Page 56 - MASHRAE 35th Anniversary

Table 2: ASHRAE 52.2:2017 Air Filter Efficiency Classification (ASHRAE,2017)
Standard 52.2 Minimum Efficiency Reporting Value (MERV)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Composite Average Particle Size Efficiency , % in Size Range, 􏰀m
Average Arrestance %
Range 1
0.3 - 1.0
N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 20􏰂E􏰅 35􏰂E􏰅 50􏰂E􏰅 75􏰂E􏰅 85􏰂E􏰅 95􏰂E􏰅
Range 2 1.0 to 3.0 N/A
N/A N/A N/A N/A N/A N/A 20􏰂E􏰄 35􏰂E􏰄 50􏰂E􏰄 65􏰂E􏰄 80􏰂E􏰄 85􏰂E􏰄 90􏰂E􏰄 90􏰂E􏰄 95􏰂E􏰄
Range 3 3.0 to 10.0
Table 3: ISO16890:2016 Air Filter Efficiency Classification (ISO,2016)
E􏰁<20 Aavg<65 E􏰁<20 65􏰂Aa􏰃g E􏰁<20 70􏰂Aa􏰃g E􏰁<20 75􏰂Aa􏰃g 20􏰂E􏰁 N/A 35􏰂E􏰁 N/A 50􏰂E􏰁 N/A 70􏰂E􏰁 N/A 75􏰂E􏰁 N/A 80􏰂E􏰁 N/A 85􏰂E􏰁 N/A 90􏰂E􏰁 N/A 90􏰂E􏰁 N/A 95􏰂E􏰁 N/A 95􏰂E􏰁 N/A 95􏰂E􏰁 N/A
5%. There are 49
label the filter with ePM1, ePM2.5 and ePM10, a minimum of 50% initial efficiency is required for each particle size range. Filter less than 50% in ePM10, will be labeled as ISO Coarse with defined efficiency of the arrestance test. In ASHRAE 52.2:2017, air filters which are lower than 20% efficiency in range 3 (3.0 to 10.0μm) are required to report their arrestence efficiency. The air filter efficiency labeling of the ISO16890:2016 makes it easier for the user to understand. However it is disadvantageous for the manufacturer and seller, as they will be required to increase inventory in order to provide a full range of filters to the industry.
In order to classify the filter as ePM1 and ePM2.5 , the air filter have to reach 2 criteria which are minimum 50% initial efficiency and minimum 50% passive electrostatic discharged efficiency. The air filter efficiency of ePM1 and ePM2.5 is calculated by average efficiency of the air filter before and after passive electrostatic discharged. The passive electrostatic discharge requirement will discourage industry to research and use of this technology.
The filter final pressure requirement can relate to the filter life span. ISO 16890:2016 requires the manufacturer to test dust loading capacity of the air filter ePM10 50% above with up to 300Pa and ISO Coarse filter up to 200Pa.
grades in ISO16890:2016. In order to
ISO 16890:2016 Classification
PM2.5
1.0 to 3.0
􏰀m 􏰀m 􏰀m
PM1 0.3 to 1.0
PM10 1.0 to 10.0
ISO Coarse
increments, starting at 5%
ePM1 95% ePM1 90% ePM1 85% ePM1 80% ePM1 75% ePM1 70% ePM1 65% ePM1 60% ePM1 55% ePM1 50%
ePM2.5 95%
ePM2.5 90%
ePM2.5 85%
ePM2.5 80%
ePM2.5 75%
ePM2.5 70%
ePM2.5 65%
ePM2.5 60%
ePM2.5 55%
ePM2.5 50%
50% Initial Efficiency
Minimum Minimum 50% Passive
Electrostatic Discharged efficiency
No discharge requirement
with the categories. The highest filter grade according to ISO16890:2016 is ePM1 95% and the lowest is ISO Corse
ePM10 95%
ePM10 90%
ePM10 85%
ePM10 80%
ePM10 75% 5%
ePM10 70% ePM10 65% ePM10 60% ePM10 55% ePM10 50%
Arrestance reported in
3