IFSTA Chapter 10 Operating Fire Pumps Flashcards
When operating at the pump panel, drivers must wear
full PPE
What does the placement of chocks provide
an extra measure of safety should the apparatus jump into road gear or override the parking brake system
When operating the pump when should you reach the appropriate pressure
When water is flowing
When using the tank fill valve to cool the pump what must be concidered
Tank Fill Line may be piped large enough to cause the pump to cavitate when using the onboard tank
When discharge pressure increases, intake pressure from the source will drop due to friction loss,
what happens when intake pressure drops too low
Why must you not pump below a residual pressure of 20 psi while being supplied
Allowing the discharge pressure to decrease the intake from the source can cause damage to the pump
pumping at a residual pressure below 20 psi while being supplied by other apparatus may cause the supply line to collapse or lead to cavitation
Why should supply systems maintain a residual pressure of 20 psi also
Contamination from sources outside the main may occur
overtaxing the water system may cause sediment or debris that has formed to become lose and damage the pump
what are dead end hydrants and why are they least desirable source
Hydrants served by smaller mains from only one direction and generally have higher amounts of sediment and deterioration
In Prolonged pumping operations a bypass circulator may not provide enought cooling, what other methods can be used to keep the pump from overheating
Open Discharge Drain Valve: Some need opened before valve is under pressure
Partially open tank-fill valve or tank to pump
Exact explanation of Like Volumes
10% of less = 3 lines of the same flow can be added
11 - 15% = 2 lines of the same flow can be added
16 - 25% = 1 lineof the same flow can be added
more than 25%= more water may be available but not as much as is flowing through first line
A_______ _____ is created when air inside the pump is evacuated
Pressure Differential
allows atmospheric pressure acting on the surface of the water to force water into the fire pump
With an atmospheric pressure at sea level of 14.7 psi what is a partial vacuum of -2 psi measured as
4” of mercury which causes water to rise 4.6ft
The Weight of water combined with reduced air pressure creates a balance
When drafting other than bends in plumbing, hose or appliance what else created friction loss
The Inertia of water
To what level of mercury are pumps able to develop a vacuum approximately
22” of mercury but
Compound gauges not providing accurate readings on the vacuum side it must be acknowledged that at this reading the pump is nearing the limits of its ability to supply water.
Describe cavitation
Water being discharged faster than it is coming into the pump
What causes cavitation
(Air cavities)
Air cavities are created in the pump as they move from highest vacuum into the presurized section where they collapse (fill with water)
High velocity of these cavities filling causes severe shock to pump
What occurs to the state of water during cavitation
Pressure drops below atmospheric and the boiling point of water drops to the point that water changes to a vapor creating voids of steam
Indicators of a pump cavitating
Pressure gauge on the pump will fluctuate and hose streams may pulsate (popping, sputtering sound)
The pump makes noises compared to gravel passing through the pump
The surest indicator will be a lack of reaction of the pressure gauge when increasing the throttle
In order for a pumper to reach its rated capacity during draft using a traditional strainer, how much water (in inches) must be above the
24 inches
It is also helpful to have that much clearance around the strainer to avoid drawing foreign objects
What may cause a whirlpool resulting in air entering the intake hose during draft and how can it be prevented
Rapid Intake of water may cause the pump to lose its prime
whirlpool can be fixed by placing a floating object above the strainer
What steps can be taken to use a shallow source of water
A dam can be built or the bottom be dug out
Ideally a floating strainer will be used
Negative of using a floating strainer
Since it only uses one side to allow water in, the pump may not be used at its highest capacity due to receiving lower water amount
Low-Level strainers can be used in water as low as _______ but will not allow the pump to
2 inches approx and will not allow the pump to operate at rated capacity due to drafting lower quantities
What sources can expose the pump to (when drafting) to corrosion from salt contents, or caustic chemicals that may be present in the water
Using non-potable (untreated) water sources such as that from a salt water source or ground water in the vicinity of mining operations
When debris passes through the pump what does the abrasive effect damage?
As water passes through the eye of the impeller, the area between the clearance rings and the hub of the impeller. It creates spacing that causes slippage from discharge back into intake ultimately reducing the capacity of the pump
All Fire Pumps meeting NFPA and UL requirements are rated to pump their capacity at what height of lift
10ft of lift.
a pumper in good condition can lift water a maximum of 25ft
To create an effective fire stream a lift no greater than this height is recommended
20ft
at 20 feet lift at what capacity is the pump able to work at (percent)
60% of its rated capacity
Prelem actions to connecting to the pump during draft
Engage the pump once all connections have been made and its ready to be put into operation
Park vehicle short of final drafting spot if area is limited, drive closer once all connections are made
Inspect gaskets, then connect strainer
If needed use a rubber mallet to make connections tighter
avoid placing intake hose on the ground (debris)
Fasten a rope to the end of strainer for handling
When priming a pump for draft what will the mercury reading represent in height
1” of Hg for 1 Foot of lift required
Vacuum is measured from the surface of the water to the eye of the pump
When lift is not able to be achieved during priming what is the most common reason
Air Leaks around the pump possibly from an open drain or valve
Intake relief valves may also prevent lift
Other than loose gaskets, opened valves what else can create issues when drafting
Insufficient fluid in the priming reservoir
Engine Speed (rpm) too low
Lift is Too High
High point in the intake hose creating an air pocket
Increasing the throttle setting is required to raise the pressure between _____ and ______ psi
50 and 100 psi
When should you set desired discharge pressures while drafting
Wait until water is flowing and the discharge gauge has stabilized
Discharge pressure gauge begins to fluctuate with loss of vacuum on the intake gauge indicates?
air is coming into the pump
What indicates a gradual increase in vacuum with no change to flow rate
A blockage is developing
usually caused after a pump has been operating at a high rate of discharge increasing the max velocity of water entering the strainer
Common place for blockages during draft
in the strainer
if reached easily leaves or other debris may be removed by hand or using a booster line
Pump may have to be backflushed.
Shutting down a drafting operation and what to do after for proper readiness of primer and fire pump
Deacrease engine speed to idle
take pump out of gear
allow the pump to drain
remove all connections and operate the primer pump and operate for a few seconds until primer oil or fluid comes out
Pump should be thoroughly flushed with a supply of fresh water
During stand pipe operations encountering a Pressure reducing valve what leads to inadequate pressure for hose lines
The pressure set for standpipe must match the total height where the hose is being connected to. The pressure must match that to which the valve was set to.
Standpipe frozen connection fix
double male to a double female adapter can be added to provide movement
If there isn’t enough water above the strainer?
Whirlpool can be formed allowing air into the pump
This may cause the tank-to-pump line to be a source of pressure/water leaks.
an empty onboard water tank
When drafting and opening a discharge under what pressure shall the opening be slowed down
if pressure drops below 50 psi while slowly opening a discharge, pause for a brief time to allow stabilization to prevent air entering the pump
