SIST EN ISO 29462:2013

Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow (ISO 29462:2013)

This document describes a procedure of measuring the performance of general ventilation air cleaning devices in their end use installed configuration. The performance measurements include removal efficiency by particle size and the resistance to airflow.  The procedures for test include the definition and reporting of the system airflow.
The procedure describes a method of counting ambient air particles of 0.3um to 5.0um upstream and downstream of the in-place air cleaner(s) in a functioning air handling system.  The procedure describes the reduction of particle counter data to calculate removal efficiency by particle size.  
Since filter installations vary dramatically in design and shape a protocol for evaluating the suitability of a site for filter evaluation and for system evaluation is included.  When the evaluated site conditions meet the minimum criteria established for system evaluation, the performance evaluation of the system can also be performed according to this procedure.  
The procedure for testing also describes performance specifications for the testing equipment and defines procedures of calculating and reporting the results.  This procedure is not intended for measuring performance of portable or movable room air cleaners.  This standard is not intended for evaluation of HEPA or ULPA filter installation(s).

Betriebserprobung von Filtereinrichtungen und -systemen für die allgemeine Lüftung hinsichtlich ihrer Abscheideeffizienz im eingebautem Zustand bezogen auf die Partikelgröße und den Druckverlust (ISO 29462:2013)

Diese Internationale Norm beschreibt ein Verfahren zur Messung der Leistung von Vorrichtungen für die allgemeine Luftreinigung in deren endgültigem Einbauzustand. Die Leistungsmessungen umfassen den Abscheidegrad bezogen auf die Partikelgröße und den Strömungswiderstand. Die Prüfverfahren umfassen die Definition und die Angabe des Systemluftstroms.
Es wird eine Verfahrensweise beschrieben, bei der Partikel der Umgebungsluft mit einer Größe zwischen 0,3 µm und 5,0 µm auf der An  und der Abströmseite der an ihrem Ort befindlichen Luftreiniger in einem ordnungsgemäß arbeitenden Luftbehandlungssystem gezählt werden. Beschrieben wird das Verfahren zur Verringerung der durch den Zähler ermittelten Partikel zum Zwecke der Berechnung des Abscheidegrads bezogen auf die Partikelgröße.
Da Filteranlagen sich hinsichtlich Auslegung und Form beträchtlich voneinander unterscheiden, ist ein Protokoll zur Bewertung der Eignung eines Standorts für die Bewertung des Filters und die Systembewertung enthalten. Sofern die bewerteten Standortbedingungen den für die Systembewertung festgelegten Mindestkriterien entsprechen, kann die Leistungsbewertung des Systems ebenfalls nach diesem Verfahren vorgenommen werden.
Diese Internationale Prüfnorm beschreibt auch die Leistungsspezifikationen für die Prüfausrüstung und definiert Verfahren für die Berechnung und Angabe der Ergebnisse. Diese Norm ist nicht dafür vorgesehen, die Leistung tragbarer oder ortsveränderlicher Raumluftreiniger zu messen oder Filteranlagen mit einem bei einer 0,4 µm zu erwartenden Abscheidegrad von mindestens 99 % oder höchstens 30 % zu bewerten.

Essais in-situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité en fonction de la taille des particules et de la perte de charge (ISO 29462:2013)

L'ISO 29462:2013 décrit un mode opératoire de mesurage des performances des dispositifs de filtration de l'air des ventilations générales dans leur configuration d'utilisation finale. Les mesures de performance intègrent l'efficacité d'élimination en fonction de la taille des particules et de la perte de charge. Les modes opératoires des essais intègrent la définition et la consignation du flux d'air du système.
Le mode opératoire décrit une méthode de comptage des particules dans l'air ambiant de 0,3 μm à 5,0 μm en amont et en aval du ou des filtres à air en place dans un système de traitement de l'air en fonctionnement. Le mode opératoire décrit la détermination des données du compteur de particules pour calculer l'efficacité d'élimination en fonction de la taille des particules.
Puisque les installations de filtration diffèrent considérablement par leur conception et leur forme, il a été inclus un protocole d'évaluation de l'adaptabilité d'un site à l'évaluation des filtres et des systèmes. Lorsque l'évaluation des conditions du site répond aux critères minimaux établis pour l'évaluation du système, il est également possible de réaliser l'évaluation des performances du système conformément à ce mode opératoire.
L'ISO 29462:2013 d'essai décrit également les spécifications de performance des appareils d'essai et définit les modes opératoires de calcul et de consignation des résultats. Elle n'a pas vocation à mesurer les performances de filtres à air portables ou mobiles et n'est pas destinée à évaluer les installations de filtration à rendement de filtration attendu égal ou supérieur à 99 % ou égal ou inférieur à 30 % dans le cas d'une mesure à 0,4 µm.

