REVIEW GUIDE
PIPE Coaching Notes
FLUID
1. A perfect venture with throat diameter of
1.8 inches is placed horizontally in a pipe
with a 5 in inside diameter. Eighty (80) lb
of water flow through the pipe each
second. What is the difference between
the pipe and venturi throat static
pressure?
a. 29.9 lb/in2
b. 34.8 lb/in2
c. 5020 lb/in2
d. 72.3 lb/in2
2. What is the expected head loss per mile
of a closed circular pipe (17 in inside
diameter), friction factor of 0.03 when
3300 of water flow under pressure?
a. 38 ft
b. 3.580 ft
c. 0.007 ft
d. 0.64 ft
3. A rigid container is closed at one end and
measure 8 in diameter by 12 in long. The
container is held vertically and is slowly
moved downward until the pressure in
the container is 15.5 psia. What will be the
depth of the water surface measure from
the free water surface?
a. 22 in
b. 9.2 in
c. 12 in
d. 9.8 in
4. The pressure drop across a turbine is 25
psi. The flow rate is 55 gallons per
minute. Calculate the power output of the
turbine.
a. 0.802 hp
b. 0.41 hp
c. 1.05 hp
d. 2.54 hp
5. Two tubes are mounted to the roof of a
car. One tube points to the front of the car
while the other point to the rear. The
tubes are connected to a manometer
filled with fluid of specific gravity 0.60.
When the height difference is 2 inches,
what is the car’s speed?
a. 46 mph
b. 43.8 mph
c. 50 mph
d. 62 mph
6. What is the density of a stone that weighs
19.9 lb (88 N) in air and 12.4 lb (55 N) in
water?
a. 2,651.2 kg/m3
b. 2,612.5 kg/m3
c. 2,578.2 kg/m3
d. 26,700 kg/m3
7. The flow rate of water through a cast iron
pipe is 5000 gpm. The pipe is 1 ft and the
coefficient of friction f = 0.0173. What is
the pressure drop over a 100 ft length of
pipe?
a. 4.404 ft of water
b. 5.404 ft of water
c. 6.404 ft of water
d. 7.404 ft of water
8. Pressure drop across a turbine is 30 psi,
the flow rate is 60 gpm. Calculate the
power output of the turbine.
a. 0.41 hp
b. 1.05 hp
c. 6.30 hp
d. 2.54 hp
9. The fluid in a manometer tube is 60%
water and 40% alcohol (SG = 0.8). What
is the monometer fluid height difference
if a 6.2 psi pressure is applied across the
tow ends of a manometer?
a. 15.5 in
b. 186 in
c. 36 in
d. 215 in
10. An air bubble rises from the bottom of a
well where the temperature is 25°C, to
the surface where the temperature is
27°C. Find the percent increase in volume
of the bubble if the depth of the well is
5m. Atmospheric pressure is 101.528
kPa.
a. 49.3
b. 31.3
c. 56.7
d. 38.6
11. An empty, open can is 30 cm high with
a 10-cm diameter. The can, with the open
REVIEW GUIDE
end down, is pushed under water with a
density of 1000 kg/m3. Find the water
level in the can when the top of the can is
50 cm below the surface.
a. 17.20 cm
b. 2.12 cm
c. 4.20 cm
d. 5.87 cm
12. A 24 inches long rod floats vertically in
water. It has a 1 sq. in. cross section and
has a specific gravity of 0.6. What length
L is submerged?
a. 14.4 in
b. 2.4 in
c. 9.6 in
d. 18.0 in
13. Flow of water taking over in a pipe
having a velocity of 10 m/s. Determine the
velocity head of the water.
a. 50.1 m
b. 5.1 m
c. 8.2 m
d. 100 m
14. The length of pipe is 168 meters. If the
pressure drop is 50 kPa for every 30
meters, what is the total pressure drop?
a. 260 kPa
b. 300 kPa
c. 280 kPa
d. 100 kPa
15. Hydraulic efficiency 85%, find Q in li/s.
Power developed 10,500 kW under head
of 320 m.
a. 3935
b. 3452
c. 3271
d. 3623
16. A cylindrical pipe with water flowing
downward at 0.02 m3/s having top
diameter of 0.08, bottom diameter of 0.04
and height of 1.5 m. Find the pressure
between the pipes.
a. 104 kPa
b. 87 kPa
c. 120 kPa
d. 143 kPa
17. A fluid that has a velocity of 18 m/s will
have an equivalent head of:
a. 16.51 m
b. 12.44 m
c. 18.34 m
d. 10.34 m
18. Determine the size of pipe which will
deliver 5 liters of medium oil (v = 6.10 x
PIPE Coaching Notes
10-6 m2/s) assuming laminar
conditions.
a. 522 mm
b. 454 mm
c. 550 mm
d. 650 mm
flow
19. The power available in a jet having a
cross-sectional area of 0.005 m2 with a
velocity of 25.80 m/s.
a. 34 kW
b. 49 kW
c. 43 kW
d. 23 kW
20. The type of flow occupying in a 30 cm
diameter pipe which water flows at a
velocity of 2.10 m/s. Use v = 1.13 x 10-6
m2/s for water.
a. Turbulent
b. Constant
c. Laminar
d. None of these
21. A man weighing 64 kg causes a flat area
30 cm thick to be just fully submerged in
a sea water (SG = 1.03). Neglecting
weight the area must be:
a. 0.085 m2
b. 0.756 m2
c. 0.172 m2
d. 0.062 m2
22. What force is exerted by water jet 50
mm diameter if it strikes a wall at the rate
of 15 m/s?
a. 342 N
b. 442 N
c. 764 N
d. 563 N
23. A 300 mm x 75 mm venture meter is
inserted in a 300 mm diameter pipeline
where water flows at 55 liters/sec.
Neglecting friction loss, compute the
drop in pressure head from the inlet to
the throat.
a. 8 m
b. 10 m
c. 6 m
d. 12 m
24. A jet of water 50 mm diameter with a
velocity of 35 m/s is being discharged in
a horizontal direction from a nozzle
mounted on a fire truck. The force
required to hold the nozzle stationary is:
a. 1.34 kN
b. 2.40 kN
REVIEW GUIDE
c. 4.23 kN
d. 3.23 kN
25. An open storage vessel has 3 m of oil
(SG = 0.82) and 6 m of water. The
pressure at the bottom is:
a. 45 kPa
b. 65 kPa
c. 83 kPa
d. 92 kPa
26. A 200 mm diameter pipe gradually
reduces to a 100 mm diameter. The 200
mm diameter pipe is connected to
another pipe having a pressure of 600
kPa horizontally with a flow of 0.04 m3/s.
Find the pressure at the 100 mm
diameter.
a. 588 kPa
b. 642 kPa
c. 566 kPa
d. 598 kPa
27. A 200 mm diameter pipe discharges
water at the rate of 200 li/s. Point 1 on the
pipe has a pressure of 280 kPa and 3.4 m
below point 1 is point 2 with a pressure
of 300 kPa. Compute the head loss
between points 1 and 2.
a. 4.2 m
b. 2.5 m
c. 6.3 m
d. 1.4 m
28. An object weighs 90 N in air and when
immersed in water weighs 50 N. Compute
the specific gravity of the object.
a. 1.25
b. 3.25
c. 2.25
d. 4.25
29. Water is flowing in a pipe with radius of
25.4 cm at a velocity of 3 m/s. The
viscosity of water is 1.13 Pa.s. What is the
Reynolds number?
a. 1,348
b. 2,357
c. 1,567
d. 2,312
30. The flow of water through a cast iron
pipe is 10,000 gpm. The pipe is 18 inches
in diameter. What is the flow velocity?
a. 16.2 ft/s
b. 15.2 ft/s
c. 14.8 ft/s
d. 12.6 ft/s
PIPE Coaching Notes
31. What is the water pressure if
manometer is 0.3 m Hg? Mercury is 13.6
times heavier than water.
a. 40 kPa
b. 38 kPa
c. 45 kPa
d. 35 kPa
32. What is the pressure of a 100 cm
column of water?
a. 10.81 kPa
b. 9.81 kPa
c. 11.81 kPa
d. 11.23 kPa
33. Determine the velocity of the liquid in a
tank at the bottom, given that surface h =
5 m.
a. 10.81 m/s
b. 9.9 m/s
c. 11.81 m/s
d. 11.23 m/s
34. The flow rate of water through a cast
iron pipe is 10,000 gpm. The pipe is 18
inches diameter and the coefficient of
friction f = 0.02. What does the pressure
drop over a 500 ft length of pipe?
a. 1,023.36 lb/ft2 b. 1,230.36 lb/ft2
c. 2,103.36 lb/ft2 d. 2,013.36 lb/ft2
35. A venturi meter with a 12 cm throat is
installed in an 18 cm pipe which is
inclined upward at an angle of 30o to the
horizontal. If the distance between
pressure tape along the pipe is 2 m, the
differential pressure is 90 kPa. What is
the discharge of water in m3/s? Assume
coefficient of 0.98.
a. 0.185 m3/s
b. 0.156 m3/s
c. 0.175 m3/s
d. 0.165 m3/s
36. What is the density of a stone that
weighs 100 N in air and 60 N in water?
a. 2,500 kg/m3
b. 2,600 kg/m3
c. 2,700 kg/m3
d. 2,800 kg/m3
37. A 2 m long rod floats vertically in water.
It has a 7 cm2 cross sectional area and a
specific gravity of 0.6. What length, L, is
submerged?
a. 1.2 m
b. 1.5 m
REVIEW GUIDE
c. 1.3 m
d. 1.4 m
38. The density of ice is 917 kg/m3, and the
approximate density of sea water in which
an iceberg float is 1025 kg/m3. What
fraction of iceberg is beneath the water
surface?
a. 0.89
b. 0.71
c. 0.45
d. 0.29
39. A barrel contains a 0.15 m layer of oil
floating on water that is 0.30 mm deep. If
the density of the oil is 600 kg/m3, what
is the pressure (gage) at the oil-water
interface?
a. 883 Pa
b. 900 Pa
c. 742 Pa
d. 924 Pa
40. A fluid that has a velocity of 18 m/s will
have an equivalent head of:
a. 16.51 m
b. 18.34 m
c. 13.56 m
d. 11.41 m
41. The length of pipe is 168 m. If the
pressure drop is 50 kPa for every 30 m,
what is the total pressure drop?
a. 240 kPa
b. 280 kPa
c. 260 kPa
d. 220 kPa
42. Find the volume flow rate of water in L/s
if the power developed under a head of
320 m is 10,500 kW and the hydraulic
efficiency is 85%.
a. 3,935
b. 3,293
c. 3,271
d. 3,721
43. Water flows in a pipe with a velocity of
10 m/s. Determine the velocity head of
the water.
a. 5.1 m
b. 6.8 m
c. 1.5 m
d. 8.6 m
PIPE Coaching Notes
flow of discharge is 1.2 m3/s, determine
the capacity of air compressor.
a. 4.32 m3/s
b. 3.33 m3/s
c. 6.85 m3/s
d. 7.42 m3/s
2. The discharge pressure of an air
compressor is 5 times the suction
pressure. If volume flow of suction is 0.1
m3/s, what is the compressor power
assuming n = 1.35 and suction pressure
is 98 kPa?
a. 21.67 kW
b. 19.57 kW
c. 25.87 kW
d. 10.45 kW
3. A 10 Hp motor is used to drive an air
compressor. The compressor efficiency
is 75%. Determine the compressor work.
a. 6.0 kW
b. 6.5 kW
c. 7.6 kW
d. 5.6 kW
4. The initial condition of air in an air
compressor is 98 kPa and 27°C and
discharges air at 400 kPa. The bore and
stroke are 355 mm and 381 mm,
respectively with percent clearance of 5%
running at 300 rpm. Find the volume of
air at suction.
a. 600 m3/hr
b. 610 m3/hr
c. 620 m3/hr
d. 630 m3/hr
5. An air compressor has a suction volume
of 0.25 m3/s at 97 kPa and discharges to
650 kPa. How much power saved by the
compressor if there are two stages?
a. 8.27 kW
b. 6.54 kW
c. 3.86 kW
d. 10.0 kW
AIR COMPRESSOR
6. The suction condition of an air is 98 kPa,
27°C and 0.2 m3/s. If the surrounding air
is 100 kPa and 20°C, determine the free
air capacity in m3/s.
a. 0.15
b. 0.19
c. 0.25
d. 0.23
1. An air compressor takes air at 100 kPa
and discharges to 600 kPa. If the volume
7. A 355 mm x 381 mm air compressor has
a piston displacement of 0.1885 m3/s.
REVIEW GUIDE
Determine the operating speed of the
compressor.
a. 250 rpm
b. 300 rpm
c. 350 rpm
d. 600 rpm
8. Determine the percent clearance of an air
compressor having 87% volumetric
efficiency and compressor air pressure to
be thrice the suction pressure.
a. 5%
b. 7%
c. 15%
d. 11%
9. The compressor work of an air
compressor is 100 kW. If the piston
speed is 15 m3/min, determine the mean
effective pressure.
a. 200 kPa
b. 300 kPa
c. 400 kPa
d. 600 kPa
10. A double acting air compressor has 16
in x 7 in, 600 rpm has what volume
displacement?
a. 688 ft3/min
b. 755 ft3/min
c. 488 ft3/min
d. 977 ft3/min
11. A two-stage air compressor has a
suction pressure of 14 psi and discharge
pressure of 130 psig. What is the
intercooler pressure in kPag?
a. 209 kPag
b. 600 kPag
c. 477 kPag
d. 300 kPag
12. A two stage air compressor has an
intercooler pressure of 3 kg/cm2. What is
the discharge pressure if suction
pressure is 1 kg/cm2?
a. 3 kg/cm2
b. 9 kg/cm2
c. 23 kg/cm2
d. 15 kg/cm2
13. The piston speed of an air compressor
is 140 m/min and has a volume
displacement of 0.2 m3/s. Determine the
diameter of compressor cylinder.
a. 500 mm
b. 358 mm
c. 467 mm
d. 246 mm
PIPE Coaching Notes
14. An air compressor piston displacement
is 5000 cm3 when operates at 900 rpm
and volumetric efficiency of 75%.
Determine the mass flow of air standard
density.
a. 365.3 kg/hr
b. 243.5 kg/hr
c. 386 kg/hr
d. 465.2 kg/hr
15. A two-stage compressor air at 100 kPa
and 22°C discharges to 690 kPa. If
intercooler intake is 105°C, determine the
value of n.
a. 1.400
b. 1.358
c. 1.345
d. 1.288
16. The piston displacement of a double
acting compressor running at 300 rpm is
0.4 m3/sec. If bore and stroke are unity,
determine the length of stroke.
a. 350 mm
b. 380 mm
c. 371 mm
d. 400 mm
17. An air compressor takes air at 97 kPa at
the rate of 0.5 m3/s and discharge 500
kPa. If power input to the compressor is
120 kW, determine the heat loss in the
compressor.
a. 26.5 kW
b. 18.55 kW
c. 30.45 kW
d. 22.36 kW
18. A single acting air compressor has a
volumetric efficiency of 87%, operates at
500 rpm. It takes in air at 100 kPa and
30°C and discharges it at 600 kPa. The air
handled is 6 m3/min measured at
discharge condition. If compression is
isentropic, find mean effective pressure
in kPa.
a. 182
b. 983
c. 198
d. 204
19. A single acting reciprocating air
compressor has a clearance volume of
10%. Air is received at 90 kPa and 90.3°C
and is discharged at 600 kPa. The
REVIEW GUIDE
compression
and expansion
are
polytropic with n = 1.28. The pressure
drop is 5 kPa at suction port and 10 kPa
at discharge port. The compressor piston
displacement is 500 cm3 when operating
900 rpm. Determine the mass of
compressed air in kg/hr.
a. 16.76
b. 20.45
c. 98.33
d. 28.23
20. A single acting air compressor operates
at 150 rpm with an initial condition of air
at 97.9 kPa and 27°C and discharges the
air at 379 kPa to a cylindrical tank. The
bore and stroke are 355 mm and 381 mm
respectively, with 5% clearance. If the
surrounding air is at 100 kPa and 20°C
while the compression and expansion
process are PV1.3 = C, determine air
capacity, m3/s.
a. 0.0919
b. 2.13
c. 1.23
d. 4.23
21. The piston displacement of a double
acting compressor is 0.358 m3/s, delivers
gas from 101.325 kPa and 300 K to 675
kPa at the rate of 0.166 m3/s at 150 rpm.
