SIST EN 779:2004
(Main)Particulate air filters for general ventilation - Determination of the filtration performance
Particulate air filters for general ventilation - Determination of the filtration performance
This European Standard refers to particulate air filters for general ventilation. These filters are classified according to their performance as measured in this test procedure. This European Standard contains requirements to be met by particulate air filters. It describes testing methods and the test-rig for measuring filter performance.
Partikel-Luftfilter für die allgemeine Raumlufttechnik - Bestimmung der Filterleistung
Diese Europäische Norm gilt für Partikel-Luftfilter für die allgemeine Raumlufttechnik. Diese Filter werden entsprechend ihrer Leistung klassifiziert, die nach diesem Prüfverfahren gemessen wird.
Diese Europäische Norm enthält Anforderungen für Partikel-Luftfilter. Sie beschreibt Prüfverfahren und den Prüfstand zur Messung der Filterleistung.
Um Ergebnisse zu Vergleichs- und Klassifizierungszwecken zu erhalten, werden Partikel-Luftfilter mit zwei synthetischen Aerosolen geprüft, und zwar mit einem feinen Aerosol zur Messung des Wirkungsgrades in Abhängigkeit von der Partikelgröße in einem Partikelgrößenbereich von 0,2 µm bis 3,0 µm und einem groben Aerosol, um Informationen über die Staubspeicherfähigkeit und bei Grobstaubfiltern auch über den Abscheidegrad hinsichtlich groben Staubes (Abscheidung) zu erhalten.
Diese Europäische Norm gilt für Luftfilter, die mit einem Volumenstrom im Bereich von 0,24 m3/s (850 m3/h) bis 1,5 m3/s (5400 m3/h) geprüft werden und deren Anfangswirkungsgrad (mit feinem Aerosol) für Partikel von 0,4 µm geringer als 98 % ist.
Die gemäß dieser Norm erhaltenen Leistungsergebnisse können nicht unmittelbar zur quantitativen Vorhersage von Wirkungsgrad und Lebensdauer für den Anwendungsfall des Filters benutzt werden. Andere sich auf die Leistung auswirkende Faktoren, die berücksichtigt werden müssen, werden in Anhang A (normativ) und Anhang B (informativ) beschrieben.
Filtres a air de ventilation général pour l'élimination des particules - Détermination des performances de filtration
La présente Norme européenne traite des filtres a air utilisés pour capter les particules en ventilation générale. Ces filtres sont classés selon leur rendement, mesuré suivant la présente procédure d'essai.
La présente Norme européenne renferme les exigences que doivent remplir les filtres a air. Elle décrit des méthodes d'essai ainsi que le banc d'essai a utiliser pour mesurer le rendement des filtres.
Pour permettre une comparaison des résultats, et donc une classification, il convient de contrôler les filtres a air avec deux aérosols synthétiques, un aérosol fin pour mesurer le rendement de filtration en tant que fonction de la taille des particules avec une plage de dimensions de particules de 0,2 µm a 3,0 µm, et un aérosol grossier pour obtenir des informations a propos de la capacité de colmatage et, dans le cas des filtres grossiers, l'efficacité de filtration vis a vis de la poussiere de chargement grossiere (rendement gravimétrique).
La présente Norme européenne s'applique aux filtres ayant un rendement initial inférieur a 98 % pour des particules de 0,4 µm. Il convient que les filtres soient etre soumis a l'essai a des débits d'air compris entre 0,24 m3/s (850 m3/h) et 1,5 m3/s (5 400 m3/h).
Les résultats obtenus a l'aide de la présente norme ne peuvent pas etre utilisés quantitativement pour prévoir le rendement d'un filtre en service, en ce qui concerne a la fois le rendement et la durée de vie. Les influences a prendre en compte sont décrites dans l'annexe A (normative) et l'annexe B (informative).
Particulate air filters for general ventilation - Determination of the filtration performance
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 779:2004
01-maj-2004
1DGRPHãþD
SIST EN 779:2000
Particulate air filters for general ventilation - Determination of the filtration
performance
Particulate air filters for general ventilation - Determination of the filtration performance
Partikel-Luftfilter für die allgemeine Raumlufttechnik - Bestimmung der Filterleistung
Filtres a air de ventilation général pour l'élimination des particules - Détermination des
performances de filtration
Ta slovenski standard je istoveten z: EN 779:2002
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
SIST EN 779:2004 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN 779
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2002
ICS 91.140.30 Supersedes EN 779:1993
English version
Particulate air filters for general ventilation - Determination of the
filtration performance
Filtres à air de ventilation générale pour l'élimination des Partikel-Luftfilter für die allgemeine Raumlufttechnik -
particules - Détermination des performances de filtration Bestimmung der Filterleistung
This European Standard was approved by CEN on 14 September 2002.
