Tracer-gas leak testing

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A tracer-gas leak testing method is a nondestructive testing method that detects gas leaks. A variety of methods with different sensitivities exist. Tracer-gas leak testing is used in the petrochemical industry, the automotive industry, and in the manufacture of semiconductors, among other uses.


Several tracer-gas leak testing methods exist, including:

Method selection[edit]

Typical leakage rates[edit]

The nature of the product or the process and the process gases will set the leak rate requirement:

System Allowed leak rate (mbar L/s)
Chemical process equipment 10−1–1
Beverage can 10−5 –10−6
Vacuum pumped system 10−5–10−7
IC-package 10−7–10−8
Airbag cartridge 10−8
Pacemaker 10−9
Closed vacuum system 10−9

Sensitivity of methods[edit]

Based on the target leak rate, the table below will help to choose the most suitable method.[1]

Method Sensitivity (leak rate in mbar l/s)
Ultrasonics 10−1
Bubble test in water 10−2
Pressure decay 10−2
Vacuum decay 10−2
Acoustic emission detectors 10−3
Bubble test in soapy water 10−4
Gas-specific thermal conductivity detector 10−5
Halogen detector 10−5
Photoacoustic spectroscopy 10−6
Hydrogen sniffer 10−6
Residual gas analyser 10−7
Dye penetrant 10−8
Radioactive tracer 10−10
Helium mass spectrometry vacuum testing 10−11


Typical applications of tracer-gas leak testing include:


Several standards apply to leak testing and more specifically to tracer-gas leak testing methods, for example:

  • BS EN 1779:1999; leak tightness by indication or measurement of gas leakage,
  • BS EN 13185:2001 Non-destructive testing. Leak testing. Tracer gas method,
  • BS EN 13192:2002 Non-destructive testing. Leak testing. Calibration of reference leaks for gases.


  1. ^ "Leak Detection Sensitivity Guide - VIC Leak Detection". VIC Leak Detection. Retrieved 2017-06-15.
  2. ^ Townsend, Mark; correspondent, defence (2007-11-11). "MoD accused over spy plane deaths". The Guardian. ISSN 0261-3077. Retrieved 2017-06-15.