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BRITISH STANDARD BS EN
1822-1:1998
The European Standard EN 1822-1:1998 has the status of a
British Standard
ICS 23.120
NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW
High efficiency air
filters (HEPA and
ULPA) Ð
Part 1: Classification, performance
testing, marking
This British Standard, having
been prepared under the
direction of the Engineering
Sector Board, was published
under the authority of the
Standards Board and comes into
effect on 15 November 1998
BSI 1998
ISBN 0 580 29837 X
BS EN 1822-1:1998
Amendments issued since publication
Amd. No. Date Text affected
National foreword
This British Standard is the English language version of EN 1822-1:1998.
The UK participation in its preparation was entrusted by Technical Committee
MCE/21, Filters for gases and liquids, to Subcommittee MCE/21/3, Air filters other
than for air supply for IC engines and compressors, which has the responsibility to:
Ð aid enquirers to understand the text;
Ð present to the responsible European committee any enquiries on the
interpretation, or proposals for change, and keep the UK interests informed;
Ð monitor related international and European developments and promulgate
them in the UK.
A list of organizations represented on this committee can be obtained on request to
its secretary.
Cross-references
The British Standards which implement international or European publications
referred to in this document may be found in the BSI Standards Catalogue under the
section entitled ªInternational Standards Correspondence Indexº, or by using the
ªFindº facility of the BSI Standards Electronic Catalogue.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
Compliance with a British Standard does not of itself confer immunity
from legal obligations.
Summary of pages
This document comprises a front cover, an inside front cover, the EN title page,
pages 2 to 12, an inside back cover and a back cover.
CEN
European Committee for Standardization
Comite EuropeÂen de Normalisation
EuropaÈisches Komitee fuÈ r Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national
Members.
Ref. No. EN 1822-1:1998 E
EUROPEAN STANDARD EN 1822-1
NORME EUROPEÂ ENNE
EUROPAÈ ISCHE NORM April 1998
ICS 23.120
Descriptors: air filters, cleaning equipment for gases, ventilation, air conditioning, definitions, classifications, specifications, tests,
aerosols, test conditions, effectiveness
English version
High efficiency air filters (HEPA and ULPA) Ð
Part 1: Classification, performance testing, marking
Filtres aÁ air aÁ treÁs haute efficacite et filtres aÁ air aÁ
treÁs faible peÂneÂtration (HEPA et ULPA) Ð
Partie 1: Classification, essais de performance et
marquage
Schwebstoffilter (HEPA und ULPA) Ð
Teil 1: Klassifikation, LeistungspruÈfung,
Kennzeichnung
This European Standard was approved by CEN on 6 March 1998.
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 Central Secretariat 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 Central Secretariat has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and
United Kingdom.
Page 2
EN 1822-1:1998
BSI 1998
Foreword
This European Standard has been prepared by
Technical Committee CEN/TC 195, Air filters for
general air cleaning, the secretariat of which is held by
DIN.
It is dealing with the performance testing of high
efficiency particulate air filters (HEPA) and ultra low
penetration air filters (ULPA).
The complete European Standard High efficiency air
filters (HEPA and ULPA) will consist of the following
parts:
Part 1 Classification, performance testing,
marking
Part 2 Aerosol production, measuring equipment,
particle counting statistics
Part 3 Testing flat sheet filter media
Part 4 Determining leakage of filter elements
(Scan method)
Part 5 Determining the efficiency of filter elements
As decided by CEN/TC 195, this European Standard is
based on particle counting methods which actually
cover most needs of different applications. The
difference between this European Standard and
previous national standards lies in the technique used
for the determination of the overall efficiency. Instead
of mass relationships, this new technique is based on
particle counting at the most penetrating particle size
(MPPS; range: 0,15 to 0,30 mm). It also allows ultra low
penetration air filters to be tested, which is not
possible with the previous test methods because of
their inadequate sensitivity.
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 October 1998,
and conflicting national standards shall be withdrawn
at the latest by October 1998.
According to the CEN/CENELEC Internal Regulations,
the national standards organizations of the following
countries are bound to implement this European
standard: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Iceland, Ireland,
Italy, Luxembourg, Netherlands, Norway, Portugal,
Spain, Sweden, Switzerland and the United Kingdom.
