SIST EN ISO 16890-1:2017

SLOVENSKI STANDARD
01-marec-2017
1DGRPHãþD
SIST EN 779:2012
=UDþQLILOWULSULVSORãQHPSUH]UDþHYDQMXGHO7HKQLþQHVSHFLILNDFLMH]DKWHYHLQ
NODVLILNDFLMVNLVLVWHPXþLQNRYLWRVWLQDSRGODJLGUREQLKGHOFHYH30,62

Air filters for general ventilation - Part 1: Technical specifications, requirements and
classification system based upon particulate matter efficiency (ePM) (ISO 16890-1:2016)
Luftfilter für die allgemeine Raumlufttechnik - Teil 1: Technische Bestimmungen,
Anforderungen und Effizienzklassifizierungssystem basierend auf Feinstaub (PM) (ISO
16890-1:2016)
Filtres à air pour ventilation générale - Partie 1: Spécifications techniques, exigences et
système de classification du rendement fondé sur les particules en suspension (PM)
(ISO 16890-1:2016)
Ta slovenski standard je istoveten z: EN ISO 16890-1:2016
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 16890-1
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2016
EUROPÄISCHE NORM
ICS 91.140.30 Supersedes EN 779:2012
English Version
Air filters for general ventilation - Part 1: Technical
specifications, requirements and classification system
based upon particulate matter efficiency (ePM) (ISO
16890-1:2016)
Filtres à air de ventilation générale - Partie 1: Luftfilter für die allgemeine Raumlufttechnik - Teil 1:
Spécifications techniques, exigences et système de Technische Bestimmungen, Anforderungen und
classification fondé sur l'efficacité des particules en Effizienzklassifizierungssystem basierend auf
suspension (ePM) (ISO 16890-1:2016) Feinstaub (PM) (ISO 16890-1:2016)
This European Standard was approved by CEN on 19 September 2016.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16890-1:2016 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 16890-1:2016) has been prepared by Technical Committee ISO/TC 142
"Cleaning equipment for air and other gases" in collaboration with Technical Committee CEN/TC 195
“Air filters for general air cleaning” the secretariat of which is held by UNI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2017, and conflicting national standards shall be
withdrawn at the latest by June 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN 779:2012.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 16890-1:2016 has been approved by CEN as EN ISO 16890-1:2016 without any
modification.
INTERNATIONAL ISO
STANDARD 16890-1
First edition
2016-12-01
Air filters for general ventilation —
Part 1:
Technical specifications, requirements
and classification system based upon
particulate matter efficiency (ePM)
Filtres à air de ventilation générale —
Partie 1: Spécifications techniques, exigences et système de
classification fondé sur l’efficacité des particules en suspension (ePM)
Reference number
ISO 16890-1:2016(E)
©
ISO 2016
ISO 16890-1:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 4
5 Technical specifications and requirements . 5
5.1 General . 5
5.2 Material . 5
5.3 Nominal air flow rate . 5
5.4 Resistance to air flow . 5
5.5 Fractional efficiency curves (particle size efficiency spectrum) . 5
5.6 Arrestance . 5
6 Test methods and procedure . 6
7 Classification system based on particulate matter efficiency (ePM) .6
7.1 Definition of a standardized particles size distribution of ambient air . 6
7.2 Calculation of the particulate matter efficiencies (ePM) . 9
7.3 Classification . 9
8 Reporting .10
8.1 General .10
8.2 Interpretation of test reports .11
8.3 Summary .12
Annex A (informative) Shedding from filters .17
Annex B (informative) Examples .19
Annex C (informative) Estimation of downstream fine dust concentrations .23
Bibliography .26
ISO 16890-1:2016(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 142, Cleaning equipment for air and other gases.
This first edition of ISO 16890-1, together with ISO 16890-2, ISO 16890-3 and ISO 16890-4, cancels and
replaces ISO/TS 21220:2009, which has been technically revised.
