NDT Leak Testing Techniques 4

Question 1

Which leak testing method is BEST suited for detecting leaks in underground pipelines without excavation?

Accepted Answer

Acoustic emission or acoustic leak detection

Answer

Acoustic emission and acoustic leak detection methods can locate leak sources in buried pipelines by detecting the sound generated by escaping fluid.

Question 2

In a vacuum bell jar leak test using a helium mass spectrometer, what is the test configuration?

Accepted Answer

The part is placed in a vacuum chamber; helium is applied outside, and the detector monitors inside

Answer

In the vacuum bell jar method, the part interior is evacuated and connected to the detector, and helium applied outside permeates through leaks to be detected.

Question 3

What is the significance of the 'leak rate' unit 'Pa·m³/s' (or atm·cc/s) in leak testing?

Accepted Answer

It quantifies the volumetric flow of gas through a leak at a given pressure differential

Answer

Leak rate units like Pa·m³/s express the volume of gas passing through a leak per unit time at a specified pressure, quantifying how much gas is lost.

Question 4

What condition must be met before performing a pneumatic pressure leak test on a pressure vessel?

Accepted Answer

A risk assessment must confirm pneumatic testing is safe, as compressed gas stores more energy than liquid

Answer

Because compressed gas stores significantly more energy than liquid, a pneumatic test requires a safety risk assessment before proceeding.

Question 5

A refrigerant system leak is most commonly detected using which instrument?

Accepted Answer

Electronic halogen (refrigerant) leak detector

Answer

Electronic halogen or refrigerant-specific detectors sense refrigerant molecules escaping from a leak and are standard tools in HVAC/R leak testing.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

NDT Leak Testing Techniques 4