Terensko preskušanje splošnih prezračevalnih filtrirnih naprav in sistemov na kraju samem (kraju vgradnje) glede učinkovitosti odstranjevanja delcev po njihovi velikosti in glede upornosti proti zračnemu toku (ISO 29462:2013)

Ta mednarodni standard opisuje postopek merjenja zmogljivosti splošnih prezračevalnih filtrirnih naprav v nameščenih konfiguracijah za končno uporabo. Meritve delovanja vključujejo učinkovitost odstranjevanja delcev po njihovi velikosti in upornosti proti zračnemu toku. Postopki za preskus vključujejo opredelitev in poročanje pretoka zraka sistema. Postopek opisuje metodo štetja delcev v zunanjem zraku od 0,3 μm do 5,0 μm za uporabo proti toku in v smeri toka v nameščenih čistilnikih zraka v delujočih sistemih za uravnavanje zraka. Postopek opisuje zmanjševanje podatkov števca delcev za izračun učinkovitosti odstranjevanja glede na velikost delcev. Filtrirne inštalacije se lahko po načrtu in obliki občutno razlikujejo, zato je vključen protokol za ocenjevanje primernosti mesta za ocenjevanje filtra in ocenjevanje sistema. Ko pogoji mesta ocenjevanja dosegajo minimalna merila, določena za ocenjevanje sistema, se lahko po tem postopku izvede ocenjevanje delovanja sistema. Ta mednarodni standard za preskušanje opisuje tudi specifikacije delovanja za preskusno opremo ter določa postopke za izračunavanje in poročanje rezultatov. Ta standard ni namenjen za merjenje delovanja prenosnih ali premičnih čistilnikov zraka v prostorih ali za ocenjevanje filtrirnih inštalacij s pričakovano učinkovitostjo filtracije 99 % ali višjo oziroma 30 % ali nižjo, pri merjenju delcev velikosti 0,4 μm.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 24-Sep-2011
• Publication Date: 25-Jul-2013
• Withdrawal Date: 08-Sep-2022
• ICS: 13.040.20 - Ambient atmospheres
• ICS: 23.120 - Ventilators. Fans. Air-conditioners
• ICS: 91.140.30 - Ventilation and air-conditioning systems
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 08-Sep-2022
• Due Date: 01-Oct-2022
• Completion Date: 09-Sep-2022
• Ref Project: EN ISO 29462:2013 - Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow (ISO 29462:2013)

Relations

• Replaced By: SIST EN ISO 29462:2022 - Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow (ISO 29462:2022)
• Effective Date: 07-Sep-2022
• Revised: SIST EN ISO 29462:2022 - Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow (ISO 29462:2022)
• Effective Date: 02-Oct-2019

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 29462:2013
01-september-2013
7HUHQVNRSUHVNXãDQMHVSORãQLKSUH]UDþHYDOQLKILOWULUQLKQDSUDYLQVLVWHPRYQD
NUDMXVDPHPNUDMXYJUDGQMHJOHGHXþLQNRYLWRVWLRGVWUDQMHYDQMDGHOFHYSRQMLKRYL
YHOLNRVWLLQJOHGHXSRUQRVWLSURWL]UDþQHPXWRNX,62
Field testing of general ventilation filtration devices and systems for in situ removal
efficiency by particle size and resistance to airflow (ISO 29462:2013)
Betriebserprobung von Filtereinrichtungen und -systemen für die allgemeine Lüftung
hinsichtlich ihrer Abscheideeffizienz im eingebautem Zustand bezogen auf die
Partikelgröße und den Druckverlust (ISO 29462:2013)
Essais in-situ de filtres et systèmes de ventilation générale pour la mesure de l'efficacité
en fonction de la taille des particules et de la perte de charge (ISO 29462:2013)
Ta slovenski standard je istoveten z: EN ISO 29462:2013
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
23.120 =UDþQLNL9HWUQLNL.OLPDWVNH Ventilators. Fans. Air-
QDSUDYH conditioners
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
SIST EN ISO 29462:2013 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 29462:2013

