Hydraulics Flashcards
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What happens when there is excessive pressure at the heads?
Misting or fogging
If the GPM are doubled, the PSI:
quadruples
Hydraulics is:
the science of dynamic and static water
What is the weight of one gallon of water?
8.3 pounds
62.4 pounds represents the weight of
a cubic foot of water
What does PSI stand for
pounds per square inch
How many feet of water (in height) does it take to equal 1 PSI
2.31
One foot high of water will create
.433 PSI
How many feet of head are needed to produce 65 PSI: 65÷.433 =
150.1 feet of head
If you have 167 feet of head, what is the PSI? 167 X .433 =
72.3 feet of head
There is a 70 foot water tower on a hill that is 150 feet high. The water pressure at a home, being serviced by this water tower, is 70 PSI. What is the feet of head difference between the home and the base of the hill?
let y = water tower plus hill height
70÷.433 = x
y-x = _____ feet of head
58.3 feet of head
An elevation gain in the piping will yield
loss in PSI
An elevation loss in the piping will yield
an increase in PSI
What is the maximum acceptable velocity of water in pvc piping?
5 fps
What is the maximum acceptable velocity of water in copper piping?
9 fps
What is the pressure loss for 141’ of 1” Type K copper pipe flowing 12 gpm?
1.41 x 4.94 =
6.97 psi
What size Class 200 pvc pipe would be adequate if flowing 38 gpm?
refer to chart
2”
If your pipe is flowing 34 gpm, what size pipe should be used?
Class 200 1½”
How much pressure has been gained from point A to point D, due to an elevation difference?
height of water above point A (150’) - height of water above point D (220’) = x
x * .433 = y
y = 30.31 PSI gain
What is not considered in selecting the most taxed zone to work the hydraulics?
Lowest elevation
Which one of these is a rule to follow when working hydraulics?
a) Take the most direct route from the point in question back to the city main or point in question
b) Take the most direct route from the point in question back to the main line or point in question
c) Pick up the GPM at intersections, but don’t calculate the friction losses on any of the pipe running to those sprinkler heads.
d) A&C
Both A&C
A separate calculation is needed if :
a) the type of pipe is different
b) The GPM are different
c) The size of the pipe is different
d) All of the above
D) All of the above
In exercise #49, what would the design pressure be if the static pressure was 70 instead of 60?
The same (Remember the definition for design pressure: Minimum head pressure plus total pressure loss. Therefore, the static pressure does not affect the calculation of design pressure)
