Chapter 12

Question 1

When medium diameter hose (MDH) is used in relay operations, generally:

a. multiple hoselines are laid.
b. it must be supplemented with large diameter hose
(LDH).
c. it is supplemented with small diameter hose (SDH).
d. the MDH will still require only one supply line to meet fireground requirements.

Answer 1

a. multiple hoselines are laid

Question 2

When the source and relay pumpers are ready, the discharge supplying the hoseline on the source
pumper is:

a. opened and the valve on the dump line is opened.
b. closed while the valve on the dump line is opened.
c. closed and the valve on the dump line is closed.
d. opened while the valve on the dump line is closed.

Answer 2

d. opened while the valve on the dump line is closed

Question 3

When relay pumpers are equipped with an adjustable intake relief valve, one guideline is that it should be set to:

a. 10 psi (70 kPa) above the discharge pressure of the previous pumper in the relay.
b. within ten percent of the discharge pressure of the previous pumper in the relay.
c. 10 psi (70 kPa) below the discharge pressure of the previous pumper in the relay.
d. the same discharge pressure as the previous pumper in the relay.

Answer 3

a. 10 psi (70 kPa) above the discharge pressure of the previous pumper in the relay.

Question 4

Many screw-on intake pressure relief valves are also equipped with a gate valve that allows the:

a. water supply to the pump to be shut off.
b. water supply to the pump to be doubled.
c. pump to signal when water is no longer required.
d. pump to be manually shut off.

Answer 4

a. water supply to the pump to be shut off

Question 5

Centrifugal pumps are rated to pump at their maximum volume capacity at:
Select one:
a. 150 psi (1 050 kPa) at draft.
b. 100 psi (700 ka) at draft.
c. 275 psi (1 925 kPa) at draft.
d. 250 psi (1 750 kPa) at draft.

Answer 5

a. 150 psi (1 050 kPa) at draft.

Question 6

Attack pumpers equipped with an adiustable intake relief valve should be set:

a. between 50 and 75 psi
(350 and 525 kPa) to establish a stable operating condition.
b. at exactly 75 psi (525 kPa)
to establish a stable operating condition.
c. at exactly 50 psi (350 kPa) to establish a stable operating condition.
d. between 75 and 100 psi
(525 and 700 kPa) to establish a stable operating condition.

Answer 6

a. between 50 and 75 psi
(350 and 525 kPa) to establish a stable operating condition

Question 7

Which of the following statements about elevation pressure in relay operations is MOST accurate?

a. Elevation pressure is affected both by the amount of water being moved and by the topography.
b. If water supply must be pumped uphill, pressure loss on the lay is less than simple friction loss.
c. Elevation pressure is not affected by the amount of water being moved, only by the topography.
d. If water supply must be pumped downhill, pressure loss on the lay is greater than simple friction loss.

Answer 7

c. Elevation pressure is not affected by the amount of water being moved, only by the topography