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