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BD Second Class Boiler Attendant study materials
BD Second Class Boiler Attendant study resources

BD Second Class Boiler Attendant practice questions

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Question 1Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Under the Boiler Act, which authority is empowered to make rules for the registration and inspection of boilers in a state?

  1. The local municipal commissioner
  2. The Indian Standards Institution
  3. The Chief Inspector of Boilers of the state Correct answer.
  4. The factory medical officer

Explanation

The Boiler Act empowers the state government to frame rules, and the Chief Inspector of Boilers is the designated authority who administers registration, inspection and certification of boilers within the state. Municipal bodies and standards bodies have no statutory role in boiler registration.

Question 2Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

What is the primary purpose of the Boiler Act and the rules framed under it?

  1. To fix the selling price of boilers
  2. To standardise the wages of boiler operators
  3. To ensure the safe construction, operation and maintenance of boilers Correct answer.
  4. To promote the export of boiler spare parts

Explanation

The Act exists to protect persons and property from the dangers of steam boilers by regulating construction, registration, inspection and competent operation. Pricing, exports and wage fixation fall outside its scope.

Question 3Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A person holding a Second Class Boiler Attendant certificate may normally be placed in charge of which of the following?

  1. A boiler within the limits of capacity and type specified in the certificate of competency Correct answer.
  2. Only boilers used for domestic heating
  3. Any boiler of any capacity without supervision
  4. Only boilers that are out of service

Explanation

A certificate of competency is issued for a defined class and carries limits on the size and type of boiler the holder may operate. The attendant must work within those limits and cannot claim authority over all boilers.

Question 4Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which document must be kept available at the boiler site to show that the boiler has been inspected and certified as fit for use?

  1. The purchase invoice of the boiler
  2. The fuel supply contract
  3. The valid boiler inspection certificate Correct answer.
  4. The manufacturer's advertising brochure

Explanation

A boiler may not be operated unless a current certificate of inspection issued by the competent authority is in force. This certificate is the legal proof that the boiler has been examined and found fit.

Question 5Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

What is the general duty of a boiler attendant at the start of a shift?

  1. To shut down the boiler for the whole shift
  2. To check water level, pressure, fittings and the general condition of the boiler Correct answer.
  3. To record the fuel bill in the account book
  4. To increase steam pressure to the maximum immediately

Explanation

Shift handover requires the attendant to verify water level, steam pressure, safety fittings and overall condition before taking charge. This check detects abnormalities early and prevents unsafe operation.

Question 6Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which of the following is a statutory record that a boiler attendant is typically required to maintain during operation?

  1. The annual report of the parent company
  2. The list of spare parts suppliers
  3. The attendance register of the canteen staff
  4. The boiler operation log showing water level, pressure and blowdown Correct answer.

Explanation

The operation log records parameters such as water level, steam pressure, blowdown and any abnormal event, and is a key document during inspection. It provides evidence that the boiler was operated within limits.

Question 7Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

What does a certificate of competency for a boiler attendant primarily certify?

  1. That the holder has passed the prescribed examination and is competent to operate the class of boiler stated Correct answer.
  2. That the boiler has been manufactured to standard
  3. That the holder owns the boiler
  4. That the holder has paid all municipal taxes

Explanation

A certificate of competency is issued after the candidate passes the prescribed examination and demonstrates the practical competence required for the class. It certifies the holder's ability, not ownership or the condition of any particular boiler.

Question 8Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A boiler attendant notices that the water level gauge glass is broken while the boiler is steaming. What is the correct immediate action?

  1. Continue firing and watch the pressure gauge instead
  2. Stop firing and take the boiler out of service safely, then report the defect Correct answer.
  3. Tap the gauge glass to confirm the reading
  4. Increase the feed water supply to compensate

Explanation

A broken gauge glass removes the attendant's ability to confirm water level, which is a critical safety function. Firing must be stopped and the boiler secured and reported so that the defect is repaired before operation resumes.

Question 9Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Under the rules, when must a newly installed boiler be inspected before it is first put into operation?

