BS EN ISO 20485:2018,Non-destructive testing – Leak testing – Tracer gas method.BS EN ISO 20485:2018 pdf free download here.The size is 2.86M.
BS EN ISO 20485:2018 describes the techniques to be applied for the detection of a leak, using a tracer gas and a tracer gas specific leak detector.
2 Normative references
ISO 20484, Non-destructive testing- Leak testing-Vocabulary.
4 Principles of detection
A partial pressure difference of tracer gas is created across the boundary of the object to be tested. The tracer gas, having passed through the leak, is revealed by its physical or chemical properties. Chemical detection is generally based on reactions that cause a local colour change (the object surface shal therefore be visible)
5 Generation and detection of tracer gas flow
5.1 Tracer gas flows into the object (Group A techniques)
A pressure difference across the wall is obtained either by evacuation of the object, e.g. through a connection or by placing it in a pressurized chamber. Usually the test object is evacuated. Tracer gas is then applied to the external surface using a probe jet or by enclosing the object (totally or partially) in a hood or chamber filled with the tracer gas. Tracer gas leakage into the test object is detected by a sensor within or connected to the internal volume.