Preface: Leak testing of pharmaceutical packaging such as blister packs, bio process containers for serum and other biologicals, liquid-filled syringes and liquid filled & lyophilized vials ensures protection from moisture, air and bacteria. Medical products and components often require high sensitivity leak testing specifications as well. Both air and tracer gas test methods are often used to leak test these types of packages and products.
Leak Test Methods:
Air Leak Testing: A variety of automated test methods using air as the test media for detecting leaks by pressure decay or mass flow. Air leak testing involves a family of several test methods including pressure decay and mass flow using air as the test gas. These techniques are capable of measuring leakage outside-in or inside-out under vacuum or pressure conditions. Leakage is measured by creating a pressure differential across the test part and measuring the pressure rise or drop using a pressure transducer or the actual flow using a mass flow meter. This method is capable of detecting leaks down to 0.01 atmcc/sec depending on part size, part construction, and cycle time.
Helium Hard Vacuum Leak Testing: An automated method where the test part or test fixture is evacuated to full vacuum while helium is introduced to the opposite barrier of the part. This method allows for leak detection down to 1 x 10-9 atmcc/sec. Leaks in the test part can be measured inside-out or outside-in.
- For inside-out leak detection, the test part is either filled and sealed with helium inside, bombed with helium after it is sealed, or temporarily pressurized with helium during the test. The part is placed in a vacuum chamber and the chamber is evacuated.
- For outside-in leak detection, the test part is evacuated and helium is sprayed on the outside of the part. The helium leaking from the part is sampled through the vacuum line by the helium mass spectrometer leak detector.
Disposable Medical Devices
Final assembly testing is an integral part of the manufacturing process of disposable medical devices. Leak testing insures fluids will not leak outside the device, nor crosstalk between different elements of the device (as is the case with catheters). Air testing methods are commonly used, including non-destructive leak, blockage and functionality tests.
Medical Implants (High Sensitivity)
Medical implants such as pacemakers, artificial hearts, and other devices are critical to promote human health and longevity. These critical devices contain delicate and sensitive components that must be hermetically sealed to increase the product life and to protect the life of the medical implant user. The helium vacuum method is preferred due to it’s high sensitivity.