Helium Tracer Gas vs. Ultrasonic Detection: Choosing the Right Air Inleakage Testing Method

Plant teams evaluating air inleakage testing options usually end up comparing two approaches: helium mass spectrometer tracer gas testing and ultrasonic leak detection. Both have a place, but they aren't interchangeable.

Helium Tracer Gas Testing

Helium is injected around suspect joints, seals, and flanges while a mass spectrometer sampling the vacuum system detects trace amounts pulled in through the leak. Because helium is inert, small, and not naturally present in the system, this method offers extremely high sensitivity and can locate leaks other methods miss entirely, including leaks below insulation or in hard-to-access areas.

Ultrasonic Detection

Ultrasonic detectors listen for the high-frequency sound generated by air rushing through a leak path. It's fast, requires no tracer gas, and works well for larger, more accessible leaks. Sensitivity drops off, though, in noisy plant environments and for very small or shielded leak paths.

Which One Should You Use?

For a quick first pass on obvious leak candidates, ultrasonic can be useful. For a thorough, outage-window survey intended to find every meaningful leak path, including the small ones that add up, helium tracer gas testing is the more reliable choice. Many plants use both: ultrasonic for quick checks between outages, and a full helium survey during planned maintenance windows.

StrongForce's technicians bring deep hands-on experience with helium mass spectrometer leak detection to every outage. Call 833-735-3257 or email info@StrongForceInc.com to schedule a survey for your next planned outage.