prEN ISO 10121-2

SLOVENSKI STANDARD
01-oktober-2025
Preskusna metoda za ocenjevanje zmogljivosti sredstev in naprav za čiščenje
plinske faze za splošno prezračevanje - 2. del: Plinske naprave za čiščenje plinske
faze (ISO/DIS 10121-2:2025)
Test methods for assessing the performance of gas-phase air cleaning media and
devices for general ventilation - Part 2: Gas-phase air cleaning devices (GPACD)
(ISO/DIS 10121-2:2025)
Methode zur Leistungsermittlung von Medien und Vorrichtungen zur Reinigung der
Gasphase für die allgemeine Lüftung - Teil 2: Einrichtungen zur Reinigung der Gasphase
(GPACD) (ISO/DIS 10121-2:2025)
Méthodes d'essai pour l'évaluation de la performance des médias et des dispositifs de
filtration moléculaire pour la ventilation générale - Partie 2: Dispositifs de filtration
moléculaire (GPACD) (ISO/DIS 10121-2:2025)
Ta slovenski standard je istoveten z: prEN ISO 10121-2
ICS:
91.140.30 Prezračevalni in klimatski Ventilation and air-
sistemi conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 10121-2
ISO/TC 142
Test methods for assessing the
Secretariat: UNI
performance of gas-phase air
Voting begins on:
cleaning media and devices for
2025-06-17
general ventilation —
Voting terminates on:
2025-09-09
Part 2:
Gas-phase air cleaning devices
(GPACD)
Méthodes d'essai pour l'évaluation de la performance des médias
et des dispositifs de filtration moléculaire pour la ventilation
générale —
Partie 2: Dispositifs de filtration moléculaire (GPACD)
ICS: 91.140.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 10121-2:2025(en)
DRAFT
ISO/DIS 10121-2:2025(en)
International
Standard
ISO/DIS 10121-2
ISO/TC 142
Test methods for assessing the
Secretariat: UNI
performance of gas-phase air
Voting begins on:
cleaning media and devices for
general ventilation —
Voting terminates on:
Part 2:
Gas-phase air cleaning devices
(GPACD)
Méthodes d'essai pour l'évaluation de la performance des médias
et des dispositifs de filtration moléculaire pour la ventilation
générale —
Partie 2: Dispositifs de filtration moléculaire (GPACD)
ICS: 91.140.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: +41 22 749 01 11
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 10121-2:2025(en)
ii
ISO/DIS 10121-2:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 7
4.1 Symbols .7
4.2 Abbreviated terms .8
5 Testing of GPACDs . 8
5.1 General .8
5.2 Test setup and normative section of test stand .9
5.3 Raw data, sampling accuracy and normative generation parameters .10
5.4 Test parameters selected between user and supplier .11
5.4.1 General .11
5.4.2 Air flow rate and face velocity .11
5.4.3 Challenge compound . . 12
5.4.4 Challenge concentration . 12
5.4.5 Temperature and relative humidity . 12
5.4.6 Test duration . 12
5.5 Simplified benchmark setup . 12
5.5.1 General . 12
5.5.2 Initial removal efficiency test . 12
5.5.3 Challenge test concentration . 13
5.5.4 GPACDs for VOC tested with toluene . 13
5.5.5 GPACDs for acids and bases tested with SO and NH , respectively . 13
2 3
5.5.6 Retentivity test .14
6 Test sequence . 14
6.1 General .14
6.2 Conditioning and pressure drop determination .14
6.2.1 Procedure .14
6.2.2 Calculations . . 15
6.2.3 Reporting and graphs . 15
6.3 Initial removal efficiency . 15
6.3.1 Procedure (continued from 6.2.1) . .16
6.3.2 Calculations . .16
6.3.3 Reporting and graphs .17
6.4 Capacity determination .17
6.4.1 Procedure (continued from 6.2.1 or 6.3.1) .17
6.4.2 Calculations . .18
6.4.3 Reporting and graphs .19
6.5 Retentivity determination . 20
6.5.1 Procedure (continued from 6.4.1) . 20
6.5.2 Calculations . . 20
6.5.3 Reporting and graphs . 20
7 Validation of test setup.21
7.1 General .21
7.2 Determination of rise time and decay time .21
7.2.1 Procedure .21
7.2.2 Calculations . .21
7.2.3 Reporting and graphs . 22
8 Evaluation and report .23
8.1 Test report introduction . 23

iii
ISO/DIS 10121-2:2025(en)
8.2 Test report example . 23
9 Safety features . .26
Annex A (normative) Test equipment requirements, equipment validation and routine
operation .28
Annex B (informative) Challenge compounds, generation sources and analysis techniques .32
Annex C (informative) Test equipment designs .37
Bibliography .40

