Boiler Construction & Design
questions with answers newest
edition (Q1–Q15)
1. What is the usual maximum temperature for low-pressure steam?
A. 100°F
B. 212°F
C. 250°F
D. 300°F
Answer: C
Rationale: Low-pressure steam boilers generally operate at temperatures up to about 250°F
.
2. Which is the most common type of boiler for small commercial buildings?
A. Water-tube
B. Fire-tube
C. Electric immersion
D. Steam drum boiler
Answer: B
Rationale: Fire-tube boilers are simpler, cheaper, and suitable for low to medium pressure
applications .
3. What is the main advantage of water-tube boilers over fire-tube?
A. Simpler construction
B. Higher pressure and faster steam generation
C. Easier maintenance
D. Lower initial cost
Answer: B
Rationale: Water-tube boilers handle higher pressures and allow quicker steam production .
4. Water tubes are found in:
A. Fire-tube boilers
B. Water-tube boilers
C. Steam drums only
D. Economizers
Answer: B
Rationale: Water-tube boilers route water through tubes heated by flame .
,5. A boiler is producing 40,000 lb of steam/hr at a pressure of 100 PSI and a steam
temperature of 500°F. The steam produced is:
A. Saturated steam
B. Superheated steam
C. Wet steam
D. Flash steam
Answer: B
Rationale: Steam heated above its saturation temperature at a given pressure is
superheated .
6. If the steam pressure gauge indicates 200 PSIG, the absolute pressure is:
A. 185.3 PSIA
B. 200 PSIA
C. 214.7 PSIA
D. 220 PSIA
Answer: C
Rationale: Absolute pressure = gauge pressure + atmospheric pressure (approximately 14.7
psi at sea level). 200 + 14.7 = 214.7 PSIA .
7. A boiler operating at 400 PSI has a safety valve that opens at 410 PSI and closes at 398
PSI. The blowdown is:
A. 10 psi
B. 12 psi
C. 14 psi
D. 18 psi
Answer: B
Rationale: Blowdown is the difference between opening and closing pressure: 410 − 398 =
12 psi .
8. A boiler generating 6,000 lb of steam/hr produces approximately ______ BTU/hr.
A. 600,000
B. 1,000,000
C. 6,000,000
D. 10,000,000
Answer: C
Rationale: One boiler horsepower is approximately 33,472 BTU/hr, and 1 lb of steam
represents roughly 1,000 BTU in this calculation context. 6,000 × 1,000 = 6,000,000 BTU/hr .
9. According to ASME code, a high-pressure boiler having more than 500 square feet of
heating surface shall have:
A. One safety valve
, B. Two or more safety valves
C. No safety valve
D. A rupture disk only
Answer: B
Rationale: ASME code requires two or more safety valves for high-pressure boilers with
more than 500 sq ft of heating surface .
10. One boiler horsepower is equal to how many BTU's?
A. 970.3 BTU
B. 33,472 BTU
C. 125,000 BTU
D. 288,000 BTU
Answer: B
Rationale: One boiler horsepower is defined as 33,472 BTU/hr .
11. A boiler horsepower is defined as:
A. 970.3 BTU
B. Total heating surface times evaporation factor
C. Evaporation of 34.5 lb of water from and at 212°F per hour
D. Evaporation of 34.5 lb of water from and at 212°F per 8 hours
Answer: C
Rationale: One boiler horsepower is the evaporation of 34.5 lb of water from and at 212°F
per hour .
12. A boiler's steam pressure gauge reads 150 psig. What is the absolute pressure?
A. 14.7 psia
B. 135.3 psia
C. 150 psia
D. 164.7 psia
Answer: D
Rationale: 150 psig + 14.7 psi = 164.7 psia .
