The testing process is carried out using a holiday detector, this is usually on the surface of metal objects such as the interior of a tank, chemical storage vessel and also at the depth of a structure because it is important to maintain the protective layer on a layer that is in an environment that can be said to be aggressive.
This holiday detector tool is also included in the Non-Destructive Test or NDT which is carried out on surface layers, for example on the waterproof rubber layer on concrete, where holes will be detected using the formation of an electrical circuit in areas where it is deemed sufficient to withstand an electric charge. If an electric current has been detected, then the test area can be called a conductive area, which can indicate the presence of discontinuities such as holes and several small cavities.