, and auxiliary brake as well as manually shifting to lower gears. The engine governor CANNOT control engine speed downhill
Which points are used to determine the breakover angle?
level ground and bottom of the frame
How should the palms be facing when motioning to the driver to slow down?
Downward
What serves as the primary point outside the incident area to which responding units report and recieve initial orders for action?
Base
What are some of the apparatus operation safety guidelines in a wildland incident?
position in a safe area, do not leave apparatus unattended, communicate, keep headlights on , back in, close all windows, establish anchor point, keep a charged line ready for protections, do not drive into unburned fuels higher than the vehicles clearance, use previously burned areas, drive cautious of working crews, sound horn or siren intermittently
_____ pumping is generally used to increase the volume of water available at a fire scene, while ___ pumping is most often undertaken to increase water pressure
Relay pumping and tandem pumping
What level staging is initiated when additional resources are requested by the IC?
Level II
Apparatus should not travel opposing the normal flow of traffic on highways or ramps unless…?
police have closed the road to traffic
In which zone are all incident support functions conducted at the hazardous materials incident?
Cold
Which principle of pressure is used in hydrostatic testing?
Second
How tall does a pressure of 1 psi make a column of mercury
2.04 inches
Which principle of friction loss states that for a given velocity, friction loss is approximately the same, regardless of the pressure on the water?
Fourth
What power of the diameter of the hose does friction loss very inversely for the same discharge?
Fifth
What is velocity propotional to under the second principle of friction loss?
Flow, When hoses are the same size, friction loss varies approximately with the square of the increase in the velocity of the flow.
Which principle of pressure states that the pressure at the bottom of a vessel is independant of the shape of the vessel?
sixth
What is used to create periphery-deflected fog streams?
Inside circular stem in the nozzle
Which monitors often have flow limitations when removed from the apparatus and operated from the ground?
Combination
What causes a spring-activated device to constrict or expand the space between the baffle and the interior throat in the automatic fog nozzle?
water pressure
What is the constant used when calculating nozzle reaction for fog stream nozzles?
0.0505
What is the constant when calculating nozzle reaction for solid stream nozzles?
1.57
What is generally the maximum flow for a handline?
350 gpm
What must be added to the total pressure loss when calculating the pump discharge pressure?
Nozzle pressure
What must be increased to combat the friction loss created when larger volumes of water are needed?
Pressure
How many test runs should be made for each hose size when determining friction loss in hoseline?
three or four
What is the primary consideration when determining how to effectively provide water for fire streams?
Volume of water flowing per minute
What is the only truly accurate method for determining pressure loss in a particular hose lay?
Measure pressure at both ends of the hoseline and find the difference
What is subtracted from the pump discharge pressure to determine the net pump discharge pressure?
Intake reading
4 things that a fire stream is influenced by after it leaves the nozzle and is passing through space.
Velocity, gravity, wind, and friction with air
4 things that influence the condition of the stream when it leaves the nozzle.
Operating pressure, nozzle design, nozzle adjustment, and nozzle orifice condition
Pressure for solid stream handlines.
50 psi
Pressure for solid stream master streams.
80 psi
Solid stream nozzle discharge formula in GPM.
GPM = 29.7 * d^2 * sqrt(NP) for L/min change the coefficient to 0.067
Flow from a 1-inch smooth tip at 50 psi
210 gpm
The line bounding an outward surface; the outward boundary of an object distinguished from its internal regions
Periphery
A turning or state of being turned; a turning from a straight line or given course; a bending; a deviation.
Deflection
To strike or dash about or against; clashing with a sharp collision; to come together with force
Impinge
Most constant flow nozzles use a _____.
Periphery deflected stream
Most constant flow nozzles are designed to operate at ____ psi, but some special designed nozzles can operate at ____ or ____ psi.
100 psi; 50 or 75 psi for things like high rise firefighting
Adjustable flow nozzles are usually designed to discharge the selected flow at ____ psi.
100 psi
High pressure fog nozzles operate at pressures up to ____.
800 psi
High pressure nozzles are best suited for fighting _____ fires.
Wildland
High pressure nozzles generally only discharge ____ gpm.
8-15 gpm
What is generally the max gpm that can be flowed through a handline?
