Table 1: Summary of filter classification for ASHRAE 52.2:2007 [10], EN 779:2002 [11], and EN 1822:2009 [1216].

ASHRAE 52.2:2007 [10]EN 779:2002 [11]EN 1822:2009 [1216]
ASHRAE filter class Average particles size efficiencies in micron (%)EN filter class
E1E2E3Average separation efficiency (Am)Average separation efficiency (Em) Total filtration separation efficiency (%)Local filtration separation efficiency (%)
MERV0.3–1.01.0–3.03.0–10.0

1<20G150 ≤ Am < 65
2<20
3<20G265 ≤ Am < 80
4<20
520–35 G3 80 ≤ Am < 90
635–50
750–70 G4 90 ≤ Am
8>70
9<50>85 F5 40 ≤ Em < 60
1050–65>85
1165–80>85 F6 60 ≤ Em < 80
12>80>90
13<75>90>90F780 ≤ Em < 90
1475–85>90>90F890 ≤ Em < 95
1585–95>90>90F995 ≤ Em
E1085
16>95>95>95E1195
E1299.5
17 H13 99.95 99.75
18
19 H14 99.995 99.975
20
U1599.999599.9975
U1699.9999599.99975
U1799.99999599.9999

Note: Correlations between ASHRAE and EN standard are approximate.