Contents
Page
Foreword 2
1 Scope 3
2 Normative references 3
3 Definitions, symbols and abbreviations 3
3.1 Definitions 3
3.2 Symbols and abbreviations 4
4 Classification 4
4.1 Groups of filters 4
4.2 Classes of filters 4
5 Requirements 5
5.1 General 5
5.2 Material 5
5.3 Nominal air volume flow rate 5
5.4 Pressure difference 5
5.5 Filtration performance 5
6 Test methods 5
6.1 Test rigs 5
6.2 Test conditions 5
6.3 Test aerosols 5
6.4 Survey of test procedures 5
6.5 Test procedures 6
7 Assessment of the filter,
documentation 12
8 Marking 12
Page 3
EN 1822-1:1998
BSI 1998
1 Scope
This European Standard applies to high efficiency
particulate and ultra low penetration air filters
(HEPA and ULPA) used in the field of ventilation and
air conditioning and for technical processes, e.g. for
clean room technology or applications in the nuclear
and pharmaceutical industry.
It establishes a procedure for the determination of the
efficiency on the basis of a particle counting method
using a liquid test aerosol, and allows a standardized
classification of these filters in terms of their efficiency.
2 Normative references
This European Standard incorporates by dated or
undated reference, provisions from other publications.
Theses normative references are cited at the
appropriate places in the text and the publications are
listed hereafter. For dated references, subsequent
amendments to or revisions of any of these
publications apply to this European Standard only
when incorporated in it by amendment or revision. For
undated references the latest edition of the publication
referred to applies.
EN 1822-2, High efficiency air filters (HEPA and
ULPA) Ð Part 2: Aerosol production, measuring
equipment, particle counting statistics.
EN 1882-3, High efficiency air filters (HEPA and
ULPA) Ð Part 3: Testing flat sheet filter media.
prEN 1882-4, High efficiency air filters (HEPA and
ULPA) Ð Part 4: Determining leakage of filter
elements (Scan method).
prEN 1882-5, High efficiency air filters (HEPA and
ULPA) Ð Part 5: Determining the efficiency of filter
elements.
EN ISO 5167-1, Measurement of fluid flow by means of
pressure differential device Ð Part 1: Orifice plates,
nozzles and Venturi tubes inserted in circular cross-
section conduits running full
(ISO 5167-1:1991).
3 Definitions, symbols and
abbreviations
3.1 Definitions
For the purposes of this standard, the following
definitions apply.
3.1.1
filter medium
flat sheet filter material, unfolded
3.1.2
folded pack
a pack of the filter medium formed by uniform
individual folds
3.1.3
filter element (filter)
a folded pack enclosed by a frame
3.1.4
penetration
the ratio of the particle number concentration
downstream of the filter to the concentration upstream
3.1.5
efficiency
the ratio of the number of particles held back by the
filter to the number of the particles impinging on the
filter
3.1.6
particle size efficiency
the efficiency for a specific particle diameter. The
efficiency plotted as a function of the particle diameter
gives the efficiency curve
3.1.7
minimum filter efficiency
the minimum of the efficiency curve under given
operating conditions of the filter (see 3.1.24)
3.1.8
overall efficiency
the efficiency, averaged over the whole superficial face
area of a filter element under given operating
conditions of the filter
3.1.9
local efficiency
the efficiency at a specific point of the filter element
under given operating conditions of the filter
3.1.10
nominal air volume flow rate
the air volume flow rate for which the filter element to
be tested is specified
3.1.11
filter face area
the cross-sectional area of the filter element including
the frame
3.1.12
superficial face area
the cross-sectional area of the filter element which is
passed by the air flow
3.1.13
effective filter medium area
the effective cross-sectional area of the filter medium
in the filter element (without adhesive areas,
struts etc.) which is passed by the air flow
3.1.14
nominal filter medium face velocity
the nominal air volume flow rate divided by the
effective filter medium area
Page 4
EN 1822-1:1998
BSI 1998
3.1.15
leak
a point in the filter element at which the local
efficiency falls below a given limit value
3.1.16
particle number concentration
the number of particles per unit volume of the carrier
gas (air)
3.1.17
counting rate
the number of counting events per unit time
3.1.18
particle size
the geometrical diameter of the particles of the test
aerosol
3.1.19
mean particle diameter
median value of the particle number distribution of the
test aerosol
3.1.20
monodisperse
an aerosol is referred to as monodisperse when the
width of its distribution function, described by the
geometric standard deviation, is less than sg = 1,15.