350 gpm
What psi is a fog master stream generally operated at?
100 psi
the three basic types of master stream appliances
fixed, combination, and portable.
Are any special nozzles, such as a cellar nozzle required to be carried per NFPA 1901?
NO
What is another term for a cellar nozzle?
Distributor
If a cellar nozzle is not equipped with a shutoff, an _____ should be placed at a convenient location back from the nozzle.
In-line shutoff
Can a cellar nozzle be used for an attic fire?
YES
General dimensions of a piercing nozzle.
3-6 ft long of 1.5 inch diameter pipe
The chimney nozzle is designed to be placed on the end of a _____.
Booster hose
At a nozzle pressure of 100 psi, the chimney nozzle only produces ______ gpm.
1.5 - 3 gpm
Nozzle reaction clearly illustrates ____.
Newton’s Third Law of Motion
Calculation for solid stream nozzle reaction. (NR in pounds)
NR = 1.57 * d^2 * NP (coeff of 0.0015 for newtons)
Rule of thumb to calculate solid stream nozzle reaction.
NR = Q/3
Calculation for fog stream nozzle reaction.
NR = 0.0505 * Q * sqrt(NP)
Rule of thumb to calculate fog stream nozzle reaction
NR = Q/2
Name the 5 ways that a driver can determine pressure loss and pump discharge pressure while on the fireground.
- Flowmeters 2. Hydraulic calculators 3. Pump charts 5. Condensed Q formula 6. GPM flowing
Flowmeters are particularly advantageous when supplying which type of nozzles?
Automatic nozzles
A flowmeter must provide a readout in increments no larger than _____ gpm.
10 gpm
What are the two types of flowmeters commonly used in the fire service?
Paddlewheel and spring probe
What accuracy/tolerance should flowmeters be calibrated to?
Plus or minus 3 percent
How close does the flowmeter digital readout need to be to the valve control for the discharge?
Within 6 inches
3 Applications for flowmeters
- Diagnosing waterflow problems 2. Relay Pumping 3. Standpipe Operations
What can be assumed if a firefighter has no water volume at the end of the hose, but there is no reduction in the flowmeter reading?
The hose has burst
When relay pumping how can you use a flowmeter to your advantage?
Increase the engine speed until the flowmeter reading no longer increases.
What are the types of hydraulic calculators?
Manual (mechanical) and electronic
Who usually supplies the FD with mechanical hydraulic calculators?
By hose and nozzle manufacturers
What are the inputs into an electronic hydraulic calculator? (4 things)
water flow, size of hose, length of hose lay, and elevation changes
What should you round pump discharge pressures to?
The nearest 5 psi
Can the condensed Q formula be used with metric measurements?
NO, only customary
Which hose sizes can the condensed Q formula be used with?
3, 4, and 5 inch hose
Condensed Q 3-inch formula
FL per 100 ft = Q^2 Divide Q by 100
Condensed Q 4-inch formula
FL per 100 ft = (Q^2)/5 Divide Q by 100
Condensed Q 5-inch formula
FL per 100 ft = (Q^2)/15 Divide Q by 100
The GPM flowing method of calculating friction loss is applicable to which hose streams?
Both solid and fog
What is an advantage of the GPM flowing method of calculating friction loss?
It can be used for hose sizes smaller than 2.5-inch
Does the GPM flowing method of calculating friction losses work in metric system
NO
How does the GPM flowing method work?
Subtract 10 from the first 2 numbers of the GPM flowing to give the FL per 100 ft
On some newer apparatus the pump will not ____ if the parking brake is not set.
Throttle up
What do you do if you are trying to place a PTO pump into gear and the light does not illuminate?
Repeat the procedure of putting the pump into gear
If the pump has been drained and is full of air, how do you allow the air to escape?
Open a discharge or the tank fill valve so that air can escape and water can fill the pump
Operating at a negative pressure (pulling a vacuum) from a fire hydrant is dangerous because it increases the possibility of damage to the fire pump due to ____.
Cavitation
To avoid possible damage to the water system, do not allow the incoming pressure for a hydrant to drop below ____.
20 psi; In rare instances this may happen, but intake pressure should NEVER be allowed to drop to zero
The hydrant closest to the fire is _____ the best choice.
