ASME ASME Pressure Testing and Inspection 2 — Questions and Answers
Question 1: In ASME pressure vessel inspection, what does 'corrosion allowance' represent?
- The maximum corrosion rate allowed by the operating permit
- Additional wall thickness added during design to allow for material loss during service life (Correct answer)
- The amount of material that can be corroded before the next inspection
- The difference between calculated and actual wall thickness at time of fabrication
Correct answer: Additional wall thickness added during design to allow for material loss during service life
Corrosion allowance is additional wall thickness intentionally added during design to compensate for anticipated material loss due to corrosion over the vessel's service life.
Question 2: Under ASME Section V Article 2, what is the purpose of radiographic 'image quality indicators' (IQIs or penetrameters)?
- To calibrate the X-ray machine output in mR/hr
- To demonstrate the radiographic sensitivity and ensure the technique can detect a specified minimum flaw size (Correct answer)
- To verify the film density is within acceptable limits
- To identify the radiographer who performed the examination
Correct answer: To demonstrate the radiographic sensitivity and ensure the technique can detect a specified minimum flaw size
IQIs (penetrameters) demonstrate that the radiographic technique has sufficient sensitivity to detect a minimum flaw size, ensuring the examination is meaningful.
Question 3: What is the purpose of an ASME 'U' (Universal) stamp on a pressure vessel?
- It certifies the vessel passed ultrasonic examination
- It identifies the vessel as manufactured to ASME Section VIII Division 1 (Correct answer)
- It indicates the vessel is rated for unfired (un-heated) service only
- It certifies the vessel was fabricated in the United States
Correct answer: It identifies the vessel as manufactured to ASME Section VIII Division 1
The ASME 'U' stamp on a pressure vessel data report certifies that the vessel was manufactured in accordance with ASME Boiler and Pressure Vessel Code Section VIII Division 1.
Question 4: Under ASME Section VIII, what is 'MAWP' for a pressure vessel?
- The pressure at which the vessel was hydrostatically tested
- The maximum pressure at the most severe coincident temperature for which the vessel is designed (Correct answer)
- The average working pressure during normal operation
- The pressure stamped on the nameplate plus 10% safety margin
Correct answer: The maximum pressure at the most severe coincident temperature for which the vessel is designed
Maximum Allowable Working Pressure (MAWP) is the maximum pressure at which the most severe coincident temperature can be applied to a completed vessel, as determined by the weakest element's Code-allowable stress.
Question 5: In ASME Section V UT examination, what is 'calibration' of an ultrasonic instrument?
- Verifying the ultrasonic instrument meets manufacturer's specifications
- Setting the gain and time base using a reference reflector of known size to establish sensitivity and range (Correct answer)
- Calculating the attenuation of sound in the material being tested
- Verifying the probe frequency matches the material thickness
Correct answer: Setting the gain and time base using a reference reflector of known size to establish sensitivity and range
Calibration in UT involves using a reference block with known reflectors to set the instrument's sensitivity and distance calibration so that indications can be accurately characterized.
Question 6: What is the significance of the 'A-scan' display in ultrasonic testing?
- A plan view showing the top surface of the test piece
- A waveform display showing signal amplitude versus time (depth), used to identify and size reflectors (Correct answer)
- A cross-sectional image of the test piece reconstructed from multiple UT scans
- A calibration record showing the instrument's linearity
Correct answer: A waveform display showing signal amplitude versus time (depth), used to identify and size reflectors
An A-scan is the basic UT display presenting ultrasonic signal amplitude on the vertical axis versus time-of-flight (depth) on the horizontal axis, used to detect and locate reflectors.
ASME ASME Pressure Testing and Inspection 2
In ASME pressure vessel inspection, what does 'corrosion allowance' represent?