Maryland Stationary Engineer Grade 1 Exam
2026 – 100% Actual Exam Q&A | High-
Pressure Boiler Study Guide & Verified
Answers
Part 1: Boiler Theory & Construction (Questions 1-25)
1. Which type of boiler has the water inside the tubes with heat and gases of combustion
circulating around them?
A) Firetube
B) Watertube
C) Cast iron sectional
D) Scotch Marine
Explanation: Watertube boilers are designed for high-pressure applications because
the smaller diameter tubes can withstand higher internal pressures.
2. A "Grade 1" Maryland license allows the holder to operate boilers of what maximum
horsepower?
A) 500 HP
B) 1,000 HP
C) 5,000 HP
D) Unlimited
Explanation: The Grade 1 license is the highest Maryland tier and has no horsepower
restrictions.
3. What is the standard temperature for a "High-Temperature Hot Water" boiler?
A) Over 120°F
B) Over 212°F
C) Over 250°F
D) Under 200°F
Explanation: Per ASME and MD state code, high-temperature hot water boilers
operate at temperatures over 250°F or pressures over 160 psi.
4. The heating surface of a boiler is measured on which side?
A) The insulation side
B) The side exposed to the fire or hot gases
C) The outer casing
D) The top half only
, Explanation: Boiler heating surface is defined as the area that has water on one side
and hot gases on the other.
5. What type of stay is used to support the flat surfaces of a firetube boiler?
A) Tension stay
B) Staybolt
C) Diagonal stay
D) Through-stay
Explanation: Staybolts are commonly used to support flat plates against internal
pressure, especially in water-leg areas.
6. What is the latent heat of evaporation for water at atmospheric pressure?
A) 144 BTUs
B) 180 BTUs
C) 970.3 BTUs
D) 1,150 BTUs
Explanation: It takes 970.3 BTUs to change 1 lb of water at 212°F to 1 lb of steam at
212°F.
7. In a watertube boiler, the mud drum is located at:
A) The highest point of the boiler
B) The lowest point of the water side
C) Inside the steam drum
D) Behind the burner
Explanation: The mud drum (lower drum) acts as a collection point for sediment and
sludge to be blown down.
8. Which ASME Code section governs the construction of High-Pressure Power Boilers?
A) Section I
B) Section IV
C) Section VI
D) Section VIII
Explanation: Section I is for boilers operating over 15 psi steam or 160 psi water.
9. A furnace explosion is caused by a buildup of:
A) Too much water
B) Unburned fuel and air
C) Scale on tubes
D) Nitrogen
Explanation: Furnace explosions (puff-backs) occur when fuel accumulates and ignites
suddenly in the combustion chamber.
, 10. What is the purpose of the "dry pipe" in a steam drum?
A) To add chemicals
B) To remove moisture from the steam before it leaves the boiler
C) To cool the steam
D) To prevent scale
Explanation: The dry pipe or separator ensures "dry" steam enters the header,
preventing water hammer.
11. A "Babcock & Wilcox" boiler is an example of a:
A) Firetube boiler
B) Watertube boiler
C) Electric boiler
D) Locomotive boiler
Explanation: B&W is a classic designer of longitudinal and cross-drum watertube
boilers.
12. The safety valve on a boiler is designed to prevent:
A) Low water
B) Overpressure
C) High water
D) Flame failure
Explanation: The safety valve is the final mechanical defense against pressure vessel
rupture.
13. Which valve is used to regulate the flow of feedwater into a boiler?
A) Gate valve
B) Globe valve (or Needle valve)
C) Check valve
D) Butterfly valve
Explanation: Globe valves are used for throttling or regulating flow due to their internal
design.
14. The term "Total Heat" of steam is the sum of:
A) Latent heat + Superheat
B) Sensible heat + Latent heat
C) Flash steam + Dry steam
D) Pressure + Temperature
Explanation: Enthalpy (total heat) includes the heat used to raise water to boiling and
the heat used to turn it to steam.
