Chapter 5: Water Flow Analysis

Question 1

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]

Answer 1

Perform water flow analysis testing at that point

Question 2

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]

Answer 2

5 years

Question 3

Whose responsibility is it to test private hydrants?

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 3

The owner’s responsibility

Question 4

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]

Answer 4

Insurance providers

Question 5

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]

Answer 5

200 psi

Question 6

A pitot tube and gauge (or just pitot gauge) measures the:

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 6

Stream’s velocity pressure

Question 7

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]

Answer 7

200 psi

Question 8

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]

Answer 8

Centered

Question 9

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]

Answer 9

1/2 the diameter of the opening

Question 10

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]

Answer 10

Above the horizontal plane

Question 11

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]

Answer 11

The value halfway between the high and low extremes

Question 12

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]

Answer 12

A water stream diffuser

Question 13

Water flow tests are also commonly referred to as:

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 13

Fire flow tests

Question 14

Before a fire department conducts a flow test, it should notify:
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 14

The responsible water department official

Question 15

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]

Answer 15

The owner or representative of the water system

Question 16

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]

Answer 16

At least 15 inches

Question 17

Before beginning a flow test, personnel should:

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 17

Inspect the condition of the hydrants they are using for the test

Question 18

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]

Answer 18

At least 2, The test hydrant, and the flow hydrant(s)

Question 19

No water is discharged from this hydrant during a water supply test?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 19

The test hydrant

Question 20

The test hydrant must be located between the:

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 20

Flow hydrant and the water source

Question 21

What sized outlets should be used to perform a flow test?

[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 21

The 2 1/2” discharges

Question 22

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]

Answer 22

Sixteenth of an inch

Question 23

When testing flow, residual pressure should never drop below ___ psi?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 23

20 psi

Question 24

Why shouldn’t we use the large discharge when flow testing a hydrant?
[Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 24

Because it contains voids. The stream is not solid

Question 25

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]

Answer 25

Open enough hydrants to drop the static pressure of the test hydrant by at least 10 percent

Question 26

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]

Answer 26

25 percent

Question 27

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]

Answer 27

Place a straight-stream nozzle with orifices smaller than 2 1/2" on the hydrant outlet to increase the flow flow velocity

Question 28

Flow test conducted next to elevated storage tanks should be tested: [Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 28

With the storage tank shut off

Question 29

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]

Answer 29

1. Involves determining the flow volume from the flow hydrant 2. Involves plotting all the given info on a chart to determine the available flow at the test hydrant

Question 30

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]

Answer 30

Sixteenth of an inch

Question 31

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]

Answer 31

20 psi

Question 32

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]

Answer 32

20 psi

Question 33

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]

Answer 33

Graphical method

Question 34

Mathematical calculation used to determine available water flow uses a variation of the: [Fire Service Hydraulics and Water Supply: Chapter 5: Water Flow Analysis]

Answer 34

Hazen-Williams formula