What is the EN 1822 Standard?
The EN 1822 standard is a European testing and classification standard used to verify the performance of high-efficiency air filters, including EPA, HEPA, and ULPA filters. Rather than relying on nominal claims, EN 1822 defines how filters must be tested, how efficiency is measured, and how results are classified under controlled laboratory conditions.
At its core, EN 1822 exists to answer a single critical question: Does this filter actually perform at the efficiency it claims, under worst-case particle conditions?
This distinction matters in air filtration systems used in regulated and high-risk environments, where performance assumptions can lead to compliance failures, contamination risk, or system inefficiency.
Who Develops and Governs EN 1822?
EN 1822 is developed under the European standardisation framework and is governed through recognised standards bodies responsible for harmonising technical requirements across Europe. It is designed to provide a consistent, repeatable, and verifiable method for testing filters efficient at capturing fine and ultrafine particles.
Importantly, EN 1822 aligns with international best practice and has partially transitioned into the EN ISO 29463 series, now recognised as an international standard for high-efficiency air filter testing.
This transition reflects the global need for:
- Comparable test results
- Unified testing procedures
- Consistent filter classification across markets
Declared Performance vs Independently Tested Performance
One of the most important contributions of the EN 1822 standard is its clear separation between claims and verification.
Many filters are described as:
- “HEPA-type”
- “Medical-grade”
- “High efficiency”
However, EN 1822 only recognises performance that has been measured through defined testing procedures, using calibrated equipment such as a particle counter, controlled test aerosol, and statistically valid particle counting methods.
In simple terms:
- Declared performance is what a manufacturer claims
- EN 1822 performance is what has been independently tested and classified
Evolution and Regulatory Context of the EN 1822 Standard
Why EN 1822 Was Created (1998)
The EN 1822 standard was first introduced in 1998 to address inconsistencies in how high-efficiency particulate air filters were being tested and described across Europe. Prior to this, HEPA filters were often rated using fixed particle sizes or outdated methodologies that did not reflect real-world worst-case behaviour.
The goal was to create a scientifically defensible method that would:
- Identify the weakest performance point of a filter
- Detect leakage that could bypass filter media
- Standardise filter classification across applications
Key Updates Leading to EN 1822:2019
Over time, improvements in particle measurement technology and a better understanding of aerosol physics led to updates of the standard. These revisions culminated in EN 1822:2019, which refined testing accuracy and aligned parts of the methodology with global practices.
This version remains the most relevant reference point when discussing EN 1822 compliance today.
Transition to EN ISO 29463: What Changed and Why It Matters
Testing procedures originally defined within EN 1822 Parts 2 to 5 were later transitioned into the EN ISO 29463 series. This shift was not merely administrative—it represented a move towards international harmonisation of HEPA and ULPA filter testing.
For decision-makers, this matters because:
- Specifications may reference both EN 1822 and ISO 29463
- Tenders often require clarity on which parts apply
- Auditors expect current, correctly referenced standards
Using outdated references can result in non-compliant specifications, even if the filter itself performs well.
Why Current Standards Matter in Specifications and Audits
In compliance-driven environments, referencing the correct version of a standard is as important as the filter itself. Auditors, quality teams, and regulatory bodies assess not only performance, but also documentation accuracy.
Failure to reference EN 1822:2019 or its ISO equivalents can:
- Delay approvals
- Trigger re-testing requirements
- Undermine procurement decisions
This is a common but avoidable issue in long-term air filtration projects.
Structure of the EN 1822 & ISO 29463 Standards
Understanding the structure of the standard helps clarify where failures are most likely to occur and why multiple test stages are required.
EN 1822-1: Classification, Performance Testing, and Marking
This part defines:
- Filter class (EPA, HEPA, ULPA)
- Minimum efficiency thresholds
- Labelling and identification requirements
It ensures filters can be correctly identified, traced, and installed, reducing the risk of specification or installation errors.
EN ISO 29463-2: Aerosol Generation and Measurement
This section governs how the test aerosol is produced and measured. Controlled aerosol generation is essential because inconsistent particle size distributions can distort efficiency results.
Accurate particle counting ensures results are repeatable, comparable, and statistically valid.
EN ISO 29463-3: Flat Sheet Filter Media Testing
Here, the raw filter media is tested before it is assembled into a finished filter. While important, this step alone is not sufficient, as excellent media performance does not guarantee a leak-free final filter.
This distinction is often misunderstood outside professional circles.
EN ISO 29463-4: Leakage Testing (Scan Test)
The scan test is one of the most critical elements of the EN 1822 framework. It identifies localised leaks caused by:
- Media defects
- Seal failures
- Frame integrity issues
In real systems, leakage, not media failure, is the most common cause of underperformance.
EN ISO 29463-5: Filter Element Efficiency Testing
This final step validates the overall performance of the assembled filter. It confirms that the complete unit meets its filter class efficiency under MPPS conditions.
Crucially, EN 1822 requires individual filter testing, not just batch testing.
How EN 1822 Defines Filter Efficiency?
MPPS (Most Penetrating Particle Size)
Unlike older standards that test at a fixed particle size, EN 1822 evaluates filters at their most penetrating particle size (MPPS), the size range where a filter is least efficient.
Typically, MPPS falls between 0.1 and 0.3 microns, depending on media structure and airflow conditions. Testing at MPPS ensures:
- Worst-case performance is measured
- Efficiency claims are conservative
- Overstated marketing claims are avoided
From a commercial perspective, MPPS testing protects buyers by ensuring the filter performs under the most demanding conditions, not just ideal ones.
EN 1822 Filter Classifications Explained
Under EN 1822, filters are classified based on their measured efficiency at the MPPS (most penetrating particle size), not on nominal or marketing claims. This classification framework applies to EPA, HEPA, and ULPA filters, ensuring consistency across a wide range of air filtration applications.
1. Group E – EPA Filters (Efficient Particulate Air Filter)
Group E (EPA) filters include E10, E11, and E12 classes. These filters are designed to provide high levels of particulate removal but do not meet HEPA-level performance under EN 1822.
Typical characteristics of Group E filters include:
- Use in pre-filtration or intermediate filtration stages
- Application in HVAC systems where ultra-high efficiency is not required
- Lower pressure drop compared to HEPA and ULPA filters
Efficiency ranges at MPPS:
- E10: ≥ 85%
- E11: ≥ 95%
- E12: ≥ 99.5%
2. Group H – HEPA Filters (High Efficiency Particulate Air)
Group H represents what most professionals refer to as true HEPA filters under the EN 1822 standard. This group includes H13 and H14, both widely used in healthcare and pharmaceutical industry environments and cleanrooms.
Key characteristics of Group H filters:
- Tested at MPPS using controlled test aerosol
- Subject to scan test and leak test requirements
- Individually tested, not batch-certified
Efficiency at MPPS:
- H13: ≥ 99.95%
- H14: ≥ 99.995%
3. Group U – ULPA Filters (Ultra Low Penetration Air)
ULPA filters (U15, U16, U17) represent the highest efficiency classes under EN 1822 and ISO 29463. These filters are used in ultra-critical applications, particularly in advanced electronics, semiconductor fabrication, and specialised research environments.
Typical features of ULPA filters include:
- Extremely high efficiency against ultrafine particles
- Significantly higher resistance to airflow
- Increased cost and energy impact
While ULPA filters deliver exceptional performance, they are not universally appropriate. Over-specification can lead to unnecessary operational cost, reduced airflow, and system inefficiencies without delivering additional practical benefit.
EN 1822 Classification Table (With Practical Interpretation)
| Filter Class (EN 1822) | Filter Group | Filter Class (ISO 29463) | Overall Efficiency (%) |
| E10 | Group E – EPA | Not covered | ≥ 85% |
| E11 | Group E – EPA | ISO 15 E | ≥ 95% |
| E12 | Group E – EPA | ISO 25 E | ≥ 99.5% |
| H13 | Group H – HEPA | ISO 35 H | ≥ 99.95% |
| H14 | Group H – HEPA | ISO 45 H | ≥ 99.995% |
| U15 | Group U – ULPA | ISO 55 U | ≥ 99.9995% |
| U16 | Group U – ULPA | ISO 65 U | ≥ 99.99995% |
| U17 | Group U – ULPA | ISO 75 U | ≥ 99.999995% |
How HEPA Filters Are Tested Under EN 1822?
