What Methods of Leak Detection and Seal Integrity Testing Are Available?

Several seal integrity and package leak detection methods exist, but which is appropriate for your industry and application?

Below are nine methods — separated into four groups — with an overview of what each testing method is and how it works.  For more details about the packaging suitability, advantages, disadvantages and corresponding industry-recognised American Society for Testing and Materials (ASTM) standard of a specific method, click on the ‘read more’ link to go to its dedicated page.

Burst Testing, Bubble Emission and Altitude Testing Methods

Burst Testing Seal Integrity Method

Burst testing is a leak detection and seal integrity testing method to determine the level of pressure packaging can withstand. It involves inserting a needle probe through a self-sealed, adhesive-backed septum and inflating the pack with gas until it bursts. The operator records the highest pressure reached before the pack bursts, providing critical information on its seal integrity.

Bubble Emission Package Leak Detection Method

Bubble emission testing determines the internal pressure a flexible packaging seal can withstand. Often used to identify leaks in Modified Atmosphere Packaging (MAP) environments, this method works on the pressure differential principle.

The packaging sits in a clear acrylic test chamber filled with water. The headspace is placed under a predetermined vacuum level, creating a pressure differential that causes the packaging to expand.

A stream of bubbles emitting from the packaging indicates the presence of a leak and allows the operator to pinpoint its location.

Altitude Simulation Package Seal Integrity Test

An altitude simulation is a method of checking the package seal integrity of products intended for shipping via air freight or ground freight across mountainous regions where altitude changes will cause extreme changes in pressure.

During the test, the operator places a sealed package in a chamber that can simulate altitude changes and ascent and descent rates to mimic the conditions experienced during transportation.

Force Decay (Reactive Force Leak Detection), Seal Strength and Vacuum Decay

Force Decay Leak Detection Method

Force decay — also called reactive force — is a leak detection and seal integrity method appropriate for testing flexible packaging such as sachets, pouches and pods, and solid products with flexible seals. It operates on the established principle of measuring the reactive force generated by a pack when subjected to a vacuum.

The test sample sits in a vacuum chamber connected to a force sensor. Evacuating the chamber causes the package to expand and exert pressure on the sensor. This pressure — or the reactive force — is used to determine leaks in the packaging.

Seal Strength Integrity Test

The seal strength test measures the integrity of seals in packages and flexible materials to ensure the contents within are secure.

This test is commonly used in the pharmaceutical, manufacturing and food industries to identify potential weaknesses in packaging and measure the strength of seals between rigid and flexible materials, such as a yoghurt pot and its lid.

Vacuum Decay Seal Integrity Method

The vacuum decay test involves placing packaging in a tightly fitted chamber or collapsible bag. A pump removes air to a predetermined level, creating a vacuum, while a sensor continuously measures the pressure inside the environment.

Dye Penetration Testing

Destructive Methylene Blue Dye Penetration Test (Vacuum Desiccator)

Methylene blue dye penetration — or a vacuum desiccator test — is an industry-standard leak detection and seal integrity testing method. Packaging is submerged into a blue dye solution and placed in a vacuum chamber (or desiccator). The chamber forces air from any opening within the pack and draws in the blue dye solution. If there are no leaks, the dye will not penetrate the package but remain on the outside.

Dye Penetration Seal Integrity Method

Dye penetration involves applying dye on one side of a section of a seal and — after a predetermined length of time — checking the opposite side of the seal to see whether the dye has penetrated it.

Flow Rate Seal Integrity Method

Flow rate testing is similar to burst testing in that it involves inserting a needle probe through an adhesive-backed septum and gently inflating the packaging with gas. However, while burst testing measures the pressure level the packaging can withstand before tearing, a flow rate test measures the flow required to maintain the pressure administered.

Learn More about Leak Detection and Seal Integrity

Seal integrity testing is pivotal in protecting against leaks or defects and ensuring packaging is safe and effective across multiple use cases and industries. Learn more about leak detection methods and applications by using the links below:

• Learn more about leak detection and seal integrity testing and why it is important
• Learn more about burst, bubble emission and altitude simulation package seal integrity testing
• Learn more about force decay, seal strength and vacuum decay testing
• Learn more about dye penetration seal integrity testing
• Learn more about flow rate seal integrity testing
• Learn more about how to select the right leak detection and seal integrity method for your business
• Learn more about how frequently seal integrity testing should be carried out
• Learn more about how documents and records of seal integrity testing can be stored

Explore Our Range of Leak Detection and Seal Integrity Testing Equipment at LIMAB UK

Our team of product specialists at LIMAB UK get to know the unique needs of your business and provide one-to-one support to find the best package leak detection and seal integrity testing method for you. Request a consultation today by calling +44 (0)1823 668633, emailing hello@limab.co.uk or submitting a contact form.