Chapter 8 Theoretical Pressure Calculations (U.S.)

Question 1

Why is it necessary to know the amount of friction and pressure loss in fire hose?

Answer 1

To produce effective fire streams

Question 2

Which of the following is NOT a cause of friction loss?

Answer 2

A. Hose condition
B. Hydrant condition*
C. Coupling condition
D. Volume of water flowing per minute

Question 3

The calculation of friction loss must take into account the:

Answer 3

length and diameter of the hoseline.

Question 4

Together, friction loss and elevation pressure loss are referred to as:

Answer 4

total pressure loss.

Question 5

FL: In order to get results indicative of averages that can be expected on the fireground, it is necessary to test:

Answer 5

the same hose that would be used on the fireground.

Question 6

FL: Departments should test:

Answer 6

only one type of hose at a time.

Question 7

FL: If testing lengths of 50-feet hose, lay out:

Answer 7

300 feet of hose.

Question 8

FL: If testing lengths of 100-feet hose, lay out:

Answer 8

400 feet of hose.

Question 9

FL: If using a pitot tube to determine the nozzle pressure and corresponding flow of water, use:

Answer 9

a smoothbore nozzle.

Question 10

FL: If using a flowmeter to determine the nozzle pressure and corresponding flow of water, use:

Answer 10

any nozzle.

Question 11

FL: Insert gauge one in the hoseline at the connection between the first and second sections of hose away from the discharge. Insert gauge two:

Answer 11

200 feet from gauge one.

Question 12

FL: How many test runs should be made for each size hose?

Answer 12

Three to four

Question 13

Appliance friction loss is insignificant in cases where the total flow through these appliances is less than:

Answer 13

350 gpm.

Question 14

Assume a ___ loss for loss for flows less than 350 gpm.

Answer 14

0 psi

Question 15

Assume a ___ loss for each appliance in a hose assembly when flowing 350 gpm or more.

Answer 15

10 psi

Question 16

Friction loss caused by ___ is generally insignificant in the overall pressure loss in a hose assembly.

Answer 16

handline nozzles

Question 17

Assume a friction loss of ___ in all master stream appliances, regardless of the flow.

Answer 17

25 psi

Question 18

Elevation pressure is created by elevation differences between:

Answer 18

the nozzle and the pump.

Question 19

Water exerts a pressure of ___ per foot of elevation.

Answer 19

0.434 psi

Question 20

When a nozzle is operating at an elevation higher than the apparatus, this is known as:

Answer 20

elevation pressure loss

Question 21

Operating a nozzle lower than the pump results in:

Answer 21

elevation pressure gain

Question 22

Which of the following is NOT a simple hose layout?

Answer 22

A. Single hoseline
B. Standpipe operations*
C. Siamesed hoselines (equal length)
D. Wyed hoselines (equal length)

Question 23

Which of the following is the most commonly used hose lay?

Answer 23

A. Single hoseline*
B. Multiple hoselines (equal length)
C. Siamesed hoselines (unequal length)
D. Wyed hoselines (equal length)

Question 24

Which of the following presents the simplest friction loss calculations?

Answer 24

A. Single hoseline*
B. Multiple hoselines (equal length)
C. Siamesed hoselines (equal length)
D. Wyed hoselines (unequal length)

Question 25

When determining the loss in equal length multiple lines whose diameters are the same, it is necessary to perform calculations for:

Answer 25

only one line.

Question 26

When the diameters of hoselines vary, friction loss calculations must be made for each hoseline, and then set for:

Answer 26

the highest pressure.

Question 27

When using a wye, it is important that the attack lines wyed from the supply line are:

Answer 27

the same length and diameter.

Question 28

Which of the following is NOT a complex hose layout?

Answer 28

A. Manifold hoselines B. Standpipe operations C. Wyed hoselines (equal length)* D. Multiple hoselines (unequal length)

Question 29

In most cases, fire departments have predetermined pressures for:

Answer 29

Standpipe operations