Vacuum decay is more sensitive than pressure decay due to the volume and pressure that is being measured.
Why Leak Detection Matters
Ensuring the integrity of sealed packages, medical devices, and pharmaceutical containers is critical to product safety and regulatory compliance. Two widely adopted non-destructive test methods are Vacuum Decay and Pressure Decay.
Understanding the strengths and limitations of each helps you choose the right solution for your application.
Principles of Operation
🔹 Vacuum Decay
The test chamber is evacuated to a set vacuum.
The package is isolated.
Any gas ingress through leaks reduces the vacuum.
The rise in pressure indicates a leak.
🔹 Pressure Decay
The chamber or package is pressurized.
It is then isolated.
Any gas egress through leaks reduces the pressure.
The drop in pressure indicates a leak.
Pressure decay also introduces the possibility of forcing environmental contaminants through a defect into the samples, violating a non-destructive test
Key Differences
| Feature | Vacuum Decay | Pressure Decay |
|---|---|---|
| Sensitivity | Very high (ideal for micro-leaks) | Moderate |
| Direction | Detects ingress (gas enters) | Detects egress (gas exits) |
| Risk of Contamination | Low | Higher (may force contaminants inward) |
| Best Use | High-integrity, low-leak applications | Larger leaks, cost-driven testing |
Advantages
✅ Vacuum Decay
Detects the smallest leaks (sub-micron)
Non-destructive and contamination-free
Preferred for pharmaceuticals & medical devices
✅ Pressure Decay
Simple setup and lower equipment cost
Suitable for robust containers
Faster for larger leaks
