Sniffing Leak Test
What is a Sniffing Leak Test?
Sniffing (or sniffer leak detection) is the trace gas method that tells you exactly where a part leaks. The part is charged with a trace gas — helium or 5%/95% hydrogen forming gas — and a sniffer probe is moved along welds, joints, seals, and fittings. The probe continuously samples the surrounding air; when it passes over a leak, escaping trace gas is drawn in and the signal spikes, pinpointing the leak site and its approximate leak rate.
Because the detector responds to the trace gas itself, sniffing routinely finds leaks in the 10⁻⁵ to 10⁻⁷ mbar·l/s range — far beyond what a bubble dunk or a pressure change can resolve — with no vacuum chamber and no immersion. It is the natural companion to whole-part methods like accumulation or hard vacuum testing: those tell you that a part leaks and by how much; sniffing tells you where, so the part can be reworked instead of scrapped. See all trace gas leak testing methods.
Here’s how it works:
- Charge — the part is evacuated, then filled with helium or forming gas to its specified test pressure (a Zaxis Z-Charge manages evacuate → purge → charge automatically).
- Scan — an operator or robot moves the sniffer probe along seams, joints, and fittings at a controlled distance and speed.
- Sample — the probe continuously draws in surrounding air and delivers it to the detector’s sensor.
- Locate — passing over a leak, the trace gas concentration spikes; the signal peak marks the exact leak location.
- Judge & recover — the peak is compared to the calibrated reject limit for a definitive PASS/FAIL, then the gas is vented or reclaimed.
A leak shows up as a sharp signal peak as the probe passes over it — the signal stays at background everywhere the part is tight. Zaxis sniffing leak test systems manage the entire sequence automatically.
Sample Applications:
- Locating leaks in EV battery cooling plates, fittings & housings
- HVAC/R brazed joints, coils & service valves
- Medical device assemblies & luer connections
- Fuel systems, brake lines & hydraulic fittings
- Weld seam & gasket inspection on tanks and heat exchangers
- Rework & repair verification after a failed whole-part leak test
Not sure whether sniffing or a whole-part trace gas method fits your reject limit? Contact Zaxis — our engineers will help you choose the right combination for your spec and takt time.
Why Choose Sniffing Leak Testing for Your Products
Sniffing pairs trace gas sensitivity with the simplest possible setup: charge the part, scan the probe, read the result. It is the fastest way to turn a rejected part into a repaired one.
- Finds the leak, not just the part — pinpoints the exact location so parts are repaired instead of scrapped
- High sensitivity, simple setup — 10⁻⁵–10⁻⁷ mbar·l/s with no vacuum chamber or immersion tank
- Works on any size part — the probe goes to the part, not the part into a chamber
- Low-cost tracer option — 5%/95% hydrogen forming gas is inexpensive, non-flammable, and ideal for high volume
- Automation-ready — robotic probe scanning with a Zaxis controller takes operator technique out of the equation
- Perfect partner to whole-part tests — screen with accumulation or hard vacuum, then sniff rejects to locate the leak
Contact Zaxis Inc today to build the right sniffing solution for your product.
Suggested Leak Testers For Sniffing
Helium leak detector engineered for production sniffing — fast response, calibrated reject limits, and a clear PASS/FAIL for every operator.
Prepares the part for sniffing — evacuate, purge, and charge with helium or forming gas to test pressure, identical every cycle.
The 8″ modular platform that sequences charge, sniff, and recovery — and logs a quantitative result for every part.
Sniffing leak testing with helium or hydrogen forming gas locates individual leaks quickly and affordably, making it a production favorite in HVAC/R, EV battery, and medical device manufacturing. Zaxis builds complete sniffing solutions — charge station, detector, and controller — with the fixtures and support to put a definitive PASS/FAIL at your operator’s fingertips. Explore all trace gas leak testing methods or request a quote to get started.