  1. Before being put into use, for registration and initial certification Correct answer.
  2. Only after a breakdown occurs
  3. Only after the first year of operation
  4. Only when the owner changes

Explanation

A new boiler must be inspected and registered before it is first operated, so that its construction, fittings and settings are verified as satisfactory. Operating an uncertified boiler is a contravention of the Act.

Question 10Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which of the following best describes the attendant's responsibility when handing over charge at the end of a shift?

  1. Switch off the boiler and leave it unattended
  2. Hand over only the keys to the boiler house
  3. Record the boiler condition and communicate all defects and abnormalities to the relieving attendant Correct answer.
  4. Leave without informing anyone if the boiler is running smoothly

Explanation

Proper handover requires a recorded and verbal briefing on boiler condition, water level, pressure, fuel state and any defects, so that the relieving attendant is not taken by surprise. Silent departure can leave an unsafe condition undetected.

Question 11Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A boiler attendant is directed by a supervisor to operate a boiler at a pressure above the certified maximum. What should the attendant do?

  1. Refuse to exceed the certified limit and report the instruction Correct answer.
  2. Operate above the limit but note it in the log
  3. Comply at once because the supervisor is senior
  4. Raise the safety valve setting to allow the higher pressure

Explanation

The certified maximum working pressure is a legal and safety limit, and the attendant must not exceed it even on instruction. The correct response is to refuse and report the matter so that the pressure limit is enforced.

Question 12Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

What is the purpose of the periodic internal inspection of a boiler required under the rules?

  1. To check the attendance of the operating staff
  2. To examine the internal surfaces, stays and fittings for defects such as corrosion or cracking Correct answer.
  3. To verify the fuel consumption figures
  4. To assess the market value of the boiler

Explanation

Internal inspection allows the inspector to examine shell surfaces, tube plates, stays and fittings for corrosion, cracking or deformation that cannot be seen from outside. The findings determine whether the boiler remains fit for continued service.

Question 13Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

An accident occurs at a boiler causing injury to a worker. What is the attendant's immediate obligation under the rules?

  1. Report the accident promptly to the owner and the Inspector of Boilers Correct answer.
  2. Repair the boiler personally before anyone arrives
  3. Discuss it only with co-workers
  4. Wait until the next scheduled inspection to mention it

Explanation

Boiler accidents must be reported promptly to the owner and to the Inspector of Boilers, and the site should be preserved as far as possible for investigation. Delay or concealment obstructs the statutory inquiry and is itself an offence.

Question 14Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A Second Class Boiler Attendant is asked to take charge of a boiler that is outside the capacity limits of the certificate. What is the correct position?

  1. The attendant may take charge for up to one month
  2. The attendant may take charge if a fitter is present
  3. The attendant may take charge if the owner gives written consent
  4. The attendant is not competent to take charge of that boiler under the certificate Correct answer.

Explanation

A certificate of competency authorises operation only within the class and capacity limits stated on it. Taking charge outside those limits is outside the holder's legal competence, and the owner must engage a suitably certified attendant instead.

Question 15Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which of the following conditions would most clearly justify a boiler attendant refusing to start a boiler?

  1. The boiler house floor has been freshly painted
  2. The fuel stock is lower than usual
  3. The safety valve is seized and cannot lift Correct answer.
  4. The steam header is lagged

Explanation

A seized safety valve means the boiler has no reliable overpressure protection, so it must not be fired until the valve is freed and tested. The other listed conditions are either cosmetic or unrelated to immediate safety.

Question 16Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Why does the law require that a boiler be under the charge of a certified attendant whenever it is in operation?

  1. To ensure that the boiler is operated by a person with demonstrated competence and knowledge of emergency procedures Correct answer.
  2. To make sure the fuel bill is paid on time
  3. To reduce the number of employees in the plant
  4. To increase the sale of boiler accessories

Explanation

Operation by a competent, certified person is the central safeguard of the Act, because most boiler accidents arise from poor operation and failure to respond to abnormal conditions. Certification provides evidence of the required knowledge and practical skill.

Question 17Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

During an inspection, the Inspector of Boilers finds a defect and directs that the boiler be taken out of service. What must the attendant do?