The EN 1822 testing procedure is designed to identify both media efficiency limitations and assembly-related failures. This multi-step approach reflects real-world risks in high-efficiency air filtration.
Step 1 – Flat Sheet Filter Media Testing
In this stage, the raw filter media is tested using a controlled test aerosol and a calibrated particle counter. The goal is to determine the intrinsic filtration capability of the media itself.
While necessary, this step has limitations:
- It does not account for manufacturing defects
- It does not detect leakage around seals or frames
This is why EN 1822 does not rely on media testing alone.
Step 2 – Leakage Testing (Scan Test)
The scan test is one of the most critical elements of EN 1822. Using a scanning probe and particle counting equipment, the entire filter face and seal area are examined for localised penetration.
This step detects:
- Pinholes in the media
- Seal failures
- Frame integrity issues
In practice, most HEPA filter failures occur due to leakage rather than poor media efficiency, making this step essential for meaningful classification.
Step 3 – Overall Filter Efficiency Testing
The final step measures the overall efficiency of the assembled filter at MPPS. This confirms that the complete filter element meets the required filter class under EN 1822.
Key principles at this stage include:
- Individual filter testing, not batch averages
- Verification under worst-case particle size conditions
- Generation of documented test results for traceability
Typical documentation includes efficiency reports, leakage maps, and classification confirmation, materials often required during audits or quality reviews.
Appropriate Applications for EN 1822
EN 1822 is most relevant where verified high-efficiency air filtration is essential, including:
- Hospitals and healthcare facilities
- Pharmaceutical and life-science manufacturing
- Cleanrooms and controlled environments
- Electronics and semiconductor industries
In these sectors, EN 1822 supports risk management, regulatory compliance, and operational reliability.
Common Mistakes Buyers Make When Choosing EN 1822 HEPA Filters
1. Assuming “HEPA” automatically means EN 1822 compliant
Many products are labelled as a high-efficiency particulate air solution without having undergone the required EN 1822 testing procedure, including scan test and leak test verification.
2. Focusing only on overall efficiency figures
Buyers often overlook local efficiency, which EN 1822 treats as equally critical. Even a small local leak can compromise air filtration performance in sensitive environments.
3. Over-specifying filter class without system consideration
Choosing H14 or ULPA filters where H13 would be sufficient can increase pressure drop, energy consumption, and operational cost without improving real-world outcomes.
4. Ignoring documentation and traceability
EN 1822 compliance is not just about performance; it is about evidence, including particle counting results, individual filter reports, and clear marking.
5. Using outdated standard references
Specifications that reference older versions of EN 1822 without recognising ISO 29463 updates can lead to audit complications or tender challenges.
Best EN 1822 Certified HEPA Air Purification Solutions in Ireland
For organisations and individuals seeking air purification systems that align with the principles of EN 1822 testing, IQAir’s product ranges are designed with these standards in mind.
- IQAir HealthPro Series – Designed around high-efficiency particulate air filtration principles, with a strong focus on filter integrity and performance consistency.
- IQAir Cleanroom Series – Developed for controlled environments where HEPA and ULPA filters are used in line with rigorous testing and verification expectations.
Clean Air Technology Ltd is the official distributor of IQAir premier quality air purifiers in Ireland. Get in touch with us today.
Key Takeaways
- EN 1822 is a testing and classification standard, not a marketing label
- MPPS (most penetrating particle size) is central to understanding real HEPA performance
- Local leakage detection is as important as overall efficiency
- Filter class selection must be risk- and application-driven
- Proper documentation and traceability are essential for compliance
- Higher efficiency does not automatically mean better system performance