First Class Steam License Actual Exam
100 Questions with Correct Answers
and Detailed Rationales
1. When starting any boiler that has been closed down overnight, what precautions must
be observed?
A. Immediately light the burner and increase firing rate
B. Make a physical observation of the boiler and its systems; walk around to check for
abnormal conditions
C. Open the main steam stop valve first
D. Reduce water level before startup
Correct Answer: B
Rationale: A thorough visual inspection is critical before startup. Walk around the boiler to
check for flammable material at dampers, fuel leaks, and damaged electrical conduits. Check
all boiler systems including feedwater and fuel. For gas-fired boilers, a furnace prepurge is
essential and must never be altered or bypassed .
2. When water is boiling, the water in the boiler and steam above it are at __________.
A. Different temperatures
B. Different pressures
C. The same temperature and pressure
D. The same temperature but different pressures
Correct Answer: C
Rationale: When water is boiling, the water and steam above it are at the same temperature
and pressure, representing saturation conditions .
3. How long can an operating boiler be left unattended?
A. 5 minutes
B. 10 minutes
C. 30 minutes
D. 60 minutes
Correct Answer: B
Rationale: Operating boilers require regular monitoring and should not be left unattended
for extended periods. The general guideline is no more than 10 minutes .
,4. A steaming boiler can have the water in the gauge glass go from half full to empty in a
matter of __________ if water is not added.
A. Hours
B. Minutes
C. Days
D. Seconds
Correct Answer: B
Rationale: The water level can drop rapidly under load. Operators must maintain constant
vigilance and ensure adequate feedwater supply .
5. If the pressure gauge on the boiler registers 150 psi and the safety valve is set to open at
100 psi, what would you do?
A. Increase boiler load
B. Most likely the pressure gauge has failed; quickly isolate and replace the gauge
C. Open the safety valve manually
D. Reduce feedwater flow
Correct Answer: B
Rationale: For such excessive pressure to occur, both operating and high-pressure limit
controls would have to fail, plus the safety valve. The boiler would also show indications
such as excessive vibration and abnormal sounds .
6. If the boiler is generating 20,000 lb/hr of steam, it must be supplied with _______ lb/hr
of feedwater.
A. 10,000
B. 20,000
C. 40,000
D. 5,000
Correct Answer: B
Rationale: Mass balance dictates that the feedwater input must equal the steam output.
One pound of water produces one pound of steam .
7. One pound of water is needed to produce _______ of steam.
A. 0.5 lb
B. 1 lb
C. 2 lb
D. 5 lb
Correct Answer: B
, Rationale: One pound of water is needed to produce 1 lb of steam due to conservation of
mass .
8. Superheated steam has more _______ than saturated steam at the same pressure.
A. Moisture
B. Heat energy
C. Density
D. Volume
Correct Answer: B
Rationale: Superheated steam has more heat energy than saturated steam at the same
pressure because it has been heated beyond its saturation temperature .
9. The flow of steam maintained through a superheater should never be less than ___% of
boiler capacity.
A. 10%
B. 25%
C. 50%
D. 75%
Correct Answer: B
Rationale: The flow of steam maintained through a superheater should never be less than
25% of boiler capacity to prevent tube overheating .
10. A cyclone separator is a cylindrical device that separates water droplets from steam
using __________.
A. Gravity
B. Centrifugal force
C. Magnetic force
D. Filtration
Correct Answer: B
Rationale: A cyclone separator separates water droplets from steam using centrifugal force .
11. The dry pipe separator is located in the __________.
A. Lower part of the steam drum
B. Upper part of the steam drum
C. Mud drum
D. Superheater outlet
Correct Answer: B
100 Questions with Correct Answers
and Detailed Rationales
1. When starting any boiler that has been closed down overnight, what precautions must
be observed?
A. Immediately light the burner and increase firing rate
B. Make a physical observation of the boiler and its systems; walk around to check for
abnormal conditions
C. Open the main steam stop valve first
D. Reduce water level before startup
Correct Answer: B
Rationale: A thorough visual inspection is critical before startup. Walk around the boiler to
check for flammable material at dampers, fuel leaks, and damaged electrical conduits. Check
all boiler systems including feedwater and fuel. For gas-fired boilers, a furnace prepurge is
essential and must never be altered or bypassed .
2. When water is boiling, the water in the boiler and steam above it are at __________.
A. Different temperatures
B. Different pressures
C. The same temperature and pressure
D. The same temperature but different pressures
Correct Answer: C
Rationale: When water is boiling, the water and steam above it are at the same temperature
and pressure, representing saturation conditions .
3. How long can an operating boiler be left unattended?
A. 5 minutes
B. 10 minutes
C. 30 minutes
D. 60 minutes
Correct Answer: B
Rationale: Operating boilers require regular monitoring and should not be left unattended
for extended periods. The general guideline is no more than 10 minutes .
,4. A steaming boiler can have the water in the gauge glass go from half full to empty in a
matter of __________ if water is not added.
A. Hours
B. Minutes
C. Days
D. Seconds
Correct Answer: B
Rationale: The water level can drop rapidly under load. Operators must maintain constant
vigilance and ensure adequate feedwater supply .
5. If the pressure gauge on the boiler registers 150 psi and the safety valve is set to open at
100 psi, what would you do?
A. Increase boiler load
B. Most likely the pressure gauge has failed; quickly isolate and replace the gauge
C. Open the safety valve manually
D. Reduce feedwater flow
Correct Answer: B
Rationale: For such excessive pressure to occur, both operating and high-pressure limit
controls would have to fail, plus the safety valve. The boiler would also show indications
such as excessive vibration and abnormal sounds .
6. If the boiler is generating 20,000 lb/hr of steam, it must be supplied with _______ lb/hr
of feedwater.
A. 10,000
B. 20,000
C. 40,000
D. 5,000
Correct Answer: B
Rationale: Mass balance dictates that the feedwater input must equal the steam output.
One pound of water produces one pound of steam .
7. One pound of water is needed to produce _______ of steam.
A. 0.5 lb
B. 1 lb
C. 2 lb
D. 5 lb
Correct Answer: B
, Rationale: One pound of water is needed to produce 1 lb of steam due to conservation of
mass .
8. Superheated steam has more _______ than saturated steam at the same pressure.
A. Moisture
B. Heat energy
C. Density
D. Volume
Correct Answer: B
Rationale: Superheated steam has more heat energy than saturated steam at the same
pressure because it has been heated beyond its saturation temperature .
9. The flow of steam maintained through a superheater should never be less than ___% of
boiler capacity.
A. 10%
B. 25%
C. 50%
D. 75%
Correct Answer: B
Rationale: The flow of steam maintained through a superheater should never be less than
25% of boiler capacity to prevent tube overheating .
10. A cyclone separator is a cylindrical device that separates water droplets from steam
using __________.
A. Gravity
B. Centrifugal force
C. Magnetic force
D. Filtration
Correct Answer: B
Rationale: A cyclone separator separates water droplets from steam using centrifugal force .
11. The dry pipe separator is located in the __________.
A. Lower part of the steam drum
B. Upper part of the steam drum
C. Mud drum
D. Superheater outlet
Correct Answer: B
