Chapter 9 Fireground Hydraulic Calculations

Question 1

Flowmeters provide:

Answer 1

water flow in gpm (L/min).

Question 2

Flowmeters are particularly advantageous in:

Answer 2

supplying hoselines or master stream devices equipped with automatic nozzles.

Question 3

Flowmeters are allowed to be used instead of pressure gauges on all discharges:

Answer 3

1½ to 3 inches (38 mm to 77 mm) in diameter.

Question 4

What size discharges may be equipped with a flowmeter but must also have a pressure gauge?

Answer 4

3½ inches or larger

Question 5

Flowmeters must provide a readout in increments no larger than:

Answer 5

10 gpm (38 L/min).

Question 6

Which of the following are basic types of flowmeters?

Answer 6

Paddlewheel and spring probe

Question 7

Which of the following statements about spring probe flowmeters is TRUE?

Answer 7

A. It is located at the top of the pipe so that sediment does not deposit on it.
B. Its placement reduces the problems of impeded flow and damage by debris.
C. It is relatively maintenance free because its spring probe has only one moving part.*
D. It may be used instead of pressure gauges on all discharges regardless of diameter.

Question 8

How accurate should flowmeters be when properly calibrated and in good working condition?

Answer 8

+/- 3 percent

Question 9

Flowmeters have a discharge readout display mounted within ___ of the valve control for each discharge equipped.

Answer 9

6 inches (150 mm)

Question 10

A central flowmeter device provides the driver/operator with all of the following EXCEPT:

Answer 10

A. the amount of foam being flowed.
B. the required pump discharge pressure needed.*
C. the flow through any particular discharge at that time.
D. the total amount of water being flowed through the pump at that time.

Question 11

Which of the following is NOT a flowmeter application?

Answer 11

A. Relay pumping
B. Standpipe operations
C. Pump discharge pressures*
D. Diagnosing waterflow problems

Question 12

If water volume at the nozzle suddenly diminishes, but there is no reduction in the flowmeter reading, what is the most likely assumption?

Answer 12

The hose has burst.

Question 13

Use of a flowmeter during relay pumping makes it possible to feed a supply line without having to know the:

Answer 13

number of gallons flowing from the pumper receiving the water.

Question 14

When using a flowmeter for relay pumping, as the engine speed increases:

Answer 14

the discharge and gpm (L/min) reading increase.

Question 15

When using a flowmeter for relay pumping, do not allow the incoming pressure to drop too much below:

Answer 15

20 psi (140 kPa).

Question 16

Manual or mechanical hydraulic calculators operate by moving a slide or dial in which the ___ are indicated.

Answer 16

A. Water flow
B. Size of hose
C. Length of the hose lay
D. All of the above*

Question 17

Electronic hydraulic calculators allow the driver/operator to input all of the following EXCEPT:

Answer 17

A. water flow.
B. size of hose.
C. length of hose lay.
D. pump discharge pressure.*

Question 18

Which of the following statements about hydraulic calculators is TRUE?

Answer 18

A. They are particularly advantageous when supplying hoselines or master stream devices equipped with automatic nozzles.
B. They make it possible for driver/operators to pump the correct volume of water to nozzles without having to know the length of hoseline.
C. They make it possible to feed a supply line without having to know the number of gallons (liters) flowing from the pumper receiving the water.
D. They enable the driver/operator to determine the pump discharge pressure required to supply a hose layout without having to perform tedious mental hydraulic calculations.*

Question 19

Which of the following is NOT a column on a pump chart?

Answer 19

A. NP column
B. FL column*
C. Nozzle column
D. GPM (L/min) column

Question 20

What is the first step in developing a pump chart?

Answer 20

Identifying all nozzles, devices, and hose layouts used by the department

Question 21

When calculating the required pump discharge pressures for each of the listed layouts, be certain to include friction loss in master stream appliances flowing in excess of:

Answer 21

350 gpm (1 400 L/min).

Question 22

When calculating the required pump discharge pressures for each of the listed layouts, round pump discharge pressure to the nearest:

Answer 22

5 psi (35 kPa).

Question 23

What is the hand method used to estimate?

Answer 23

Friction loss

Question 24

To what size hoselines may the hand method be applied?

Answer 24

1¾- and 2½-inch

Question 25

The hand method starts with:

Answer 25

the thumb of the left hand.

Question 26

When applied to 2½-inch hose, each finger is numbered at the base in terms of:

Answer 26

hundreds of gallons per minute.

Question 27

In order for the hand method to be applied to 1¾-inch hose, calculate the friction loss in 100 feet of 1¾-inch hose by going to the finger that corresponds to the flow you are using and multiplying the number at the tip of the finger by:

Answer 27

the number at the base of the same finger

Question 28

What is the GPM flowing method used to estimate?

Answer 28

Friction loss

Question 29

What does the driver/operator need to know in order to use the GPM flowing method?

Answer 29

Water flow in gpm

Question 30

When using the GPM flowing method for 2½-inch hose, subtract ___ from the first two numbers of the gpm flow.

Answer 30

10

Question 31

When using the GPM flowing method for 1½-inch hose, multiply the flow times ___, then subtract ___ from the first two numbers of the gpm flow.

Answer 31

4; 10