ISO 16890 consists of the following parts, under the general title Air filters for general ventilation:
— Part 1: Technical specifications, requirements and classification system based upon particulate matter
efficiency (ePM)
— Part 2: Measurement of fractional efficiency and air flow resistance
— Part 3: Determination of the gravimetric efficiency and the air flow resistance versus the mass of test
dust captured
— Part 4: Conditioning method to determine the minimum fractional test efficiency
iv © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
Introduction
The effects of particulate matter (PM) on human health have been extensively studied in the past
decades. The results are that fine dust can be a serious health hazard, contributing to or even causing
respiratory and cardiovascular diseases. Different classes of particulate matter can be defined according
to the particle size range. The most important ones are PM , PM and PM . The U.S. Environmental
10 2,5 1
Protection Agency (EPA), the World Health Organization (WHO) and the European Union define
PM as particulate matter which passes through a size-selective inlet with a 50 % efficiency cut-off
at 10 µm aerodynamic diameter. PM and PM are similarly defined. However, this definition is not
2,5 1
precise if there is no further characterization of the sampling method and the sampling inlet with a
clearly defined separation curve. In Europe, the reference method for the sampling and measurement
of PM is described in EN 12341. The measurement principle is based on the collection on a filter of the
PM fraction of ambient particulate matter and the gravimetric mass determination (see EU Council
Directive 1999/30/EC of 22 April 1999).
As the precise definition of PM , PM and PM is quite complex and not simple to measure, public
10 2,5 1
authorities, like the U.S. EPA or the German Federal Environmental Agency (Umweltbundesamt),
increasingly use in their publications the more simple denotation of PM as being the particle size
fraction less or equal to 10 µm. Since this deviation to the above mentioned complex “official” definition
does not have a significant impact on a filter element’s particle removal efficiency, the ISO 16890 series
refers to this simplified definition of PM , PM and PM .
10 2,5 1
Particulate matter in the context of the ISO 16890 series describes a size fraction of the natural aerosol
(liquid and solid particles) suspended in ambient air. The symbol ePM describes the efficiency of an air
x
cleaning device to particles with an optical diameter between 0,3 µm and x µm. The following particle
size ranges are used in the ISO 16890 series for the listed efficiency values.
Table 1 — Optical particle diameter size ranges for the definition of the efficiencies, ePM
x
Efficiency Size range, µm
ePM 0,3 ≤ × ≤10
ePM 0,3 ≤ × ≤2,5
2,5
ePM 0,3 ≤ × ≤1
Air filters for general ventilation are widely used in heating, ventilation and air-conditioning applications
of buildings. In this application, air filters significantly influence the indoor air quality and, hence, the
health of people, by reducing the concentration of particulate matter. To enable design engineers and
maintenance personnel to choose the correct filter types, there is an interest from international trade
and manufacturing for a well-defined, common method of testing and classifying air filters according
to their particle efficiencies, especially with respect to the removal of particulate matter. Current
regional standards are applying totally different testing and classification methods, which do not allow
any comparison with each other, and thus hinder global trade with common products. Additionally,
the current industry standards have known limitations by generating results which often are far away
from filter performance in service, i.e. overstating the particle removal efficiency of many products.
With this new ISO 16890 series, a completely new approach for a classification system is adopted, which
gives better and more meaningful results compared to the existing standards.
The ISO 16890 series describes the equipment, materials, technical specifications, requirements,
qualifications and procedures to produce the laboratory performance data and efficiency classification
based upon the measured fractional efficiency converted into a particulate matter efficiency (ePM)
reporting system.
Air filter elements according to the ISO 16890 series are evaluated in the laboratory by their ability
to remove aerosol particulate expressed as the efficiency values ePM , ePM and ePM . The air
1 2,5 10
filter elements can then be classified according to the procedures defined in this part of ISO 16890.
