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
Which leak testing method is most appropriate for detecting very small leaks in hermetically sealed electronic packages?
Answer: Helium mass spectrometer leak testing
Helium mass spectrometer leak testing is the most sensitive method available and is widely used for hermetically sealed electronic components.
In tracer gas leak testing, what property of helium makes it the preferred tracer gas?
Answer: Low background concentration in air and small atomic size
Helium's very low natural atmospheric concentration (~5 ppm) and small atomic size allow it to pass through tiny leaks and be detected at very low levels.
What does the term 'minimum detectable leak rate' refer to in leak testing?
Answer: The smallest leak rate that a detector can reliably identify above background noise
Minimum detectable leak rate is the smallest leak signal that can be distinguished from background noise with acceptable confidence.
A pressure decay test shows a steady pressure drop over time. What is the most likely cause?
Answer: A leak allowing gas to escape the test volume
Steady pressure decay in a closed system is a primary indicator of a leak allowing gas to escape.
Which standard governs leak testing methods for pressure-containing equipment in the United States?
Answer: ASME Boiler and Pressure Vessel Code Section V
ASME BPVC Section V, Article 10 specifically addresses leak testing methods for pressure-retaining equipment.
In vacuum leak testing, a helium sniffer probe is used to detect leaks by:
Answer: Pressurizing the part with helium while sniffing the exterior for leaking helium
In the sniffer (pressurization) method, the part is filled with helium under pressure and the exterior is scanned with a sniffer probe to detect escaping helium.
What is the primary advantage of using a halogen leak detector over a bubble test?
Answer: It provides quantitative leak rate measurement and higher sensitivity
Halogen detectors offer much higher sensitivity than bubble tests and can provide quantitative leak rate data.