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 a pressure relief valve (PRV)?
A. To regulate system pressure
B. To protect the system from overpressure
C. To control temperature
D. To filter contaminants
Rationale: Relief valves are safety devices designed to open at a set pressure to
prevent system overpressure.
2) According to the ASME Boiler & Pressure Vessel Code, welders must be
qualified by:
A. Employer certification
B. Performance qualification tests
C. Visual inspection
D. Manufacturer documentation
Rationale: ASME requires welders pass performance qualification tests to verify
ability to make sound welds.
,3) What does NDE stand for?
A. Non-disruptive examination
B. Normal destructive evaluation
C. Nondestructive Examination
D. New design engineering
Rationale: NDE refers to inspection methods that do not damage the part being
examined.
4) Which NDE method uses high-frequency sound waves to detect flaws?
A. Radiographic Testing
B. Ultrasonic Testing
C. Magnetic Particle
D. Liquid Penetrant
Rationale: Ultrasonic testing utilizes high-frequency sound to detect internal
discontinuities.
5) What is cavitation in a boiler water system?
A. Excessive steam pressure
B. Chemical contamination
C. Formation of vapor bubbles due to local low pressure
D. Air entrainment
Rationale: Cavitation occurs when vapor bubbles form and collapse, potentially
damaging surfaces.
6) Which weld discontinuity is best detected by liquid penetrant inspection?
A. Internal porosity
B. Lack of fusion
C. Surface cracks
D. Inclusions
, Rationale: Liquid penetrant is effective for detecting surface-open flaws.
7) The ASME Code Section VIII covers:
A. Power boilers
B. Pressure vessels
C. Piping
D. Nuclear components
Rationale: Section VIII of ASME covers construction of pressure vessels.
8) Proper venting of a closed vessel prevents:
A. Heat loss
B. Vacuum conditions during cooldown
C. Corrosion
D. Noise
Rationale: Venting prevents vacuum formation and potential structural collapse
when cooling.
9) What gas is most often used for shielding in Gas Metal Arc Welding (GMAW)?
A. Helium only
B. Argon or Argon/CO₂ mix
C. Oxygen
D. Nitrogen
Rationale: Argon and argon blends shield molten metal from atmospheric
contamination.
10) In magnetic particle testing, magnetic particles are used to:
A. Clean the surface
B. Cool the part
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 a pressure relief valve (PRV)?
A. To regulate system pressure
B. To protect the system from overpressure
C. To control temperature
D. To filter contaminants
Rationale: Relief valves are safety devices designed to open at a set pressure to
prevent system overpressure.
2) According to the ASME Boiler & Pressure Vessel Code, welders must be
qualified by:
A. Employer certification
B. Performance qualification tests
C. Visual inspection
D. Manufacturer documentation
Rationale: ASME requires welders pass performance qualification tests to verify
ability to make sound welds.
,3) What does NDE stand for?
A. Non-disruptive examination
B. Normal destructive evaluation
C. Nondestructive Examination
D. New design engineering
Rationale: NDE refers to inspection methods that do not damage the part being
examined.
4) Which NDE method uses high-frequency sound waves to detect flaws?
A. Radiographic Testing
B. Ultrasonic Testing
C. Magnetic Particle
D. Liquid Penetrant
Rationale: Ultrasonic testing utilizes high-frequency sound to detect internal
discontinuities.
5) What is cavitation in a boiler water system?
A. Excessive steam pressure
B. Chemical contamination
C. Formation of vapor bubbles due to local low pressure
D. Air entrainment
Rationale: Cavitation occurs when vapor bubbles form and collapse, potentially
damaging surfaces.
6) Which weld discontinuity is best detected by liquid penetrant inspection?
A. Internal porosity
B. Lack of fusion
C. Surface cracks
D. Inclusions
, Rationale: Liquid penetrant is effective for detecting surface-open flaws.
7) The ASME Code Section VIII covers:
A. Power boilers
B. Pressure vessels
C. Piping
D. Nuclear components
Rationale: Section VIII of ASME covers construction of pressure vessels.
8) Proper venting of a closed vessel prevents:
A. Heat loss
B. Vacuum conditions during cooldown
C. Corrosion
D. Noise
Rationale: Venting prevents vacuum formation and potential structural collapse
when cooling.
9) What gas is most often used for shielding in Gas Metal Arc Welding (GMAW)?
A. Helium only
B. Argon or Argon/CO₂ mix
C. Oxygen
D. Nitrogen
Rationale: Argon and argon blends shield molten metal from atmospheric
contamination.
10) In magnetic particle testing, magnetic particles are used to:
A. Clean the surface
B. Cool the part