Value of n for compression and
expansion is 1.33. Find the compressor
percent clearance.
a. 16.96
b. 14.23
c. 12.34
d. 18.44
22. The piston displacement of a double
acting compressor is 0.358 m3/s, delivers
gas from 101.325 kPa and 300°K to 675
kPa at the rate of 0.166 m3/s at 150 rpm.
Value of n for compression and
expansion is 1.33. Find the bore and
stroke assuming bore = stroke.
a. 300 mm
b. 400mm
c. 350 mm
d. 450 mm
23. A 2-stage, double acting, L-type air
compressor 16” x 10” x 7”, 600 rpm, has
PIPE Coaching Notes
a free air unloader at each end for
capacity control. It is driven through Vbelts by a 150 Hp electric motor, 460 V,
3 phase, 60 Hz, 1200 rpm. Barometric
pressure is 125 psi gage. Calculate piston
displacement in m3/hr.
a. 562 m3/hr
b. 762 m3/hr
c. 649 m3/hr, 1661 m3/hr
d. 833 m3/hr, 724 m3/hr
24. A two-cylinder single-acting air
compressor is directly coupled to an
electric motor running at 1000 rpm. Other
data are as follows:
Size of each cylinder
= 150 mm x 200 mm
Clearance volume
= 10% of displacement
Exponent (n) for both compression and
re-expansion process = 1.6
Air constant = 1.4
Air molecular mass M = 29
Calculate the volume rate of air delivery in
terms of standard air for a delivery
pressure 8 times ambient pressure under
ambient air conditions of 300 °K and 1
bar.
a. 2 m3/hr
b. 4 m3/hr
c. 3 m3/hr
d. 5 m3/hr
25. A two stage compressor with first stage
piston displacement of 94,390 cm3/s is
driven by a motor. Motor output is 35 Hp,
suction temperature is 22°C, volumetric
efficiency is 85%. Mechanical efficiency is
95%, the intercooler pressure is 30 psi
gage. Air temperature in and out of the
intercooler are 105°C and 44°C. Final
discharge pressure is 100 psi gage,
suction estimated 14.5 psi. Find the
compression efficiency.
a. 77.60%
b. 63.34%
c. 87.34%
d. 98.23%
REVIEW GUIDE
26. An air compressor is to compress 8.5
m3/min from 98.56 kPa to 985.6 kPa.
Assuming conditions are ideal, and with n
= 1.3, what will be the saving in work due
to two staging?
a. Zero
b. 4.6 kW
c. 5.6 kW
d. 3.5 kW
27. A single stage air compressor handles
0.454 m3/s of atmospheric pressure,
27°C air, and delivers it to a receiver at
652.75 kPa. Its volumetric efficiency on
an isothermal basis is 0.85 and its
mechanical efficiency is 0.90. If it
operates at 350 rpm, what power in kW is
required to drive it?
a. 95
b. 112
c. 120
d. 100
28. A two stage compressor receives 0.50
kg/s of air at 120 kPa and 300°K and
delivers it at 7 MPa. Find the heat
transferred in the intercooler.
a. 118.14 kW
b. 124.55 kW
c. 233.34 kW
d. 187.34 kW
29. An air compressor is tested, and it is
found that the electric motor used 37.3
kW when the compressor handled 0.189
m3/s of air at 101.4 kPa and 300 °K and
discharged it at 377.1 kPa. Determine the
adiabatic efficiency.
a. 67.34%
b. 76.34%
c. 81.89%
d. 92.34%
30. An air compressor is tested, and it is
found that the electric motor used 37.6
kW when the compressor handled 0.189
m3/s of air at 101.4 kPa and 300°K and
discharged it at 377.1 kPa. Determine the
isothermal efficiency.
a. 67.34%
b. 76.34%
c. 81.89%
d. 67.48%
PIPE Coaching Notes
31. Calculate the volumetric efficiency of a
single-cylinder,
double
acting
compressor with a bore and stroke of
0.45 x 0.45 m. The compressor is tested
at 150 rpm and found to deliver gas from
101.3 kPa and 300°K to 675 kPa at a rate
of 0.166 m3/s when n =1.33 for expansion
and compression process.
a. 46.39%
b. 56.23%
c. 48.34%
d. 74.23%
32. A reciprocating compressor with a 3%
clearance receives air at 100 kPa and
300°K and discharges it at 1.0 MPa. The
expansion
and compression
are
polytropic with n = 1.25. There is a 5%
pressure drop through the inlet and outlet
valves. Find the volumetric efficiency.
a. 76.23%
b. 82.50%
c. 98.33%
d. 65.33%
33. A reciprocating compressor has a 5%
clearance with a bore and stroke of 25 x
30 cm. The compressor operates at 50
rpm. The air enters the cylinder at 27°C
and 96 kPa and discharges in 2000 kPa.
If n = 1.3, determine the compressor
power.
a. 2.34 kW
b. 18.45 kW
c. 27.25 kW
d. 34.32 kW
34. A water-jacketed air compressor
handles 0.143 m3/s air entering at 96.5
kPa and 21°C and leaving at 480 kPa and
132°C; 10.9 kg/hr of cooling water enters
the jacket at 15°C and leaves at 21°C.
Determine the compressor power.
a. 26.163 kW
b. 17.23 kW
c. 34.44 kW
d. 19.33 kW
35. A 2-stage compressor operates between
constant pressure limits of 98.6 kPa and
1.103 MPa. The swept volume of the lowpressure piston is 0.142 m3. Due to
REVIEW GUIDE
PIPE Coaching Notes
failure of the cooling water supply to the
intercooler, air is passed to the highpressure cylinder without reduction in
temperature. Using PV1.2 = C, determine
the percentage increase in power.
a. 26
b. 21
c. 11
d. 16
4. The suction pressure of a pump reads 2
in. of mercury vacuum and discharge
pressure reads 130 psi is used to deliver
100 gpm of water with specific volume of
0.0163 ft3/lb. Determine the pump work.
a. 4.6 kW
b. 5.7 kW
c. 7.4 kW
d. 9.4 kW
36. An ideal-single stage air compressor
without clearance takes in air at a 100 kPa
with a temperature of 16°C and delivered
at 413 kPa after isentropic compression.
