What Gas Is Used for Leak Detection?

Helium is the most widely used gas for leak detection in industrial applications, though several other gases can be used depending on specific testing requirements. The choice of gas primarily depends on three factors: 

1. The type of system being tested
2. The required sensitivity
3. Cost considerations

This guide breaks down the most popular leak detection gases based on these criteria. We’ll also discuss the available detection methods and other notable factors to consider when choosing your preferred gas.

Tip: Check out WestAir’s gas safety solutions.

Understanding Leak Detection Gases

Leak detection is a critical process in many industries, from manufacturing to medical equipment testing. To perform it effectively, you need to find a gas that checks the following boxes:

• Safety during use
• Accurate results
• Cost-effectiveness for the given application

Helium: The Gold Standard

Helium is the industry standard for leak detection due to its unique properties. Its extremely small molecular size lets it penetrate through the tiniest of gaps, making it ideal for detecting even microscopic leaks.

The inert nature of helium also means it won’t react with other materials or create potentially dangerous situations. This makes it particularly valuable in sensitive environments like medical device manufacturing and semiconductor production.

Helium leak detectors can identify extraordinarily small leaks, with detection capabilities ranging from 10^-1 to 10^-12 mbar·l/s. This exceptional sensitivity makes it invaluable for applications that require outstanding precision.

Hydrogen: The Cost-Effective Alternative

Hydrogen is gaining popularity as a leak detection gas, especially in applications where cost is a significant factor. When used in a mixture of 95% nitrogen and 5% hydrogen, it provides an excellent balance of safety and effectiveness.

Hydrogen has a molecular size nearly as small as helium, so it’s also highly effective at penetrating through minute openings. Combined with its lower cost and greater availability, this property makes it an attractive option for many industrial applications.

Modern hydrogen leak detectors use sophisticated sensors based on thermal conductivity principles. These devices can detect extremely low concentrations of hydrogen, making them suitable for a wide range of testing scenarios.

Specialized Gases for Specific Applications

Besides helium or hydrogen, carbon dioxide is an effective tracer gas in certain applications where its larger molecular size is advantageous. Its widespread availability and relative low cost make it an attractive option for specific testing scenarios.

Sulfur hexafluoride (SF6) is also a popular option, especially for leak detection for electrical equipment. Its unique properties make it particularly suitable for testing high-voltage systems and specialized industrial applications.

Detection Methods and Equipment

The effectiveness of leak detection doesn’t only depend on the chosen gas – the employed detection method is also a key consideration. Generally speaking, you can choose between three options:

• The sniffer method: involves pressurizing the test piece with the tracer gas and using a specialized probe to detect any escaping gas.
• Vacuum chamber testing: provides the highest sensitivity for leak detection. This method involves placing the test piece in a sealed chamber and monitoring for the presence of tracer gas under vacuum conditions.
• Ultrasonic detection: offers a different approach useful for pressurized systems. This method can detect the high-frequency sounds produced by escaping gases, making it effective for large-scale industrial applications.

Selecting the Right Gas for Your Application

The choice of leak detection gas should consider several factors, most notably:

• The required sensitivity
• Testing environment
• Budget constraints

While helium offers the highest sensitivity, hydrogen might be more practical for regular testing needs.

Safety considerations are another crucial factor when selecting a tracer gas. The chosen gas should pose minimal risk to operators and equipment while providing reliable results.

It’s worth mentioning that cost-effectiveness extends beyond the price of the gas itself. Various factors contribute to the overall economic impact of the chosen method such as,

• Equipment requirements
• Testing time
• Operational efficiency

Through careful consideration of these factors, businesses can select the most appropriate leak detection gas for their specific needs. This ensures both effective testing and optimal resource utilization in their leak detection programs.