NOT always
Many departments that prefer forward lays us a _____ to aid this process.
four-way hydrant valve
On dry barrel hydrants it is recommended that ____ be attached to the unused hydrant discharges
gate valves
When using 2.5 or 3 inch line to supply a pumper directly off hydrant pressure it is recommended that the lines be _____.
as short as possible to avoid excess friction loss
In a reverse lay, if threaded couplings are used, hose beds should be loaded so that the first coupling to come off is ____.
Male
The _____ lay is the most direct way to supplement hydrant pressure and perform drafting operations.
Reverse lay
When reverse laying a supply hose, it is ____ to use a four-way hydrant valve.
NOT necessary
After fully opened, how far should the valve stem of a hydrant be closed to prevent strain on the stem and internal components?
One-quarter turn
What are the three methods for determining how much more water a hydrant can supply?
- Percentage method 2. First-digit method 3. Squaring the lines method
Formula to calculate drop in pressure as a percentage
Percent drop = (Static-Residual)*100 / Static
Percent decrease in pumper intake pressure vs how many additional lines can be added
0-10% - 3 times that amount being delivered. 11-15% - 2 times. 16-25% - Same amount being delivered. 25+% - More water might be available, but not as much as is being delivered
Can the first-digit method be used with metrics?
NO
Explain the first digit method
Multiply the first digit of the static pressure by 1, 2, or 3. Compare this result to the pressure drop. If the 1 times the first digit is greater than the pressure drop than 3 lines can be added. 2 times than 2 lines can be added. 3 times than 1 line can be added.
Explain the Squared method for determining how many additional lines can be added.
Static pressure must be known. Find the difference in static and residual pressures. Square the number of lines that would be flowing and multiply this by the pressure difference. Subtract this new difference from the original static pressure and if it is about 20 psi, it will work.
Steps for shutting down the pump (4 things)
- slow engine to idle
- take pressure control device out of service
- slowly close discharge valves
- place transmission into neutral
The maximum amount of vacuum that most pumps develop is approximately ____ of mercury.
22 inches
Are compound gauges accurate on the negative side?
NO
Describe the movement of air bubbles as the pump cavitates.
They move from the point of highest vacuum into the pressurized section where they collapse or fill with fluid.
Describe 3 things that affect the point at which cavitation begins.
- Temperature of the water 2. Height of the lift 3. Amount of water being discharged
The best indication of cavitation is ____.
The lack of reaction on the pressure gauge to changes in the setting of the throttle
When does cavitation often result?
With inadequate piping from the water tank
What is the maximum theoretical lift when drafting?
33.9 ft
What is the required vacuum for primer?
22 inches of mercury
Drafting site choice is dictated by the following 3 factors.
- Amount of water 2. Type of water 3. Accessibility of water
What is the most important factor in the choice of the draft site?
The amount of water available
What is a limitation of a floating strainer?
It can only take in water on one side
Where does a low-level strainer sit and how low can water be drafted down to?
It sits on the bottom of a tank or pool; 2 inches
When drafting, Water that is below ____ or above ____ may adversely impact the pump’s ability to reach capacity.
35 degrees F and 90 degrees F
When drafting, What is the most common type of contamination and possible the most damaging water?
Dirty or sandy water
When drafting, As the amount of lift increases what 3 things occur?
- Elevation pressure increases 2. Less friction loss can be overcome 3. Capacity of the pump decreases
What is the maximum lift considered reasonable for most pumpers?
20 ft
At 20 feet of lift, that amount of water that can be supplied is only about ____ of the rated capacity of the pump.
60 percent
When priming the pump for drafting, the transfer valve should be set to the _____ setting.
Parallel (Volume)
Most priming pumps are intended to work best when the engine is set between _____.
1000-1200 rpm
When drafting and after the pump has primed, what should you increase the pressure to?
Between 50-100 psi
When drafting, any deviation from _____ is a signal that another pumper should be used for drafting.
Normal engine temperature
What is the most common problem when drafting?
Air leaks on the intake side of the pump
What other type of strainer can be used in shallow water where whirlpooling is a problem?
A floating dock strainer
In most cases it is desirable to _____ before pumping into and FDC system.
