In high-efficiency filtration systems, even a tiny defect can compromise performance.
That’s why the leak test (scan test) is one of the most critical procedures under standards like EN 1822 and ISO 29463.
This article explains how HEPA filter leak testing works, why it is essential, and what equipment is required.
1. What Is a HEPA Leak Test?
A HEPA leak test is used to detect local defects in a filter.
Unlike overall efficiency testing, it focuses on:
- Pinholes
- Media damage
- Frame sealing issues
- Manufacturing defects
👉 Even a high-efficiency filter can fail if local leakage exists
2. What Is the Scan Test?
The scan test is a method where the entire filter surface is scanned using a probe.
How it works:
- Generate aerosol upstream
- Measure baseline concentration
- Move scanning probe across filter surface
- Detect local penetration
👉 Any abnormal increase in downstream concentration indicates a leak
3. Why Scan Testing Is Critical
HEPA filters are used in environments where air cleanliness is essential:
- Cleanrooms
- Pharmaceutical production
- Semiconductor manufacturing
👉 In these environments:
One small leak = system failure
4. Key Parameters in Leak Testing
4.1 Aerosol Type
- PAO / DOP commonly used
- Stable particle generation required
4.2 Scanning Speed
- Too fast → leaks may be missed
- Too slow → inefficient testing
👉 Must follow standard requirements
4.3 Probe Position
- Distance from filter surface matters
- Affects detection sensitivity
4.4 Acceptance Criteria
Typical leak criteria:
- Local penetration ≤ 0.01% (H13/H14 reference)
👉 Depends on filter class
5. Common Challenges in Scan Testing
In real applications, several issues can affect results:
❌ Unstable aerosol concentration
❌ Inconsistent scanning speed
❌ Poor probe positioning
❌ Human error in manual scanning
👉 These lead to:
- False positives
- Missed leaks
- Inconsistent results
6. Manual vs Automatic Scan Testing
| Method | Advantages | Limitations |
|---|---|---|
| Manual | Flexible | High error risk |
| Automatic | Accurate, repeatable | Higher initial cost |
👉 Most modern labs prefer automated systems
7. Why Professional Equipment Is Necessary
Leak testing is not just “checking”—it requires:
- Precise motion control
- Stable aerosol generation
- High-sensitivity detection
- Data recording and analysis
👉 Without proper equipment, results are unreliable
8. Recommended Testing Solution
The SC-L8023 Scanning Filter Tester from SCPUR is designed for high-precision HEPA leak testing.
Key Features
- Automated scanning system
- High-sensitivity particle detection
- Stable aerosol generation
- Accurate positioning and speed control
👉 Ensures compliance with EN 1822 and ISO 29463
9. Typical Applications
Scan testing is used in:
- HEPA filter manufacturing
- Cleanroom validation
- Pharmaceutical facilities
- Semiconductor fabs
👉 Essential wherever high air cleanliness is required
10. Conclusion
HEPA filter leak testing is a critical step in ensuring filter performance and system safety.
The scan test provides:
✔ Detection of local defects
✔ Assurance of filter integrity
✔ Compliance with international standards
