Leak Testing: Air Decay Leak Testing Methods

TQC provide air decay leak testing solutions for all types of components to measure air pressure decay.

For these solutions, standard leak testing measurement instruments are incorporated to find a change in air pressure or air flow on the components being tested.

TQC offer test pressures between vacuum and, typically, 16bar (150psig) as standard,  with leak testing measurements down to a resolution of 1 atm.mm3/sec. All air decay leak test parameters may be programmed into the instruments supplied as part of the solution, and the resulting data is available for subsequent Statistical Process Control (SPC) analysis.

When comparing leak testing methods, air decay leak testing features are –


Air decay leak testing facility for
medical filters

Overpressure air decay testing (above 0 bar)

  • Offers the lowest cost solution
  • Simple to understand results data
  • Direct value results
  • Direct calibration
  • Temperature dependent process (alternative test method is vacuum)
  • Best used when component under test is stable

Overpressure air decay leak testing is suitable for the following component and environment applications:


Vacuum leak testing facility for
automotive oil sumps

Vacuum air decay testing (below 0 bar)

  • Offers more robust leak testing (for? What applications that are different to the above?)
  • Greater integrity of data (I’m making it up now, but differentiate between the two methods. One above is cheaper, this one is more expensive. Demonstrate why.)
  • Limits temperature dependency effects
  • Assists sealing loading
  • Reduced stabilisation time
  • Often a faster throughput
  • Indirect leak calculation
  • Offers complex fault detection

Vacuum air decay leak testing is suitable for the following component and environment applications:

  • Volumes up to 5 litres
  • Parts subject to moderate temperature variation

Read more about our Vacuum Air Decay Leak Testing machines.

Flow Testing

For larger leaks and larger internal test volumes one can use a flow testing instrument. These instruments maintain an accurate test pressure whilst recording the gas flow with a flowmeter. Depending upton the test volume this tends to be a technique for checking larger leaks.

To find out more about how we can help you with your air decay leak testing requirements:

We build all machines in-house, applying our 25+ years experience in specialised test and automated handling machines to the engineering projects we undertake. We offer customer support, backup and service call-out for all projects, whatever the size.

Get in touch with us to discuss your requirements and we will be happy to offer our professional advice and visit you at your site.

TQC Ltd, Hooton Street, Carlton Road, Nottingham, NG3 2NJ, United Kingdom
Tel: +44 (0)115 9503561   |   Fax: +44 (0)115 9484642   |   E-mail: sales@tqc.co.uk