Confirm the presence of fire
Multistage pumps should be in _____ position when pumping to an FDC.
Parallel (Volume)
If specific pump pressures are not available, the general rule of thumb is to discharge ____ psi into the FDC.
150 psi
Pump discharge pressures in excess of ____ are not encouraged unless the standpipe system has been designed to withstand higher pressures.
185 psi
If a standpipe is equipped with pressure reducing valves, the discharge pressure should be based on the ____
Total height of the standpipe
As a last resort, ____ can be laid up the interior stairwell to take the place of a standpipe.
supply hose
In most circumstances the maximum lift is no more than ____.
25 ft
Equation for max lift in terms of inches mercury
L = 1.13Hg
_____ is the height a column of water may be lifted in sufficient quantity to provide a reliable fire flow.
Dependable lift, drivers are more concerned with dependable lift than theoretical lift
Every fire pump in good repair should have a dependable lift of at least ___.
14.7 ft
Equation for pressure correction
Pressure correction = (lift + total intake hose friction loss) / 2.3
What are the two types of static water supplies to draw from?
Natural and man made
What two primary factors should be considered when evaluating a natural static water supply source?
Adequacy and accessibility
What is a solution if an inaccessible water supply source is the only possible source?
Use portable pumps to get the water to a pumper
When using a ladder and salvage cover to make a dam, how long should you leave the cover to form a flap?
About 4 feet
Cisterns vary in capacity; sizes from _____ are common.
10,000 to 100,000 gallons
Pool capacity equation
Capacity in gallons = L * W * D * 7.5
Agricultural irrigation systems may flow in excess of _____.
1000 gpm
Which type of apparatus can be used for relay pumping?
Any type of apparatus equipped with a sufficiently large fire pump
The source pumper should be the pumper with ____.
The largest pumping capacity
Hose tenders usually carry ____.
A mile or more of large diameter (4 inches or greater) hose
Large diameter hose ranges in size from ____ to ____ with the most common sizes being ____.
3.5 inch to 6 inch; 4 and 5 inch hose
In the most basic sense, a relay operation is based on two things.
- The amount of water required at an emergency scene 2. The distance from the emergency scene to the water source
If it is desirable to increase the amount of flow through a relay, one of three things must happen.
- Increase the size of the hose or the number of hoses in the relay 2. Increase the pump discharge pressure 3. Increase the number of pumpers in the relay
All fire department pumpers are rated to pump their max capacity at ____ psi from a draft.
150 psi
In relay pumping, what should intake pressure relief valves be set to?
10 psi above the discharge pressure of the previous pumper in the relay
When decreasing the pressure in a relay, which unit throttles down first?
The attack pumper
The maximum capacity of a relay is determined by _____ and _____.
The smallest capacity pumper and the smallest hoseline used in the relay.
In a relay, the intake relief valve of the attack pumper should be set between ___
50 and 75 psi
Relay operations should be shut down from ___ first.
The fire scene first
What is an advantage of using shuttle operations over relay pumping?
No labor intensive hose loading
What are the three major components of a shuttle operation?
The fill site, the shuttle route, and the dump site
NFPA 1901 requires that tenders have a filling rate of ____.
1000 gpm, because of this the fill site pumper should be at least 1000 gpm
At what gallonage are water tender type apparatus usually switched to tandem axle?
2000 gallons
Water tenders that are used strictly for shuttle operations DO NOT require a fire pump if ___.
They are equipped with a suitable gravity dump system
Tenders with ____ pumps or larger are usually called pumper-tenders.
750 gpm
What are the pumping specs of a vacuum tanker?
Filling rate - 2000 gpm
Lift capability - 22 ft
Dump rate - 1750 gpm
If a tender uses smaller lines to fill there should be ___.
At least two external direct tank fill connections
While NFPA only requires one dump valve, it is highly recommended that each tender is equipped with ___.
At least three; one at the rear and one on each side
Gravity dumps usually employ an ____ or larger round or square valve that extends to the exterior of the apparatus.
8 inches
_____ valves increase the safety of the operation by eliminating the need for someone to exit the cab of the tender.
Remote controlled dump valves
When possible, select a fill site that is capable of providing ____ gpm.