  1. Ask the fuel supplier whether operation may continue
  2. Comply with the direction and stop operation until the defect is rectified and clearance is given Correct answer.
  3. Operate at reduced pressure without informing anyone
  4. Continue operation until the next annual inspection

Explanation

A direction issued by the Inspector of Boilers is binding, and the boiler must remain out of service until the defect is rectified and the boiler is cleared for use. Continuing to operate would be a contravention and a serious safety risk.

Question 18Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

How does the Boiler Act treat the transfer of a boiler from one owner to another?

  1. The boiler must be scrapped on transfer
  2. No record of the transfer is required
  3. The new owner may operate without any certificate
  4. The transfer requires intimation and registration formalities so that the certificate remains valid Correct answer.

Explanation

A change of ownership must be notified and the register updated so that responsibility for the boiler is clearly established. Operation without a valid certificate in the new owner's name is not permitted.

Question 19Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

An attendant observes that the low-water alarm has failed during a routine test. Which course of action best reflects the legal duty of care?

  1. Stop the boiler, lock it out and report the failure for repair and retesting Correct answer.
  2. Use the gauge glass as a substitute alarm and keep firing
  3. Note the failure and continue operating until the next shutdown
  4. Ignore the alarm because it is only an auxiliary device

Explanation

A failed low-water alarm removes a critical protective device, and the boiler should be secured and the defect repaired and retested before operation resumes. The gauge glass is a level indicator, not a substitute for an automatic protective alarm.

Question 20Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which statement correctly describes the relationship between the Boiler Act and the rules made under it?

  1. The rules override the Act whenever they conflict
  2. The Act sets the framework and the rules supply the detailed procedural and technical requirements Correct answer.
  3. The Act applies only to factories and the rules only to hospitals
  4. The rules are advisory and have no legal force

Explanation

The Act establishes the broad statutory framework, powers and offences, while the rules prescribe the detailed procedures, standards and forms. Rules made under an Act derive their authority from it and cannot override its provisions.

Question 21Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A candidate applies for a Second Class Boiler Attendant certificate after failing the practical test once. What is the usual position regarding re-examination?

  1. The candidate may apply again in accordance with the prescribed procedure and any waiting period Correct answer.
  2. The candidate must first obtain a First Class certificate
  3. The candidate is permanently barred from reapplying
  4. The candidate is automatically issued the certificate

Explanation

A failed attempt does not permanently disqualify a candidate; the rules allow a fresh application subject to the prescribed procedure and any waiting period. The certificate is never issued automatically without passing the examination.

Question 22Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

A boiler is due for its statutory inspection but the owner wants to postpone it because production demand is high. What is the lawful position?

  1. Operation may continue indefinitely if production demand is high
  2. Operation beyond the validity of the certificate is not permitted, and the inspection must be arranged before it lapses Correct answer.
  3. The attendant may extend the certificate by signing the log book
  4. The inspector may be replaced by a senior operator for the inspection

Explanation

The certificate of inspection is valid only for the period stated, and operation after it lapses is unlawful regardless of production pressure. The inspection must be arranged before expiry so that the boiler's fitness is confirmed.

Question 23Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

Which of the following best explains why the rules require the attendant to record blowdown operations in the log?

  1. To provide evidence that dissolved solids control and water level management were carried out as required Correct answer.
  2. To prove that the fuel supplier delivered on time
  3. To record the number of visitors to the boiler house
  4. To calculate the salary of the attendant

Explanation

Blowdown removes dissolved solids and controls the concentration in the boiler water, and the log entry provides evidence that this routine was performed. The record also helps trace any water-level or carry-over problem during investigation.

Question 24Boiler Laws, Rules and Regulations (Boiler Act and Rules, licensing requirements, duties and responsibilities of boiler attendants)

An attendant suspects that a safety valve has been tampered with and set above the certified pressure. What is the appropriate response?

  1. Adjust it lower personally without informing anyone
  2. Leave it as it is, since a higher setting gives more steam output
  3. Report the condition at once and prevent operation until the valve is correctly set and sealed Correct answer.
  4. Operate the boiler at the higher pressure to match the setting

Explanation

A safety valve set above the certified pressure defeats the boiler's overpressure protection, which is a serious hazard. The condition must be reported and operation prevented until the valve is properly set and sealed by an authorised person.