What is the discharge work done by the
compressor in kJ/kg?
a. -59.22
b. -52.43
c. -54.75
d. -56.13
Answer: -145 KJ/kg (no answer in the
given choices)
5. A pump is to deliver 150 gpm of water at
ahead of 120 m. If pump efficiency is
70%, what is the horsepower rating of
motor required to drive the pump?
a. 40.44 Hp
b. 25.66 Hp
c. 38.44 Hp
d. 21.33 Hp
PUMPS
1. A double suction centrifugal pumps
delivers 70 ft3/s of water at a head of 12
m and running at 1250 rpm. What is the
specific speed of the pump?
a. 5014 rpm
b. 5453 rpm
c. 2345 rpm
d. 9968 rpm
2. The pump centerline of a centrifugal
pump is located 2.5 m above from the
high tide level. The sea water varies two
meters from high tide to low tide level. If
friction loss at the suction is 0.8 m,
determine the total suction head.
a. 5.30 m
b. 2.30 m
c. 6.30 m
d. 8.23 m
3. A centrifugal pump requires 40 ft head to
deliver water from low level to higher
level. If pump speed is 1600 rpm,
determine the impeller diameter of the
centrifugal pump.
a. 185 mm
b. 160 mm
c. 154 mm
d. 176 mm
6. A motor is used to d rive a pump having
an efficiency of 85% and 70 %
respectively. What is the combined
efficiency of pump and motor?
a. 59.50%
b. 61.50%
c. 62.50%
d. 65.50%
7. In a boiler feed pump, the enthalpy at the
entrance is 765 kJ/kg. If pump has a head
of 900 m, what is the exit enthalpy of the
pump?
a. 897 kJ/kg
b. 465 kJ/kg
c. 774 kJ/kg
d. 864 kJ/kg
8. A submersible pump delivers 350 gpm of
water to a height of 5 ft from the ground.
The pump was installed 120 ft below the
ground level and a drawdown of 8 ft
during the operation. If water level is 25
ft above the pump, determine the pump
power.
a. 7.13 kW
b. 4.86 kW
c. 7.24 kW
d. 864 kW
9. Determine the number of stages needed
for a centrifugal pump if it is used to
deliver 400 gal/min of water and pump
power of 15 Hp. Each impeller develops a
head of 38 ft.
a. 6
b. 4
PIPE Coaching Notes
REVIEW GUIDE
c. 8
d. 7
10. A boiler feed pump receives 50 li/sec of
water with specific volume of 0.00112 m
3
/kg at ahead of 750 m. What is the power
output of driving motor if pump efficiency
is 65%?
a. 505.32 kW
b. 643.54 kW
c. 785.56 kW
d. 356.45 kW
11. What power can a boiler feed pump can
deliver a mass of 35 kg/s water at a head
of 500 m?
a. 356.56 kW
b. 354.54 kW
c. 456.64 kW
d. 171.67 kW
12. A pump running at 100 rpm delivers
water against a head of 30 m. If pump
speed will increase to 120 rpm, what is
the increase in head?
a. 43.2 m
b. 13.2 m
c. 34.6 m
d. 56.3 m
13. A pump is used to deliver 50 li/sec of
sea water at a speed of 120 rpm. If speed
will increase to 135 rpm, determine the
increase in pump capacity.
a. 56.25 li/sec
b. 34.56 li/sec
c. 87.54li/sec
d. 6.260 li/sec
14. A 15 kW motor running at 350 rpm is
used to drive a pump. If speed will be
changed to 370 rpm, what is the increase
in power?
a. 2.72 kW
b. 17.72 kW
c. 56.45 kW
d. 5.67 kW
15. A certain pump is used to deliver 150
gpm of water having a density of 61.2
lb/ft3. The suction and discharge gage
reads 4 in Hg vacuum and 25 psi,
respectively. The discharge gage is 2 ft
above the suction gage. What is the brake
power of the motor if pump efficiency is
75%?
a. 3.24 Hp
b. 2.67 Hp
c. 5.45 Hp
d. 6.89 Hp
16. The discharge pipe of a pump is 400 mm
in diameter delivers 0.5 m3/s of water to
a building which maintains a pressure of
100 kPa at a height of 30 m above the
reservoir. If equivalent head is 2 m, what
power must be furnished by the pump?
a. 211 kW
b. 480 kW
c. 340 kW
d. 240 kW
17. A centrifugal pump is designed for 1800
rpm and head of 61m. Determine the
speed of impeller if diameter is reducing
from 305 mm to 254 mm.
a. 1000 rpm
b. 1250 rpm
c. 1500 rpm
d. 1600 rpm
18. Water from a reservoir A 10 m elevation
is drawn by a motor driven pump to an
upper reservoir B at 72 m elevation.
Suction and discharge head loss are 0.15
m, respectively. For discharge rate of 15
li/sec, find the power input to the motor if
overall efficiency is 65%.
a. 12.65 kW
b. 23.54 kW
c. 14.17 kW
d. 45.35 kW
19. The elevation of suction reservoir is 5 m
above the pump centerline and delivers to
85 m elevation tank which maintain 150
kPa. If 1.5 m3/sec of water is used to
deliver a total head of 3 m, determine the
power needed by the pump.
a. 1446 kW
b. 2546 kW
c. 4675 kW
d. 3456 kW
20. Water from a reservoir is pumped over
a hill through a pipe 900 mm in diameter
and a pressure of one kg/cm2 is
maintained at the pipe discharge where
the pipe is 85m from the pump centerline.
The pump has a positive suction head of
5m. Pumping rate of the pump at 1000
rpm is 1.5 m3/sec. Friction losses is
REVIEW GUIDE
equivalent to 3m of head loss. What
amount of energy must be furnished by
the pump in kW?
a. 1372 kW
b. 1523 kW
c. 1234 kW
d. 1723 kW
21. Water from a reservoir is pumped over
a hill through a pipe 450 mm in diameter
and a pressure of 1 kg/cm2 is maintained
at the summit. Water discharge is 30 m
above the reservoir. The quantity pumped
is 0.5 m3/s. Frictional losses in the
discharge and suction pipe and pump is
equivalent to 1.5m head loss. The speed
of the pump is 800 rpm what amount of
energy must be furnished by the pump in
kW?
a. 202
b. 206
c. 204
d. 208
22. Water from an open reservoir A at 8m
elevation is drawn by a motor-driven
pump to an open reservoir B at 70 m
elevation. The inside diameter of the
suction pipe is 200 mm and 150 mm for
the discharge pipe. The suction line has a
loss of head three times that of the
velocity head in the 200 mm pipe. The
discharge line has a loss of head twenty
times that of the velocity head in the
discharge pipeline. The pump centerline
is at 4m. Overall efficiency of the system
is 78%. For a discharge rate of 10 li/sec,
find the power input to the motor and the
pressure gage reading installed just at the
outlet and inlet of the pump in kPag.
a. 2.34 kW
b. 5.45 kW
c. 6.59 kW
d. 7.84 kW
23. A pump is to deliver 80 gpm of water at
140°F with a discharge pressure of 150
psig. Suction pressure indicates 2 inches
of mercury vacuum. The diameter of
suction and discharge pipes are 5 inches,
PIPE Coaching Notes
respectively. The pump has an efficiency
of 70%, while the motor efficiency is 80%.
Determine power input to the drive
motor.
a. 7.23 kW
b. 2.34 kW
c. 8.34 kW
d. 9.39 kW
24. Determine the water horsepower and
the mechanical efficiency of a centrifugal
water pump which has an input of 3.5 Hp
if the pump has an 8 inches nominal size
suction and 6 inches nominal size
discharge if it handles 150 gpm of water
at 150°F. The suction line gage shows 4”
Hg vacuum and the discharge gage
shows 26 psi. The discharge gage is
located 2 feet above the center of the
discharge pipeline and pump inlet and
discharge lines are at the same elevation.
a. 2.52 hp
b. 6.33 hp
c. 4.23 hp
d. 8.34 hp
25. A boiler feed pump receives 40 liters per
second at 4 MPa and 180°C. It operates
against a total head of 900 m with an
efficiency of 60%. Determine the enthalpy
leaving the pump in kJ/kg.
a. 783.45
b. 773.57
c. 756.23
d. 765.23
26. A boiler feed pump receives 40 liters per
second at 180°C. It operates against a
total head of 900 m with an efficiency of
60%. Determine power output of the
driving motor in kW.
a. 453.23
b. 623.34
c. 983.45
d. 523.27
27. A boiler feed pump receives 40 liters per
second at 180°C. It operates against a
total head of 900 m with an efficiency of
60%. Determine discharge pressure in
kPa for a suction pressure of 4 MPa.
a. 11,850 kPa
b. 13,455 kPa
c. 12,566 kPa
d. 14,233 kPa
REVIEW GUIDE
28. A boiler feed pump receives 45 li/sec of
water at 190°C and enthalpy of 839.33
kJ/kg. It operates against a head of 952m
with efficiency of 70%. Estimate the water
leaving temperature assuming that the
temperature rise as due to the
inefficiency of the input energy.
a. 191°C
b. 143°C
c. 123°C
d. 165°C
29. A submersible, multi-stage, centrifugal
deep well pump 260 gpm capacity is
installed in a well 27 feet below the static
water level. Drawdown when pumping at
rated capacity is 10 feet. The pump
delivers the water into a 25,000 gallons
capacity overhead storage tank. Total
discharge head developed by pump,
including friction in piping is 243 feet.