1000 gpm
____ are ideal locations for dump sites.
Parking lots
The ____ route of travel is considered to the be the optimum arrangement when conducting shuttle operations.
Circular route of travel
____ can result in the D/O being unable to slow or stop the vehicle at the bottom of a hill.
Brake fade
IFSTA recommends that a ____ be used to fill tenders at all fill site operations.
Pumper
What are the firefighters that handle the tender fill lines referred to?
Make and break personnel
Unless the fill site pumper is connected to a ____ it is generally not recommended to fill more than one tender at a time.
High flow hydrant
What are the three methods of operating a dump site?
- Direct pumping operations 2. Nurse tender operations 3. Portable water tank operations
Tractor trailer tenders are often used as nurse tenders because ___.
They have a high capacity
_____ are most suitable for continuous water supply operations.
Portable dump tank sites
What affects the actual volume of flow through a dump valve? (3 things)
- Design and size of the dump valve 2. Baffling in the tank 3. Venting capability of the tank
Does pumping and dumping at the same time really save that much time?
Not really, it generally better just to use the dump valve
A single portable tank works on fires that require relatively low overall flow rates (less than ____)
300 gpm
What is the simplest form of dump site operation?
One where only one portable tank is used
What is the recommended capacity of a portable water tank
500 gallons more than the apparatus carrying it has
The most common number of portable tanks used for most jurisdictions is ___ to ___.
2 to 5 tanks
What method of connecting portable tanks is generally discouraged by most authorities on water shuttles?
Drain to Drain connection
The most efficient method of connecting portable water tanks uses ___.
Jet siphons
If four or more portable tanks are to be used, it is advantageous to ___.
Have a second pumper at the dump site to support the jet siphons
Most tenders only dump ____ of their load before heading to be refilled.
90 percent
ISO travel time equation for shuttle operations
Travel time in minutes = 0.65 + 1.7 * (Distance in miles)
What speed is the ISO travel time equation based on?
35 mph
ISO handling time equation for shuttle operations
Handling time = Fill site time + Dump site time
ISO tender flow rate equation
Tender flow rate = (Tender water tank size - 10%) / (Travel time + handling time)
A majority of the foams used today are the _____ type.
Mechanical type, which must be mixed and aerated before they can be used
Define foam solution.
The mixture of foam concentrate and water before the air has been introduced
List several polar solvent fuels (5 things)
Alcohol, ether, acetone, lacquer thinner, and ketones
T/F Many polar solvent foams will work with hydrocarbon fuels
TRUE, but hydrocarbon foams will not work for polar solvent fires
Many modern fuel blends, which include gasoline with ____ or more solvent additives, should be considered as ____.
15 percent; Polar solvents
Usual limits of class A foams
0.1 to 1 %
In the induction mode, the venturi device is known as the ____.
Eductor
The injection method of mixing foam is usually used by ____.
Apparatus mounted or fixed fire protection system applications
What is the simplest method of mixing foam.
Batch mixing
Give an example of a premixed foam system.
Water can
55 gallon barrels of foam are more commonly used with ____.
Industrial applications
Is a standard atmospheric vented foam storage tank acceptable for use?
No, the tank should be airtight
Foam tanks on municipal pumper range from ___ to ___.
20 to 200 gallons
Foam pumpers and tenders may carry up to ____ of foam concentrate.
8000 gallons
Class A foam has been used since the ____.
1940s
The shelf life of class A foam can be as much as ___ if stored properly
20 years
With class A foams, most nozzles produce a more stable foam at ___ concentration, than they will at 0.4 or 0.5% concentrations.
1.00%
With class A foams, using percentages greater than ___ with standard fog nozzles does not appear to increase fire fighting performance.
0.50%
Class A foam proportioning for fire attack and overhaul with fog nozzle
0.2 to 0.5% concentrate
Class A foam proportioning for exposure protection with fog nozzle
0.5 to 1.0% foam concentrate
Class A foam proportioning anytime a air aspirating nozzle is used
0.3 to 0.7% foam concentrate
Class A foam proportioning when using CAFS
0.2 to 0.5% foam concentrate
Protein based foams have a normal shelf life of ___ years.
10 years
Synthetic foams have a shelf life of about ___ to ___ years.
