Group Number 
'MERV' Rating 
E3 
E3 
E3 
Average Arrestance
(ASHRAE 52.1) 
Minimum
Final Resistance
(In. W.G.) 
Average Particles
Size Efficiency (PSE)
0.3  1.0 Microns 
Average Particles
Size Efficiency (PSE)
1.0  3.0 Microns 
Average Particles
Size Efficiency (PSE)
3.0  10.0 Microns 
1 
1
2
3
4 



 



 
Less than 20%
Less than 20%
Less than 20%
Less than 20% 
Less than 65%
65%  69.9%
70%  74.9%
75% or Greater 
0.3"
0.3"
0.3"
0.3" 
2 
5
6
7
8 



 



 
20% 
34.9%
35%  49.9%
50%  69.9%
70%  84.9% 



 
0.6"
0.6"
0.6"
0.6" 
3 
9
10
11
12 



 
Less than 50%
50%  64.9%
65%  79.9%
80%  89.9% 
85% or Greater
85% or Greater
85% or Greater
90% or Greater 



 
1.0"
1.0"
1.0"
1.0" 
4 
13
14
15
16 
Less than
75%
75%  84.9%
85%  94.9%
95% or Greater 
90% or
Greater
90% or Greater
90% or Greater
95% or Greater 
90% or
Greater
90% or Greater
90% or Greater
95% or Greater 



 
1.4"
1.4"
1.4"
1.4" 
Notes:
1) Ashrae Standard 52.2 tests are to be conducted at one of (7)
seven air flow rates.
118 FPM  (0.60 m/s)
492 FPM  (2.50 m/s)
246 FPM  (1.25 m/s)
630 FPM  (3.20 m/s)
295 FPM  (1.50 m/s)
748 FPM  (3.80 m/s)
374 FPM  (1.90 m/s) 
2) The
air flow rate at which the filter was tested is
included in the MERV
Rating (10 @ 2.50 m/s)
3) Filter with efficiency of less than 20%
(MERV1
through MERV4) must also
be tested for
arrestance per ASHRAE
Standard 52.1
4) Final resistance must be at least twice
the
intial resistance at the
test air flow rate or the
values shown in the table
above or whichever
is greater.

Close Window 