Tracer-gas leak testing under ISO 20485

LEAKLAB · TESTING AND ENGINEERING

Choose vacuum or sniffer arrangements according to the object and whether the task is local leak location or integral measurement.

Choose the gas path

Identify the test boundary and desired result first. Then agree the pressure-difference direction, tracer-gas composition, exposure method and detection route. Helium arrangements can include external spray on an evacuated object, internal tracer gas with external sniffing, or an integral chamber or hood test.

Method and metrology are related, separate tasks

The source service references ISO 20485:2017 for tracer-gas leak detection. The edition and acceptance requirements are agreed after reviewing the customer’s specification. This page does not assign a universal pressure, helium concentration or allowable leak rate.

Reference-leak calibration under ISO 20486 addresses a separate metrological task. The instrument specification, full-system response and product acceptance requirement should not be treated as the same quantity.

Preparing and verifying the test

1. Review the drawing, materials, internal volumes, test boundary and required result.
2. Agree the document edition, allowable pressure difference, vacuum and temperature, acceptance criterion and required system sensitivity.
3. Clean and dry the object, prepare fixtures and exclude leakage from the test connections.
4. Check instrument metrological status and the working characteristics of the complete arrangement; use an appropriate reference response for the selected method.
5. Perform the agreed scan or measurement cycle and record the actual conditions. Confirm suspected leaks by repeat tracer-gas exposure where applicable.
6. Check system stability after the test and report the result against the agreed criterion.

What the customer receives

The agreed scope can include a test programme, operating or inspection instructions, measured results, a map of located leaks and a technical conclusion. The report identifies the object and tested regions, applicable programme, instruments and metrological status, pressure and temperature, response checks, observations and limitations.

Define your task

Send a drawing or sketch, material, dimensions and volume, working pressure, allowable vacuum and temperature, leak-tightness requirement, number of items, site and schedule. These inputs determine the method, fixture, equipment and reporting scope.