The particulate removal efficiency of the filter element is measured as a function of the particle size in
the range of 0,3 µm to 10 µm of the unloaded and unconditioned filter element as per the procedures
defined in ISO 16890-2. After the initial particulate removal efficiency testing, the air filter element is
ISO 16890-1:2016(E)
conditioned according to the procedures defined in ISO 16890-4 and the particulate removal efficiency
is repeated on the conditioned filter element. This is done to provide information about the intensity of
any electrostatic removal mechanism which may or may not be present with the filter element for test.
The average efficiency of the filter is determined by calculating the mean between the initial efficiency
and the conditioned efficiency for each size range. The average efficiency is used to calculate the ePM
x
efficiencies by weighting these values to the standardized and normalized particle size distribution of
the related ambient aerosol fraction. When comparing filters tested in accordance with the ISO 16890
series, the fractional efficiency values shall always be compared among the same ePM class (ex. ePM
x 1
of filter A with ePM of filter B). The test dust capacity and the initial arrestance of a filter element are
determined as per the test procedures defined in ISO 16890-3.
vi © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 16890-1:2016(E)
Air filters for general ventilation —
Part 1:
Technical specifications, requirements and classification
system based upon particulate matter efficiency (ePM)
1 Scope
This part of ISO 16890 establishes an efficiency classification system of air filters for general ventilation
based upon particulate matter (PM). It also provides an overview of the test procedures, and specifies
general requirements for assessing and marking the filters, as well as for documenting the test results.
It is intended for use in conjunction with ISO 16890-2, ISO 16890-3 and ISO 16890-4.
The test method described in this part of ISO 16890 is applicable for air flow rates between 0,25 m /s
3 3 3 3 3
(900 m /h, 530 ft /min) and 1,5 m /s (5 400 m /h, 3 178 ft /min), referring to a test rig with a nominal
face area of 610 mm × 610 mm (24 inch × 24 inch).
ISO 16890 (all parts) refers to particulate air filter elements for general ventilation having an
ePM efficiency less than or equal to 99 % when tested according to the procedures defined within
ISO 16890-1, ISO 16890-2, ISO 16890-3 and ISO 16890-4. Air filter elements with a higher initial
efficiency are evaluated by other applicable test methods (see ISO 29463-1, ISO 29463-2, ISO 29463-3,
ISO 29463-4 and ISO 29463-5).
Filter elements used in portable room-air cleaners are excluded from the scope of this part of ISO 16890.
The performance results obtained in accordance with ISO 16890 (all parts) cannot by themselves be
quantitatively applied to predict performance in service with regard to efficiency and lifetime. Other
factors influencing performance to be taken into account are described in Annex A.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 15957, Test dusts for evaluating air cleaning equipment
ISO 16890-2, Air filter for general ventilation — Part 2: Measurement of fractional efficiency and air flow
resistance
ISO 16890-3, Air filter for general ventilation — Part 3: Determination of the gravimetric efficiency and the
air flow resistance versus the mass of test dust captured
ISO 16890-4, Air filter for general ventilation — Part 4: Conditioning method to determine the minimum
fractional test efficiency
ISO 29464:2011, Cleaning equipment for air and other gases — Terminology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 29464 and the following apply.
3.1 Arrestance and efficiency
ISO 16890-1:2016(E)
3.1.1
arrestance
gravimetric efficiency
A
measure of the ability of a filter to remove mass of a standard test dust from the air passing through it,
under given operating conditions
Note 1 to entry: This measure is expressed as a weight percentage.
3.1.2
initial arrestance
initial gravimetric efficiency
A
i
ratio of the mass of a standard test dust retained by the filter to the mass of dust fed after the first
loading cycle in a filter test
Note 1 to entry: This measure is expressed as a weight percentage.