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SIST EN ISO 29462:2013


EUROPEAN STANDARD
EN ISO 29462

NORME EUROPÉENNE

EUROPÄISCHE NORM
March 2013
ICS 91.140.30
English Version
Field testing of general ventilation filtration devices and systems
for in situ removal efficiency by particle size and resistance to
airflow (ISO 29462:2013)
Essais in situ de filtres et systèmes de ventilation générale Betriebserprobung von Filtereinrichtungen und -systemen
pour la mesure de l'efficacité en fonction de la taille des für die allgemeine Lüftung hinsichtlich ihrer
particules et de la perte de charge (ISO 29462:2013) Abscheideeffizienz im eingebautem Zustand bezogen auf
die Partikelgröße und den Druckverlust (ISO 29462:2013)
This European Standard was approved by CEN on 1 March 2013.

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

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 29462:2013: E
worldwide for CEN national Members.

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SIST EN ISO 29462:2013
EN ISO 29462:2013 (E)
Contents Page
Foreword .3

2

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SIST EN ISO 29462:2013
EN ISO 29462:2013 (E)
Foreword
This document (EN ISO 29462:2013) 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 September 2013, and conflicting national standards shall be
withdrawn at the latest by September 2013.
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.
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 29462:2013 has been approved by CEN as EN ISO 29462:2013 without any modification.
3

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SIST EN ISO 29462:2013

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SIST EN ISO 29462:2013
INTERNATIONAL ISO
STANDARD 29462
First edition
2013-03-15
Field testing of general ventilation
filtration devices and systems for in
situ removal efficiency by particle size
and resistance to airflow
Essais in situ de filtres et systèmes de ventilation générale pour la
mesure de l’efficacité en fonction de la taille des particules et de la
perte de charge
Reference number
ISO 29462:2013(E)
©
ISO 2013

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SIST EN ISO 29462:2013
ISO 29462:2013(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

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SIST EN ISO 29462:2013
ISO 29462:2013(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviations . 1
3.1 Terms and definitions . 1
3.2 Abbreviations . 3
4 Test equipment and setup . 3
4.1 Particle counter . 3
4.2 Diluter . 3
4.3 Pump . 4
4.4 Sampling system . 4
4.5 Air velocity measurement instrument . 6
4.6 Relative humidity measurement instrument . . 6
4.7 Temperature measurement instrument . 6
4.8 Resistance to airflow measurement instrument . 6
4.9 Test equipment maintenance and calibration . 7
5 Site evaluation . 7
5.1 General . 7
5.2 Filter installation pre-testing inspection . 7
5.3 Approval for testing . 7
6 Test procedure . 8
6.1 Air velocity . 8
6.2 Relative humidity . 8
6.3 Temperature . 8
6.4 Resistance to airflow . 9
6.5 Removal efficiency . 9
6.6 Sampling probes .12
7 Expression of results .14
7.1 General information .14
7.2 Data collection .15
8 Errors and data analyses .16
8.1 General .16
8.2 Relative humidity .16
8.3 Air temperature .16
8.4 Aerosol composition .16
8.5 Uniformity of aerosol concentration .17
8.6 Coincidence errors — Particle counter .17
8.7 Particle losses.17
9 Calculation of results .17
9.1 Calculation of removal efficiency .17
9.2 Calculation of uncertainty .20
9.3 Coefficient of variation (CV) .20
10 Optional enhanced test system .21
10.1 Application of enhanced test .21
10.2 Principle of the enhanced test system .22
10.3 Determination of the corrected particle size .23
10.4 Presentation of results .24
Annex A (informative) Filter installation pre-testing inspection form .25
© ISO 2013 – All rights reserved iii

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SIST EN ISO 29462:2013
ISO 29462:2013(E)

Annex B (informative) Approval for testing form .28
Annex C (informative) Example of how to complete testing .30
Bibliography .46
iv © ISO 2013 – All rights reserved

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SIST EN ISO 29462:2013
ISO 29462:2013(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
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.
ISO 29462 was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases.
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SIST EN ISO 29462:2013
ISO 29462:2013(E)

