Leak Testing Techniques Flashcards
7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Leak Testing Techniques flashcards as text
During a hydrostatic leak test, why is it important to vent all air from the system before pressurizing?
Answer: Trapped air can compress and store energy, creating a potential explosion hazard
Unlike water, trapped air compresses under pressure and stores energy that can cause a violent failure if a rupture occurs.
Which leak testing technique is classified as a 'through-wall' method?
Answer: Acoustic emission monitoring
Acoustic emission detects stress waves generated by active leaks passing through the wall of a structure, making it a through-wall technique.
What effect does temperature have on pressure decay leak testing results?
Answer: Temperature increases cause pressure increases, which can mask or simulate leaks
Per the ideal gas law, rising temperature increases pressure in a sealed system, which can mask actual leaks or simulate false positives during pressure decay tests.
What is the purpose of a 'reference leak' in a mass spectrometer leak test setup?
Answer: To create a controlled baseline for verifying detector sensitivity and calibration
A reference (calibrated) leak provides a known leak rate to verify that the mass spectrometer system is responding correctly and is properly calibrated.
In which industry is the 'bombing' or pressurization method of helium leak testing most commonly used?
Answer: Aerospace and electronics hermetic package testing
The helium bombing method is widely used in aerospace and electronics to test hermetically sealed packages for micro-leaks.
What does a 'gross leak' mean in the context of NDT leak testing?
Answer: A relatively large leak detectable by less sensitive methods such as bubble or soap solution tests
A gross leak is a large-rate leak detectable by simple methods, as opposed to fine leaks that require highly sensitive instrumentation.
Why must leak testing personnel be qualified and certified for NDT applications?
Answer: Proper training ensures correct test setup, interpretation, and reliable results that protect safety
Qualified personnel correctly apply test parameters, interpret results, and identify rejectable conditions, directly impacting safety and quality outcomes.