Just Wait...

Filter classification

Compilation of the various filter classes commonly used.

Filter classification

Recommended degrees of separation depending on the environment and indoor requirements.

Outdoor air Supply air
PM2.5 PM10 ePM1 ePM1 ePM2.5 ePM10 ePM10
ODA 1 ≤10 ≤20 60% 50% 60% 60% 50%
ODA 2 ≤15 ≤30 80% 70% 70% 80% 60%
ODA 3 >10 >20 90% 80% 80% 90% 80%

Filter classes

Group Class Average degree of separation
Particle diameter Particle exemple
% μm
Grov G1 50≤Am<65 20-200 Hair straw, fluff
G2 65≤Am<80 10-100 Sand, leaves, fat
G3 80≤Am<90 10-100 Flying earth, visible dust
G4 90≤Am 10-100 visible dust
Group Class Average degree of separation
Particle diameter Particle exemple
% μm
Medel M5 40≤Em<60 10-100 Pollen, visible dust
M6 60≤Em<80 10-25 Spores
Fin F7 80≤Em<90 5-20 Toner particles, combustion particles, allergens
F8 90≤Em<95 0,1 Bacteria, mold, fungal spores
F9 95≤Em 0,1 Bacteria, mold, fungal spores
Group Class Efficiency
Particle diameter Particle exemple
% μm
EPA E10 85 5-20 Toner particles
E11 95 0,3-5 Oil smoke
E12 99,5 0,2-2,5 Bacteria
Hepa H13 99,95 0,01-1 Tobacco smoke, asbestos, mold
H14 99,995 0,01-1 Virus
ULPA U15 99,9995 0,01-1 Dangerous live virus, extreme requirements
U16 99,99995 0,002-0,05 Virus
U17 99,999995 Extreme demands on filtration and purity

Comparison of the different classification systems

Filter class ePM1 ePM2,5 ePM10
G1 - G4 ISO Coarse ISO Coarse ISO Coarse
M5 5-35% 10-45% 40-70%
M6 10-40% 20-50% 60-80%
F7 40-65% 65-75% 80-90%
F8 65-90% 75-95% 90-100%
F9 80-90% 85-95% 90-100%



The filtration efficiency of the most penetrating particle size (MPPS).


Is an abbreviation of Efficiency Particulate Air.


Is an abbreviation of High Efficiency Particulate Air.


Is an abbreviation of Ultra Low Penetration Air.


Refers to particle separation of a specified size of particle.


Is a way of categorizing the particle content in the indoor air depending on the activity being conducted.

Category Description Examples of activities
General ventilation Industrial ventilation
SUP 1 High hygiene requirements Hospital, clean room
SUP 2 Rooms with permanent residence Medium hygiene requirements Offices, housing, schools, pharmaceutical manufacturing
SUP 3 Rooms with temporary stay Basic hygiene requirements Warehouse, data hall, shopping mall
SUP 4 Rooms with short stay Without hygiene requirements Storage room, toilet, stairwell, production facilities
SUP 5 Room with no stay Heavy industry Trash, parking, steelworks, smelters


Is a way to categorize the particle content of the outdoor air.

Category PM2,5 PM10 Description
μg/m3 μg/m3
ODA 1 ≤10 ≤20 Outdoor air that can be temporarily contaminated by particles
ODA 2 ≤15 ≤30 Outdoor air with high particle contents
ODA 3 >15 >30 Outdoor air with very high particle contents