Tracer-gas leak testing method

Tracer-gas leak testing method is a nondestructive testing method.

Types

Several tracer-gas leak testing methods exist among which the methods of choice are:

Method selection

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

Typical leak rates
SystemAllowed Leak RateComments
Chemical process equipment10−1 to 1 mbar l/shigh process flows
Beverage can low 10−5 to 10−6 mbar l/s retention of CO2
Vacuum pumped system 10−5 to 10−7 mbar l/s permanent pumping
IC-package 10−7 to 10−8 mbar l/s lifetime control
Airbag cartridge10−8 mbar l/s lifetime control
Pacemaker10−9 mbar l/s Bio compatibility
Closed vacuum system10−9 mbar l/s X-Ray tube

Based on the target leak rate the table below wil help to choose the most suitable method.

Leak test performances
mbar l/s10210110010−110−210−310−410−510−610−710−810−910−1010−1110−12
Bubble test in water---------------->
Bubble test soapy water------------------------>
Pressure decay-------------------->
Acoustic (US)-------------------->
Vacuum decay-------------------->
Corona tester-------------------->
Thermal conductivity---------------------------->
Halogen sniffer*---------------------------->
Hydrogen sniffer--------------------------------->
Helium sniffer--------------------------------->
Halogen detector*-------------------------------->
Dye penetrant---------------------------------------->>
Radio-isotope------------------------------------------------>>>>
Mass spectrometer---------------------------------------------------->>>>>>

Typical applications of tracer gas leak testing include:

Another element of consideration is the dimension of the part to be tested as well as to take into consideration the law of physics, specially the rules that govern the flow of gas at different pressure. <<stub>>

Standards

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

References

  1. Federal Equipment Leak Regulations for the Chemical Manufacturing Industry
  2. Case of a Cracker accident in Japan
  3. See paragraph "Description of the drawings"
  4. Helium Leak Testing
  5. Leak testing for medical equipment
  6. Leaky spy plane crash
  7. Leak Repair
  8. New SF6 Breaker Leak Study
  9. Helium as a tracer gas
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