Calculate brake horsepower required to
drive the pump if pump efficiency is 70%.
a. 31.31
b. 41.41
c. 21.21
d. 51.51
30. A submersible, multi-stage, centrifugal
deep well pump 260 gpm capacity is
installed in a well 27 feet below the static
water level and running at 3450 rpm.
Drawdown when pumping at rated
capacity overhead storage tank. Total
discharge head developed by pump,
including friction in piping is 243 feet.
Calculate the diameter of the impeller of
this pump in inches if each impeller
diameter developed a head of 38 ft.
a. 3.28
b. 5.33
c. 4.23
d. 6.34
31. A double suction, single stage,
centrifugal pump delivers 900 m3/hr of
sea water (SG = 1.03) from a source
where the water level varies two meters
from high tide to low tide level. The pump
centerline is located 2.6 meters above the
PIPE Coaching Notes
surface of the water at high tide level. The
pump discharges into a surface
condenser, 3 m above pump centerline.
Loss of head due to friction in suction
pipe is 0.8 m and that in the discharge
side is 3 m. Pump is directly coupled to a
1750 rpm, 460 V, 3 phase, 60 Hz motor.
Calculate the specific speed of pump in
rpm.
a. 3131 rpm
b. 5151 rpm
c. 4141 rpm
d. 6161 rpm
32. A pump driven by an electric motor
moves 25 gal/min of water from reservoir
A to reservoir B, lifting the water to a total
of 245 feet. The efficiency of the pump
and motor are 64% and 84% respectively.
What size of motor (HP) is required?
a. 1 Hp
b. 3 Hp
c. 4 Hp
d. 7.5 Hp
33. Water is pumped at 1 m3/s to an
elevation of 5 m through a flexible hose
using a 100% efficiency pump rated at
100 kW. Using the same length of hose,
what size of motor is needed to pump 1
m3/s of water to a tank with no elevation
gain? In both cases both ends of hose are
at atmospheric pressure. Neglect kinetic
energy.
a. 51 kW
b. 18 kW
c. 43 kW
d. 22 kW
34. A vacuum pump is used to drain a
flooded mine shaft of 20°C water. The
pump pressure of water at this
temperature is 2.34 kPa. The pump is
incapable of lifting the water higher than
10.16 m. What is the atmospheric
pressure?
a. 109
b. 112
c. 98
d. 101.9
35. It is desired to deliver 5 gpm at a head
of 640 m in a single stage pump having
REVIEW GUIDE
specific speed not to exceed 40. If the
speed is not to exceed 1352 rpm, how
many stages are required?
a. 3
b. 4
c. 5
d. 2
36. The rate of flow of water in a pump
installation is 60.6 kg/s. The intake static
gage is located 1.22 m below the pump
center line and reads 68.95 kPa gage; the
discharge static gage is 0.61 m below the
pump centerline and reads 344.76 kPa
gage. The gages are located close to the
pump as much as possible. The areas of
the intake and discharge pipes are 0.093
m2 and 0.069 m2, respectively. The pump
efficiency is 70%. Take density of water
equals 1000 kg/m3. What is the hydraulic
power in kW?
a. 17.0
b. 24.5
c. 31.9
d. 15.2
37. Water in rural areas is often extracted
from underground water source whose
free surface is 60 m below ground level.
The water is to be raised 5m above the
ground by a pump. The diameter of the
pipe is 10 cm at the inlet and 15 cm at the
exit. Neglecting any heat interaction with
the surroundings and frictional heating
effects, what is the necessary power
input to the pump for a steady flow of
water at the rate of 15 li/sec in kW if pump
efficiency is 85%?
a. 9.54
b. 5.343
c. 7.82
d. 11.23
38. A pump lifts water at a rate of 283 lps
from a lake and force it into a tank 8 m
above the level of the water at a pressure
of 137 kPa. What is the power required in
kilowatts.
a. 71
b. 41
c. 61
d. 51
PIPE Coaching Notes
39. A pump receives 8 kg/s of water at 220
kPa and 110°C and discharges it at 1100
kPa. Compute for the power required in
kilowatts.
a. 8.126
b. 5.082
c. 7.041
d. 6.104
40. A fuel pump is delivering 10 gallons per
minute of oil with a specific gravity of
0.83. The total head is 9.14 m, find how
much energy does the pump consumes
in KJ per hour.
a. 169
b. 199
c. 189
d. 179
41. A pump discharges 150 liters per
second of water to a height of 75 meters.
If the efficiency is 75% and the speed of
the pump is 1800 rpm, what is the torque
in N-m to which the drive shaft is
subjected?
a. 771
b. 781
c. 791
d. 681
42. A pump with a 400 mm diameter suction
and a 350 mm diameter discharge pipe is
to deliver 20,000 liters per minute of
15.6°C water. Calculate the pump head in
meters if suction gage is 7.5 cm below
pump centerline and reads 127 mm Hg
vacuum and discharge gage is 45 cm
above the pump centerline and reads 75
kPa.
a. 15 m
b. 5 m
c. 20 m
d. 10 m
43. A centrifugal pump delivers 300,000
liters per hour of water to a pressurized
tank whose pressure is 280 kPa. The
source of water is 5m below the pump.
The diameter of the suction pipe is 300
mm, and the discharge pipe is 250 mm.
Calculate the kW rating of the driving
motor assuming the pump efficiency to
be 72%.
REVIEW GUIDE
a. 41.75 kW
c. 43.26 kW
b. 35.75 kW
d. 38.16 kW
44. A centrifugal pump delivers 80 liters per
second of water on test. Suction gage
reads 10 mm Hg vacuum and 1.2 meters
below pump centerline. Power input is 70
kW. Find the total dynamic head in
meters.
a. 66
b. 60
c. 62
d. 64
45. A pump delivers 500 gpm of water
against a total head of 200 ft and
operating at 1770 rpm. Changes have
increased the total head to 375 ft. At what
rpm should the pump be operated to
achieve the new head at the same
efficiency?
a. 2800 rpm
b. 3600 rpm
c. 3434 rpm
d. 2424 rpm
PIPE Coaching Notes
49. The suction pressure of a pump reads
2 in. of mercury vacuum and discharge
pressure reads 130 psi is used to deliver
100 gpm of water with specific volume of
0.0163 ft³/lb. Determine the pump work.
a. 4.6 kW
b. 7.4 kW
c. 5.7 kW
d. 8.4 kW
50. A pump is to deliver 150 gpm of water
at a head of 120 m. If pump efficiency is
70%, what is the horsepower rating of
motor required to drive the pump?
a. 40.44 HP
b. 38.44 HP
c. 25.66 HP
d. 21.33 HP
51. A motor is used to drive a pump having
an efficiency of 85% and 70%
respectively. What is the combined
efficiency of pump and motor?
