ASTM D4991 Leak Testing

ASTM D4991 Package Leak Testing of Containers by Vacuum Method

ASTM D4991 covers the testing of empty containers for resistance under differential pressure conditions. As an ISTA and ISO 17025 certified lab, we realize the importance of leakage testing of empty rigid containers. Meeting the ASTM D4991 requirements can be difficult. We understand the challenges and guide companies through the process.

Keystone administers accurate test reports that are delivered quickly. Our pricing is competitive and we offer volume discounts. We also provide the peace of mind that all of your needs will be met. Therefore, our proven process helps avoid product launch delays. 

Request a quote to learn why we are one of the fastest-growing package test labs in the country. Have a question about ASTM D4991 leakage testing? Contact us and we will determine the best course of action.

Summary of ASTM D4991 Leak Testing Information

As mentioned above, the ASTM D4991 test method covers the testing of empty containers under differential pressure conditions. Examples include those which can occur during air transport. The ASTM vacuum method is suitable for testing rigid containers intended for the transportation of hazardous liquids.

This standard does not purport to address all of the safety concerns associated with its use. It is required to have suitable means to hold the test specimen with a closure not more than 25mm under the surface of the test fluid.

Scope of the ASTM D4991 Vacuum Integrity Testing

An empty rigid container is pressurized by immersion in an ethylene glycol-water solution and a transparent test chamber. The container is then subjected to a gradually increasing partial vacuum. Lastly, the container is observed for signs of leakage. Evidence is present when air bubbles during de-pressurization or fluid in the container after re-pressurization is found.

Prior to testing, a vacuum is drawn to at least a 95 kPA differential and maintained for 10 minutes in order to remove air dissolved in the fluid. More than one specimen can be tested at one time provided that there is sufficient space in the testing chamber. This allows clear observation of each specimen.

Significance of Rigid Packaging and Leak Testing

Containers may be pressurized in accordance with this test method without modification to the closure or the body of the container. This test procedure established the point at which leakage starts, with a limit of 95-kPa differential. See test method D3078 for flexible packages.

ASTM D4991 is not suitable for some packages. This includes packages with paper cap seals. Leakage testing is not fitting for packages where the test fluid may rapidly deteriorate the packaging.

Test specimens consist of containers including their closures. The containers are emptied and cleaned prior to the testing. Lastly, each container is closed for testing in the same manner as it would be closed for actual shipment. Unless otherwise specified, use at least three test specimens.

After testing, a report is created and includes the following information:

  • Total number of specimens tested
  • Number of specimens tested at one time
  • Test pressure requirement
  • Whether each test specimen leaked and at what pressure differential
  • Whether the test was performed at ambient temperature
  • Whether the test fluid was apparent in each test specimen after testing

Why is ASTM D4991 Leak Testing Important?

ASTM D4991 package integrity testing is essential to ensure product safety, quality, regulatory compliance, and customer satisfaction. It helps prevent potential hazards, extends product shelf life, and safeguards a brand’s reputation in the market.

Regulatory Compliance

For certain industries, especially pharmaceuticals and food, package integrity testing is often mandated by regulatory agencies. Compliance with such standards is necessary to ensure that the packaged products meet safety and quality requirements.

Shelf Life and Freshness

A secure package seal helps maintain the product’s freshness and extends its shelf life. If the package seal is compromised, the product’s quality may deteriorate more quickly, leading to potential customer dissatisfaction or even health risks.

Consumer Safety

In industries like pharmaceuticals and medical devices, a compromised package seal could lead to potential health risks for consumers. Proper integrity testing helps identify weak seals or faulty packaging that could result in leakage or contamination.

Cost Savings

Detecting seal failures early in the production process can help reduce waste and save costs associated with product loss or rework.

Expert ASTM D4991 Rigid Container Leak Testing

Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. In addition to ASTM D4991 performance testing, Keystone has a full scope of expertise including cold chain, leak penetration, and vibration. We can accommodate flexible and rigid packages of all sizes, including large pallets. 

Request a quote to learn firsthand why so many companies partner with Keystone to achieve their packaged product certification needs.


For more referenced ASTM standards and similar testing, please follow the links below:


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