iv
ISO/DIS 10121-2:2025(en)
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases.
This second edition cancels and replaces the first edition (ISO 10121-2: 2013), which has been technically
revised.
The main changes are as follows:
— Feedback from the earlier systematic review in 2018 of this standard, doc (ISO/TC142 N058) and from
the earlier systematic review in 2019 of the related ISO 10121-1, doc (ISO/TC142 N666) have been
considered and included where applicable:
— terms and definitions have been updated to conform with ISO 29464:2024;
— the toluene concentration have been adjusted in the simplified benchmark test for initial efficiency
and all other challenge concentrations now conform with ISO 10121-1 and ISO 10121-3;
— test compounds have been reviewed in Annex B and concentration recommendations have been
removed for compounds requiring special attention
— clauses 5.5.1, 6.2.1, 6.3.1, 6.4, 6.4.1, 6.4.3, 6.5, 6.5.1 and 7.2.1 have been reworded and clarified .In addition,
challenge gas, species or compound have been changed to compound unless a specific gas e.g SO is
discussed.
— the formula in 6.3.2 have been corrected;.
A list of all parts in the ISO 10121 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO/DIS 10121-2:2025(en)
Introduction
There is an increasing use and need for gas-phase filtration in general filtration applications. This demand
can be expected to increase rapidly due to the increasing pollution problems in the world together with
an increasing awareness that solutions to the problems are available in the form of filtration devices or,
phrased more technically, gas-phase air cleaning devices (GPACD). The performance of devices relies to a
large extent on the performance of a gas-phase air cleaning media (GPACM) incorporated in the device. Still
applications and device performance are often poorly understood by the users and suppliers of such media
and devices. Media tests may also be adequate to offer data for real applications if actual low concentrations
(< 100 ppb) and longer exposure times (>weeks) can be used in the test, provided that the geometrical
configuration, packing density and flow conditions of the small-scale test specimen are equal to those used
in the real applications. Such tests are however not included in the scope of ISO 10121. ISO 10121 attempts
to increase understanding and communication by supplying a more standardized interface between media
[1]
suppliers, device suppliers and end users. At present, standards exist for general ventilation in Japan by
[3] [6]
JIS, automotive filters by ISO, in-duct sorptive media gas-phase air-cleaning devices by ASHRAE and for
[7] [8]
adsorptive media by ASHRAE and ASTM. No international standard for general filtration exists today.
This document prescribes methods, test equipment, data interpretation and reporting for gas-phase
air cleaning devices intended for the removal of gas-phase contamination from air in general ventilation
applications.
In addition, information is given in a number of annexes:
— Annex A describes the normative validation procedure in detail in a tabulated form.
— Annex B gives a list of possible test compounds, generation sources and suggests suitable analysis
equipment for common test compounds in addition to reference techniques given for the simplified
benchmark setup in Clause 5.5.
— Annex C discusses different test stand designs.
A general introduction to molecular filtration and molecular filtration testing can be found in the scientific
literature.
The ISO 10121 series consists of three parts.
— ISO 10121-1 covers three different media configurations and aims to provide a standardized interface
between media suppliers and producers of air cleaning devices. It may also be used between media
suppliers and end customers with regards to loose fill media properties.
— ISO 10121-2 aims to provide a standardized interface between suppliers of air cleaning devices and end
customers seeking the most cost-efficient way to employ gas-phase filtration.
— ISO 10121-3 provides a classification system for the specific application of GPACDs in general, ventilation
systems for cleaning of outdoor air polluted by local urban sources and/or long-range transboundary air
pollution.
vi
DRAFT International Standard ISO/DIS 10121-2:2025(en)
Test methods for assessing the performance of gas-phase air
cleaning media and devices for general ventilation —
Part 2:
Gas-phase air cleaning devices (GPACD)
1 Scope
This document aims to provide an objective test method to estimate the performance of any full size gas
filtration device (GPACD) for general filtration regardless of media or technique used in the device. In fact,
the goal of this document is to avoid relating the test data to internal parameters altogether. The benefit with
this approach is that customers of GPACDs will be able to concentrate on price/performance and suppliers
will have access to a normative and objective test standard that will not require the release of proprietary
information or reverse engineering of the product.
To ensure objectivity for test equipment suppliers, no specific design of the test apparatus is specified.
Instead requirements of apparatus properties and validation tests are specified. However, different
design examples in present use are outlined. This document can also be used with technologies such as
scrubbers, absorbers, non-sorptive devices or packed columns as long as they fit into the test apparatus,
can be meaningfully judged by the test method and are intended for general ventilation applications, both
residential and non-residential. Nuclear and military applications are specifically excluded.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 29464:2024, Cleaning of air and other gases — Vocabulary
ISO 10121-1, Test methods for assessing the performance of gas-phase air cleaning media and devices for general
ventilation — Gas-phase air cleaning media (GPACM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in in ISO 29464 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
absorption
transport and dissolution of one substance into another to form a mixture having the characteristics of a
solution
[SOURCE: ISO 29464:2024; 3.5.1]

