EN1822 Standard – High Efficiency air filters (HEPA and ULPA)

EN 1822 classifies EPA, HEPA and ULPA filters by their efficiency at the most penetrating particle size (MPPS). Part 1 of the standard, EN 1822-1:2019, carries the classification table: eight classes from E10 to U17. An H13 filter has to reach 99.95% integral efficiency at MPPS, an H14 filter 99.995%. Below is the full table, what the integral and local values actually mean, and the two places engineers most often misread the standard.

Importance of EN1822

The EN1822 standard was developed by the European Committee for Standardization (CEN) to establish uniform criteria for the testing, classification, and quality control of HEPA and ULPA filters. By creating a unified set of guidelines, the standard ensures that these filters meet the specific performance requirements necessary to protect sensitive environments from contamination, safeguarding both people and processes from harmful airborne particles.

Parts of EN1822

The EN1822 standard is composed of several parts, each addressing specific aspects of filter testing and classification:

• EN 1822-1: 2019 – High efficiency air filters (EPA, HEPA and ULPA) – Part 1: Classification, performance testing, marking.
• EN1822-2: This section details the aerosol production, measuring equipment, and test systems used to evaluate filter performance. No longer valid. Replaced by EN ISO 29463-2:2018.
• EN1822-3: This part explains the testing process for determining the efficiency of flat sheet filter media. No longer valid. Replaced by EN ISO 29463-3.
• EN1822-4: This section provides guidelines for leak testing of filters. No longer valid. Replaced by EN ISO 29463-4:2018.
• EN1822-5: This part explains the process for determining the efficiency of filter elements. No longer valid. Replaced by EN ISO 29463-5:2018.

This is the point most people miss. Since the 2019 revision, EN 1822 only owns the classification. Every test method it relies on now sits in the EN ISO 29463 series, and the normative references clause of EN 1822-1:2019 points there, not at the old Parts 2 to 5. If someone quotes EN 1822-4 for a scan test today, they are quoting a withdrawn document. How ISO 29463 is structured is worth reading alongside this.

Filter classes under EN 1822-1:2019

The standard covers three groups. E stands for EPA (efficient particulate air), H for HEPA, U for ULPA. The E classes are not HEPA filters and must not be marketed as such, which is the single most common misuse of this table.

Class	Integral efficiency (%)	Integral penetration (%)	Local efficiency (%)	Local penetration (%)
E10	≥ 85	≤ 15	not specified	not specified
E11	≥ 95	≤ 5	not specified	not specified
E12	≥ 99.5	≤ 0.5	not specified	not specified
H13	≥ 99.95	≤ 0.05	≥ 99.75	≤ 0.25
H14	≥ 99.995	≤ 0.005	≥ 99.975	≤ 0.025
U15	≥ 99.9995	≤ 0.0005	≥ 99.9975	≤ 0.0025
U16	≥ 99.99995	≤ 0.00005	≥ 99.99975	≤ 0.00025
U17	≥ 99.999995	≤ 0.000005	≥ 99.9999	≤ 0.0001

Integral value and local value are not the same thing

The integral value is the efficiency of the whole filter, averaged across the face. The local value is the worst single point found during the scan. A filter passes only if both limits are met, so an H14 filter with an average of 99.996% still fails if one spot on the pleat pack leaks past 0.025% penetration. This is why factory scan testing matters more than a datasheet number.

For the E classes, EN 1822-1 specifies no local value at all. There is no leak scan requirement for E10, E11 or E12, which is exactly why an E12 at 99.5% is not a substitute for an H13 in a cleanroom, even though the numbers look close.

What MPPS actually means

MPPS is the particle size at which a given filter medium performs worst. It is not a fixed number. The standard requires it to be determined by measurement for the medium being tested. For conventional glass fibre media it usually falls somewhere around 0.1 to 0.25 µm. For ePTFE membrane media it sits lower, which is one reason the two media types cannot be compared on a single efficiency figure.

Filter Selection and Maintenance

Selecting the appropriate filter for a specific application requires considering factors such as the required level of air cleanliness, process sensitivity, and potential contaminant sources. By referring to the EN1822 classification system, users can ensure that the selected filter meets the necessary performance criteria for their needs.

Proper maintenance of HEPA and ULPA filters is crucial for their continued efficiency and longevity. The EN1822 standard mandates regular leak testing and monitoring to detect potential filter damage or loss of efficiency. Additionally, adhering to a filter replacement schedule based on the manufacturer’s recommendations is essential to maintain optimal air quality in sensitive environments.

The EN1822 standard plays a crucial role in ensuring the performance and reliability of HEPA and ULPA filters across various industries. By providing a comprehensive set of guidelines for testing, classification, and quality control, the standard guarantees that these filters meet the stringent requirements necessary to protect sensitive processes and environments. Understanding the details of the EN1822 standard is essential for selecting the appropriate filter and maintaining the air quality of critical applications.

Compliance and Certification

To ensure compliance with the EN1822 standard, filter manufacturers must submit their products for testing and evaluation by accredited laboratories. These laboratories use the methods and procedures defined in the standard to assess the filter’s performance, efficiency, and overall quality.

Upon successful evaluation, the filter will receive a certification demonstrating its compliance with the EN1822 standard. This certification is typically displayed on the product’s packaging or documentation, providing users with confidence that the filter meets the necessary performance requirements.

Importance of Quality Control

Manufacturers must adhere to stringent quality control processes to ensure that their filters consistently meet the EN1822 standard. This includes monitoring production processes, conducting regular in-house testing, and addressing any deviations or issues promptly. By maintaining a rigorous quality control program, manufacturers can guarantee the reliability and performance of their HEPA and ULPA filters.

Applications of EN1822 Filters

HEPA and ULPA filters compliant with the EN1822 standard are used in a wide range of applications where air quality is of utmost importance. Some of these applications include:

Cleanrooms: In industries such as pharmaceuticals, biotechnology, and electronics, maintaining a contamination-free environment is crucial for the integrity of processes and products.
Hospitals and Medical Facilities: Air filtration is essential to prevent the spread of airborne pathogens and protect patients, particularly in operating rooms, intensive care units, and isolation rooms.
Laboratories: Research facilities, including those working with hazardous materials, rely on high-quality air filtration to safeguard both personnel and experiments.
Aerospace and Defense: Advanced technologies and sensitive equipment require contamination-free environments to ensure optimal performance and reliability.

By understanding the EN1822 standard in detail, users can make informed decisions about filter selection and maintenance, ultimately contributing to the protection of sensitive environments and the people and processes within them. The standard’s comprehensive guidelines, rigorous testing procedures, and classification system guarantee that HEPA and ULPA filters meet the stringent requirements necessary for a wide range of critical applications.

Related reading

• ISO 29463 and how its classes map onto EN 1822
• How HEPA filters are scan tested in the factory
• On-site leak testing of installed HEPA filters to ISO 14644-3:2019
• Why gasket and housing surfaces have to be harmonised

Source

EN 1822-1:2019, High efficiency air filters (EPA, HEPA and ULPA) – Part 1: Classification, performance testing, marking. CEN, European Committee for Standardization. The classification table above is Table 1 of that document.