Aerosols whose distribution has a geometric standard
deviation between sg = 1,15 and sg = 1,5 are referred to
as quasi-monodisperse
3.1.21
polydisperse
an aerosol is referred to as polydisperse if its
distribution shows a geometric standard deviation of
sg > 1,5
3.1.22
HEPA filter
high efficiency particulate air filter, classes H 10 to H 14
(see Table 1)
3.1.23
ULPA filter
ultra low penetration air filter, classes U 15 to U 17
(see Table 1)
3.1.24
most penetrating particle size (MPPS)
the particle size at which the minimum of the particle
size efficiency curve occurs (see 3.1.7)
3.2 Symbols and abbreviations
For the purposes of this standard, the following
symbols and abbreviations apply.
dp Particle diameter
E Efficiency
P Penetration
p Pressure
RH Relative humidity
T Temperature
sg Geometric standard deviation
CNC Condensation nucleus counter
DEHS Sebacic acid-bis (2-ethyl hexyl-) ester
(trivial name: di-ethyl-hexyl-sebacate)
DMA Differential electric mobility analyser
DMPS Differential mobility particle sizer
DOP Phthalic acid-bis (2-ethyl hexyl-) ester
(trivial name: di-octyl-phthalate)
MPPS Most penetrating particle size
OPC Optical particle counter
4 Classification
Filter elements are classified in groups and classes
according to their filtration performance (efficiency or
penetration).
4.1 Groups of filters
According to this standard, filter elements fall into one
of the following groups:
Ð group H: HEPA filters;
Ð group U: ULPA filters.
4.2 Classes of filters
Filter elements of group H and U are classified
according to their performance (see 5.5).
Group H filters are subdivided in five classes:
Ð H 10
Ð H 11
Ð H 12
Ð H 13
Ð H 14
Group U filters are subdivided in three classes:
Ð U 15
Ð U 16
Ð U 17
Page 5
EN 1822-1:1998
BSI 1998
Table 1 Ð Classification of HEPA and ULPA filters
Filter class Overall value Local value1) 2)
Efficiency (%) Penetration (%) Efficiency (%) Penetration (%)
H 10 85 15 Ð Ð
H 11 95 5 Ð Ð
H 12 99,5 0,5 Ð Ð
H 13 99,95 0,05 99,75 0,25
H 14 99,995 0,005 99,975 0,025
U 15 99,999 5 0,000 5 99,997 5 0,002 5
U 16 99,999 95 0,000 05 99,999 75 0,000 25
U 17 99,999 995 0,000 005 99,999 9 0,000 1
1) See 6.5.2 and prEN 1822-4.
2) Local values lower than those given in the Table may be agreed between supplier and purchaser.
5 Requirements
5.1 General
The filter element shall be designed or marked so as to
prevent incorrect mounting.
The filter element shall be designed so that when
correctly mounted in the ventilation duct, no leak
occurs at the sealing edge.
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 is permitted,
provided no leaks occur in the resulting filter.
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 so that it will
withstand mechanical constraints that are likely to be
encountered during normal use.
Dust or fibres released from the filter media by the air
flow through the filter element shall not constitute a
hazard or nuisance for the people (or devices) exposed
to filtered air.
5.3 Nominal air volume flow rate
The filter element shall be tested at its nominal air
volume flow rate for which the filter has been
designed by the manufacturer.
5.4 Pressure difference
The pressure difference across the filter element is
recorded at the norminal air volume flow rate.
5.5 Filtration performance
The filtration performance is expressed by the
efficiency or penetration.
After testing in accordance with clause 6, filter
elements are classified according to Table 1.
6 Test methods
6.1 Test rigs
The test rigs are described in detail in EN 1822-3,
prEN 1822-4 and prEN 1822-5. The individual methods
of measurement and the measuring instruments are
described in EN 1822-2.
