Chapter 5: Water Flow Analysis Flashcards
The only truly reliable method for determining the amount of available flow at any chosen point in the system is to:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Perform water flow analysis testing at that point
Flow tests should be done at least every __ years, as well as after any extensive water main improvements or extensions have been made?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
5 years
Whose responsibility is it to test private hydrants?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The owner’s responsibility
Who often specifies the frequency and extent of the tests to be done to private hydrant?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Insurance providers
Static pressure gauges used for water system testing should be capable of measuring at least ___ psi?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
200 psi
A pitot tube and gauge (or just pitot gauge) measures the:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Stream’s velocity pressure
Pitot gauges used for water systems testing should be capable of measuring at least ___ psi?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
200 psi
When using a pitot gauge, the small opening or point should be ______ in the stream?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Centered
When using a pitot gauge, the small opening or point should be held away from the butt or nozzle at a distance of approximately:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
1/2 the diameter of the opening
When using a pitot gauge, keeping the air chamber in this position will help avoid needle fluctuations?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Above the horizontal plane
When using a pitot gauge, if the needle is fluctuating, what value should be recorded?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The value halfway between the high and low extremes
What device can be placed on a hydrant during testing to avoid damages to landscaping?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
A water stream diffuser
Water flow tests are also commonly referred to as:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Fire flow tests
Before a fire department conducts a flow test, it should notify:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The responsible water department official
To avoid liability associated with testing private water systems, who should accompany the fire department when conducting the test?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The owner or representative of the water system
What is the required distance from the bottom of the butt of a hydrant to the grade?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
At least 15 inches
Before beginning a flow test, personnel should:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Inspect the condition of the hydrants they are using for the test
The least amount of fire hydrants needed to perform a proper water supply test and their given names are:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
At least 2, The test hydrant, and the flow hydrant(s)
No water is discharged from this hydrant during a water supply test?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The test hydrant
The test hydrant must be located between the:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Flow hydrant and the water source
What sized outlets should be used to perform a flow test?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
The 2 1/2” discharges
Use a ruler with a scale that measures to at least _________ of an inch to determine the actual diameter of the outlet or nozzle opening.
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Sixteenth of an inch
When testing flow, residual pressure should never drop below ___ psi?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
20 psi
Why shouldn’t we use the large discharge when flow testing a hydrant?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Because it contains voids. The stream is not solid
How do you determine how many flow hydrants should be opened during a flow test?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Open enough hydrants to drop the static pressure of the test hydrant by at least 10 percent
To get more accurate results for flow testing, the static pressure drop at the test hydrant should be as close to ___ percent?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
25 percent
What can you do if while doing a flow test, the pressure of the hydrant is so low that no flow registers on the pitot gauge?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Place a straight-stream nozzle with orifices smaller than 2 1/2” on the hydrant outlet to increase the flow flow velocity
Flow test conducted next to elevated storage tanks should be tested:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
With the storage tank shut off
When computing flow test results, there are 2 calculations that must be performed. They are:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
- Involves determining the flow volume from the flow hydrant
- Involves plotting all the given info on a chart to determine the available flow at the test hydrant
The internal diameter of a hydrants discharges can vary by a couple of _________ of an inch one way or the other from the stated size?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Sixteenth of an inch
Many state health departments require water supply systems to maintain ___ psi minimum to prevent the possibility of external water being drawn into the system at main connections?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
20 psi
Most fire department pumper operating manuals recommend that intake pressures on the pump during hydrant operations not be allowed to drop below ___ psi?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
20 psi
The method of manual calculation most commonly used to determine available water flow is the:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Graphical method
Mathematical calculation used to determine available water flow uses a variation of the:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]
Hazen-Williams formula