a. 59.50%
b. 62.50%
c. 61.50%
d. 65.50%
46. A double suction centrifugal pumps
delivers 70 ft³/sec of water at a head of
12 m and running at 1250 rpm. What is
the specific speed of the pump?
a. 5014 rpm
b. 2345 rpm
c. 6453 rpm
d. 9968 rpm
52. In a boiler feed pump, the enthalpy at
the entrance is 765 KJ/kg, the pump has
a head of 900 m. What is the exit enthalpy
of the pump?
a. 897 kJ/kg
b. 774 kJ/kg
c. 465 kJ/kg
d. 864 kJ/kg
47. The pump centerline of a centrifugal
pump is located 2.5 m above from the
high tide level. The sea water varies two
meters from high tide to low tide level. If
friction loss at the suction is 0.8 m,
determine the total suction head.
a. 5.30 m
b. 6.30 m
c. 2.30 m
d. 8.23 m
53. A submersible pump delivers 350 gpm
of water to a height of 5 ft from the
ground. The pump was installed 120 ft
below the ground level and a drawdown
of 8 ft during the operation. If water level
is 25 ft above the pump, determine the
pump power.
a. 7.13 kW
b. 7.24 kW
c. 4.86 kW
d. 864 kW
48. A centrifugal pump requires 40 ft head
to deliver water from low level to higher
level. If pump speed is 1600 rpm,
determine the impeller diameter of the
centrifugal pump.
a. 185 mm
b. 154 mm
c. 160 mm
d. 176 mm
54. Determine the number of stages
needed for a centrifugal pump if it is used
to deliver 400 gal/min of water and pump
power of 15 HP. Each impeller develops
a head of 38 ft.
a. 6
b. 8
PIPE Coaching Notes
REVIEW GUIDE
c. 4
d. 7
55. A boiler feed pump receives 50 li/sec of
water with specific volume of 0.00112
m³/kg at a head of 750 m. What is the
power output of driving motor if pump
efficiency is 65%?
a. 505.32 kW
b. 785.56 kW
c. 643.54 kW
d. 356.45 kW
56. What power can a boiler feed pump can
deliver a mass of 35 kg/s water at a head
of 500 m?
a. 356.56 kW
b. 456.64 kW
c. 354.54 kW
d. 171.67 kW
57. A pump running at 100 rpm delivers
water against a head of 30 m. If pump
speed well increased to 120 rpm, what is
the increase in head?
a. 43.2 m
b. 34.6 m
c. 13.2 m
d. 56.3 m
58. A pump is used to deliver 50 li/sec of
sea water at a speed of 120 rpm. If speed
will increase to 135 rpm, determine the
increase in pump capacity.
a. 56.25 li/s
b. 87.54 li/s
c. 34.56 li/s
d. 6.260 li/s
59. A 15 kW motor running at 350 rpm is
used to drive a pump. If speed will change
to 370 rpm, what is the increase in
power?
a. 2.72 kW
b. 56.45 kW
c. 17.72 kW
d. 5.67 kW
60. A certain pump is used to deliver 150
gpm of water having a density of 61.2
lb/ft³. The suction and discharge gage
reads 4 in Hg vacuum and 25 psi,
respectively. The discharge gage is 2 ft
above the suction gage. What is the brake
power of the motor if pump efficiency is
75%?
a. 3.24 HP
b. 5.45 HP
c. 2.67 HP
d. 6.89 HP
61. The discharge pipe of a pump is 400 mm
in diameter delivers 0.5 m³/sec of water
to a building which maintains a pressure
of 100 kPa at a height of 30 m above the
reservoir. If the equivalent head is 2 m,
what power must be furnished by the
pump?
a. 211 kW
b. 340 kW
c. 480 kW
d. 240 kW
62. A centrifugal pump is designed for 1800
rpm and head of 61 m. Determine the
speed if impeller diameter is reduced
from 305 mm to 254 mm.
a. 1000 rpm
b. 1500 rpm
c. 1250 rpm
d. 1600 rpm
63. Water from a reservoir a 10 m elevation
is drawn by a motor driven pump to an
upper reservoir B at 72 m elevation.
Suction and discharge head loss are 0.15
m, respectively. For discharge rate of 15
li/s, find the power input to the motor if
overall efficiency is 65%.
a. 12.65 kW
b. 14.17 kW
c. 23.54 kW
d. 45.35 kW
64. The elevation of suction reservoir is 5 m
above the pump centerline and delivers to
85 m elevation tank which maintain 150
kPa. If 1.5 m³/sec of water is used to
deliver a total head of 3 m, determine the
power needed by the pump.
a. 1446 kW
b. 4675 kW
b. 2567 kW
d. 3456 kW
65. Water from a reservoir is pumped over
a hill through a pipe 900 mm in diameter
and a pressure of 1 kg/cm² is maintained
at the pipe discharge where the pipe is 85
m from the pump centerline. The pump
has a positive suction head of 5 m.
Pumping rate of the pump at 1000 rpm is
REVIEW GUIDE
1.5 m³/s. Friction losses is equivalent to 3
m of head loss. What amount of energy
must be furnished by the pump in kW?
a. 1372 kW
b. 1234 kW
c. 1523 kW
d. 1723 kW
65. Water from a reservoir is pumped over
a hill through a pipe 450 mm in diameter
and a pressure of 1 kg/cm² is maintained
at the summit. Water discharge is 30 m
above the reservoir. The quantity pumped
is 0.5 m³/s. Frictional losses in the
discharge and suction pipe and pump is
equivalent to 1.5 m head loss. The speed
of the pump is 800 rpm, what amount of
energy must be furnished by the pump in
kW?
a. 202
b. 204
c. 206
d. 208
66. Water from an open reservoir A at 8 m
elevation is drawn by a motor-driven
pump to an open reservoir B at 70 m
elevation. The inside diameter of the
suction pipe is 200 mm and 150 mm for
the discharge pipe. The suction line has a
loss of head three times that of the
velocity head in the 200 mm pipe. The
discharge line has a loss of head twenty
times that of the velocity head in the
discharge pipeline. The pump centerline
is at 4 m. Overall efficiency of the system
is 78%. For a discharge rate of 10 li/sec,
find the power input to the motor and the
pressure gage readings installed just at
the outlet and inlet of the pump in kPag?
a. 3.34 kW
b. 6.59 kW
c. 5.45 kW
d. 7.84 kW
67. A pump is to deliver 80 gpm of water at
140oF with a discharge pressure of 150
psig. Suction pressure indicates 2 inches
of mercury vacuum. The diameter of
suction and discharge pipes are 5 inches
PIPE Coaching Notes
and 4 inches, respectively. The pump has
an efficiency of 70%, while the motor
efficiency is 80%. Determine power input
to the drive motor.
a. 7.23 kW
b. 8.34 kW
c. 2.34 kW
d. 9.39 kW
68. Determine the water horsepower and
the mechanical efficiency of a centrifugal
water pump which has an input of 3.5 HP
if the pump has an 8 inches nominal size
suction and 6 inches nominal size
discharge if it handles 150 gpm of water
at 150-degree Fahrenheit. The suction
line gage shows 4” Hg vacuum and the
discharge gage shows 26 psi. The
discharge gage is located 2 feet above the
center of the discharge pipeline and the
pump inlet and discharge lines are at the
same elevation.
a. 2.52 HP
b. 4.23 HP
c. 6.33 HP
d. 8.34 HP
69. A boiler feed pump receives 40 liters per
second at 4 MPa and 180 °C. It operates
against a total head of 900 m with an
efficiency of 60%. Determine the enthalpy
leaving the pump in kJ/kg.
a. 783.45
b. 756.23
c. 773.57
d. 765.23
70. A boiler feed pump receives 40 liters per
second at 180 °C. It operates against a
total head of 900 m with an efficiency of
60%. Determine power output of the
driving motor in kW.
a. 453.23
b. 983.45
c. 623.34
d. 523.27
71. A boiler feed pump receives 40 liters per
second at 180 °C. It operates against a
total head of 900 m with an efficiency of
60%. Determine discharge pressure in
kPa for a suction pressure of 4 MPa.
a. 11,850 kPa b. 12,566 kPa
REVIEW GUIDE
c. 13,455 kPa
d. 14.289 kPa
72. A boiler feed pump receives 45 li/sec of
water at 190 °C and enthalpy of 839.33
kJ/kg. It operates against a head of 952 m
with an efficiency of 70%. Estimate the
water leaving temperature assuming that
the temperature rise is due to the
inefficiency of the input energy.
a. 19oC
b. 123oC
c. 143oC
d. 165oC
73. A submersible, multi-stage, centrifugal
deep well pump with 260 gpm capacity is
installed in a well 27 ft below the static
water level. Drawdown when pumping at
rated capacity is 10 feet. The pump
delvers the water into a 25,000 gallons
capacity overhead storage tank. Total
discharge head developed by pump,
including friction in piping is 243 feet.
