ASHRAE 52.2: Filter testing was originated from America in 1930 (ASHVE and AFI code). It was then reviewed and modified in 1967 and 1968. ASRHAE collaborated with American National Standard Institude (ANSI) in 1992 to create ASHRAE-ANSI 52.1. Finally updated to ASHRAE 52.2 in 2007.
EUROVENT 4/4 and 4/5: Eurovent 4/5 was established in 1974 by modifying existing ASHRAE 52-68 to suit the applications in Europe. Eurovent 4/5 is catered for primary and secondary filter while Eurovent 4/4 is catered for high efficiency filters
EN 779: It was the first European’s Air filter test method in 1993, built on the foundations of Eurovent 4/5. This standard was modified later in 2002 and 2012. Only covers primary and secondary filters.
EN 1882: It is the improvisation from Eurovent 4/4 in 1998. This standard was modified only once in 2010. It covers high efficiency filters (E10 and above).
AIR FILTERS and EFFICIENCY CLASSIFICATION
| CLASSIFICATION | Arrestance or Dust Spot Efficiency | US ASHRAE 52.2 | European Union EN779 Class | Typical Controlled Contaminant | Application | |
|---|---|---|---|---|---|---|
| PRE Filter (G Class) | AFI <65 % M | MERV 1 | G1 | Am< 65% | Particle bigger than 10.0µm （Pollen） （Spanish moss） （Dust mites） （Sanding dust） （Spray paint dust） （Textile fibers） | Gross filter, domestic and commercial |
| AFI 65%-70% | MERV 2 | G2 | 65%≦Am< 80% | |||
| AFI 70%-75% | MERV 3 | |||||
| AFI 75%-80% | MERV 4 | |||||
| AFI 80%-85% | MERV 5 | G3 | 80%≦Am<90% | Particle size within 3.0µm-10.0µm (Mold） (Spores） (Hair spray） (Cement dust） (Snuff） (Powdered milk） | Commercial, industrial, paint shop |
|
| AFI 85%-90% | MERV 6 | |||||
| NBS 25%-30% | MERV 7 | G4 | 90%≦Am | |||
| NBS 30%-35% | MERV 8 | |||||
| MEDIUM Filter (F Class) | NBS 40%-45% | MERV 9 | F5 | 40%≦Em< 60% | Particle Size within 1.0µm-3.0µm (Lead dust） (Milled flour） (Coal dust） (Auto emissions） (Nebulizer drop） (Welding fumes） | IAQ concerned commercial & industrial, medical |
| NBS 50%-55% | MERV 10 | |||||
| NBS 60%-65% | MERV 11 | F6 | 60%≦Em< 80% | |||
| NBS 70%-75% | MERV 12 | |||||
| NBS 80%-85% | MERV 13 | F7 | 80%≦Em< 90% | Particle size within 0.3µm-1.0µm (All bacteria） (cooking oil） (Most smoke） (Copier toner） (Most face powder） (Most paint pigments） | IAQ concerned commercial, industrial, medical, food etc |
|
| NBS 90%-95% | MERV 14 | F8 | 90%≦Em< 95% | |||
| NBS>95% | MERV 15 | F9 | 95%≦Em | |||
| MERV 16 | ||||||
| HEPA Filter (H Class) | ≧95% at 0.3µm | H10 | ≧85% at MPPS | Particle size bigger than 0.3µm (Virus [unattached]） (Carbon dust） (Sea salt） (All combustion smoke） (Radon progeny） | All types of cleanrooms | |
| ≧98% at 0.3µm | H11 | ≧95% at MPPS | ||||
| ≧99.97% at 0.3µm | TYPE A | |||||
| ≧99.99% at 0.3µm | TYPE C | H12 | ≧99.5% at MPPS | |||
| ≧99.995% at 0.3µm | H13 | ≧99.95% at MPPS | ||||
| ≧99.999% at 0.3µm | TYPE D | H14 | ≧99.995% at MPPS | |||
| ULPA Filter (U Class) | ≧99.9995% at 0.12µm | TYPE F | H15 | ≧99.9995% at MPPS | Particle size bigger than 0.12µm | super cleanroom |
| ≧99.99995% at 0.12µm | H16 | ≧99.99995% at MPPS | ||||
| ≧99.999995% at 0.12µm | H17 | ≧99.999995% at MPPS | ||||
1. AFI : American Filter Institute
2. NBS : National Bureau of Standards
3. ASHRAE : American Society of Heating Refrigerating & Air-conditioning Engineers
4. MERV : Minimum Efficiency Reporting Value
5. MPPS : Most Penetrating Particle Size
6. HEPA : High Efficiency Particulate Air Filter
7. ULPA : Ultra Low Penetration Air Filter
8. Am : Average Arrestance Efficiency for Coarse Filters
9. Em : Average Efficiency for Fine Filters
10. IEST : Institute of Environmental Sciences and Technology
FREQUENTLY ASKED QUESTIONS
Eurovent 4.5 and Eurovent 4.4 are two distinct standards developed by Eurovent, a European association of air conditioning and refrigeration manufacturers. Eurovent 4.5 is designed for primary and secondary filters, while Eurovent 4.4 is specifically tailored for high-efficiency filters. The main difference lies in the filter efficiency classification, with Eurovent 4.5 focusing on lower to medium efficiency filters and Eurovent 4.4 catering to higher efficiency filters. This distinction enables manufacturers to design and test filters according to specific application requirements.
EN 779 and EN 1882 are two European standards for air filter testing, with distinct focuses. EN 779, introduced in 1993, is primarily designed for primary and secondary filters, while EN 1882, introduced in 1998, is focused on high-efficiency filters (E10 and above). The key difference lies in the filter efficiency classification and the testing procedures employed. EN 779 is more geared towards general ventilation applications, whereas EN 1882 is suited for critical applications requiring high-efficiency filtration.
The revisions to EN 779 (2002, 2012) and EN 1882 (2010) have introduced significant changes to air filter testing and classification. These updates have refined the testing procedures, expanded the scope of filter types, and improved the accuracy of filter efficiency classification. The revisions have also ensured that air filters meet increasingly stringent requirements for indoor air quality, energy efficiency, and environmental sustainability. As a result, manufacturers must adapt their filter designs and testing protocols to comply with the revised standards.
The ASHRAE 52.2, Eurovent, and EN standards have far-reaching implications for the global air filter market. These standards influence filter design, testing, and classification, ultimately affecting the performance, safety, and energy efficiency of air filtration systems. Manufacturers must comply with these standards to ensure their products meet regional and international requirements. This compliance drives innovation, improves product quality, and enhances customer confidence in air filter products. Furthermore, the standards facilitate trade and commerce by providing a common language and framework for air filter specifications and performance.