3.1.3
average arrestance
average gravimetric efficiency
A
m
ratio of the total mass of a standard test dust retained by the filter to the total mass of dust fed up to
final test pressure differential
3.1.4
efficiency
fraction or percentage of a challenge contaminant that is removed by a filter
3.1.5
fractional efficiency
ability of an air cleaning device to remove particles of a specific size or size range
Note 1 to entry: The efficiency plotted as a function of particle size (3.7.1) gives the particle size efficiency
spectrum.
[SOURCE: ISO 29464:2011, 3.1.61]
3.1.6
particulate matter efficiency
ePM
x
efficiency (3.1.4) of an air cleaning device to reduce the mass concentration of particles with an optical
diameter between 0,3 µm and x µm
3.2
filter element
structure made of the filtering material, its supports and its interfaces with the filter housing
3.3
group designation
designation of a group of filters fulfilling certain requirements in the filter classification
Note 1 to entry: This part of ISO 16890 defines four groups of filters. Group designations are “ISO coarse”, “ISO
ePM10”, “ISO ePM2,5” and “ISO ePM1” as defined in Table 4.
3.4 Air flow rates
2 © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
3.4.1
air flow rate
q
V
volume of air passing through the filter per unit time
[SOURCE: ISO 29464:2011, 3.2.38]
3.4.2
nominal air flow rate
q
V,nom
air flow rate (3.4.1) specified by the manufacturer
3.4.3
test air flow rate
q
Vt
air flow rate (3.4.1) used for testing
3.5 Particulate matter
3.5.1
particulate matter
PM
solid and/or liquid particles suspended in ambient air
3.5.2
particulate matter PM
particulate matter (3.5.1) which passes through a size-selective inlet with a 50 % efficiency cut-off at
10 μm aerodynamic diameter
3.5.3
particulate matter PM
2,5
particulate matter (3.5.1) which passes through a size-selective inlet with a 50 % efficiency cut-off at
2,5 μm aerodynamic diameter
3.5.4
particulate matter PM
particulate matter (3.5.1) which passes through a size-selective inlet with a 50 % efficiency cut-off at
1 μm aerodynamic diameter
3.6
particle counter
device for detecting and counting numbers of discrete airborne particles present in a sample of air
[SOURCE: ISO 29464:2011, 3.27]
3.7 Particle size and diameter
3.7.1
particle size
particle diameter
geometric diameter (equivalent spherical, optical or aerodynamic, depending on context) of the
particles of an aerosol
[SOURCE: ISO 29464:2011, 3.1.126]
ISO 16890-1:2016(E)
3.7.2
particle size distribution
presentation, in the form of tables of numbers or of graphs, of the experimental results obtained using a
method or an apparatus capable of measuring the equivalent diameter of particles in a sample or capable
of giving the proportion of particles for which the equivalent diameter lies between defined limits
[SOURCE: ISO 29464:2011, 3.1.128]
3.8
resistance to air flow
pressure differential
difference in pressure between two points in an airflow system at specified conditions, especially when
measured across the filter element (3.2)
3.9
test dust capacity
amount of a standard test dust held by the filter at final test pressure differential
4 Symbols and abbreviated terms
A Initial arrestance, %
i
d Lower limit particle diameter in a size range i, µm
i
d Upper limit particle diameter in a size range i, µm
i+1
Geometric mean diameter of a size range i, µm
d
i
Δd Width of a particle diameter size range i, µm
i
Δln d Logarithmic width of a particle diameter size range, i; ln is the natural logarithm to the
i
base of e, where e is an irrational and transcendental constant approximately equal to
2,718 281 828
Δlndd=−ln lndd= ln(/ d ) , dimensionless
ii++11ii i
d Median particle size of the log-normal distribution, µm
E Initial fractional efficiency of particle size range, i, of the untreated and unloaded filter
i
element, % (equals to the efficiency values E of the untreated filter element resulting
ps
from ISO 16890-2)
E Fractional efficiency of particle size range, i, of the filter element after an artificial
D,i
conditioning step, % (equals to the efficiency values E of the filter element resulting
ps
from ISO 16890-2 after a conditioning step has been carried out according to
ISO 16890-4)
E Average fractional efficiency of particle size range i, %
A,i
ePM Minimum efficiency value with x=1 µm, 2,5 µm or 10 µm of the conditioned filter
x, min
element, %
ePM Efficiency with x=1 µm, 2,5 µm or 10 µm, %
x
q (d) Discrete particle volume distribution, dimensionless
Q (d) Cumulative particle volume distribution, dimensionless
σ Standard deviation of the log-normal distribution
g
4 © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
y Mixing ratio of the bimodal particle size distribution
ASHRAE American Society of Heating Refrigeration and Air Conditioning Engineers
CEN European Committee for Standardization
5 Technical specifications and requirements
5.1 General
The filter element shall be designed or marked for air flow direction in a way that prevents incorrect
mounting.
