Hydraulics Flashcards
How many gallons in 1 cubic foot of water?
7.481
Bonus : how many cubic inches in one gallon - 231
True or false
1) water contracts as it cools until 32 degrees, then expands
2. ) water that is heated expands when it reaches 39 degrees
1) false
2) true
It contracts as it cools to a temperature of 39 deg. F., then expands as it cools below that point even through the solid state.
Likewise, ice contracts as it is heated,
melts at 32 deg. and continues to contract until it reaches 39 deg. F., at which point the process is reversed and it expands with added heat.
Water expands .0001 (one ten-thousandth) of itself for each degree change of temperature above or below 39 deg. F.
What is the weight of one cubic foot of water, according to the AOTM
62.425 - or 62.5
One gallon of water weighs how many pounds?
8.35
Bonus : according to the AOTM what adds to the density of water? Minerals and salt
The AOTM states that atmospheric pressure is what?
14.7
Bonus: pressure increases or decreases with altitude? Decreases
be it gravity, atmospheric, or mechanical, or a combination of the three, is the primary factor In pumping water to produce fire streams.
These 3 types of pressure are referred to as what by the AOTM?
Applied pressure
True or false
According to the AOTM mechanical pressure is the primary factor in pumping?
True
Define:
static pressure
Flow pressure
Residual pressure
means the pressure of the water without motion or standing still
cannot be as great as static pressure because when the fire stream is set in motion it is subJected to all the hindrances thewaterway possesses, such as friction, short bends, etc
Is what is left, or the pressure remaining when the valve is open and water is flowing
What is the maximum theoretical height to which it would be possible to lift water by suction at sea level?
33.9 feet
Bonus : because it is impossible to achieve theoretical lift due to not being able to achieve a perfect vacuum, what is the actual lift possible? Two thirds of 33.9 OR 22-2/3
True or false, the amount of lift that is possible increases as elevation increases every 1000 feet
False - decreases about 1 foot for every 1000 feet gained in elevation
True OR False
According to the AOTM drafting warm or hot water reduces the amount of possible lift
True - do to increased water vapor
Which factor increases friction loss, pressure or flow velocity?
Flow velocity
Is this statement true according to the AOTM:
Solid stream nozzles are identified by the diameter of the, nozzle tip employed. Spray nozzles are designated by the size of hose coupling.
True
According to the AOTM, a good fire stream is said to do what?
Reach the seat of a fire in a solid mass and will deliver 9/10 of its whole volume into a 15” circle and 3/4 of its mass into a 10” circle
At what degrees does a fire stream achieve its greatest horizontal reach ?
30, 60, 45 or 75 degrees?
30
75 degrees is the common vertical angle
What percentage of increased nozzle reaction is expected when first opening a nozzle?
12, 15, 20, or 26 %
20%
True OR False
Nozzle reaction is greater in a smoothbore nozzle
True
According to the AOTM, the entire pumping operation can be based on one principle, what is it?
Pressure differentials
When pumping to an unknown grade, whether up or down hill, what should you use to calculate F.L?
5%, 10%, or 20%
10%
According to the AOTM, what can have an effect on the quantity of water availability at the pump when operating within the limitations of the hydrant and the pump ?
Direction of hydrant, color of hydrant or hydrant hook up?
Hydrant hook up
The AOTM states that pump hook ups should normally be done in a manner to supply maximum amount of water when available. What are the 3 factors that should be taken into consideration in obtaining maximum water flow?
1) connect to 4” on hydrant if possible, it doubles the flow of water
2) avoid front suctions due to bends and size of plumbing it reduces the output of the pump
3) avoid kinks in suction side
How to you test to see if your pump is cavitation Get?
Throttle up. If there’s no increase in pressure, then you are close to cavitation
According to the AOTM, what pressure should the pump operator be pumping to a LP before it is flowing?
25-40psi above operating pressure
The AOTM states that some pumps can go from series to parallel at any pressure, however some must have a ______ psi or less pressure differential between the discharge and intake
40 psi
When changing between pressure and volume on a pump that allows you to do so at any pressure, what should the pump operator consider ?
Going from volume to pressure can increase nozzle reaction, observe gauges closely and be prepared to make changes