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 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 Management Centre 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, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 779:2002 E
worldwide for CEN national Members.
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EN 779:2002 (E)
Contents
page
Foreword.4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions.6
4 Symbols and abbreviated terms.9
5 Requirements .11
6 Classification.11
7 Test rig and equipment .12
7.1 Test conditions .12
7.2 Test rig .12
7.3 Aerosol generation .16
7.3.1 DEHS Test Aerosol .16
7.3.2 Neutralisation (conditioning) of aerosol.16
7.4 Aerosol sampling system .18
7.5 Flow measurement .20
7.6 Particle counter.20
7.7 Differential pressure measuring equipment .20
7.8 Dust feeder .20
8 Qualification of test rig and apparatus .23
8.1 Air velocity uniformity in the test duct .23
8.2 Aerosol uniformity in the test duct .23
8.3 Particle counter sizing accuracy.24
8.4 Particle counter zero test.25
8.5 Particle counter overload test .25
8.6 100 % efficiency test.25
8.7 Zero % efficiency test .26
8.8 Aerosol generator response time.26
8.9 Pressure equipment calibration .26
8.10 Pressure drop checking.26
8.11 Dust feeder air flow rate.27
8.12 Neutraliser .29
8.13 Summary of qualification requirements .29
8.14 Apparatus maintenance .30
9 Test materials.30
9.1 Test air - cleanliness, temperature and humidity .30
9.2 Test aerosol.30
9.3 Loading dust.31
9.4 Final filter.31
10 Test procedure .32
10.1 Preparation of filter to be tested.32
10.2 Initial pressure drop .32
10.3 Initial efficiency .32
10.3.1 Efficiency of discharged filter media .32
10.3.2 Efficiency measurement.32
10.4 Dust loading .33
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EN 779:2002 (E)
10.4.1 Dust loading procedure.33
10.4.2 Arrestance .34
10.4.3 Efficiency .35
10.4.4 Average efficiency .35
10.4.5 Dust holding capacity.35
11 Uncertainty calculation of the test results .36
12 Reporting .37
12.1 General.37
12.2 Summary.38
12.3 Efficiency .39
12.4 Pressure drop and air flow rate.40
12.5 Arrestance and dust holding capacity.40
12.6 Marking .40
Annex A (normative) Electrostatic discharging procedure .49
A.1 General.49
A.2 Test method for discharging of filter material .49
A.2.1 Equipment .49
A.2.2 Preparation of test samples.50
A.2.3 Measurement of the filter efficiency .50
A.2.4 Isopropanol test.50
A.3 Expression of results .50
Annex B (informative) Shedding from filters.51
B.1 General.51
B.2 Shedding.51
B.2.1 Particle bounce .51
B.2.2 Release of fibres or particulate matter from filter material .51
B.2.3 Re-entrainment of particles .51
B.3 Testing .52
B.4 References.52
Annex C (informative) Commentary .53
C.1 General.53
C.2 Classification.53
C.3 Test.53
C.3.1 Test aerosol.53
C.3.2 Loading dust .54
C.3.3 Distribution and sampling of aerosols .54
C.3.4 Particle counter characteristics .54
C.3.5 Flat sheet test.54
C.4 Filtration characteristics .55
C.4.1 General.55
C.4.2 Pressure drop.55
C.4.3 Discharged efficiency.55
Annex D (informative) Pressure drop calculation.57
Annex E (informative) Example of a completed test report .59
E.1 Example of test reports.59
E.2 Examples of calculations.67
A.3 Final results at 450 Pa .70
Bibliography .71
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EN 779:2002 (E)
Foreword
This document (EN 779:2002) has been prepared by Technical Committee CEN/TC 195 "Air filters for general air
cleaning", the secretariat of which is held by DIN.
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 May 2003, and conflicting national standards shall be withdrawn at the latest by
May 2003.
This European Standard deals with the performance testing of particulate air filters for general ventilation and su-
persedes EN 779:1993, which describes an obsolete test method.