The filter shall be designed in a way that no leaks occur along the sealing edge when correctly mounted
in the ventilation duct. If, for any reason, dimensions do not allow testing of a filter under standard test
conditions, assembly of two or more filters of the same type or model are permitted, provided no leaks
occur in the resulting filter configuration.
5.2 Material
The filter element shall be made of suitable material to withstand normal usage and exposures to those
temperatures, humidities and corrosive environments that are likely to be encountered.
The filter element shall be designed to withstand mechanical constraints that are likely to occur during
normal use.
5.3 Nominal air flow rate
The filter element shall be tested at its nominal air flow rate for which the filter has been designed by
the manufacturer.
3 3 3
However, many national and association bodies use 0,944 m /s (2 000 ft /min or 3 400 m /h) as nominal
air flow for classification or rating of air filters that are nominal 610 mm × 610 mm (24 inch × 24 inch)
in face area. Therefore, if the manufacturer does not specify a nominal air flow rate, the filter shall be
tested at 0,944 m /s. The air flow velocity associated with this air flow rate is 2,54 m/s (500 ft/min).
5.4 Resistance to air flow
The resistance to air flow (pressure differential) across the filter element is recorded at the test air
flow rate as described in detail in ISO 16890-2.
5.5 Fractional efficiency curves (particle size efficiency spectrum)
The initial fractional efficiency curve, E , of the unloaded and unconditioned filter element as a function
i
of the particle size is measured at the test air flow rate in accordance with ISO 16890-2.
The fractional efficiency curve, E , of the filter element after an artificial conditioning step defined in
D,i
ISO 16890-4 is determined as a function of the particle size in accordance with ISO 16890-2.
5.6 Arrestance
The initial arrestance, the resistance to air flow versus the mass of test dust captured and the test dust
capacity are determined in accordance with ISO 16890-3 using L2 test dust as specified in ISO 15957.
ISO 16890-1:2016(E)
6 Test methods and procedure
The technical specifications of the test rig(s), the related test conditions, test aerosols and standard
test dust used for this part of ISO 16890 are described in detail in ISO 16890-2, ISO 16890-3 and
ISO 16890-4. The full test according to this part of ISO 16890 consists of the steps given below, which
all shall be carried out with the same filter test specimen under the same test conditions and at the
same test air flow rate:
a) measure the resistance to air flow as a function of the air flow rate according to ISO 16890-2;
b) measure the initial fractional efficiency curve, E , of the unloaded and unconditioned filter element
i
as a function of the particle size in accordance with ISO 16890-2;
c) carry out an artificial conditioning step in accordance with ISO 16890-4;
d) measure the fractional efficiency curve, E , of the conditioned filter element as a function of
D,i
the particle size in accordance with ISO 16890-2, which is equal to the minimum fractional test
efficiency;
e) calculate the ePM efficiencies as defined in Clause 7;
f) load the filter with synthetic L2 test dust as specified in ISO 15957 according to the procedures
described in ISO 16890-3 to determine the initial arrestance, the resistance to air flow versus the
mass of test dust captured and the test dust capacity (this step is optional for filters of group ISO
ePM10, ePM2,5 or ePM1).
