National Board Inservice Inspector (NB-IS)
Certification Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary purpose of an inservice inspection?
A. To certify new pressure vessels
B. To ensure continued safe operation of pressure-retaining
equipment
C. To perform destructive testing
D. To design new boiler systems
Inservice inspections verify that pressure equipment is safe to
operate and meets regulatory standards.
2. Which code governs the inspection of pressure vessels in the
United States?
A. ASME B31.3
B. ASME Section V and Section VIII
C. API 510
D. OSHA Standard 1910
ASME codes provide standards for the construction and inspection
of pressure vessels, including inservice inspections.
3. When inspecting a boiler, what is the first step an NB-IS inspector
should take?
A. Start non-destructive testing immediately
, B. Review vessel history and previous inspection reports
C. Fill the vessel with water
D. Measure wall thickness
Understanding prior inspection findings and vessel history guides
the current inspection process.
4. Which type of inspection requires the inspector to check for
corrosion, cracking, and deformation?
A. Hydrostatic testing
B. Radiographic testing
C. External and internal visual inspection
D. Ultrasonic testing
Visual inspections are critical for identifying surface defects and
signs of deterioration.
5. For a pressurized vessel, what is the minimum acceptable wall
thickness determined by?
A. Manufacturer’s original design only
B. Inspector’s judgment
C. ASME code formulas considering corrosion allowance and
design pressure
D. Vessel age
Code formulas ensure the vessel maintains structural integrity
under operating conditions.
6. What is the purpose of a hydrostatic test?
A. To measure operating temperature
B. To verify the pressure vessel can safely handle its design
pressure
C. To remove scale buildup
, D. To check valve functionality
Hydrostatic testing subjects the vessel to pressures higher than
normal operation to check for leaks or weakness.
7. How often should an inservice inspection typically occur for
boilers?
A. Every month
B. Every week
C. Annually or as prescribed by code
D. Only when a problem arises
Frequency of inspections is set to ensure ongoing safety without
unnecessary downtime.
8. Which non-destructive testing method is commonly used to
detect internal flaws?
A. Visual inspection
B. Hydrostatic testing
C. Ultrasonic testing
D. Painting the vessel
Ultrasonic testing uses sound waves to detect internal defects
without damaging the vessel.
9. When evaluating a welded joint, what defect is most critical?
A. Surface rust
B. Paint peeling
C. Cracking or lack of fusion
D. Minor scratches
Cracks or incomplete fusion compromise structural integrity and
can lead to catastrophic failure.
, 10. What should be done if a pressure vessel is found with a
defect exceeding allowable limits?
A. Ignore it if it looks minor
B. Schedule the next inspection sooner
C. Repair or remove the vessel from service until corrected
D. Reduce operating pressure
Code compliance requires defective equipment to be repaired or
taken out of service to prevent accidents.
11. Which material property is essential to know when
evaluating a vessel for corrosion?
A. Color
B. Chemical composition and hardness
C. Weight
D. Manufacturer’s label design
Material properties affect how the vessel reacts to corrosion and
wear.
12. What is the purpose of a pressure relief device?
A. To increase pressure
B. To prevent overpressure that could cause vessel failure
C. To reduce corrosion
D. To mark inspection dates
Pressure relief valves are safety devices designed to protect
against excessive pressure buildup.
13. Which type of vessel inspection requires opening the vessel?
A. External visual inspection
B. Internal inspection
C. Hydrostatic test only
Certification Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2026 Q&A | Instant Download Pdf
1. What is the primary purpose of an inservice inspection?
A. To certify new pressure vessels
B. To ensure continued safe operation of pressure-retaining
equipment
C. To perform destructive testing
D. To design new boiler systems
Inservice inspections verify that pressure equipment is safe to
operate and meets regulatory standards.
2. Which code governs the inspection of pressure vessels in the
United States?
A. ASME B31.3
B. ASME Section V and Section VIII
C. API 510
D. OSHA Standard 1910
ASME codes provide standards for the construction and inspection
of pressure vessels, including inservice inspections.
3. When inspecting a boiler, what is the first step an NB-IS inspector
should take?
A. Start non-destructive testing immediately
, B. Review vessel history and previous inspection reports
C. Fill the vessel with water
D. Measure wall thickness
Understanding prior inspection findings and vessel history guides
the current inspection process.
4. Which type of inspection requires the inspector to check for
corrosion, cracking, and deformation?
A. Hydrostatic testing
B. Radiographic testing
C. External and internal visual inspection
D. Ultrasonic testing
Visual inspections are critical for identifying surface defects and
signs of deterioration.
5. For a pressurized vessel, what is the minimum acceptable wall
thickness determined by?
A. Manufacturer’s original design only
B. Inspector’s judgment
C. ASME code formulas considering corrosion allowance and
design pressure
D. Vessel age
Code formulas ensure the vessel maintains structural integrity
under operating conditions.
6. What is the purpose of a hydrostatic test?
A. To measure operating temperature
B. To verify the pressure vessel can safely handle its design
pressure
C. To remove scale buildup
, D. To check valve functionality
Hydrostatic testing subjects the vessel to pressures higher than
normal operation to check for leaks or weakness.
7. How often should an inservice inspection typically occur for
boilers?
A. Every month
B. Every week
C. Annually or as prescribed by code
D. Only when a problem arises
Frequency of inspections is set to ensure ongoing safety without
unnecessary downtime.
8. Which non-destructive testing method is commonly used to
detect internal flaws?
A. Visual inspection
B. Hydrostatic testing
C. Ultrasonic testing
D. Painting the vessel
Ultrasonic testing uses sound waves to detect internal defects
without damaging the vessel.
9. When evaluating a welded joint, what defect is most critical?
A. Surface rust
B. Paint peeling
C. Cracking or lack of fusion
D. Minor scratches
Cracks or incomplete fusion compromise structural integrity and
can lead to catastrophic failure.
, 10. What should be done if a pressure vessel is found with a
defect exceeding allowable limits?
A. Ignore it if it looks minor
B. Schedule the next inspection sooner
C. Repair or remove the vessel from service until corrected
D. Reduce operating pressure
Code compliance requires defective equipment to be repaired or
taken out of service to prevent accidents.
11. Which material property is essential to know when
evaluating a vessel for corrosion?
A. Color
B. Chemical composition and hardness
C. Weight
D. Manufacturer’s label design
Material properties affect how the vessel reacts to corrosion and
wear.
12. What is the purpose of a pressure relief device?
A. To increase pressure
B. To prevent overpressure that could cause vessel failure
C. To reduce corrosion
D. To mark inspection dates
Pressure relief valves are safety devices designed to protect
against excessive pressure buildup.
13. Which type of vessel inspection requires opening the vessel?
A. External visual inspection
B. Internal inspection
C. Hydrostatic test only