13. What does 212°F equal on the Celsius scale?
A. 32°C
B. 100°C
C. 180°C
D. 212°C
Answer: B
Rationale: 212°F is the boiling point of water at atmospheric pressure, which equals 100°C .
questions with answers newest
edition (Q1–Q15)
1. What is the usual maximum temperature for low-pressure steam?
A. 100°F
B. 212°F
C. 250°F
D. 300°F
Answer: C
Rationale: Low-pressure steam boilers generally operate at temperatures up to about 250°F
.
2. Which is the most common type of boiler for small commercial buildings?
A. Water-tube
B. Fire-tube
C. Electric immersion
D. Steam drum boiler
Answer: B
Rationale: Fire-tube boilers are simpler, cheaper, and suitable for low to medium pressure
applications .
3. What is the main advantage of water-tube boilers over fire-tube?
A. Simpler construction
B. Higher pressure and faster steam generation
C. Easier maintenance
D. Lower initial cost
Answer: B
Rationale: Water-tube boilers handle higher pressures and allow quicker steam production .
4. Water tubes are found in:
A. Fire-tube boilers
B. Water-tube boilers
C. Steam drums only
D. Economizers
Answer: B
Rationale: Water-tube boilers route water through tubes heated by flame .
,5. A boiler is producing 40,000 lb of steam/hr at a pressure of 100 PSI and a steam
temperature of 500°F. The steam produced is:
A. Saturated steam
B. Superheated steam
C. Wet steam
D. Flash steam
Answer: B
Rationale: Steam heated above its saturation temperature at a given pressure is
superheated .
6. If the steam pressure gauge indicates 200 PSIG, the absolute pressure is:
A. 185.3 PSIA
B. 200 PSIA
C. 214.7 PSIA
D. 220 PSIA
Answer: C
Rationale: Absolute pressure = gauge pressure + atmospheric pressure (approximately 14.7
psi at sea level). 200 + 14.7 = 214.7 PSIA .
7. A boiler operating at 400 PSI has a safety valve that opens at 410 PSI and closes at 398
PSI. The blowdown is:
A. 10 psi
B. 12 psi
C. 14 psi
D. 18 psi
Answer: B
Rationale: Blowdown is the difference between opening and closing pressure: 410 − 398 =
12 psi .
8. A boiler generating 6,000 lb of steam/hr produces approximately ______ BTU/hr.
A. 600,000
B. 1,000,000
C. 6,000,000
D. 10,000,000
Answer: C
Rationale: One boiler horsepower is approximately 33,472 BTU/hr, and 1 lb of steam
represents roughly 1,000 BTU in this calculation context. 6,000 × 1,000 = 6,000,000 BTU/hr .
9. According to ASME code, a high-pressure boiler having more than 500 square feet of
heating surface shall have:
A. One safety valve
, B. Two or more safety valves
C. No safety valve
D. A rupture disk only
Answer: B
Rationale: ASME code requires two or more safety valves for high-pressure boilers with
more than 500 sq ft of heating surface .
10. One boiler horsepower is equal to how many BTU's?
A. 970.3 BTU
B. 33,472 BTU
C. 125,000 BTU
D. 288,000 BTU
Answer: B
Rationale: One boiler horsepower is defined as 33,472 BTU/hr .
11. A boiler horsepower is defined as:
A. 970.3 BTU
B. Total heating surface times evaporation factor
C. Evaporation of 34.5 lb of water from and at 212°F per hour
D. Evaporation of 34.5 lb of water from and at 212°F per 8 hours
Answer: C
Rationale: One boiler horsepower is the evaporation of 34.5 lb of water from and at 212°F
per hour .
12. A boiler's steam pressure gauge reads 150 psig. What is the absolute pressure?
A. 14.7 psia
B. 135.3 psia
C. 150 psia
D. 164.7 psia
Answer: D
Rationale: 150 psig + 14.7 psi = 164.7 psia .
13. What does 212°F equal on the Celsius scale?
A. 32°C
B. 100°C
C. 180°C
D. 212°C
Answer: B
Rationale: 212°F is the boiling point of water at atmospheric pressure, which equals 100°C .