Calculate brake horsepower required to
drive the pump if pump efficiency is 70%.
a. 31.31
b. 21.21
c. 41.41
d. 51.51
74. A submersible multi-stage, centrifugal
deep well pump w/ 260 gpm capacity is
installed in a well 27 ft below the static
water level and running at 3450 rpm.
Drawdown when pumping at rated
capacity is 10 ft. The pump delivers the
water into a 25,000 gallons capacity
overhead storage tank. Total discharge
head developed by pump, including
friction in piping is 243 ft. Calculate the
diameter of impeller of this pump in
inches if each impeller diameter
developed a head of 38 ft.
a. 3.28
b. 4.23
c. 5.33
d. 6.34
75. A double suction, single storage,
centrifugal pump delivers 900 m³/hr of
sea water (SG = 1.03) from a source
PIPE Coaching Notes
where the water level varies two meters
from high tide to low tide level. The pump
centerline is located 2.6 m above the
surface of the water at high tide level. The
pump discharges into a surface
condenser, 3 m above pump centerline.
Loss of head due to friction in suction
pipe is 0.8 m and that in the discharge
side is 3 m. Pump is directly coupled to a
1750 rpm, 460 V, 3 phase, 60 Hz motor.
Calculate the specific speed of pump in
rpm.
a. 3131
b. 5151
c. 4141
d. 6161
76. Water is pumped at 1 m3/sec to an
elevation of 5 m through a flexible hose
using a 100% efficiency pump rated at
100 kW. Using the same length of hose,
what size of motor is needed to pump 1
m³/sec of water to a tank with no
elevation gain? In both cases both ends
of hose are at atmospheric pressure.
Neglect kinetic energy.
a. 51 kW
b. 43 kW
c. 18 kW
d. 22 kW
77. A vacuum pump is used to drain a
flooded mine shaft at 20 °C water. The
pump pressure of water at this
temperature is 2.34 kPa. The pump is
incapable of lifting the water higher than
10.6 m. What is the atmospheric
pressure?
a. 109 kPa
b. 98 kPa
c. 112 kPa
d. 101.9 kPa
78. It is desired to deliver 5 gpm at a head
of 640 m in a single stage pump having a
specific speed not to exceed 40. If the
speed is not to exceed 1352 rpm, how
many stages are required?
a. 3
b. 5
c. 4
d. 2
PIPE Coaching Notes
REVIEW GUIDE
79. The rate of flow of water in a pump
installation is 60.6 kg/s. The intake static
gage is located 1.22 m below the pump
center line and reads 68.95 kPa gage; the
discharge static gage is 0.61 m below the
pump centerline and reads 344.75 kPa
gage. The gages are located close to the
pump as much as possible. The area of
the intake and discharge pipes are 0.093
m², respectively. The pumps efficiency is
70%. Take density of water equals 1000
kg/m³. What is the hydraulic power in kW?
a. 17
b. 31.9
c. 24.5
d. 15.2
80. A pump driven by an electric motor
moves 25 gal/min of water from reservoir
A to reservoir B, lifting the water to a total
of 245 ft. The efficiency of the pump and
motor are 64% and 84% respectively.
What size of motor (HP) is required?
a. 5 HP
b. 4 HP
c. 3 HP
d. 7.5 HP
81. Water in the rural areas is often
extracted from underground water
source whose free surface is 60 m below
ground level. The water is to be raised 5
m above the ground by a pump. The
diameter of the pipe is 10 cm at the inlet
and 15 cm at the exit. Neglecting any heat
interaction with the surroundings and
frictional heating effects, what is the
necessary power input to the pump for a
steady flow of water at the rate of 15
li/sec in kW if pump efficiency is 85%?
a. 9.54
b. 7.82
c. 5.343
d. 11.23
82. A pump lifts water at a rate of 283 li/sec
from a lake and force it into a tank 8 m
above the level of the water at a pressure
of 137 kPa. What is the power required in
kilowatts?
a. 71
c. 41
b. 61
d. 51
83. A pump receives 8 kg/s of water at 220
kPa and 110 °C and discharges it at 1100
kPa. Compute for the power required in
kilowatts.
a. 8.126
b. 7.041
c. 5.082
d. 6.104
84. A fuel pump is delivering 10 gpm of oil
with a specific gravity of 0.83. The total
head is 9.14 m, find how much energy
does the pump consumes in kJ/hr.
a. 169
b. 189
c. 199
d. 179
85. A pump discharges 150 liters per
second of water to a height of 75 meters.
If the efficiency is 75% and the speed of
the pump is 1800 rpm, what is the torque
in Nm to which the drive shaft is
subjected?
a. 771
b. 791
c. 781
d. 681
86. A pump w/ 400 mm diameter suction
and a 350 mm diameter discharge pipe is
to deliver 20,000 li/min of 15.6 °C water.
Calculate the pump head in meters if
suction gage is 7.5 cm below pump
centerline and reads 127 mm Hg vacuum
and discharge gage is 45 cm above the
pump centerline and reads 75 kPa.
a. 15 m
b. 20 m
c. 5 m
d. 10 m
87. A centrifugal pump delivers 300,000 li/hr
of water to a pressurized tank whose
pressure is 280 kPa. The source of water
is 5 m below the pump. The diameter of
the suction pipe is 300 mm, and the
discharge pipe is 250 mm. Calculate the
kW rating of the driving motor assuming
the pump efficiency to be 72%.
REVIEW GUIDE
a. 41.75 kW
c. 35.75 kW
b. 43.28 kW
d. 38.16 kW
88. A centrifugal pump delivers 80 li/sec of
water on test. Suction gage reads 10 mm
Hg vacuum and 1.2 m below pump
centerline. Power input is 70 kW. Find the
total dynamic head in meters.
a. 66
b. 62
c. 60
d. 64
89. A pump delivers 500 gpm of water
against a total head of 200 ft and
operating at 1770 rpm. Changes have
increased the total head to 375 ft. At what
rpm should the pump be operated to
achieve the new head at the same
efficiency?
a. 2800 rpm
b. 3434 rpm
c. 3600 rpm
d. 2424 rpm
90. A DC driven pump running at 100 rpm
delivers 30 liters per second of water at
40°C against a total pumping head of 27
m with a pump efficiency of 60%.
Barometer pressure is 758 mm Hg
absolute. What pump speed and capacity
would result if the pump rpm were
increased to produce a pumping head of
36 m assuming no change in efficiency?
a. 115.47 rpm, 34.64 li/s
b. 110.51 rpm,34.46 li/s
c. 115.47 rpm,38.68 li/s
d. 110.51 rpm,38.68 li/s
91. A single acting reciprocating pump has
a diameter of 0.12 meter and a stroke of
0.25 m. Compute the theoretical
discharge if the pump delivers water at 60
rpm.
a. 0.5965 m³/min
b. 0.1698 m³/min
c. 0.05965 m³/min
d. 0.01698 m³/min
PIPE Coaching Notes
92. A single acting reciprocating pump w/ a
diameter of 0.18 m and a stroke of 0.30
m, delivers water at a rate of 0.18 m³/min.