EN 779 is based on the test method according to Eurovent 4/9:1997. In addition, it contains extensive test rig quali-
fication procedures together with procedures which give some information regarding the real life behaviour of par-
ticulate air filters (see ”Introduction”).
Annex A is normative. Annexes B to E are informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following coun-
tries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Swe-
den, Switzerland and the United Kingdom.
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EN 779:2002 (E)
Introduction
General
The procedures described in this standard have been developed from those given in EN 779:1993 and Eurovent
4/9:1997. The basic design of test rig given in EN 779:1993 is retained with the exception of the “dust-spot” atmos-
pheric aerosol opacity test equipment. Instead, a challenge aerosol of DEHS (or equivalent) is dispersed evenly
across the duct upstream of the filter being tested. Representative upstream and downstream samples are ana-
lysed by an optical particle counter (OPC) to provide filter particle size efficiency data.
Classification
The EN 779:1993 classification system (comprising groups F and G filters) has been retained; classification is now
determined from the average filtration efficiency with respect to liquid DEHS particles of 0,4 μm diameter. Classifi-
cation of F filters is based on performance with respect to 0,4 mm particles because of practical evidence that the
EN 779:1993 classification based on the “dust-spot” opacity test is very closely matched. Filters found to have an
average efficiency value of less then 40 % will be allocated to group G and the efficiency reported as
“< 40 %”. The classification of G filters is based on their average arrestance with the loading dust.
Test aerosol
A challenge aerosol of DEHS (or equivalent) was chosen for the efficiency test for the following reasons:
experience has already been gained by users of the Eurovent 4/9 test method so that much suitable equip-
ment already exists;
liquid aerosols are easy to generate in the concentrations, size range and degree of consistency required;
the DEHS could be used as a neutral test aerosol without charge or be charged to the Boltzmann equilibrium
charge level. In this standard the aerosol should be brought to the Boltzmann charge distribution;
spherical latex particles are used to calibrate particle counters. The determination of the particle size of spheri-
cal liquid particles using optical particle counters is more accurate than would be the case with solid particles
of nonspherical salt and test dusts.
The aerosol should be brought to the Boltzmann charge distribution to represent the charge distribution of aged
ambient atmospheric aerosol.
Filtration characteristics
Initiatives to address the potential problems of particle re-entrainment, shedding and the in-service charge neutrali-
sation characteristics of certain types of media have been included in annexes A and B.
Certain types of filter media rely on electrostatic effects to achieve high efficiencies at low resistance to air flow.
Exposure to some types of challenge, such as combustion particles in normal atmospheric air or oil mist, may neu-
tralise such charges with the result that filter performance suffers. It is important that the users are aware of the
potential for performance degradation when loss of charge occurs. It is also important that means be available for
identifying cases where the potential exists. The normative test procedure, described in annex A, provides tech-
niques for identifying this type of behaviour. This procedure is used to determine whether the filter efficiency is de-
pendent on the electrostatic removal mechanism and to provide quantitative information about the importance of
the electrostatic removal.
In an ideal filtration process, each particle would be permanently arrested at the first contact with a filter fibre, but
incoming particles may impact on a captured particle and dislodge it into the air stream. Fibres or particles from the
filter itself could also be released, due to mechanical forces. From the user’s point of view it might be important to
5
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EN 779:2002 (E)
know this, but such behaviour would probably not be detected by a particle counter system according to this stan-
dard.
1 Scope
This European Standard refers to particulate air filters for general ventilation. These filters are classified according
to their performance as measured in this test procedure.
This European Standard contains requirements to be met by particulate air filters. It describes testing methods and
the test rig for measuring filter performance.
In order to obtain results for comparison and classification purposes, particulate air filters are tested against two
synthetic aerosols, a fine aerosol for measurement of filtration efficiency as a function of particle size within a parti-
cle size range 0,2 mm to 3,0 mm, and a coarse one for obtaining information about dust holding capacity and, in the
case of coarse filters, filtration efficiency with respect to coarse loading dust (arrestance).
This European Standard applies to air filters having an initial efficiency of less than 98 % with respect to 0,4 μm
3 3 3 3
particles. Filters should be tested at an air flow rate between 0,24 m /s (850 m /h) and 1,5 m /s (5 400 m /h).
The performance results obtained in accordance with this standard 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 (normative) and annex B (informative).
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
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 (including amendments).
EN 1822-1, High efficiency air filters (HEPA and ULPA) - Part 1: Classification, performance testing, marking.
