Accumulation Leak Test
What is an Accumulation Leak Test?
Accumulation leak testing measures a part’s total leak rate without a vacuum chamber. The part is charged with a trace gas — helium or 5%/95% hydrogen forming gas — and enclosed in a simple chamber at ambient pressure. Any gas escaping the part accumulates in the chamber during a timed dwell while a fan keeps it evenly mixed; a trace gas sensor tracks the concentration, and the rate of rise is the part’s total leak rate.
Accumulation is the practical middle path of trace gas testing: it delivers a quantitative, whole-part result like hard vacuum testing — reaching the 10⁻⁵ to 10⁻⁶ mbar·l/s range with a dwell tuned to your spec — but the chamber only has to fit the part, not hold a vacuum. That makes it especially attractive for large parts like battery packs and tanks, and far less costly to build and maintain. 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).
- Enclose — the part goes into the accumulation chamber at ambient pressure; a fan keeps the internal volume evenly mixed.
- Dwell — escaping trace gas collects in the chamber for a timed period matched to your reject limit.
- Measure — the sensor tracks trace gas concentration; the rate of rise is the part’s total leak rate.
- Judge & recover — the rise is compared to the calibrated reject limit for a definitive PASS/FAIL, then the chamber is flushed and the gas vented or reclaimed.
A tight part leaves the chamber at background; a leaking part produces a steady rise whose slope is the leak rate. Zaxis accumulation leak test systems run the entire sequence automatically.
Sample Applications:
- EV battery packs & modules
- Fuel tanks & filler systems
- HVAC/R assemblies & heat exchangers
- Airbag inflators & safety devices
- Transmission housings & castings
- Sealed medical & electronic enclosures
Wondering whether accumulation dwell times fit your takt time — or whether your limit calls for hard vacuum instead? Contact Zaxis — our engineers will size the chamber, dwell, and gas for your spec.
Why Choose Accumulation Leak Testing for Your Products
Accumulation gives you the number that matters — total leakage — with the simplest chamber that can hold your part. It is trace gas sensitivity engineered for value.
- Total leak rate without vacuum-chamber cost — the enclosure only has to fit the part, not hold a hard vacuum
- Scales to very large parts — battery packs, tanks, and assemblies that no vacuum chamber could swallow
- Simple and robust — no high-vacuum pumps to maintain, easy to integrate into a production line
- Operator-independent — the chamber and sensor do the work; results do not depend on technique
- Tunable sensitivity — dwell time and chamber volume adjust the method to your reject limit
- Forming gas economics — inexpensive, non-flammable 5%/95% hydrogen keeps running costs low
Contact Zaxis Inc today to build the right accumulation solution for your product.
Suggested Leak Testers For Accumulation Testing
Prepares the part for the chamber — evacuate, purge, and charge with helium or forming gas to test pressure, identical every cycle.
Helium detection for accumulation and sniffing — calibrated reject limits and a clear PASS/FAIL for every part.
The 8″ modular platform that sequences charge, dwell, measurement, and recovery — and logs a quantitative result for every part.
Accumulation leak testing delivers quantitative, whole-part trace gas results at a fraction of the cost of a hard vacuum system — and it is often the only practical way to leak test very large assemblies. Zaxis builds complete accumulation solutions — charge station, chamber, sensor, and controller — engineered as one integrated cell. Explore all trace gas leak testing methods or request a quote to get started.