What is the percentage slip it delivers at
25 revolutions per minute?
a. 5.7%
b. 8.4%
c. 10.5%
d. 1.6%
93. Water is flowing through a pipe at 15
li/sec. The inlet diameter of the pipe is 12
cm, and the exit diameter is 15 cm. If
water is to be pumped from water source
and heat loss is 2 kW, determine the
power input to the pump.
a. 2.2 kW
b. 3.2 kW
c. 1.2 kW
d. 4.2 kW
94. A pump delivers 100 li/sec of water at a
head of 50 m. Find the waterpower.
a. 29 kW
b. 39 kW
c. 49 kW
d. 59 kW
FANS AND BLOWERS
1. A fan whose static efficiency is 40% has
a capacity of 60,000 ft3/hr at 60°F and
barometer of 30 in Hg and gives a static
pressure of 2 in of water column on full
delivery. What size of electric motor
should be used to drive the fan?
a. ½ Hp
b. 1 Hp
c. 2 Hp
d. 1 ½ Hp
2. A fan draws 1.42 m3 per second of air at
a static pressure of 2/54 cm water
through a duct 300 mm diameter and
discharges it through a duct of 275 mm
diameter. Determine the static fan
efficiency if total fan mechanical is 70%
and air is measured at 25°C and 760 mm
Hg.
a. 50.11%
b. 54.34%
c. 65.37%
d. 45.34%
3. Find the air horsepower of an industrial
fan that delivers 25 m3/s of air through a
REVIEW GUIDE
900 mm by 1200 mm outlet. Static
pressure is 127 mm of water gage and air
density is 1.18 kg/m3.
a. 65.35 Hp
b. 52.35 Hp
c. 60.35 Hp
d. 70.35 Hp
4. A boiler requires 90,000 m3/hr of standard
air. The mechanical efficiency of fan to be
installed is 65%. Determine the size of
driving motor assuming fan can deliver a
total pressure of 150 mm of water gage.
a. 56.6 kW
b. 78.5 kW
c. 45.5 kW
d. 23.5 kW
5. At 1.2 kg/m3 air density a fan develops a
brake power of 100 KW. It operates at 98
kPa and 32°C with the same speed, what
is the new brake power of the fan?
a. 68.4 kW
b. 36.7 kW
c. 67.5 kW
d. 93.3 kW
6. A fan has a suction pressure of 30 mm
water vacuum with air velocity of 3 m/s.
The discharge has 150 mm of water gage
and discharge velocity of 7m/s.
Determine the total head of fan if air
density is 1.2 kg/m3.
a. 150 m
b. 152 m
c. 154 m
d. 156 m
7. A 50 kW motor is used to drive a fan that
has a total head of 110 m. If fan efficiency
is 70%, what is the maximum capacity of
the fan using standard density of air?
a. 27 m3/s
b. 29 m3/s
c. 31 m3/s
d. 33 m3/s
8. A fan using standard air condition can
develop a static pressure head of 310 mm
water gage. If fan will operate 93°C and
735 mm of Hg, find the new static
pressure required.
a. 150 mm water gage
b. 180 mm water gage
c. 241 mm water gage
PIPE Coaching Notes
d. 456 mm water gage
9. The total head of fan is 185 m and has a
static pressure of 210 mm of water gage,
what is the velocity of air flowing if
density of air is 1.15 kg/m3?
a. 6.85 m/s
b. 3.45 m/s
c. 4.75 m/s
d. 8.54 m/s
10. The volume flow of air delivered by fan
is 20 m3/s and 180 mm water gage. The
density of air is 1.185 kg/m3 and motor
power needed to drive the fan is 44 KW.
What is the fan efficiency?
a. 70.26%
b. 80.26%
c. 75.26%
d. 90.26%
11. A fan is listed as having the following
performances with standard air:
Volume discharged = 120 m3/s
Speed = 7.0 rps
Static pressure = 310 mm water gage
Brake power required = 620 KW
The system duct will remain the same and
the fan will discharge the same volume of
120 m3/s of air at 93°C and a barometric
pressure of 735 mm Hg when its speed
is 7.0 rps. Find the brake power input and
the static pressure required.
a. 231 mm water b. 251 mm water
c. 241 mm water d. 261 mm water
12. Air enters a fan through a duct at velocity
of 6.3 m/s and an inlet static pressure of
2.5 cm of water less than atmospheric
pressure. The air leaves the fan through
a duct a t a velocity of 11.24 m/s and a
discharge static pressure of 7.62 cm of
water above the atmospheric pressure. If
the specific weight of the air is 1.20 kg/m3
and the fan delivers 9.45 m3/s, what is the
fan efficiency when the power input to the
fan is 12.75 kW at the coupling?
a. 71.81%
b. 91.23%
c. 81.34%
d. 61.34%
REVIEW GUIDE
13. A fan delivers 4.7 m3/s at a static
pressure of 5.08 cm of water when
operating at a speed of 400 rpm. The
power input required is 2.863 kW. If 7.05
m3/s are desired in the same fan and
installation, find the pressure in cm of
water.
a. 7.62
b. 17.14
c. 11.43
d. 5.08
14. A fan described in a manufacturer’s table
is rated to deliver 500 m3/min at a static
pressure (gage) of 254 cm of water when
running at 250 rpm and requiring 3.6 kW.
If the fan speed is changed to 305 rpm
and air handled were at 65% instead of
standard 21°C, find the power in kW.
a. 3.82
b. 5.08
c. 4.66
d. 5.68
15. Air is flowing in a duct with velocity of
7.62 m/s and static pressure of 2.16 cm
water gauge. The duct diameter is 1.22
m, the barometric pressure 99.4 kPa and
the gage fluid temperature and air
temperature are 30°C. What is the total
pressure against which the fan will
operate in cm of water?
a. 3.25
b. 2.5
c. 3.75
d. 1.25
16. What horsepower is supplied to air
moving at 20 fpm through a 2 x 3 ft duct
under a pressure of 3 in. water gage?
a. 0.786 hp
b. 0.642 hp
c. 0.741 hp
d. 0.0566 hp
17. Air is flowing in a duct with velocity of
7.62 m/s and a static pressure of 2.16
cm water gage. The duct diameter is
1.22 m, the barometric pressure 99.4
kPa and the gauge fluid temperature and
air temperature are 30C. What is the
PIPE Coaching Notes
total pressure of air against which the
fan will operate in cm of water?
a. 3.25
b. 3.75
c. 2.50
d. 1.25
18. A fan draws 1.42 m3/s of air at a static
pressure of 2.54 cm of water through a
duct at 300 mm in diameter and
discharges it through a duct of 275 mm
diameter. Determine the static fan
efficiency if the total fan mechanical
efficiency is 70% and air is measured at
25C and 760 mm Hg.
a. 60%
b. 30%
c. 50%
d. 40%
19. A certain fan delivers 12,000 cfm at a
static pressure of 1 in. WG when
operating at a speed of 400 rpm and
requires an input of 4 hp. If the same
installation 15,000 cfm are desired, what
will be the new speed, and the new
power needs?
a. 450 rpm, 6.81 hp
b. 500 rpm, 6.81 hp
c. 500 rpm, 7.81 hp
d. 450 rpm, 7.81 hp
20. A fan whose static efficiency is 40% has
a capacity of 60,000 ft3/hr at 60°F and
barometer of 30 in Hg and gives a static
pressure of 2 in of water column on full
delivery. What size of electric motor
should be used to drive the fan?
a. ½ Hp
b. 1 Hp
c. 2 Hp
d. 1 ½ Hp