Question 25Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

In a fire-tube boiler, which component encloses the hot gases that pass through the water space?

  1. The superheater
  2. The tubes Correct answer.
  3. The steam drum
  4. The water-wall

Explanation

In a fire-tube boiler the products of combustion travel through tubes that are surrounded by water, so the heat passes from the gas inside each tube into the surrounding water. The tubes therefore carry hot gas, while the shell holds the water and steam.

Question 26Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which statement correctly describes the relative water content of a water-tube boiler compared with a fire-tube boiler of similar output?

  1. A water-tube boiler holds less water per unit of output Correct answer.
  2. A water-tube boiler contains no water in the tubes
  3. A water-tube boiler holds more water per unit of output
  4. Both designs hold exactly the same water volume

Explanation

Water-tube boilers circulate water inside many small tubes, so the total water content is small relative to evaporative capacity. This low water content allows rapid steam raising and quicker response to load changes.

Question 27Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

What is the main structural function of a boiler shell?

  1. To preheat the feedwater before entry
  2. To regulate the burner firing rate
  3. To contain the pressure and support the internal parts Correct answer.
  4. To remove moisture from the steam

Explanation

The shell is the pressure-containing envelope that holds water and steam and carries the mountings and internal fittings. It must resist internal pressure and support components such as tubes, stays, and baffles.

Question 28Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A water-wall in a boiler furnace is best described as:

  1. A baffle plate that directs gas flow across the tubes
  2. A row of tubes lined with refractory that forms the furnace boundary Correct answer.
  3. A steel plate that separates the steam and water spaces
  4. A wall of brick that insulates the boiler casing

Explanation

Water-walls are tubes arranged along the furnace boundary, usually covered with refractory or studs, and they absorb radiant heat while protecting the casing. They increase heat transfer and help control furnace exit temperature.

Question 29Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which fitting is used to indicate the water level in a boiler shell?

  1. A water gauge glass Correct answer.
  2. A pressure gauge
  3. A blowdown valve
  4. A safety valve

Explanation

The water gauge glass is mounted so that its lower end connects to the water space and its upper end to the steam space, showing the operating water level. It is a direct-reading device and is a statutory mounting on most boilers.

Question 30Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

What is the purpose of a fusible plug in a boiler?

  1. To measure the steam temperature
  2. To relieve excess steam pressure
  3. To drain water from the boiler
  4. To melt and warn of low water level or overheating Correct answer.

Explanation

A fusible plug contains a low-melting alloy that melts if the metal around it becomes overheated, typically because the water level has fallen. The melting opens a passage that releases steam into the furnace, giving an audible warning and reducing the risk of overheating.

Question 31Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which boiler type is commonly used where a compact, packaged unit with rapid steam raising is required for low to medium pressure?

  1. A waste-heat boiler
  2. A packaged fire-tube boiler Correct answer.
  3. A large utility water-tube boiler
  4. A marine water-tube boiler

Explanation

Packaged fire-tube boilers are factory-assembled, compact, and simple to operate, making them suitable for low to medium pressure process steam. Their large water content gives steady output but slower response than water-tube designs.

Question 32Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

In a boiler, the term 'mountings' refers to:

  1. Fittings attached to the boiler for safety and operation Correct answer.
  2. The refractory lining of the furnace
  3. The tubes that carry water
  4. The structural supports under the shell

Explanation

Mountings are the fittings and accessories attached to the pressure parts, such as safety valves, gauge glasses, pressure gauges, and feed check valves. They allow safe operation, monitoring, and control of the boiler.

Question 33Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Why is a fire-tube boiler generally limited to lower pressures than a water-tube boiler?

  1. The water volume is too small for high pressure
  2. The tubes cannot withstand any internal pressure
  3. The furnace cannot be fitted with a burner
  4. The large shell diameter must resist pressure, requiring thick plates Correct answer.

Explanation

The cylindrical shell of a fire-tube boiler has a large diameter, so the plate thickness needed to resist pressure grows quickly as pressure rises. This makes high-pressure construction heavy and costly, limiting the practical pressure range.