20-25 years
When can different brands of foams be mixed together?
When they meet mil-specs
Class B foams are mixed in proportions ___ to ___ percent.
1 to 6%
Concentration proportion normally used for polar solvent fires
3 to 6 percent
NFPA 11
Standard for Low-, Medium- and High-expansion foams
Expansion ratio for low expansion foams
Up to 20:1
Expansion ratio for medium expansion foams
20:1 to 200:1
Expansion ratio for high expansion foams
200:1 to 1000:1
Regular protein foam (made from animal products) is ____ used in the fire service today.
Rarely
Is a fluoroprotein foam synthetic?
Yes, this is a combination of protein and synthetic foam
Fluoroprotein foam can be formulated to be alcohol resistant by adding ___.
Ammonia salts
Fluoroprotein foam will maintain its alcohol resistive properties for ___ minutes.
15 minutes
What is the most commonly used foam today?
AFFF
Which type of foam can “heal” over?
AFFF
When alcohol resistant AFFFs are applied to polar solvent fires, they create a ___ rather than a film over the fuel
Membrane
How should alcohol resistant AFFF be applied?
Sprayed over the top of the fuel rather than plunged into it
What is the base of high expansion foams?
Detergent
_____ introduce compressed air into the foam solution before it is discharged into the hoseline.
High energy foam systems
The pressure at the outlet of an eductor (back pressure) must not exceed ___.
70 percent of the eductor inlet pressure
Using an eductor inlet pressure lower than the rated pressure results in ____ foam concentrates.
lean
Foam concentrate inlet to the eductor should not be more than ___.
6 ft
What are the flow capabilities of a self educting master stream?
350 to 14000 gpm
What is a JRC?
Jet ratio controller, used for providing foam concentrate to self educting master streams
How far away and what elevation change are acceptable when a JRC is used?
3000 ft away and up to 50 ft elevation change
The flow of water to the JRC represents about ___ percent of the total flow in the system.
2.5 percent
What does a JRC proportion the concentrate at?
A 66.5 percent solution
Installed in-line eductors are most commonly used to proportion ____.
Class B foams
Why are in-line eductors not effective for proportioning class A foams?
Because class A foams have such low proportions (0.1 to 1.0%)
In around-the-pump proportioners, how much water is sent to the bypass line that educts the foam?
10-40 gpm
What is one of the most accurate proportioners used?
Bypass type balanced pressure proportioner
Can a apparatus with a bypass type balanced pressure proportioner discharge water and foam at the same time from different discharges?
YES
How is a variable flow variable rate direct injection proportioner powered?
From the apparatus electrical system (Large volume systems may use electric and hydraulic)
What proportions can variable flow variable rate proportioners provide?
0.1 to 3.0%
Can variable flow variable rate proportioners be used with alcohol resistant foams?
NO, due to the high viscosity of the concentrate
Generally batch mixing is only used with _____ foam concentrates and regular ____ concentrates.
Class a, AFFF (not alcohol resistant)
Class A foam solutions do not retain their foam properties if mixed for longer than ____.
24 hours
How much airflow is used for 1 gallon of foam solution flow to produce a very dry solution up to 100 gpm?
2 cfm
Most structural and wildland fire attacks with CAFS are done with an airflow rate of ___ to ___.
0.5 to 1.0 cfm of foam solution
What are expansion ratios using fog nozzles?
2:1 to 4:1
What is the only type of nozzle that can be used with protein or fluoroprotein foams?
Air aspirating nozzle
When is the rain down method used for foam application?
The the roll on or bank down method are not feasible
What is the primary technique for foam application on elevated storage tanks?
Rain down method
nfpa 1150
standeard on foam chemicals for fire in class a fuels
What are other terms for durable agents?
gelling agents, fire blocking gels, and aqueous fire fighting gels
Durable agents are ____.
water-absorbent polymers
Durable agents consist primarily of ___.
water
Durable agent proportion percentages
- Fire extinguishment - 1 percent 2. Fire line construction - 1.5 to 2 percent 3. Structure protection - 2-3 percent
How long will durable agents adhere to vertical surfaces?
Up to 24 hours
Durable agents can be ____ with a fine water mist to extend their protection for several days.
rehydrated
