Leak Testing (LT) Review Questions

Question 1

Which of the following systems or components are not good candidates for leak testing?
A. Piping and pressure vessels
B. Refrigerator piping
C. Vacuum chambers
D. Sintered material components

Answer 1

D. Sintered material components

Question 2

A helium mass spectrometer is used in which of the following NDT techniques or methods?
A. X-Ray spectrocopy
B. Optical holography
C. Acoustic holography
D. Leak testing

Answer 2

D. Leak testing

Question 3

Which of the following is a technique of leak testing?
A. Static
B. Gaseous diffusion
C. Dynamic
D. Direct probe

Answer 3

D. Direct probe

Question 4

Potentially, the most sensitive leak testing technique is the?
A. Bubble test
B. Pressure change test
C. Mass spectrometer test
D. Liquid penetrant test

Answer 4

C. Mass spectrometer test

Question 5

Establishing differential pressure between the test object and environment is an essential element in which of the following NDT methods?
A. X-Ray diffraction
B. Neutron radiography
C. Leak testing
D. Eddy current testing

Answer 5

C. Leak testing

Question 6

Which of the following best describes the type of leak test used when the interior of the test object is evaluated and the tracer gas is applied to the exterior, while the leak detector is connected to the evacuating system?
A. Static leak test
B. Helium leak test
C. Dynamic leak test
D. Halogen leak test

Answer 6

C. Dynamic leak test

Question 7

Assuming no significant leakage, if the temperature increased during a pressure drop leak test, the pressure in the system under test would?
A. Increase
B. Remain the same
C. Decrease
D. First increase, then decrease to its former level

Answer 7

A. Increase

Question 8

If the sensitivity of the halogen leak detector is constant throughout a test, which of the following is true upon completion of the test?
A. No leaks smaller than a certain size have gone undetected
B. The total leak rate of the test object is less than a certain amount
C. The instrument and the test procedure were capable of detecting leakage of a certain size during the test
D. The instrument and the test procedure were only capable of detecting leakage of a certain size upstream from the tracer gas during the test.

Answer 8

C. The instrument and the test procedure were capable of detecting leakage of a certain size during testing.

Question 9

All leak detection methods are dependent upon:
A. Barometric pressure
B. Gas or fluid flow
C. Mass spectrometer analysis
D. Mean free paths of helium flow

Answer 9

B. Gas or fluid flow

Question 10

In an evaluated system, sensitivity of a pressure change leak test is dependent not only on the pressure change observed, but also on the degree of outgassing. Outgassing is best defined as:
A. The viscosity of the pressurizing gas
B. Being directly proportional to the temperature of the gas
C. The release of gas from materials in a vacuum
D. The drop in test pressure due to leakage from the vacuum manifold

Answer 10

C. The release of gas from materials in a vacuum