MD STATIONARY ENGINEER GRADE 1 EXAM
PREP QUESTIONS AND ANSWERS + FULL
RATIONALES (BOILERS, TURBINES & ASME
CODES)
Ace the Maryland Grade 1 Stationary Engineer Licensing
Exam with this comprehensive, high-yield master question
bank. Featuring premium multiple-choice questions, this resource
delivers verified answers and clear, step-by-step rationales
directly following every single question. Master critical exam
topics instantly, including high-pressure boiler operations, steam
turbine dynamics, water treatment chemistry, and mandatory
ASME safety codes.
Question 1
What is the primary purpose of a continuous blowdown system on
a high-pressure steam boiler?
A. To remove accumulated sludge from the bottom drum
B. To control the concentration of total dissolved solids (TDS) in
the boiler water
C. To lower the water level quickly during an emergency
D. To recover heat from the exhaust steam
Answer: B. To control the concentration of total dissolved solids
(TDS) in the boiler water
Rationale: Continuous blowdown is located near the surface
,of the boiler water where dissolved solids are most
concentrated. Its primary function is to continuously remove
these solids to prevent foaming, carryover, and scale
formation.
Question 2
Which of the following conditions would most likely cause a
furnace explosion (firebox explosion) in an oil-fired boiler?
A. High fuel oil temperature
B. Excess combustion air
C. Failure to purge the furnace before ignition
D. Low water level
Answer: C. Failure to purge the furnace before ignition
Rationale: Failing to purge the furnace allows unburned fuel
vapors to accumulate in the combustion chamber. If an
ignition source is introduced, these vapors can ignite
violently, causing a devastating firebox explosion.
Question 3
In a closed feedwater heater, how does the pressure of the
extracted steam compare to the pressure of the feedwater inside
the tubes?
A. The extracted steam pressure is always higher than the
feedwater pressure.
B. The extracted steam pressure is always lower than the
feedwater pressure.
C. The pressures are perfectly equalized via a pressure-reducing
station.
,D. The extracted steam pressure fluctuates independently above
and below the tube pressure.
Answer: B. The extracted steam pressure is always lower than
the feedwater pressure.
Rationale: In high-pressure power plants, the feedwater
inside the tubes is discharged directly from the boiler feed
pump, placing it at a pressure higher than boiler operating
pressure. The extracted steam comes from turbine extraction
stages and is significantly lower in pressure than the
pumped feedwater.
Question 4
What is the primary function of a deaerator in a high-pressure
steam plant?
A. To filter out suspended iron oxide particles.
B. To raise the pH of the feedwater using ammonia injection.
C. To remove dissolved gases, specifically oxygen and carbon
dioxide, from the feedwater.
D. To cool down the condensate before it enters the boiler feed
pump.
Answer: C. To remove dissolved gases, specifically oxygen and
carbon dioxide, from the feedwater.
Rationale: A deaerator uses mechanical agitation and steam
heating to reduce the solubility of dissolved gases in water,
allowing oxygen and carbon dioxide to be vented. This
prevents oxygen pitting and carbonic acid corrosion in the
boiler tubes.
, Question 5
Which type of safety valve is typically required on a power boiler
operating under ASME Section I rules?
A. Weighted-lever safety valve
B. Direct spring-loaded pop safety valve
C. Pilot-operated relief valve with manual override
D. Temperature and pressure (T&P) relief valve
Answer: B. Direct spring-loaded pop safety valve
Rationale: ASME Section I strictly mandates direct spring-
loaded safety valves for power boilers. Weighted-lever valves
are banned due to the ease of tampering, and standard relief
valves do not have the rapid "pop" opening characteristic
required for steam vapor service.
Question 6
What chemical compound is primarily responsible for the
formation of hard, glass-like scale inside high-pressure boiler
tubes?