The initial fractional efficiency curve, E , of the untreated and unloaded filter element (see 5.5) and the
i
fractional efficiency curves, E , after an artificial conditioning step are used to calculate the average
D,i
fractional efficiency curve, E , using Formula (1).
A,i
EE=⋅05,( + E ) (1)
AD,,ii i
NOTE For further explanations on the test procedure according to ISO 16890-4, please refer to 8.2.
The procedure described in ISO 16890-4 quantitatively shows the extent of the electrostatic charge
effect on the initial performance of the filter element without dust load. It indicates the level of
efficiency obtainable with the charge effect completely removed and with no compensating increase
in mechanical efficiency. Hence, the fractional efficiencies, E , after an artificial conditioning step
D,i
could underestimate the fractional efficiencies under real service conditions. Since the real minimum
fractional efficiencies encountered during service strongly depend on the operating conditions defined
by numerous uncontrolled parameters, its real value lays unpredictably between the initial and the
conditioned value. For good sense, in this part of ISO 16890, the average between the initial and the
conditioned value is used to predict the real fractional efficiencies of a filter during service, as defined
by Formula (1). Therefore, it shall be noted that fractional efficiencies measured in real service may
differ significantly from the ones given in this part of ISO 16890. Additionally, the chemical treatment
of a filter medium applied in ISO 16890-4 as an artificial ageing step may affect the structure of the
fibre matrix of a filter medium or chemically affect the fibres or even fully destroy the filter medium.
Hence, not all types of filters and media may be applicable to the mandatory procedure described in
ISO 16890-4 and, in this case, cannot be classified according to this part of ISO 16890.
7 Classification system based on particulate matter efficiency (ePM)
7.1 Definition of a standardized particles size distribution of ambient air
To evaluate air filters according to their ePM efficiencies, standardized volume distribution functions
of the particle size are used which globally represent the average ambient air of urban and rural areas,
respectively. Typically, in the size range of interest (>0,3 µm), the particle sizes in ambient air are
bimodal distributed with a fine and coarse mode. Fine filters, mostly designed to filter out the PM
and PM particle size fractions, are evaluated using a size distribution which represents urban areas,
2,5
6 © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
while fine filters predominantly designed to filter out the PM fraction are evaluated using a size
distribution which represents rural areas.
NOTE The actual particle size distribution of ambient air depends on many different factors. Hence,
depending on the location, the season of the year and the weather conditions, the actual measured particle size
distribution may differ significantly from the standardized one given in this part of ISO 16890.
This bimodal distribution is represented by combining lognormal distributions for the coarse and the
fine mode as given in Formula (3).
 2 
lndd−ln
 
()
1 50
fd(,σ ,)d = ⋅−exp (2)
 
g 50
 
lnσπ⋅ 2
g
2⋅ lnσ
()
g
 
 
In Formula (2), fd(,σ ,)d represents the lognormal distribution function for one mode, coarse or
g50
fine, where d is the variable particle size, for which the distribution is calculated, and the standard
deviation, σ , and the median particle size, d , are the scaling parameters. The bimodal distribution is
g 50
derived as given in Formula (3) by combining the lognormal distributions for the coarse (B) and the
fine (A) mode, weighted with the mixing ratio, y.
dQd()
qd() == yf⋅+(,ddσσ,) ()1−⋅yf (,dd,) (3)
3 gA 50AgBB50
dlnd
where the parameters are defined to the values given in Table 2, representing urban and rural areas.
Table 2 — Parameters for the distribution function as given in Formula (3) for urban and rural
environments
urban rural
qd() qd()
3u i 3r i
A B A B
d d
0,3 μm 10 μm 0,25 μm 11 μm
50 , u 50 , r
σ σ
2,2 3,1 2,2 4
gu, g,r
y 0,45 y 0,18
u r
Figure 1 shows a graphical plot of Formula (3) using the parameters given in Table 2.