EN ISO 5167-1:1995, Measurement of fluid flow by means of pressure differential devices - Part 1: Orifice plates,
nozzles and Venturi tubes inserted in circular cross-section conduits running full (ISO 5167-1:1991).
ISO 2854, Statistical interpretation of data - Techniques of estimation and tests relating to means and variances.
ISO 12103-1, Road vehicles - Test dust for filter evaluation - Part 1: Arizona test dust.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
arrestance
weighted (mass) removal of loading dust (expressed in %)
3.2
average arrestance
ratio of the total amount of loading dust retained by the filter to the total amount of dust fed up to final pressure
drop. Average arrestance is used for classification of G-filters (expressed in %)
3.3
average efficiency - E
m
weighted average of the efficiencies for the different specified dust loading levels up to final pressure drop. Average
efficiency is used for classification of F-filters (expressed in %)
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EN 779:2002 (E)
3.4
average efficiency - E
i,j
average efficiency for a size range ”i” at different dust loading intervals ”j” (expressed in %)
3.5
charged filter
filter which is electrostatically charged or polarised
3.6
coarse filter
filter classified in one of the classes G1 to G4
3.7
counting rate
number of counting events per unit of time
3.8
DEHS
liquid (DiEthylHexylSebacate) for generating the test aerosol
3.9
dust holding capacity
amount of loading dust retained by the filter up to final pressure drop (expressed in grams)
3.10
face area
area of the inside section of the test duct immediately upstream of the filter under test (nominal values
2
0,61 m · 0,61 m = 0,37 m )
3.11
face velocity
air flow rate divided by the face area (expressed in m/s)
3.12
final filter
air filter used to collect the loading dust passing the filter under test
3.13
final pressure drop - recommended
maximum operating pressure drop of the filter as recommended by the manufacturer at rated air flow (expressed in
Pa)
3.14
final pressure drop
pressure drop up to which the filtration performance is measured for classification purposes (expressed in Pa)
3.15
fine filter
filter classified in one of the classes F5 to F9
3.16
HEPA filter
High Efficiency Particulate Air Filter, classes H10 to H14 according to EN 1822-1. A filter intended to purify the air
upstream of the test circuit
3.17
ULPA filter
Ultra Low Penetration Air Filter, classes U15 to U17 according to EN 1822-1
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EN 779:2002 (E)
3.18
initial arrestance
arrestance of the first 30 g loading dust increment (expressed in %)
3.19
initial efficiency
efficiency of the clean filter operating at the test air flow rate (expressed in % for each size range of selected parti-
cles)
3.20
initial pressure drop
pressure drop of the clean filter operating at its test air flow rate (expressed in Pa)
3.21
isokinetic sampling
sampling of the air within a duct such the probe inlet air velocity is the same as the velocity in the duct at the sam-
pling point
3.22
loading dust
synthetic test dust specifically formulated for determining the dust holding capacity and arrestance of the filter
3.23
mean diameter
geometric average of the size range diameter (expressed in μm)
3.24
media velocity
air flow rate divided by the net effective filtering area (expressed in m/s to an accuracy of three significant figures)
3.25
net effective filtering area
2
area of filter medium in the filter which collects dust (expressed in m )
3.26
neutralisation
bringing the aerosol to a Boltzmann charge distribution (same amount of positive as negative ions in the aerosol)
3.27
particle bounce
it describes the behaviour of particles that impinge on the filter without being retained
3.28
particle size
equivalent optical diameter of a particle
3.29
particle number concentration
number of particles per unit of volume of the test air
3.30
penetration
ratio of the particle concentration downstream to upstream of the filter (expressed in %)
3.31
re-entrainment
releasing to the air flow of particles previously collected on the filter
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EN 779:2002 (E)
3.32
shedding
releasing to the air flow of particles due to particle bounce and re-entrainment effects, and to the release of fibres or
particulate matter from the filter or filtering material
3.33
synthetic test dust
dust specifically formulated for determining the dust holding capacity and arrestance of the filter
3.34
test air flow rate
3
volumetric rate of air flow through the filter under test (expressed in m /s for a reference air density of
3
1,20 kg/m )
3.35
test aerosol
aerosol used for determining the efficiency of the filter
3.36
test air
air to be used for testing purposes
4 Symbols and abbreviated terms
For the application of this European Standard, the following symbols and abbreviated terms apply.
A Arrestance
A Arrestance in loading phase ”j”, %
j
A A
...
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