A. Sodium chloride
B. Silica (Silicon dioxide)
C. Sodium sulfite
D. Calcium sulfate
Answer: B. Silica (Silicon dioxide)
Rationale: Silica is notoriously difficult to remove once it
deposits on boiler tubes, forming a hard, glassy insulating
layer. At high temperatures and pressures, it can also
PREP QUESTIONS AND ANSWERS + FULL
RATIONALES (BOILERS, TURBINES & ASME
CODES)
Ace the Maryland Grade 1 Stationary Engineer Licensing
Exam with this comprehensive, high-yield master question
bank. Featuring premium multiple-choice questions, this resource
delivers verified answers and clear, step-by-step rationales
directly following every single question. Master critical exam
topics instantly, including high-pressure boiler operations, steam
turbine dynamics, water treatment chemistry, and mandatory
ASME safety codes.
Question 1
What is the primary purpose of a continuous blowdown system on
a high-pressure steam boiler?
A. To remove accumulated sludge from the bottom drum
B. To control the concentration of total dissolved solids (TDS) in
the boiler water
C. To lower the water level quickly during an emergency
D. To recover heat from the exhaust steam
Answer: B. To control the concentration of total dissolved solids
(TDS) in the boiler water
Rationale: Continuous blowdown is located near the surface
,of the boiler water where dissolved solids are most
concentrated. Its primary function is to continuously remove
these solids to prevent foaming, carryover, and scale
formation.
Question 2
Which of the following conditions would most likely cause a
furnace explosion (firebox explosion) in an oil-fired boiler?
A. High fuel oil temperature
B. Excess combustion air
C. Failure to purge the furnace before ignition
D. Low water level
Answer: C. Failure to purge the furnace before ignition
Rationale: Failing to purge the furnace allows unburned fuel
vapors to accumulate in the combustion chamber. If an
ignition source is introduced, these vapors can ignite
violently, causing a devastating firebox explosion.
Question 3
In a closed feedwater heater, how does the pressure of the
extracted steam compare to the pressure of the feedwater inside
the tubes?
A. The extracted steam pressure is always higher than the
feedwater pressure.
B. The extracted steam pressure is always lower than the
feedwater pressure.
C. The pressures are perfectly equalized via a pressure-reducing
station.
,D. The extracted steam pressure fluctuates independently above
and below the tube pressure.
Answer: B. The extracted steam pressure is always lower than
the feedwater pressure.
Rationale: In high-pressure power plants, the feedwater
inside the tubes is discharged directly from the boiler feed
pump, placing it at a pressure higher than boiler operating
pressure. The extracted steam comes from turbine extraction
stages and is significantly lower in pressure than the
pumped feedwater.
Question 4
What is the primary function of a deaerator in a high-pressure
steam plant?
A. To filter out suspended iron oxide particles.
B. To raise the pH of the feedwater using ammonia injection.
C. To remove dissolved gases, specifically oxygen and carbon
dioxide, from the feedwater.
D. To cool down the condensate before it enters the boiler feed
pump.
Answer: C. To remove dissolved gases, specifically oxygen and
carbon dioxide, from the feedwater.
Rationale: A deaerator uses mechanical agitation and steam
heating to reduce the solubility of dissolved gases in water,
allowing oxygen and carbon dioxide to be vented. This
prevents oxygen pitting and carbonic acid corrosion in the
boiler tubes.
, Question 5
Which type of safety valve is typically required on a power boiler
operating under ASME Section I rules?
A. Weighted-lever safety valve
B. Direct spring-loaded pop safety valve
C. Pilot-operated relief valve with manual override
D. Temperature and pressure (T&P) relief valve
Answer: B. Direct spring-loaded pop safety valve
Rationale: ASME Section I strictly mandates direct spring-
loaded safety valves for power boilers. Weighted-lever valves
are banned due to the ease of tampering, and standard relief
valves do not have the rapid "pop" opening characteristic
required for steam vapor service.
Question 6
What chemical compound is primarily responsible for the
formation of hard, glass-like scale inside high-pressure boiler
tubes?
A. Sodium chloride
B. Silica (Silicon dioxide)
C. Sodium sulfite
D. Calcium sulfate
Answer: B. Silica (Silicon dioxide)
Rationale: Silica is notoriously difficult to remove once it
deposits on boiler tubes, forming a hard, glassy insulating
layer. At high temperatures and pressures, it can also
