Filter Standard EN1822 for Absolute Filters / HEPA Filters

Filter Standard for Absolute Filters

Absolute filters are classified according to the latest standard NEN EN1822. This standard consists of 5 parts, which are published as follows:

• Part 1: Classification, performance testing, marking
• Part 2: Aerosol production, measuring equipment, particle counting statistics
• Part 3: Testing flat sheet filter media
• Part 4: Determining leakage of filter elements (scan method)
• Part 5: Determining the efficiency of filter elements

The biggest practical difference compared to the old standard is primarily in the class designation, where classes H10-H12 have been changed to E10-E12. Absolute filters are divided into 3 different groups:

• EPA (E) - Efficient Particulate Air Filters
• HEPA (H) - High Efficiency Particulate Air Filters
• ULPA (U) - Ultra Low Penetration Air Filters

Classification of Absolute Filters According to Standard EN1822

Filter class	Integral value Efficiency (%)	Penetration (%)	Local value Efficiency (%)	Penetration (%)
E10	≥85	≤15	*	*
E11	≥95	≤5	*	*
E12	≥99.5	≤0.5	*	*
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

*Classes E10-E12 do not undergo a local leak test.

Efficiency is measured at the particle size that is most penetrated at the nominal airflow rate. This is called the MPPS, or Most Penetrating Particle Size. For fiberglass media, the MPPS typically lies within a particle size range of 0.1 to 0.2 microns.

Deviating from the nominal airflow rate affects efficiency and pressure loss across a filter. Reducing the airflow compared to the nominal airflow increases efficiency and decreases pressure loss. Increasing the airflow compared to the nominal airflow decreases efficiency and increases pressure loss.

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