Introduction
The purpose of this International Standard is to provide a test procedure for evaluating the in-situ
performances of general ventilation filtration devices and systems. Although any filter with a filtration
efficiency at or above 99% or at or below 30% when measured at 0,4 μm could theoretically be tested
using this International Standard, it may be difficult to achieve statically acceptable results for these
type of filtration devices.
Supply air to the Heating, Ventilation and Air-Conditioning (HVAC) system contains viable and non-
viable particles of a broad size range. Over time these particles will cause problems for fans, heat
exchangers and other system parts, decreasing their function and increasing energy consumption and
maintenance. For health issues, the fine particles (<2,5 µm) are the most detrimental.
Particles in the 0,3 μm to 5,0 μm size range are typically measured by particle counters that can
determine the concentration of particles in specific size ranges. These instruments are commercially
available and will determine particle size along with the concentration level by several techniques (e.g.,
light scattering, electrical mobility separation, or aerodynamic drag). Devices based on light scattering
are currently the most convenient and commonly used instruments for this type of measurement and
are therefore the type of device used within this International Standard.
Particles in the size range 1,0 μm to 5,0 μm are present in low numbers (less than 1%, by count) in outdoor
and supply air and have higher sampling-system losses. Results in the range >1,0 μm will therefore have
lower accuracy and so the results should be interpreted with respect to this.
During in-situ measurement conditions, the optical properties of the particles may differ from the optical
properties of the particles used for calibrating the particle counter and testing it in the laboratory. Thus
the particle counter could size the particles differently but count the overall number of particles correctly.
By adding an extra reference filter, the effect of varying measuring conditions can be reduced. Additionally,
using this enhanced test method, the results can be used to correct the measured efficiencies in relation
to the efficiency of the reference filter measured in laboratory using a standardized test aerosol.
The results from using the standard method or the enhanced method will give both users and
manufacturers a better knowledge of actual filter and installation properties.
It is important to note that field measurements generally result in larger uncertainties in the results
compared to laboratory measurements. Field measurements may produce uncertainty from temporal
and spatial variability in particle concentrations, from limitations on sampling locations due to air
handling unit configurations, and from the use of field instrumentation. These factors may result in lower
accuracy and precision in the calculated fractional efficiencies compared to laboratory measurements.
This International Standard is intended to provide a practical method in which the accuracy and precision
of the result are maximized (and the precision of the result quantified) by recommending appropriate
sampling locations, sample quantities, and instrumentation. This International Standard is not intended
to serve as a filter performance rating method. The results obtained from the test method described in
this International Standard do not replace those obtained through tests conducted in the laboratory.
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SIST EN ISO 29462:2013
INTERNATIONAL STANDARD ISO 29462:2013(E)
Field testing of general ventilation filtration devices and
systems for in situ removal efficiency by particle size and
resistance to airflow
1 Scope
This International Standard describes a procedure for measuring the performance of general ventilation
air cleaning devices in their end use installed configuration. The performance measurements include
removal efficiency by particle size and the resistance to airflow. The procedures for test include the
definition and reporting of the system airflow.
The procedure describes a method of counting ambient air particles of 0,3 μm to 5,0 μm upstream and
downstream of the in-place air cleaner(s) in a functioning air handling system. The procedure describes
the reduction of particle counter data to calculate removal efficiency by particle size.
Since filter installations vary dramatically in design and shape, a protocol for evaluating the suitability
of a site for filter evaluation and for system evaluation is included. When the evaluated site conditions
meet the minimum criteria established for system evaluation, the performance evaluation of the system
can also be performed according to this procedure.
This International Standard also describes performance specifications for the testing equipment and
defines procedures for calculating and reporting the results. This International Standard is not intended
for measuring performance of portable or movable room air cleaners or for evaluation of filter installations
with and expected filtration efficiency at or above 99 % or at or below 30 % when measured at 0,4 μm.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7726, Ergonomics of the thermal environment — Instruments for measuring physical quantities
ISO 14644-3, Cleanrooms and associated controlled environments — Part 3: Test methods
ISO 21501-4, Determination of particle size distribution — Single particle light interaction methods —
Part 4: Light scattering airborne particle counter for clean spaces
3 Terms, definitions, and abbreviations
3.1 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1.1
air filter bypass
unfiltered air that has passed through the AHU filter installation but remained unfiltered because it
bypassed the installed air filters
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SIST EN ISO 29462:2013
ISO 29462:2013(E)

