4. Adopt your leak rate limits!
Hydrogen is not used as 100% pure hydrogen as tracer gas due to its flammability, but typically a mixture of 5% hydrogen in 95% nitrogen is used (this mixture is often called forming gas as it is also used in welding processes). The leak detector can only detect the hydrogen share of the tracer gas. So, the smallest detectable leak rate is higher by a factor of 20. However, the viscosity is 13% lower, so overall the leak rate limit is 17 times higher. The trigger level needs to be adjusted by a factor of 17. Some leak detectors offer to choose forming gas from the menu so that the 5% hydrogen concentration is already taken into consideration.
5. Don’t choose a leak detector just from a data sheet!
A brochure about a hydrogen leak detector is a good start if you want to look into using hydrogen as a tracer gas. However, this does not replace a real-life trial of the leak detector in your environment. Datasheets typically do not give numbers for how well a leak detector can cope with specific requirements and environmental conditions.
For a reliable solution, get a demo leak detector and try it in your environment and in your application. INFICON offers a variety of hydrogen leak detectors with different scopes and price points. The XL3000flex leak detector can be used with either helium or hydrogen in low flow or high flow operation, offering the highest flexibility.
Contact us for assistance and for planning your onsite demo!
If you want to learn more about the use of hydrogen for leak testing, please also have a look at our on-demand webinar.