Question 34Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A boiler has a cylindrical shell with flat end plates. Which construction feature is most important for supporting those flat plates against pressure?

  1. Refractory bricks
  2. Superheater coils
  3. Stays or stay tubes Correct answer.
  4. Water-walls

Explanation

Flat surfaces cannot resist internal pressure by their own shape, so they must be tied by stays or stay tubes that carry the load in tension. Without adequate staying, flat plates would distort and fail.

Question 35Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which feature distinguishes a water-tube boiler from a fire-tube boiler?

  1. The boiler has no pressure parts
  2. The shell is always horizontal
  3. Water circulates inside tubes surrounded by hot gas Correct answer.
  4. Hot gas passes through tubes surrounded by water

Explanation

In a water-tube boiler the water is inside the tubes and the hot gases pass around their outside, which is the reverse of the fire-tube arrangement. This allows smaller tube diameters and higher pressures.

Question 36Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

What is the chief advantage of a water-wall in a high-capacity furnace?

  1. It replaces the economiser
  2. It eliminates the need for a safety valve
  3. It absorbs radiant heat and protects the furnace casing from overheating Correct answer.
  4. It increases the water content of the boiler

Explanation

Water-walls absorb radiant heat from the flame, increasing steam generation and lowering the gas temperature before it reaches the convection bank. They also shield the furnace casing and refractory from excessive temperature.

Question 37Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A boiler operator observes that the water gauge glass shows no water. What is the most appropriate immediate action?

  1. Blow down the gauge glass to check again
  2. Shut off the fuel and air supply and investigate the low-water condition Correct answer.
  3. Increase the feedwater flow immediately
  4. Open the safety valve to reduce pressure

Explanation

A gauge glass showing no water indicates a serious low-water condition that may have exposed heating surfaces. Fuel must be shut off to stop overheating, and the condition should be investigated before any water is added.

Question 38Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which of the following is a direct-reading mounting that indicates steam pressure inside the boiler?

  1. A water gauge glass
  2. A fusible plug
  3. A feed check valve
  4. A Bourdon-tube pressure gauge Correct answer.

Explanation

A Bourdon-tube pressure gauge uses a curved tube that straightens under pressure to move a pointer, giving a direct reading of steam pressure. It is a required mounting on steam boilers.

Question 39Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Why are baffles fitted in the gas passages of a fire-tube boiler?

  1. To support the boiler shell against pressure
  2. To regulate the feedwater supply
  3. To direct hot gases across the tubes and improve heat transfer Correct answer.
  4. To separate steam from water

Explanation

Baffles guide the combustion gases along a defined path so that they pass repeatedly across the tubes, increasing gas velocity and contact time. This improves heat transfer and reduces stack losses.

Question 40Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which statement about the furnace of a shell boiler is correct?

  1. It is a small-diameter tube carrying water
  2. It is a large-diameter tube, often corrugated, that contains the flame Correct answer.
  3. It is a separate vessel outside the shell
  4. It is a refractory-lined chamber with no pressure parts

Explanation

In a shell boiler the furnace is commonly a large cylindrical tube, sometimes corrugated for flexibility, set within the water space to contain combustion. The corrugations help absorb expansion and strengthen the tube against external pressure.

Question 41Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A water-tube boiler is chosen for a plant needing high pressure and rapid load changes. Which property best explains this choice?

  1. The shell diameter is larger than in fire-tube boilers
  2. It requires no feedwater treatment
  3. Large water content gives steady pressure
  4. Small water content allows fast response and high pressure construction Correct answer.

Explanation

Water-tube boilers hold little water in small-diameter tubes, so they can raise steam quickly and follow load changes. The small tube diameter also allows the pressure parts to be built for high pressure.

Question 42Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

What is the function of a feed check valve on a boiler?

  1. To indicate the water level
  2. To relieve excess steam pressure
  3. To drain the boiler during blowdown
  4. To allow feedwater into the boiler while preventing backflow Correct answer.

Explanation

A feed check valve permits feedwater to enter the boiler and closes automatically to prevent boiler water from flowing back toward the feed pump. It protects the feed system and maintains one-way flow.

