What Is ASTM D4991?
ASTM D4991 is a standard test method used to evaluate empty rigid containers for resistance to leakage under differential pressure conditions, such as those that may occur during air transportation.
The container is immersed in an ethylene glycol-water solution inside a transparent chamber and exposed to a gradually increasing partial vacuum. Leakage is detected through escaping air bubbles or fluid entering the container after re-pressurization.
The method provides a differential pressure limit of approximately 95 kPa (13.8 psi) and applies to rigid containers intended for transporting hazardous liquids under UN TDG and ICAO requirements.
Why Use ASTM D4991?
ASTM D4991 helps verify that rigid containers can withstand pressure changes during air transportation without leaking. This reduces the risk of product loss, environmental exposure and safety incidents when transporting hazardous liquids.
What Should the Test Report Include?
- Identification of the containers and closures tested.
- Total number of specimens and number tested at one time.
- Required test pressure.
- Test temperature conditions.
- Pass or fail results for each specimen.
- Pressure differential at which leakage occurred.
- Presence of test fluid inside the specimen after testing.
- Any deviations from the ASTM D4991 procedure.
- Testing agency, date and responsible representative.