Leak Testing 

LTLeak Testing is a non-destructive testing (NDT) method for establishing the integrity of containment of a component or system, ie identifying whether there is a leakage path through which the process fluid could escape or, if the component or system normally operates under a vacuum, through which air could leak inwards.

Two of the main LT techniques are the tracer gas method and the pressure change method. In the former, a tracer gas is applied and if the tracer gas escapes through the leak it is detected either by a chemical reaction or a physical sensor. In the pressure change method, a pressure difference is established between the internal and external boundaries of the component or system. The pressure is then monitored over time to see if any changes due to a leak are observed.

The training and competence assessment requirements for LT operators are similar to other condition monitoring and NDT methods.

For more information on LT see:
BS EN ISO 20484:2017 Non-destructive testing – Leak testing – Vocabulary
BS EN 13185:2001 Non-destructive testing – Leak testing – Tracer gas method
BS EN 13184:2001 Non-destructive testing – Leak testing – Pressure change method.

Note: LT is also used to denote ‘lock-in thermography’ (see ‘What the Hec?!’, August 2015).

What the hec?! articles are not intended to be the definitive account on the topic or acronym in question. Readers’ comments and contributions are welcomed. Email: