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Helium leak detection technology is used to identify tiny leaks in a contained system. Other detection techniques may not be applicable due to operating limitations or if the leaks are so small that other techniques cannot find them. Due to its tiny size and inert nature, helium is an excellent choice for testing purposes. It has no effect on the materials in the item to be tested. Because of a variety of factors, helium is a preferable option as a tracer gas.

• Non-toxic, inert, and non-flammable
• The tiny atomic size makes it easy to pass through leaks

Helium is detected with a mass spectrometer or helium sniffer, however, it is also possible to utilize a residual gas analyzer. In comparison to other methods of finding leaks, helium testing is a thousand times more sensitive.

Various technologies

• SIMS 1915+

SIMS 1915+ is the ideal option for helium leak detection in pharmaceutical and medical device packaging systems. Vials, syringes, cartridges, and blister cards are some of the most common applications. Helium is commonly used to test the rubber stopper on a vial or the plunger on a syringe or cartridge assembly for leaks in parenteral goods. Sensitivity level as low as 1 x 10-10 mbar/L/sec may be measured with SIMS 1915+, which offers useful data sets instead of a basic pass/fail condition while allowing testing to be done at ambient temperature. It is important to note that each SIMS 1915+ Helium Leak Testing device is custom-built to meet client-specific requirements and package specifications.

• Cold storage package test systems

In an effort to retain product quality features, pharmaceutical and biologic firms continue to push for extended cold storage. In addition to requiring storage at temperatures below -20°C, many of these goods also require dry ice (-78.5°C) or liquid nitrogen (-200°C) for storage and delivery. However, many of the materials utilized in these package systems and responsible for preserving package integrity are not routinely evaluated at these temperatures. The glass transition state of elastomeric materials can be reached or exceeded at deep-cold or ultra-cold temperatures, causing leaks at low temperatures that would not otherwise be detected at room temperature.

• HSAM and Vial Filler

When it comes to helium-based leak testing systems, the Head Space Analyzer Module (HSAM) with vial filling assemble is a key component. As part of the HSAM, a probe measures the helium content in the headspace of a container system. With the optional vial filling assembly, previously sealed vials may be prepared for testing by replacing the headspace gas with 100 percent helium before the test is performed. After capping, this module can be used to prepare samples for testing or to prepare samples that have been kept for some time before testing. They may be used in conjunction with the VM-2 to get precise readings that can be included in flexible research designs.

• Sniffer Probe

This simple technique of tracer gas leak detection employs a sniffer probe to detect the gas's presence and locate the location of the leak. The tracer gas is initially applied to the part or system. With the sniffer probe, the operator then conducts a systematic search for probable leak spots. When it comes to finding micro leaks, sniff leak locating is quite successful. It is best used for examining smaller quantities of items. While the cost of sniffer testing depends on the kind of tracer gas utilized, it is a proven option for leak detection and localization.

• Package Test Fixtures

Outside the box, no leak testing is possible using a Helium Leak Detector. An HLD is only one component of a matrix that makes a useable system, just like a display is part of a computer system. Checking for quality packing material and sealing is a part of testing a package. By squeezing and holding it underwater, an operator checks for bubbles in a package using the manual leak testing method. The package retains atmospheric pressure when there are leaks.

• Calibrated Leak Standards

To support everyday usage, daily performance verification or system suitability tests, as well as planned certifications, LDA supplies full sets of calibrated helium leak standards. Each SIMS 1915+ has an inbuilt helium leak standard. Using a given leak rate, this technique releases a certain concentration of Helium. On each day of usage, it is utilized automatically by the instrument, or on-demand for autocalibration prior to analysis. Each external helium leak standard by LDA releases helium at a defined leak rate, similar to the internal leak standards. But instead of living inside the instrument, they attach to the test port in the same manner that a sample fixture would be installed in the system.

Some basic applications

• Glass Vials
• Pre-filled Syringes
• Bottles
• Blister Packs
• Foil Pouches
• Combination Products

Helium leak detection technology is a highly sensitive method used for detecting leaks in an enclosed system. Helium is used as a tracer gas as it is inert, non-condensable, non-flammable, and harmless. Because of its small atomic size, helium passes easily through the leaks. Thus, the change in its concentration is measured and indicated as a leakage rate. Helium is lighter than the next inert gas neon. It is also very cost-effective and can be easily delivered in various cylinders and in pure form. Hydrogen that is not inert is the only molecule smaller than helium.

Helium leak detector works on the principle of field mass spectrometer. The electric beam in the filament of the analysis tube ionizes the leaking helium gas. The ions are accelerated by increased voltage, escape through the split and later pass through the analyzer's magnetic field. The collector can only catch the helium ions and detect helium, as the circular paths of the ions rely on their mass. The ion current is transformed into an electric current using a specific detector. The current is accelerated by utilizing leak detector devices and displayed on the screen. The measured current is equivalent to the concentration of helium and hence equal to the leak.

What makes helium gas ideal for package leak testing?

• Non-toxic, inert, non-condensable, present in the atmosphere in trace amounts
• Helium gas is one of the smallest molecules to consistently and rapidly break the pathway
• Helium is non-flammable, widely available, and inexpensive
• Since it is an inert gas and does not interact with the testing component, it is, therefore, safe to use
• The noise of the instruments caused by the environmental helium is naturally minimal due to its low atmospheric level of less than 5 ppm and thus gives accurate reports

Key benefits of helium-based testing

• Helium leak detection is a highly sensitive detection technique, particularly developed to identify extremely small leaks which cannot be detected with standard leak test methods
• The leak test limit may be set at a level of 1 x 10-10 mbar L/sec, which enables unique comparisons across components, materials, formats, and manufacturing characteristics using a high-speed vacuum approach

Applications of Helium leak detection

Following are some of the common applications of helium leak detection technology:

• Glass Vials

One of the most common package systems for biotechnological and pharmaceutical products. Helium is the most appropriate and sensitive way for qualifying components for empty components and for product-filled vials.

• Pre-filled Syringes

Pre-filled syringes represent the biggest growth area of parenteral packages with the development of more sophisticated drugs for a wide range of injectable substances and increased demand for self-administration. Helium testing techniques can be developed such that these unique package systems have extremely effective test programs.

• Bottles

Bottles are one of the most used packaging methods and helium still remains the standard for quality testing purposes.

• Blister Packs

Helium is still the optimum test technique for qualifying the CFF blister cards' material components. The test procedure is based upon the detection of helium encapsulated in the packaging system as it escapes from the package via micro-channels.

• Foil Pouches

The sensitivity of the helium leak testing method provides an excellent platform to test quality control systems based on foil. This technique normalizes the helium leak rate to 100% so that all test specimens throughout the manufacturing line setup may be directly compared.

• Combination Products

Multi-chamber systems with specific needs for tests are perfectly suited for using helium leak test to guarantee that all components satisfy the rigorous leakage standards.