National Board Inservice Inspector (NB-
IS) Certification Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
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1. What is the primary purpose of the National Board Inspection Code (NBIC)?
A. Design of new pressure vessels
B. Construction of boilers
C. Inspection, repair, and alteration of pressure-retaining items
D. Welding certification
Answer: C
Rationale: NBIC governs inspection, repair, and alteration of boilers and
pressure vessels in service.
2. Which NBIC part covers inspection?
A. Part 1
B. Part 2
C. Part 3
D. Part 4
Answer: B
Rationale: NBIC Part 2 specifically addresses inspection requirements.
3. What document authorizes repairs under NBIC?
A. R-Stamp
, B. U-Stamp
C. S-Stamp
D. H-Stamp
Answer: A
Rationale: The R-Stamp indicates authorization to perform repairs and
alterations.
4. MAWP stands for:
A. Maximum Allowed Working Pressure
B. Maximum Allowable Working Pressure
C. Minimum Allowable Working Pressure
D. Maximum Applied Water Pressure
Answer: B
Rationale: MAWP is the maximum pressure at which equipment can safely
operate.
5. A pressure vessel is considered “in-service” when:
A. It is under construction
B. It is being designed
C. It is in operation or ready for operation
D. It is scrapped
Answer: C
Rationale: In-service refers to equipment currently operating or available
for use.
6. Hydrostatic testing uses:
A. Air
B. Steam
C. Water
D. Oil
Answer: C
Rationale: Water is used because it is incompressible and safer than gas.
7. What is the typical hydrostatic test pressure?
A. 1.0 × MAWP
, B. 1.1 × MAWP
C. 1.3 × MAWP
D. 1.5 × MAWP
Answer: C
Rationale: Hydrostatic tests are commonly conducted at 1.3 times MAWP.
8. Which inspection is done while equipment is operating?
A. External inspection
B. Internal inspection
C. Hydrostatic test
D. Ultrasonic testing
Answer: A
Rationale: External inspections are performed during operation.
9. Corrosion rate is typically measured in:
A. PSI/year
B. Inches/year
C. Inches per year
D. Degrees/year
Answer: C
Rationale: Corrosion rate is expressed as material loss per year.
10.Remaining life is calculated by:
A. Thickness ÷ corrosion rate
B. Corrosion rate ÷ thickness
C. Pressure ÷ thickness
D. Thickness × pressure
Answer: A
Rationale: Remaining life equals remaining thickness divided by corrosion
rate.
11.Minimum required thickness is determined by:
A. Owner
B. Inspector
C. Code calculations
IS) Certification Practice Exam Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
Download Pdf
1. What is the primary purpose of the National Board Inspection Code (NBIC)?
A. Design of new pressure vessels
B. Construction of boilers
C. Inspection, repair, and alteration of pressure-retaining items
D. Welding certification
Answer: C
Rationale: NBIC governs inspection, repair, and alteration of boilers and
pressure vessels in service.
2. Which NBIC part covers inspection?
A. Part 1
B. Part 2
C. Part 3
D. Part 4
Answer: B
Rationale: NBIC Part 2 specifically addresses inspection requirements.
3. What document authorizes repairs under NBIC?
A. R-Stamp
, B. U-Stamp
C. S-Stamp
D. H-Stamp
Answer: A
Rationale: The R-Stamp indicates authorization to perform repairs and
alterations.
4. MAWP stands for:
A. Maximum Allowed Working Pressure
B. Maximum Allowable Working Pressure
C. Minimum Allowable Working Pressure
D. Maximum Applied Water Pressure
Answer: B
Rationale: MAWP is the maximum pressure at which equipment can safely
operate.
5. A pressure vessel is considered “in-service” when:
A. It is under construction
B. It is being designed
C. It is in operation or ready for operation
D. It is scrapped
Answer: C
Rationale: In-service refers to equipment currently operating or available
for use.
6. Hydrostatic testing uses:
A. Air
B. Steam
C. Water
D. Oil
Answer: C
Rationale: Water is used because it is incompressible and safer than gas.
7. What is the typical hydrostatic test pressure?
A. 1.0 × MAWP
, B. 1.1 × MAWP
C. 1.3 × MAWP
D. 1.5 × MAWP
Answer: C
Rationale: Hydrostatic tests are commonly conducted at 1.3 times MAWP.
8. Which inspection is done while equipment is operating?
A. External inspection
B. Internal inspection
C. Hydrostatic test
D. Ultrasonic testing
Answer: A
Rationale: External inspections are performed during operation.
9. Corrosion rate is typically measured in:
A. PSI/year
B. Inches/year
C. Inches per year
D. Degrees/year
Answer: C
Rationale: Corrosion rate is expressed as material loss per year.
10.Remaining life is calculated by:
A. Thickness ÷ corrosion rate
B. Corrosion rate ÷ thickness
C. Pressure ÷ thickness
D. Thickness × pressure
Answer: A
Rationale: Remaining life equals remaining thickness divided by corrosion
rate.
11.Minimum required thickness is determined by:
A. Owner
B. Inspector
C. Code calculations
