1
Q
How to prevent pump from overheating during incident
A
- If water is not flowing for an extended period of time, pump can overheat
- Moving water through the pump must be implemented: booster cooling valve, circulator, or bypass can be set to open and circulate water back into the tank
PG 338
2
Q
Transitioning to an External water supply
A
- Connect supply line to appropriate intake of fire pump
- Make connection to intake with closed gate valve
- Open bleeder vale on the gated intake so that air can escape ahead of the water supply; shut the bleeder valve done after a steady stream of water drains from the valve
PG 338
3
Q
Residual Pressure
A
- Driver/operators should maintain a residual pressure of at least 20PSI on master intake gauge at all times
PG 340
4
Q
Choosing a Hydrant
A
- ## Closest hydrant to the fire may not always be the most prudent choice (due to pumping capability or danger in location)
5
Q
“Dead End Mains”
A
Water main that is not looped and in which water can flow in only one direction
- Generally have high amounts of sediment and deterioration
PG 340
6
Q
Forward Lay
A
- Method of laying hose from the water supply to the fire scene
- Stop at hydrant, drop end of supply line with FF, proceed to fire location
PG 341
7
Q
Four-Way Valve Hydrant Operation
A
- Connect valve to the hydrant
- Connect original supply line, laid by first pumper, to the supply line outlet
- Open the hydrant. The clapper valve has operated to allow water to flow in the supply line
- Connect second pumper to the large diameter pumper intake connection on the four-way vale
- Open pumper intake valve. Open the four-way valve on the hydrant to supply the pump without interfering with the flow through the original supply line
- Connect one of the pumper discharge outlets to the second intake of the hydrant valve
PG 343
8
Q
Reverse Lay
A
- Method of laying hose from the fire scene to the water supply
- Apparatus reports to scene before laying a supply line back to the hydrant
- Load the hose with a male coupling to come out of the bed first, using hose with threaded couplings for a reverse lay
PG 344
9
Q
Master Intake Gauge Pressure Reading
A
- When pump is full of water and pressure in the system with no water flowing, this reading indicates the static pressure in the water supply system
- This reading is important for estimating the remaining capacity of the hydrant as the water begins to move
- Driver/operator should record the static pressure reading before he/she begins to pump
PG 346
10
Q
Methods to prevent overheating of the pump
A
- Establish continual minimum flow during intermittent use of water in fire ground operations to keep the pump from overheating
- Pull a length of booster line or small diameter line and fasten it to a sturdy object
- Open the valve that supplies the booster reel and discharge water in a direction that will not interfere. The booster line may also be directed back into the tank to circulate water continuously
- Open discharge drain valve.
- Partially open the tank fill vale or tank to pump line. Even if the water tank becomes full and overflows, this result is preferable to the pump overheating
PG 347
11
Q
Residual Pressure
A
When the pumper is discharging water, the intake gauge displays the residual pressure
PG 347
12
Q
Static Pressure
A
When the pumper is not discharging water, the intake gauge displays the static pressure
PG 347
13
Q
Methods to determine how much more water the hydrant can supply
A
- Difference between static pressure and residual pressure
1. Percentage method
2. First digit method
3. Squaring the lines method
PG 347
14
Q
Percentage Method
A
- First calculate drop in pressure as a percentage:
Percent Drop = (Static-Residual)(100)/Static - Determine how much more water is available based on percentage drop:
0-10% = 3x current amount being delivered
11-15% = 2x current amount being delivered
16-25% = Same amount being delivered
25%+ = More water might be available, but not as much as is currently being delivered
PG 348
15
Q
First Digit Method
A
- Quick and easy way to calculate available water using PSI and GPM
1. Find the difference in PSI between static and residual pressures
2. Multiply the first digit of the static pressure by 1, 2, or 3 to determine how many additional lines of equal flow may be added
If PSI drop is equal to or less than the first digit of the static pressure multiplied by 1, three additional lines can be flowed
If PSI drop is equal to or less than the first digit of the static pressure multiplied by 2, two additional lines can be flowed
If PSI drop is equal to or less than the first digit of the static pressure multiplied by 1, one additional line can be flowed
PG 349
16
Q
Squaring-The-Lines Method
A
- Note static pressure before any pump discharges are open
- Must also have close idea of the volume of water initially flowed by the pumper.
- Use these numbers to determine the additional amount of water available and square the number of lines currently flowing and multiply this by the original pressure drop
PG 350
17
Q
Pressure Differential
A
Effect of altering the atmospheric pressure within a confined space by mechanical means.
