Particle Size Examples Filter Class Typical Applications
Coarse dust, particle size > 10 µm - insects
- textile fibres and hairs
- sand
- fly ash
- pollen
- spores
- cement dust		 G 1
G 2		 - simple applications (e.g. insect screens for compact machinery)
G 3
G 4		 -  pre-filters and circulation filters for civil defense shelters
-  exhaust filters for spray painting booths, kitchens, etc. 
-  inlet air filters for air conditioners and compact machines (e.g. window air conditioners, ventilators)
-  pre-filters for Filter Classes F 6 to F 8
Fine dust, particle size 1 to 10 µm - pollen
- spores
- cement dust
- fly ash
- pollen
- spores
- bacteria and germs on host particles
 F 5 -  outside-air inlet filters for rooms with low purity requirements (e.g. factories, warehouse facilities, garages)
F 5
F 6
F 7		 -  pre-filters and circulation filters in central ventilation stations
-  final filters for air conditioning of sales rooms, department stores, offices and certain production plants
-  pre-filters for Filter Classes F 9 to H 11
  - oil fumes and agglomerated soot
- tobacco smoke
- metallic-oxide smoke		 F 7
F 8
F 9		 -  final filters for air conditioning of offices, production plants, control centres, hospitals, EDP centres
-  pre-filters for Filter Classes H 11 to H 13 and activated carbon
Suspended particulates, particle size < 1 µm - germs, bacteria, viruses
- tobacco smoke
- metallic-oxide smoke		 E 10
E 11
E 12 		-  final filters for rooms with high and highest purity requirements (e.g. for laboratories, for foods processing, pharmaceutical, fine mechanical, optical or electronics plants or medical facilities)
E 11 - final filters for clean rooms, Classes 100 000 or 10 000
- oil fumes and soot in nascent state
- radioactive suspended particulates		 E 12
H 13		 -  final filters for clean rooms, Classes 10 000 or 100
-  final filters in civil defense shelters
-  exhaust air filters in nuclear plants
- aerosols H 14
U 15
U 16 		-  final filters for clean rooms, Classes 10 or 1

Fractional arrestance (approximate data) as a function of Filter Class (G 1 to F 9) in accordance with DIN EN 779. Filters initially in clean, dust-free state.

Filter Class Initial Efficiency Final Pressure Drop as per test procedure Average Arrestance(Am) Average Efficiency(Em)
for ASHRAE dust for 0.4 µm particles
  % Pa % %
G1 coarse filter G : 250 50 £ Am < 65 -
G2 < 20 250 65 £ Am < 80 -
G3   250 80 £ Am < 90 -
G4   250 0 £ Am -
F5 fine filter F : 450 - 40 £ Em < 60
F6 > 20 450 - 60 £ Em < 80
F7   450 - 80 £ Em < 90
F8   450 - 90 £ Em < 95
F9   450 - 95 £ Em

The properties of atmospheric dusts can vary significantly from those of the synthetic dust specified for use in DIN EN 779 :2. Therefore test results determined according to this test standard can not in any way be construed as indications or assurances of the performance data or service life attained by filters in actual use. Depending on their design, filters can be operated under actual site conditions to higher final pressure drops than those given here.

Please note:
This table provides approximate data regarding various filter classes for reference purposes only. Specific data applicable to an intended application must be determined at the expected air flow speed.

Classification of (H)EPA and ULPA Filters according to EN 1822-1 : 1998

Filter Class Overall Values Local Values
Arrestance
%		 Penetration
%		 Arrestance
%		 Penetration
%
E 10 85 15 - -
E 11 95 5 - -
E 12 99.5 0.5 - -
H 13 99.95 0.05 99.75 0,25
H 14 99.95 0.005 99.975 0,025
U 15 99.95 0.000 5 99.997 5 0,002 5
U 16 99.95 0.000 05 99.999 75 0,000 25
U 17 99.95 0.000 005 99.999 9 0,000 1