Methylene Blue Dye Penetration Test
What Is the Destructive Methylene Blue Dye Penetration Test (Vacuum Desiccator)?
Methylene blue dye penetration, also known as the vacuum desiccator test, works by coating packaging in a blue dye and placing it in a vacuum chamber. Evacuating the chamber will force the air to escape through any leaks or openings and draw in the blue dye solution. If there are no leaks, the dye will not penetrate the package interior.
Equipment like the Dynascan MediBLUE automates this method, making the package leak detection process quicker, simpler and more reliable.
Packaging Suitability
- Nonporous flexible food and pharmaceutical packaging with limited to ample headspace
- Rigid containers with flexible and non-flexible lid seals
- Pharmaceutical and medical device blister packaging
- Pharmaceutical vials with flexible and non-flexible lid seals
- Filled and sealed pouches, cups, trays
- Sealed empty trays
- Tyvek® lidded blisters
- Pouches
Advantages of Blue Dye Penetration Package Leak Testing
The blue dye penetrates any leaks in the packaging once the vacuum chamber returns to ambient pressure, providing rapid detection. The process is also simple and requires minimal training — operators apply the dye solution, place the sample in the vacuum chamber and visually inspect the results.
This package leak testing method can also detect gross and micron leaks, indicated by the intensity of the dye.
Disadvantages of Blue Dye Penetration Package Leak Testing
A disadvantage of the blue dye penetration testing method is that it cannot detect holes smaller than 20 µm, meaning tiny leaks may go undetected.
Operator error is also a risk. Inconsistently applying the dye solution, misinterpreting the level of coverage or not correctly sealing the vacuum chamber can cause unreliable and inaccurate results.
Perhaps the biggest drawback of this package leak detection method is that it is destructive. The dye will render the sample unusable, so manufacturers cannot apply this test to an entire production run without incurring significant costs. It’s also messy, as the coloured dye can spill and stain surfaces.
Dye Penetration Seal Integrity Testing
What Is Dye Penetration Seal Integrity Testing?
Dye penetration is a leak detection method designed to test the integrity of a specific section of a seal. It involves applying a coloured dye on one side of a seal section and visually examining the opposite side to determine if the dye has breached the seal, indicating a leak or weakness.
Relevant Standards and Packaging Suitability
- Standard Test Method for Detecting Seal Leaks in Porous Medical Packaging by Dye Penetration — F1929-15
- Standard Test Method for Detecting Leaks in Nonporous Packaging or Flexible Barrier Materials by Dye Penetration — F3039-15
- Porous and nonporous flexible food, pharmaceutical and medical device packaging
- Rigid containers with flexible lid seals
- Pharmaceutical and medical device blister packaging
- Sealed pouches, cups, trays
- Tyvek® lidded blisters and packages
Advantages of the Dye Penetration Testing Method
This seal integrity testing method enables rapid detection of surface defects. It is cost-effective, easy to perform and requires only basic instruction in the technique to ensure operators apply an even, consistent coat to reduce the risk of missing a defect.
The visual feedback provided by dye penetration also enables operators to determine the exact location of a leak.
Disadvantages of the Dye Penetration Testing Method
Although able to locate the area of a leak, dye penetration can only detect leaks on the order of 50.8 µm — six orders of magnitude larger than most permeants. It does not reliably detect small leaks in modified atmosphere, gas-flushed or hermetically sealed packaging.
As with the vacuum desiccator test, which also uses a dye solution, dye penetration will permanently mark the package sample, which may make it unsuitable for use or sale. It can also be messy, potentially staining surrounding surfaces and areas.
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 the methods of leak detection and seal integrity testing available
- 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 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.