- When air is exhausted from within the space, a low pressure environment is created and replacement air will be drawn in
- When air is blown into the space, a high pressure environment is created and air within will move to the outside
Necessary when drafting from static water source that is below the level of the fire pump
PG 352
18
Q
Cavitation
A
- Water being discharged faster than it is coming into the pump
- Occurs when air cavities are created in the pump or bubbles pass through the pump
- They move from point of highest vacuum into the pressurized section, where they collapse or fill with water
- This high velocity of water filling these cavities causes a severe shock to the pump
PG 354
19
Q
Selecting Water Drafting Site
A
- Amount of water: large quantity available; rapid replenishment (stream)
*Must be at least 24” of water over the strainer - Type or quality of water: pumping “nonpotable water” (untreated water) may be harmful to the pump; saltwater can cause corrosion to pipes; avoid dirt and sand
- Accessibility of water: choose a site with low lift to be able to supply more water
PG 356-357
20
Q
Connecting Pump for Drafting
A
- Place apparatus at location from which intake hose will be deployed
- Set parking brake, chock wheels
- Place out traffic control devices
- Do not engage pump until all connections are made and it is ready to be put in operation
- Inspect gaskets for dirt and debris; couple together strainer and intake hose
- Fasten rope to end of strainer to aid in handling of hose and proper positioning of strainer
PG 358
21
Q
Priming Pump for Drafting
A
- Must be in parallel (volume) position in two-stage pump
- Set RPMs between 1000-1200RPM
- Operate primer control (typically takes 10-15 seconds for full prime)
- Increase throttle to raise pressure to between 50-100psi
PG 360
22
Q
Operating Pump for Drafting - Problems
A
- Air leak on intake side of pump –> recheck intake hose couplings
- Whirlpool allowing air to enter pump –> not enough water above drafting strainer; place floating object above strainer
- Air leakage due to defective pump packing
PG 361
23
Q
Shutting Down Pump from Drafting
A
- Slowly decrease engine speed to idle
- Take pump out of gear
- Allow pump to drain
- Operate positive displacement primer for several seconds until primer oil or fluid comes out of primer pump discharge
PG 362
24
Q
Supporting Automatic Sprinkler Systems
A
- Agency should have policy on suggested discharge pressure for pumping FDC; if not, pump at 150psi
PG363
25
Supporting Standpipe Systems
- Wet or dry system of pipes in a large single story or multistory building, with fire hose outlets installed in different areas or on different levels of a building to be used by firefighters and/or building occupants
- Allows for quick deployment of hoseline during fire fighting operations
PG 364
26
Wet Standpipe System
- Contain water under pressure and may be used as soon as a hoseline is stretched and the vale is opened
PG 364
27
Dry Standpipe System
- Must be charged with water from the occupancy's water supply, stationary fire pump, a fire department pumper, or a combination of sources
PG 364
28
Pressure Reducing Valves
- Valve installed at standpipe connection that is designed to reduce the amount of water pressure at that discharge to a specific pressure, usually 100psi
PG 365
29
At a lift of 20 feet, a pumper can be expected to deliver about _________ % of its rated capacity?
60%
PG 357
30
The maximum amount of vacuum most pumps can create is about ______ inches of mercury?
22 (-75 kPa)
PG 354
31
As elevation increases, atmospheric pressure _________ ?
Decreases
PG 352
32
What is best lay for first-in engine that is going to supplement hydrant pressure?
Reverse Lay
PG 344
33
When drafting, as the height of the lift increases, pump capacity _________ ?
Decreases
PG 353
34
To account for pressure loss in the standpipe, ________ psi should be added to the pump discharge pressure when supplying a standpipe connection?
25
35
When using a priming pump driven by an electric motor, the engine RPM should be _________ ?
Sufficient to keep the alternator charging
PG 359
36
What is the function of a pump bypass or booster cooling valve?
Circulate pump water back to the tank
PG 338
37
A pump with a capacity greater than 1250gpm should take no longer than _________ seconds to prime?
45 seconds
PG 359
38
Atmospheric pressure decreases by approximately ________ psi for each 1000 feet of elevation?
0.5 psi
PG 352
39
An intake hose is lowered into a static body of water. If pressure within the hose is reduced 2psi less than atmospheric pressure, how high above the water surface will the water rise within the hose?
4.6ft
PG 352-353
40
You have connected the pumper to the hydrant. On a pumper built before 1991, what should be done before opening the hydrant?
Close the tank to pump valve
PG 344-345
41
What is the BEST information that cavitation is occurring?
Pump pressure does not increase when the throttle setting is increased
PG 354
42
Difference between static and residual pressure is 25%. How much additional water is available?
Additional volume equal to the current discharge volume is available
PG 349
43
When does cavitation most often occur?
Drafting
PG 354
44
What is optimal minimum inches of water to have all around a traditional strainer when drafting?
24"
PG 355
45
When using a priming pump driven by the transfer case, the engine RPM should be ________ rpm?
1000-1200 RPM
PG 359
46
How do you confirm that a PTO-driven pump has been engaged?
Dashboard indicator light should be on
PG 390
47
A pumper is connected to a hydrant and the pumper is discharging water. What does the master intake pressure gauge indicate?
Residual Pressure
PG 340
48
When drafting, the maximum recommended lift is ________ feet?
20 feet
PG 357
49
The NFPA and UL require pumps to deliver their rated capacity at _______ feet of lift?
10 feet
PG 357
50
When operating from draft, you should pause and permit pump pressure to stabilize if it drops below _______ psi while operating a discharge?
50 psi
PG 360
51
For each foot of lift, the compound gauge should indicate ______ inches of mercury?
1.0
PG 359
52
What forces water into a fire pump from a static body of water that is lower than the pump?
Atmospheric Pressure
PG 352
53
Atmospheric pressure at sea level is _______ psi?
14.7 PSI
PG 352
54
You are going to operate from tank water initially, then transition to an external water source when it becomes available. From the list below, what should you do first?
Open the tank-to-pump valve
PG 337, 394
55
A multistage pump connected to an FDC should be operated in the _______ position?
Parallel
PG 363
56
When pumping into a standpipe connection, do not exceed _______ psi unless the standpipe system has been specifically designed for higher pressures?
185 psi
PG 365
57
What do you need to know to determine if the hydrant you are using for supply can support additional hoselines?
Static pressure
PG 347-351
Engineer Testing Process
flashcards
Decks in class (12)
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