ISO 16890-1:2016(E)
Key
logarithmic distribution (this part of ISO 16890)
logarithmic distribution (cumulative)
Figure 1 — Discrete and cumulative logarithmic particle volume distribution functions of
ambient aerosol as typically found in urban and rural environments (see Reference [7])
As an example, Table 3 gives the values of the standardized proportion by volume, q , calculated using
Formula (3) for the particle counter channels recommended by ISO 16890-2.
Table 3 — Example of the standardized urban and rural particle volume distributions, q , in
ambient air for the particle size channels recommended by ISO 16890-2
Optical particle diameter in µm Discrete particle volume distribution
d d urban rural
i i+1
Δlndd= ln(/ d )
dd=⋅d
ii+1 i
ii i+1
qd() qd()
3u i 3r i
0,30 0,40 0,35 0,29 0,226 27 0,094 12
0,40 0,55 0,47 0,32 0,198 91 0,083 95
0,55 0,70 0,62 0,24 0,158 37 0,074 32
0,70 1,00 0,84 0,36 0,115 22 0,070 14
1,00 1,30 1,14 0,26 0,085 03 0,076 28
1,30 1,60 1,44 0,21 0,076 18 0,088 33
1,60 2,20 1,88 0,32 0,080 22 0,108 04
2,20 3,00 2,57 0,31 0,099 84 0,137 26
3,00 4,00 3,46 0,29 0,126 88 0,167 08
4,00 5,50 4,69 0,32 0,155 56 0,195 42
5,50 7,00 6,20 0,24 0,177 57 0,216 71
7,00 10,0 8,37 0,36 0,191 57 0,231 43
NOTE The differences between aerodynamic and optical particle diameters are neglected in this part of
ISO 16890. Additionally, it is assumed that the particle density is constant while in actual ambient air it may
depend on the particle size.
8 © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
7.2 Calculation of the particulate matter efficiencies (ePM)
The particulate matter efficiencies ePM , ePM and ePM are calculated from the average fractional
10 2,5 1
efficiencies E , [see Formula (1)] and the standardized particle size distribution defined in 7.1 [see
A,i
Formula (3)] by using Formula (4).
n n
eEPM =⋅qd()⋅⋅ΔΔlndq/(dd) ln (urban size distribution),
∑∑
1A,ii3u ii3u i
i1==i 1
n n
eEPM =⋅qd()⋅⋅ΔΔlndq/(dd) ln (urban size distribution),
∑∑
2,5A,ii3u ii3u i
i1==i 1
n n
eEPM =⋅qd()⋅⋅ΔΔlndq/(dd) ln (rural size distribution) (4)
∑∑
10 A3,iir ii3r i
i1==i 1
where dd=⋅d is the geometric mean diameter and Δlndd=−ln lndd= ln(/ d ) .
ii i+1 ii++11ii i
In Formula (4), i is the number of the channel (size range) of the particle counter under consideration
and n is the number of the channel (size range) which includes the particle size, x (d < x ≤ d ),
n n+1
where x = 10 µm for ePM , x = 2,5 µm for ePM and x = 1 µm for ePM . For the determination of
10 2,5 1
the efficiency ePM , the upper limit of the largest channel considered in Formula (4) shall be equal to
1 µm (d = 1 µm); for ePM it shall not be larger than 3,0 µm (d ≤ 3,0 µm). To determine the
n+1 2,5 n+1
efficiency, ePM , the upper limit of the largest channel considered in Formula (4) shall be equal to
10 µm (d = 10 µm). The lower size limit of the smallest channel of the particle counter taken into
n+1
account for the calculation of the efficiency values, ePM shall be equal to 0,3 µm (d = 0,3 µm). The
x 1
minimum number of channels considered in Formula (4) shall be 3 for ePM (n ≥ 3), 6 for ePM (n ≥ 6)
1 2,5
and 9 for ePM (n ≥ 9). In any case, all channels used shall be adjacent not missing out or overlapping
any particle size in-between.