2026 – 100% Actual Exam Q&A | High-
Pressure Boiler Study Guide & Verified
Answers
Part 1: Boiler Theory & Construction (Questions 1-25)
1. Which type of boiler has the water inside the tubes with heat and gases of combustion
circulating around them?
A) Firetube
B) Watertube
C) Cast iron sectional
D) Scotch Marine
Explanation: Watertube boilers are designed for high-pressure applications because
the smaller diameter tubes can withstand higher internal pressures.
2. A "Grade 1" Maryland license allows the holder to operate boilers of what maximum
horsepower?
A) 500 HP
B) 1,000 HP
C) 5,000 HP
D) Unlimited
Explanation: The Grade 1 license is the highest Maryland tier and has no horsepower
restrictions.
3. What is the standard temperature for a "High-Temperature Hot Water" boiler?
A) Over 120°F
B) Over 212°F
C) Over 250°F
D) Under 200°F
Explanation: Per ASME and MD state code, high-temperature hot water boilers
operate at temperatures over 250°F or pressures over 160 psi.
4. The heating surface of a boiler is measured on which side?
A) The insulation side
B) The side exposed to the fire or hot gases
C) The outer casing
D) The top half only
, Explanation: Boiler heating surface is defined as the area that has water on one side
and hot gases on the other.
5. What type of stay is used to support the flat surfaces of a firetube boiler?
A) Tension stay
B) Staybolt
C) Diagonal stay
D) Through-stay
Explanation: Staybolts are commonly used to support flat plates against internal
pressure, especially in water-leg areas.
6. What is the latent heat of evaporation for water at atmospheric pressure?
A) 144 BTUs
B) 180 BTUs
C) 970.3 BTUs
D) 1,150 BTUs
Explanation: It takes 970.3 BTUs to change 1 lb of water at 212°F to 1 lb of steam at
212°F.
7. In a watertube boiler, the mud drum is located at:
A) The highest point of the boiler
B) The lowest point of the water side
C) Inside the steam drum
D) Behind the burner
Explanation: The mud drum (lower drum) acts as a collection point for sediment and
sludge to be blown down.
8. Which ASME Code section governs the construction of High-Pressure Power Boilers?
A) Section I
B) Section IV
C) Section VI
D) Section VIII
Explanation: Section I is for boilers operating over 15 psi steam or 160 psi water.
9. A furnace explosion is caused by a buildup of:
A) Too much water
B) Unburned fuel and air
C) Scale on tubes
D) Nitrogen
Explanation: Furnace explosions (puff-backs) occur when fuel accumulates and ignites
suddenly in the combustion chamber.
, 10. What is the purpose of the "dry pipe" in a steam drum?
A) To add chemicals
B) To remove moisture from the steam before it leaves the boiler
C) To cool the steam
D) To prevent scale
Explanation: The dry pipe or separator ensures "dry" steam enters the header,
preventing water hammer.
11. A "Babcock & Wilcox" boiler is an example of a:
A) Firetube boiler
B) Watertube boiler
C) Electric boiler
D) Locomotive boiler
Explanation: B&W is a classic designer of longitudinal and cross-drum watertube
boilers.
12. The safety valve on a boiler is designed to prevent:
A) Low water
B) Overpressure
C) High water
D) Flame failure
Explanation: The safety valve is the final mechanical defense against pressure vessel
rupture.
13. Which valve is used to regulate the flow of feedwater into a boiler?
A) Gate valve
B) Globe valve (or Needle valve)
C) Check valve
D) Butterfly valve
Explanation: Globe valves are used for throttling or regulating flow due to their internal
design.
14. The term "Total Heat" of steam is the sum of:
A) Latent heat + Superheat
B) Sensible heat + Latent heat
C) Flash steam + Dry steam
D) Pressure + Temperature
Explanation: Enthalpy (total heat) includes the heat used to raise water to boiling and
the heat used to turn it to steam.