Question 43Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

In a boiler with a corrugated furnace tube, what is the main reason for the corrugations?

  1. To improve the appearance of the boiler
  2. To increase the water content of the boiler
  3. To accommodate thermal expansion and resist external pressure Correct answer.
  4. To provide a seat for the safety valve

Explanation

Corrugations give the furnace tube flexibility so it can expand and contract with temperature changes without overstressing the end plates. The shape also improves resistance to external pressure from the surrounding water.

Question 44Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Which combination of mountings provides protection against overpressure and low water respectively?

  1. Feed check valve and pressure gauge
  2. Safety valve and fusible plug Correct answer.
  3. Pressure gauge and feed check valve
  4. Gauge glass and blowdown valve

Explanation

The safety valve opens to relieve excessive steam pressure, while the fusible plug melts on overheating caused by low water, giving warning. Together they protect against two of the most serious boiler hazards.

Question 45Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A water-tube boiler has a steam drum and a water drum connected by generating tubes. What is the main purpose of the steam drum?

  1. To support the furnace refractory
  2. To separate steam from water and provide storage Correct answer.
  3. To contain the burner and flame
  4. To preheat the combustion air

Explanation

The steam drum provides space where steam separates from the water and is stored before leaving the boiler. Internals such as separators improve dryness, and the drum also allows feedwater and chemicals to be introduced.

Question 46Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

Why must a fire-tube boiler shell be fitted with stays in addition to being cylindrical?

  1. The cylindrical shell cannot support its own weight
  2. Stays increase the steam space volume
  3. Stays are needed to hold the burner in place
  4. Flat end plates and tube plates cannot resist pressure without support Correct answer.

Explanation

Cylindrical shells resist pressure efficiently by membrane action, but flat surfaces such as end plates and tube plates would bend and fail unless tied by stays. Stays transfer the pressure load to stronger parts of the structure.

Question 47Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A boiler originally designed for saturated steam is to be fitted with a superheater. Which change to the pressure-part arrangement is normally required?

  1. Adding tubes in the gas path to raise steam temperature Correct answer.
  2. Removing the safety valve to reduce weight
  3. Increasing the shell diameter to hold more water
  4. Replacing the water-walls with refractory brick

Explanation

A superheater consists of tubes placed in the hot gas path so that saturated steam flowing through them is heated above saturation temperature. The pressure parts are modified to include these tubes and their headers, not to enlarge the water space.

Question 48Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

In a water-tube boiler, why are the generating tubes often inclined rather than horizontal?

  1. To promote natural circulation and allow steam to rise freely Correct answer.
  2. To reduce the pressure rating of the tubes
  3. To make the boiler easier to paint
  4. To increase the water content of the tubes

Explanation

Inclined tubes allow steam bubbles to rise along the tube and water to flow in the opposite direction, establishing reliable natural circulation. Horizontal tubes can suffer steam blanketing and poor circulation.

Question 49Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

A shell boiler shows bulging of a flat end plate between stays. Which conclusion is most reasonable?

  1. The feedwater temperature is too high
  2. The staying is inadequate or a stay has failed Correct answer.
  3. The gauge glass is blocked
  4. The safety valve is set too low

Explanation

Bulging between stays indicates that the flat plate is carrying pressure load without sufficient support, usually because stays are missing, corroded, or broken. The boiler should be taken out of service and the staying inspected.

Question 50Boiler Construction, Types and Classification (fire-tube, water-tube, shell and water-wall designs, mountings and accessories)

In a Lancashire boiler, what is the primary function of the two large internal flue tubes?

  1. They carry the hot combustion gases from the furnace to the rear of the boiler Correct answer.
  2. They store reserve feedwater for sudden increases in steam demand
  3. They act as the main pressure-relief passages during overpressure
  4. They distribute saturated steam evenly along the length of the shell

Explanation

In a Lancashire boiler the two internal flues contain the furnaces and carry the hot gases along the length of the shell before they return through the external side flues. The gases give up heat to the surrounding water as they travel, so the flues are gas passages and heating surfaces, not water storage or steam distribution paths.