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 W 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 i 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
