Frequently Asked Questions

Helium leak testing is a method of fine or small leak testing used to detect and locate leaks in a sealed part or system using helium.

The four main helium leak test methods include vacuum + helium spray, helium sniffing, hard vacuum chamber, and accumulation testing. See our services page for more information on each method.

A mass spectrometer is used to analyze if and how much helium is leaking through a part. This equipment is calibrated and tuned to sense very small changes in helium or hydrogen signals.

Helium and hydrogen gas is used for leak testing because it is a small, inert gas that can easily penetrate small leaks. It is detectable at very low concentrations due to its low background presence (~5ppm).

Typically, there are industry standards dictating whether a product needs to be leak tested. However, this is not always the case. You may determine that your product requires a more sensitive leak test to avoid costly quality defects, safety concerns, or environmental risks.

The choice between helium and hydrogen for leak testing depends on the specific requirements of the application, including sensitivity, cost, and the availability of the tracer gas. Helium offers high sensitivity, making it ideal for critical applications, while hydrogen provides a more cost-effective alternative for less critical applications.

Both gases have a low background presence (~5ppm), but hydrogen can sometimes have a higher background due to several factors and processes. Typically, a 5% hydrogen and 95% nitrogen mixture is used, making the leak signal smaller than higher concentrations of helium.

Hydrogen is highly flammable and poses a risk of explosion when mixed with air in concentrations above 8%. However, using a 5% hydrogen and 95% nitrogen mix mitigates this risk significantly. Hydrogen is also considered a more environmentally conscious tracer gas.

Helium leak testing is among the most sensitive leak detection methods available, capable of detecting leaks as small as 1 e -12 mbar l/s.

Some factors that can affect the accuracy and sensitivity of helium leak testing include the equipment being used, system geometry and material, testing conditions, helium background levels, and operator technique.

Yes, there are various regulatory standards and guidelines governing helium leak testing, depending on the industry and application. Some industries, such as aerospace, automotive, and medical devices, have specific leak rate standards (e.g., ISO, ASTM, MIL-STD).

As various regulations and environmental considerations are becoming more strict across all industries, leak test standards are becoming more sensitive. Typically, a result of improving quality, increasing safety, and mitigating environmental risks.

Understand the operation of the part, including pressure, temperature, and the nature of the contents (gas, liquid, etc.). Determine the acceptable leak rate based on how a leak could affect performance, safety, and compliance often by performing a risk analysis to understand the potential impact of leaks on product performance and safety.

We can work with you to define your specific needs, develop a leak testing procedure, and provide the testing services needed to ensure high quality and safety.

Suppose you are manufacturing medical implants, and industry standards specify an acceptable leak rate of 1 x 10^-8 mbar∙l/s for helium.

1. Research Standards: Confirm that ISO 11607 (Packaging for terminally sterilized medical devices) or ASTM F2095 (Standard Test Methods for Pressure Decay Leak Test for Flexible Packages) apply.

2. Determine Acceptable Leak Rate: Based on the standard, set 1 x 10^-8 mbar∙l/s as the maximum acceptable leak rate.

3. Develop Procedure: Use a vacuum chamber helium leak detection method capable of detecting leaks down to 1 x 10^-9 mbar∙l/s.

4. Validate Testing: Calibrate the system using a calibrated leak standard of 1 x 10^-9 mbar∙l/s. Conduct multiple tests to ensure repeatability.

5. Document Criteria: Clearly state in the test protocol that any product with a leak rate above 1 x 10^-8 mbar∙l/s fails the test.

By following these steps, you can establish and implement a robust pass/fail helium leak rate criterion for your product, ensuring it meets the required standards and performs reliably in its intended application.

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