ASTM D4991

Standard Test Method for Leakage Testing of Empty Rigid Containers by Vacuum Method

Standard Summary

ASTM D4991 outlines a standardized approach for assessing the integrity of empty rigid containers under differential pressure conditions such as those which can occur during air transport. It is suitable for testing rigid containers intended for the transportation of some hazardous liquids in accordance with the United Nations

Recommendations On The Transport Of Dangerous Goods (UN TDG) and the International Civil Aviation Organization Technical Instructions For The Safe Transport Of Dangerous Goods By Air (ICAO TIs)

This method is critical for manufacturers looking to ensure that their packaging meets quality and safety standards. By utilizing vacuum pressure to -95KPa, this standard evaluates a container’s resistance to leaks, helping to guarantee that products remain uncontaminated and secure during storage and transport.

ASTM D4991 Summary

An empty rigid container to be tested is pressurized by immersion in an ethylene glycol-water solution in a transparent test chamber and subjected to a gradually increasing partial vacuum. The container is observed for signs of leakage, as evidenced by escaping air bubbles during depressurization or fluid in the container after re-pressurization.

Test Theory

The ASTM D4991 test method establishes the point at which leakage commences, with a limit of approximately 95-kPa (13.8-psi) differential.

However, ASTM D4991 may not be suitable for some packages, such as packages with paper cap seals, where the test fluid may rapidly deteriorate the packaging.

ASTM D4991 Test System

ASTM D4991 consists of below parts

Vacuum Chamber: A sealed transparent vessel that allows for the creation of a controlled vacuum environment around the container being tested, which is large enough to permit the test specimen(s) to be immersed in the test fluid with a minimum headspace of 20 %, capable of withstanding at least -1.5 atm pressure differential.
A vacuum setting and displaying control unit, such as Cell Instruments LT-02 and LT-03 Leak Tester.
The chamber is filled with a Solution of Ethylene Glycol in Water, 50 % by Volume for use as a test fluid.

Detailed Description of the Test Process

The testing process for ASTM D4991 can be broken down into several key steps

1. Preparation: Immerse one or more test specimens in the ethylene glycol-water solution inside the transparent test chamber.
2. Vacuumize the Chamber: Seal the lid, set the test time on LT-02 or LT-03 Leak Tester for 10 minutes and target vacuum to -95K(13.8 psi). Start the test so the vacuum inside chamber rises slowly to a pressure differential of 95 kPa (13.8 psi), or other specified pressure differential.
3. Vacuum Holding: Tester will maintain the vacuum for a minimum of 10 min. For test specimens which are single packagings or combination packagings in whole or part of plastic material, maintain the vacuum for 30 min. Then tester will release the vacuum slowly.
4. Analysis: Keep the test specimen(s) immersed for at least 30s at ambient pressure. Remove the test specimen(s) and examine the inside for fluid. Leakage is indicated by a continuous stream or recurring succession of bubbles. Fluid within the test specimen is also evidence of leakage.

Using Cell Instruments LT-02 Leak Tester and LT-03 Leak Tester for ASTM D4991 Method

The Cell Instruments LT-02 or LT-03 Leak Tester is an advanced testing solution specifically designed for vacuum leak testing of empty rigid containers. Its features make it particularly suitable for ASTM D4991 compliance.

Why LT-02 and LT-03?

Automatic Test Process

The user just needs to set the target vacuum and maintain time. Press Start and after vacuum duration, it releases pressure automatically.

Stablized Vacuum

A drop in vacuum will be compensated by the system directly if there is a minor leak and deformation of the sample.

Test Parameter Saving

For users who have different test conditions in test time and vacuum level, LT-03 Leak Tester provides a parameter-saving function to save operation time.

Significance of ASTM D4991 Standard

The significance of ASTM D4991 extends across various industries for several critical reasons:

Quality Assurance

Ensures that empty containers are capable of maintaining their integrity, preventing contamination or product loss.

Regulatory Compliance

Many industries are required to comply with stringent packaging regulations. ASTM D4991 helps manufacturers demonstrate adherence to these standards.

Cost Savings

Identifying potential leaks during the production phase can save significant costs related to product recalls, returns, and customer dissatisfaction.

Enhanced Product Reliability

Regular testing using ASTM D4991 enhances the overall reliability of packaging, leading to increased consumer trust in the products.

FAQ about ASTM D4991

What is ASTM D4991, and why is it important for empty rigid containers?

ASTM D4991 is a standardized method for testing the leakage of empty rigid containers under vacuum. It is essential for ensuring that containers can maintain their integrity and protect contents from contamination during storage and transport.

How is the vacuum leak test conducted according to ASTM D4991?

The test involves placing an empty rigid container in a vacuum chamber, applying a vacuum, and monitoring for any signs of leaks or structural failure.

What types of containers can be tested under ASTM D4991?

The standard applies to various empty rigid containers, but it is not suitable for some packages, such as packages with paper cap seals, where the test fluid may rapidly deteriorate the packaging.

What should I consider when preparing for an ASTM D4991 test?

Ensure the container is clean and properly sealed, the testing environment is controlled, and all equipment is calibrated to ensure accurate results.

How can I ensure compliance with ASTM D4991 in my packaging design?

Implement regular testing during the design and production phases, use high-quality materials, and work with packaging engineers experienced in ASTM standards.

What are common issues encountered during ASTM D4991 testing?

Common issues include improper sealing of containers, equipment malfunction, or external factors affecting vacuum pressure, unstable vacuum, which can lead to inaccurate test results.

Looking for reliable ASTM D4991 leak detection equipment?

Don’t miss out on the chance to optimize your quality control processes with state-of-the-art equipment.

Related Information

ASTM D3078

ASTM D3078 Comprehensive Overview of – The Most Used Package Leak Testing Method Request a Quote Standard Summary ASTM D3078,

LT-03 Leak Tester

The LT-03 Leak Tester is a state-of-the-art device engineered for rigorous assessment of package seal integrity across various industries. This equipment is crucial for verifying that packaging maintains its protective capabilities, thereby safeguarding product quality and safety. The LT-03 is particularly suited for applications involving flexible packaging but is also adaptable to test non-flexible and rigid materials through its customizable design.