3.1.2
air velocity
rate of air movement at the filter
Note 1 to entry: It is expressed in m/s (fpm) to three significant figures.
3.1.3
allowable measurable concentration of the particle counter
fifty percent of the maximum measurable concentration as stated by the manufacturer of the particle counter
3.1.4
coefficient of variation
CV
standard deviation of a group of measurements divided by the mean
3.1.5
diluter
dilution system
system for reducing the sampled concentration to avoid coincidence error in the particle counter
3.1.6
filter efficiency
removal efficiency of a filter as determined by this International Standard, where upstream and
downstream particle count measurements are taken close to the filter being tested
3.1.7
filter installation
filtration devices and systems such as a single filter or a group of filters mounted together with the same
inlet and outlet of air
3.1.8
general ventilation
process of moving air from outside the space, recirculated air, or a combination of these into or about a
space or removing it from the space
3.1.9
isoaxial sampling
sampling in which the flow in the sampler inlet is moving in the same direction as the flow being sampled
3.1.10
isokinetic sampling
technique for air sampling such that the probe inlet air velocity is the same as the velocity of the air
surrounding the sampling point
[Source: ISO 29464:2011; 3.1.144]
3.1.11
particle counter
device for detecting and counting numbers of discrete airborne particles present in a sample of air
[Source: ISO 29464:2011; 3.1.27]
3.1.12
particle size range
defined particle counter channel
3.1.13
reference filter
small dry media-type filter that has been laboratory tested for removal efficiency by particle size
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SIST EN ISO 29462:2013
ISO 29462:2013(E)

3.1.14
removal efficiency by particle size
ratio of the number of particles retained by the filter to the number of particles measured upstream of
the filter for a given particle-size range
3.1.15
resistance to airflow
loss of static pressure caused by the filter and filter loading which is measured with the filter operating
at the measured air velocity
Note 1 to entry: It is expressed in Pa (in WG) to two significant figures.
3.1.16
system efficiency
removal efficiency of a filter system where upstream and downstream particle count measurements
may be across several filter banks or other system components
3.2 Abbreviations
AHU Air Handling Unit
CV Coefficient of Variation
HEPA High Efficiency Particle Air (as per ISO 29463-1)
HVAC Heating, Ventilating and Air-Conditioning
MERV Minimum Efficiency Reporting Value
OPC Optical Particle Counter
RH Relative Humidity
ULPA Ultra Low Penetration Air
VAV Variable Air Volume
VFD Variable Frequency Drive
4 Test equipment and setup
4.1 Particle counter
The particle counter should be capable of measuring particles in the size range 0,3 µm ― 5,0 µm, in a
minimum of four ranges with a minimum of two ranges below 1,0 μm (for example: 0,3 µm ― 0,5 μm,
0,5 µm ― 1,0 μm, 1,0 µm ― 2,0 μm and 2,0 µm ― 5,0 μm). For maintenance and calibration of the particle
counter, see 4.9
4.2 Diluter
A dilution system capable of diluting the aerosol concentration so the particle concentration level is
within the acceptable concentration limit may be used. Choose a suitable dilution ratio so that the
measured concentration of particles is well within the allowable measurable concentration limits of the
particle counter so as to achieve good statistical data (see 9.1.2). If a dilution system is used, it is to be
used for both upstream and downstream sampling. The dilution system shall not change air flow to the
particle counter.
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SIST EN ISO 29462:2013
ISO 29462:2013(E)

4.3 Pump
A pump may be used to control the rate of the sample flow (q ) through the sampling probes. A pump is
s
not necessary when the counter flow (q ) to the counter or diluter is sufficient for isokinetic sampling.
pc
In this case the sample flow (q ) and the counter flow (q ) are the same.
s pc
4.4 Sampling system
4.4.1 General
Figure 1 shows the elements of a typical sampling system.
Key
1 sampling downstream 6 diluter
2 manometer 7 particle counter
3 valve 8 q – flow to particle counter
pc
4 Computer 9 pump
5 q – primary flow 10 flow meter
s
Figure 1 — Sampling system
4.4.2 Sampling probes
The sampling probe should consist of a sharp edged nozzle connected to the sample line leading to the
auxiliary pump or particle counter. The diameter of the nozzle is dependent on the sample flow (q ) in
s
order to get isokinetic sampling. The diameter should not be less than 8 mm.
4 © ISO 2013 – All rights reserved

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