6.2 Test conditions
The air in the test channel used for testing shall
comply with the following requirements:
Temperature: 23 8C ± 5 8C
Relative humidity < 75 %
The temperature and relative humidity shall remain
constant over a longer period of time.
The cleanliness of the test air shall be ensured by
appropriate pre-filtering, so that in operation without
addition of aerosol the particle number concentration
measured with the particle counting method is less
than 350 000 m23. The test specimen shall have the
same temperature as the test air.
6.3 Test aerosols
For the testing of HEPA and ULPA filters in
accordance with this standard, a liquid particle test
aerosol shall be used. Possible substances include but
are not limited to DEHS, DOP, paraffin oil (low
viscosity). For further details see 4.1 of EN 1822-2:1998.
NOTE The use of alternative materials for challenge aerosols
may also be agreed between supplier and purchaser when the
materials specified in this standard are unacceptable.
The concentration and the size distribution of the
aerosol shall be constant over time. For the leakage
testing and the efficiency test of the filter element the
mean particle diameter of the test aerosol shall
correspond to the most penetrating particle size
(MPPS) for the filter medium.
6.4 Survey of test procedures
The complete testing procedure for HEPA and ULPA
filters in accordance with this standard consists of
three steps, each of which may be implemented as an
independent test.
Page 6
EN 1822-1:1998
BSI 1998
6.4.1 Step 1
Firstly the efficiency of test samples of the filter
medium shall be determined for a range of particle
sizes at the nominal filter medium velocity. From the
efficiency vs particle size curve the most penetrating
particle size (MPPS) shall be determined, for which the
filtration efficiency of the filter medium is at a
minimum.
See 6.5.1.
6.4.2 Step 2
The filter element is tested at nominal air volume flow
rate for freedom from leaks using a test aerosol with a
mean particle size which corresponds to the MPPS.
See 6.5.2.
6.4.3 Step 3
Using the same test aerosol, again at the nominal air
volume flow rate, the overall efficiency of the filter
element is determined.
See 6.5.3.
6.4.4 On the basis of the values determined for the
local efficiency (leakage test) and the overall efficiency,
the filter can be assigned to a filter class as specified
in 5.5. This assignment is only valid if the fixed test
conditions are met.
In all three procedural steps it is permissible to use
either a monodisperse or a polydisperse test aerosol.
The particle counting method used may be a total
count method (CNC) or a method involving particle
size analysis (OPC).
Since total count particle counting methods provide no
information about the particle size, they may only be
used to determine the efficiency in procedural
step 1 with monodisperse test aerosols of a known
particle size.
For the determination of the minimum efficiency of the
sheet filter medium (see 6.4.1) the test method using a
monodisperse test aerosol has to be considered as the
reference test method. Care has to be taken for the
correlation with the reference test method if using a
polydisperse aerosol.
6.5 Test procedures
6.5.1 Testing sheet filter media
6.5.1.1 Test samples
The testing procedure requires at least five sheet
samples of the filter material.
The test samples shall be free of folds, creases, holes
and other irregularities. The test samples shall have a
minimum size of 200 mm3 200 mm.
6.5.1.2 Test apparatus
The arrangement of the test apparatus is shown in
Figure 1. An aerosol is produced in the aerosol
generator, then passed through a conditioner (for
example to evaporate a solvent) and neutralized,
before being brought together with the particle-free
mixing air to the test filter mounting assembly.
Upstream and downstream from the test filter
mounting assembly there are sampling points from
which a part of the flow is led to the particle counter.
The upstream sampling point is connected with a
dilution circuit to adjust the high particle concentration
to the measuring range of the particle counter.
When using the total count counting method (CNC) a
differential electric mobility analyser (DMA) is included
before the aerosol neutralizer to separate out a (quasi-)
monodisperse fraction of the required particle size
from the initial polydisperse aerosol.
If a counting method with particle size analysis (OPC)
is used, then the size distribution of a polydisperse
aerosol can be measured before and after the test
specimen.
Instead of using a single particle counter, which
measures the unfiltered and filtered gases
consecutively, it is also permissible to use two particle
counters of equal optical design for both
measurements.
After the downstream sampling point the test aerosol
is led through an exhaust filter and extracted by a
pump. The app