Additionally, the minimum efficiencies, ePM and ePM are defined by Formula (5).
2,5, min 1, min
n n
eEPM =⋅qd()⋅⋅ΔΔlndq/(dd) ln (5)
∑∑
xi, minD, 3u ii 3u ii
i1==i 1
7.3 Classification
The initial arrestance and the three efficiency values ePM , ePM and ePM and the minimum
1 2,5 10
efficiency values ePM and ePM shall be used to classify a filter in one of the four groups
1, min 2,5, min
given in Table 4.
Table 4 — Filter groups
Requirement
Class reporting
Group designation
value
ePM ePM ePM
1, min 2,5, min 10
Initial grav.
ISO Coarse — — <50 %
arrestance
ISO ePM10 — — ≥50 % ePM
ISO ePM2,5 — ≥50 % — ePM
2,5
ISO ePM1 ≥50 % — — ePM
The filter classes are reported as class reporting value in conjunction with the group designation. For
the reporting of the ePM classes, the class reporting values shall be rounded downwards to the nearest
multiple of 5 % points. Values larger than 95 % are reported as “>95 %”. Examples of reporting classes
are ISO Coarse 60 %, ISO ePM10 60 %, ISO ePM2,5 80 %, ISO ePM1 85 % or ISO ePM1 >95 %. Except for
filters of the group ISO Coarse, the dust loading in accordance to ISO 16890-3 and the measurement of
ISO 16890-1:2016(E)
the initial arrestance is optional. ISO coarse filters can be classified only based on the initial arrestance
and, hence, in this case, the measurement of the ePM efficiency values is optional.
x
NOTE When the test is carried out on a test rig which was originally designed to perform tests according to
the EN 779:2012 only using an aerosol consisting of untreated and undiluted DEHS or an equivalent liquid test
aerosol for the size range from 0,3 µm to 1 µm, for an ISO ePM1 dust filter (ePM ≥ 50%), it is allowable only
1, min
to report the efficiencies ePM and ePM and, in this case, only to use these two values to determine the filter
1, min 1
group and class.
Based on the test results and Table 4, filters could be assigned to two or more filter groups. For example,
a filter classified as ISO ePM1 85 % could also be classified as ISO ePM10 95 %. However, according
to this part of ISO 16890, filters shall be classified into one individual group only and only this one
classification shall be shown on the filter’s label. Nevertheless, in a full summary report, all five ePM
x
efficiency values shall be reported, namely the three efficiency values ePM , ePM and ePM and the
1 2,5 10
minimum efficiency values ePM and ePM . The reporting of the initial arrestance is optional,
1, min 2,5, min
except for ISO Coarse filters, where this value determines the filter class and, hence, its reporting is
mandatory. The efficiency comparison of different filters shall be done only within the same ISO group,
e.g. comparing ePM of filter A with ePM of filter B.
1 1
8 Reporting
8.1 General
Data given in the summary report are based on the data and test reports generated from ISO 16890-2,
ISO 16890-3 and/or ISO 16890-4 and the data analyses and classification defined in 7.3. At a minimum,
the summary test report shall include a description of the test method(s) and any deviations from it.
The summary report shall include the following:
10 © ISO 2016 – All rights reserved

ISO 16890-1:2016(E)
— type of filter;
— the number of this part of ISO 16890;
— test number;
— test aerosol;
— test air flow rate;
— summary of the results;
— measured initial fractional efficiency curve as a function of the particle size from a test report
according to ISO 16890-2;
— measured fractional efficiency curve as a function of the particle size from a test report according
to ISO 16890-2 after an artificial ageing step according to ISO 16890-4;
— ca
...