How do I choose the right tracer gas (He, H₂/’forming gas’, refrigerant)?

The choice of a tracer gas mainly depends on sensitivity, safety, and the normative framework (standards, customer requirements, legislation).

Some main options:

• Helium (He)

Very low detection limits, inert and non-flammable. Ideal for sensitive leak tests, type approvals, and situations where you want to detect very small leaks.

• H₂/N₂-forming gas (e.g. 5% H₂ / 95% N₂)

More affordable than helium and well suited for sniffing tests, provided safety (flammability, ATEX) and standards allow it. Often used as a practical alternative for large installations or routine production.

• Process medium as tracer (e.g. refrigerants such as R134a)

Applied in sector-specific standards (HVACR, refrigeration installations). This allows very practice-oriented testing, but you must consider environmental and safety requirements and the availability of suitable detectors (halogen, IR, MS).

In summary: you choose the tracer gas based on the required detection limit, the safety aspects (flammability, ATEX, toxicity), applicable standards/customer requirements, and the practical availability and cost of the gas.