Chapter 11 Operating Fire Pumps Flashcards
When does IFSTA recommend wheel chocks to be used?
Every time the apparatus is stopped with the engine running and the driver/ operator exits the cab.
Tests have indicated that the apparatus may override the parking brake system at engine speeds as low as what?
1300 RPMs
If the engine is running and the pump is turning, what must be open so that the pump will not run dry?
Intake valve
In a multi-stage pump, in most cases, the pump should remain in ______ position
series (pressure)
If a multi-stage pump is required to furnish more than ____ percent of its rated capacity, it should be set to the PARALLEL (VOLUME) position from the start
50%
If using 2 ½” or 3” hose to supply the pumper directly off hydrant pressure, it is recommended that the lines be no longer than how long?
300 ft.
What type of lay is the most direct way to supplement hydrant pressure and perform drafting operations?
Reverse Lay
When switching to an external water supply, what valve must the driver/ operator ensure is closed?
Tank-to-Pump
If the master intake gauge drops below ____ psi, do not increase the throttle further because the pump is in danger of cavitation.
20 psi
When a pumper is connected to a hydrant and is not discharging water, the pressure shown on the intake gauge is what?
static pressure
When the pumper is connected to a hydrant and IS discharging water, the pressure shown on the intake gauge is what?
residual pressure
What are the 3 methods used for determining how much more water the hydrant can supply?
- Percentage method
- First digit method
- squaring the lines method
What is the equation for using the PERCENTAGE METHOD in determining how much more water a hydrant can flow?
Percentage drop = (static-residual)(100) / static
When using the PERCENTAGE METHOD, how much additional water is available from the hydrant when the percent decrease of pumper intake pressure is:
a. 0-10
b. 11-15
c. 16-25
d. 25+
Additional water available is:
a. 3 times amount being used
b. 2 times amount being used
c. same amount being used
d. more water might be available, but not as much as is being delivered
Describe the FIRST DIGIT METHOD.
Difference in psi between static and residual = x
Multiply the first digit of the static pressure by 1,2, or 3
If the psi drop (x) ≤ first digit of static pressure multiplied by:
1–then 3 additional lines can be added
2–then 2 additional lines can be added
3–then 1 additional line can be added
When can the FIRST DIGIT METHOD NOT be used?
When using metric measurements
How can one check and see if a “dry” fire hydrant is properly draining to prevent freezing?
By placing palm of hand on outlet and feeling for slight vacuum.
What is atmospheric pressure at sea level?
14.7 psi
Is it possible to increase the capacity of a certain-sized pump? How?
Yes, by increasing the size of the intake hose.
Atmospheric pressure decreases how much for every 1000 ft. of elevation gain?
.5 psi
What is “cavitation?”
water is being discharged from the pump faster than it is coming in
What is the best indicator of cavitation?
Lack of reaction on the pressure gauge to changes in the setting of the throttle
Successfully operating a fire dept. pumper from _____ is one of the most challenging tasks that a driver/ operators face.
draft
When selecting water sources to draft, the choice is dictated by what 3 factors?
- amount of water (most important)
- type of water
- accessibility of water
In order for a pumper to approach its rated capacity using a traditional strainer, there should be a minimum of ____ feet of water over the strainer.
2 ft
How can the whirlpool effect above a strainer be prevented?
By placing a board, capped plastic bottle, or beach ball above the strainer
“Low-level” strainers can produce water in depths as little as how much water?
2 inches
What is the most common and most dangerous contamination concerning the type of water used for drafting?
dirty or sandy water
All pumps meeting NFPA and Underwriters Laboratories requirements are rated to pump their capacity at ____ ft of lift.
10 ft
For effective operation, the max lift considered reasonable for most fire dept. pumpers is about ___ ft.
20 ft
At 20 ft of lift, how much water can be supplied?
60% of the rated capacity of the pump
When priming a two-stage pump, what position should the transfer valve be placed in? Why?
PARALLEL (VOLUME)
if it was in the series (pressure) position, air may be trapped inside the pump making it more difficult to remove.
What RPMs are most priming pumps intended to be operated at?
1000 RPMs
If a prime has not been achieved in ____ amount time, stop priming and check to find out what the problem is.
30 seconds
What should you do after draining the pump and connections have been removed? Why?
Operate the mechanical primer for a few seconds until primer oil or fluid comes out of the discharge. It lubricates the primer
How should a Sprinkler System be supplied?
two 2 ½” hoselines
As a rule of thumb, one 1000 fpm rated pumper should supply the FDC for every ____ sprinklers that are estimated TO BE FLOWING.
50 sprinklers
Where should fire crews connect their attack lines to a standpipe?
Usually on the floor below the fire floor
Pump discharge pressure for STANDPIPE SYSTEMS depend on what 5 things?
- friction loss in the standpipe (25 psi)
- friction loss in the hose lay from pumper to standpipe
- friction loss of hose on the fire floor
- elevation pressure due to the height of the building
Pump discharge pressures in excess of ____ psi are not encouraged unless the standpipe system has been designed to withstand higher pressures
200 psi
