ANSWERS 2026 | Certified Cardiology
Technologist Complete Solution Guide A+
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Correct Answer: B
Rationale: In a fire-tube boiler, combustion gases (flue gases) pass through tubes that are
surrounded by water in the shell. This design is common in heating boilers and smaller industrial
applications because it has a large water volume that provides good steam reserve and requires
less stringent water quality than water-tube boilers. Option A describes a water-tube boiler.
Option C describes a firebox or pot-type boiler (rare). Option D describes an electric boiler. Fire-
tube boilers include horizontal return tubular (HRT), Scotch marine, and vertical fire-tube
designs. They are generally limited to lower pressures (up to 350 psi) due to the large diameter
shell required for higher pressures.
Question 2
Which ASME Code section applies to power boilers?
A. Section I **[CORRECT]**
B. Section IV
C. Section VIII
D. Section IX
Correct Answer: A
Rationale: ASME Boiler and Pressure Vessel Code Section I covers "Rules for Construction of
Power Boilers"—boilers that generate steam for power generation or process use at pressures
above 15 psi or heating boilers above certain horsepower ratings. Section IV (B) covers heating
boilers (low-pressure steam and hot water boilers for space heating). Section VIII (C) covers
pressure vessels (unfired). Section IX (D) covers welding and brazing qualifications. Power
boilers operate at higher pressures and temperatures than heating boilers and have more stringent
construction, inspection, and certification requirements due to the greater hazard potential.
Question 3
Boiler horsepower is defined as:
A. The weight of the boiler
,B. The amount of steam the boiler can produce
C. The equivalent of 34.5 lbs of steam per hour from feedwater at 212°F **[CORRECT]**
D. The pressure rating of the boiler
Correct Answer: C
Rationale: One boiler horsepower (BHP) is defined as the ability to evaporate 34.5 pounds of
water per hour into dry saturated steam at 212°F when feedwater is supplied at 212°F. This
equals 33,475 BTU/hr or approximately 9.8 kW. BHP is a measure of boiler output capacity, not
physical size (A), general production capability without the specific definition (B), or pressure
rating (D). Modern boilers are often rated by actual steam output (lbs/hr) or heat input/output
(BTU/hr, MBH). Understanding BHP is important for sizing boilers and comparing capacities
across different units and manufacturers.
Question 4
A Scotch marine boiler is a type of:
A. Water-tube boiler with straight tubes
B. Fire-tube boiler with a cylindrical furnace and multiple tube passes **[CORRECT]**
C. Electric resistance boiler
D. Cast iron sectional boiler
Correct Answer: B
Rationale: The Scotch marine boiler is the most common fire-tube boiler design, featuring a
cylindrical furnace (combustion chamber) surrounded by water, with multiple passes of tubes
through which flue gases travel to maximize heat transfer. The "dry back" design has a
refractory-lined rear door; the "wet back" design has a water-cooled turnaround chamber. This
design is compact, efficient, and suitable for high-pressure applications (up to 350 psi). Water-
tube boilers (A) have water inside tubes. Electric boilers (C) use resistance elements. Cast iron
boilers (D) are sectional, low-pressure heating boilers.
Question 5
In a D-type water-tube boiler, the "D" refers to:
A. The shape of the steam drum
B. The configuration of the water-cooled furnace and generating tubes **[CORRECT]**
C. The fuel type (diesel only)
D. The direction of water flow
,Correct Answer: B
Rationale: The D-type water-tube boiler has a distinctive shape formed by the water-cooled
furnace on one side and the bank of generating tubes on the other, creating a "D" shape when
viewed in cross-section. This is the most common industrial water-tube boiler design, offering
high capacity (up to 200,000+ lbs/hr steam), high pressure capability (up to 1,500+ psi), and
rapid response to load changes. The large steam drum provides steam separation space. Other
water-tube configurations include O-type (center furnace, two tube banks), A-type (two furnaces,
one tube bank), and flexible bent-tube designs.
Question 6
Which material is most commonly used for boiler pressure vessel construction?
A. Aluminum
B. Carbon steel or alloy steel **[CORRECT]**
C. Copper
D. Plastic
Correct Answer: B
Rationale: Boiler pressure vessels are constructed from carbon steel (SA-516 Grade 70, SA-285
Grade C) or alloy steels (SA-387 for high temperatures, SA-213 for tubes) due to their strength,
creep resistance, and cost-effectiveness at elevated temperatures and pressures. Aluminum (A)
lacks strength at high temperatures. Copper (C) is used for small components or heat exchangers
but not pressure vessels. Plastic (D) cannot withstand boiler temperatures and pressures. Material
selection depends on design pressure, temperature, and corrosion considerations, and must meet
ASME material specifications.
Question 7
A waste heat boiler differs from a fired boiler in that it:
A. Uses no water
B. Recovers heat from process gases or exhaust rather than direct fuel combustion
**[CORRECT]**
C. Operates at atmospheric pressure only
D. Has no safety valves
Correct Answer: B
Rationale: Waste heat boilers (heat recovery steam generators - HRSG) capture heat from hot
process gases, exhaust streams, or incineration gases rather than burning fuel directly. They
, improve overall plant efficiency by recovering otherwise wasted energy. Common applications
include combined cycle power plants (gas turbine exhaust), process industries, and incineration.
They do use water (A is incorrect), can operate at various pressures (C is incorrect), and
absolutely require safety valves (D is incorrect). Design considerations include gas side fouling,
corrosion from process contaminants, and variable heat input.
Question 8
The heating surface of a boiler is defined as:
A. The floor space occupied by the boiler
B. The area exposed to combustion gases that transfers heat to water/steam **[CORRECT]**
C. The surface area of the burner
D. The insulation area
Correct Answer: B
Rationale: Heating surface is the area (in square feet) of boiler surfaces exposed to combustion
gases that transfer heat to the water or steam. It includes tube surface area, furnace walls (if
water-cooled), and other heat transfer surfaces. Heating surface determines boiler capacity and
efficiency. Fire-tube boilers typically have larger heating surfaces for equivalent output than
water-tube boilers. Floor space (A) is footprint. Burner surface (C) and insulation (D) are not
heating surfaces. Historical boiler horsepower was based on heating surface (10 sq ft per BHP),
though modern ratings use actual steam output.
Question 9
Electric boilers are best suited for:
A. High-pressure power generation
B. Applications where emissions must be eliminated and load is relatively small
**[CORRECT]**
C. Marine propulsion
D. Large industrial process steam
Correct Answer: B
Rationale: Electric boilers use resistance or electrode heating elements to generate steam without
combustion, producing zero emissions at the point of use. They are ideal for applications
requiring clean steam (food, pharmaceuticals), locations prohibiting fuel combustion, small loads
(up to several thousand lbs/hr), or where electricity costs are low. They are not economical for
high-pressure power generation (A) or large industrial loads (D) due to high electricity costs.