Technology Review of Modern Gas Turbine Inlet Filtration Systems

Table 1

Summary of filter classification for ASHRAE 52.2:2007 [10], EN 779:2002 [11], and EN 1822:2009 [12–16].

	ASHRAE 52.2:2007 [10]				EN 779:2002 [11]		EN 1822:2009 [12–16]
ASHRAE filter class	Average particles size efficiencies in 𝑋-𝑌 micron (%)			EN filter class
	E1	E2	E3		Average separation efficiency (Am)	Average separation efficiency (Em)	Total filtration separation efficiency (%)	Local filtration separation efficiency (%)
MERV	0.3–1.0	1.0–3.0	3.0–10.0
1			<20	G1	50 ≤ Am < 65
2			<20
3			<20	G2	65 ≤ Am < 80
4			<20
5			20–35	G3	80 ≤ Am < 90
6			35–50
7			50–70	G4	90 ≤ Am
8			>70
9		<50	>85	F5		40 ≤ Em < 60
10		50–65	>85
11		65–80	>85	F6		60 ≤ Em < 80
12		>80	>90
13	<75	>90	>90	F7		80 ≤ Em < 90
14	75–85	>90	>90	F8		90 ≤ Em < 95
15	85–95	>90	>90	F9		95 ≤ Em
				E10			85
16	>95	>95	>95	E11			95
				E12			99.5
17				H13			99.95	99.75
18
19				H14			99.995	99.975
20
				U15			99.9995	99.9975
				U16			99.99995	99.99975
				U17			99.999995	99.9999

Note: Correlations between ASHRAE and EN standard are approximate.