ISO/DIS 10121-2:2025(en)
3.2
adsorbate
molecular compound in gaseous or vapour phase that can be retained by the medium
[SOURCE: ISO 29464:2024; 3.5.3]
3.3
adsorbent
solid material having the ability to retain gases or vapour on its surface through physical or chemical
processes
[SOURCE: ISO 29464:2024; 3.5.4]
3.4
adsorbent isotherm
relationship between the amount of a gas physically adsorbed on a surface and the partial pressure of the
gas at constant temperature.
3.5
adsorption
process in which the molecules of a gas or vapour adhere by physical or chemical processes to the exposed
surfaces of solid substances, both the outer surface and inner pore surface, with which they come into contact
[SOURCE: ISO 29464:2024; 3.5.7]
3.6
breakthrough
amount of gaseous contaminant in the effluent of a GPACD
Note 1 to entry: See "penetration".
3.7
breakthrough vs. time curve
plot of contaminant penetration versus time for a particular challenge concentration and air flow
[SOURCE: ISO 29464:2024; 3.5.12]
3.8
bypass
proportion of the challenge air stream that passes around the GPACD without contacting the media
[SOURCE: ISO 29464:2024; 3.1.5]
3.9
capacity
m
s
amount (mass or moles) of a selected sorbate that can be contained in the filter media of a GPACD at given
test conditions, and a specific end point
Note 1 to entry: Capacity can also be negative during desorption.
3.10
challenge concentration
concentration of the test contaminant(s) of interest in the air stream prior to filtration
[SOURCE: ISO 29464:2024; 3.5.16]
3.11
challenge compound
chemical compound that is being used as the contaminant of interest for any given test
[SOURCE: ISO 29464:2024; 3.5.15]

ISO/DIS 10121-2:2025(en)
3.12
challenge air stream
test contaminant(s) of interest diluted to the specified concentration(s) of the test prior to filtration
[SOURCE: ISO 29464:2024; 3.5.14]
3.13
channelling
disproportionate or uneven flow of gas through passages of lower resistance due to inconsistencies in the
design or production of a GPACD, particularly in packed granular beds
[SOURCE: ISO 29464:2024; 3.5.17]
3.14
chemisorption
chemical adsorption
trapping of gaseous or vapour contaminants on an adsorbent involving chemical reaction on the
adsorbent surface
[SOURCE: ISO 29464:2024; 3.5.19]
3.15
concentration
C
n
quantity of one substance dispersed in a defined amount of another
Note 1 to entry: Indices "n" denote location.
[SOURCE: ISO 29464:2024; 3.1.11]
3.16
contaminant
substance (solid, liquid, or gas) that negatively affects the intended use of a fluid
[SOURCE: ISO 29464:2024; 3.1.12]
3.17
decay time
t
Dn
time required for the gas contaminant monitoring instrument to record a reduction from an initial
value greater than 95 % of the challenge concentration to a final value of less than 5 % of the challenge
concentration (t – t ) at the downstream sampling point for a specific test (n), challenge gas and gas
END VC
flow after stopping the injection of the contaminant with no GPAC media or device present
[SOURCE: ISO 29464:2024; 3.5.21]
3.18
desorption
process in which adsorbate molecules leave the surface of the adsorbent and re-enter the air stream
Note 1 to entry: Desorption is the opposite of adsorption.
[SOURCE: ISO 29464:2024; 3.5.22]
3.19
diffusor
device that forces the air stream to achieve an even face velocity over the entire cross sectional area of a test duct.
Note 1 to entry: to entry The device may be a perforated plate.

ISO/DIS 10121-2:2025(en)
3.20
downstream
area or region into which air flows on leaving an air cleaner
[SOURCE: ISO 29464:2024; 3.1.16]
3.21
removal efficiency vs. time curve
plot of the GPAC medium or device removal efficiency against time over the duration of a challenge test for a
particular challenge concentration and air flow
[SOURCE: ISO 29464:2024; 3.5.58]
3.22
removal efficiency vs. capacity curve
plot of the GPACD removal efficiency against the integrated capacity over the duration of a challenge test for
a particular challenge concentration and air flow
[SOURCE: ISO 29464:2024; 3.5.56]
3.23
face velocity
volumetric air flow rate divided by nominal air cleaner face area
[SOURCE: ISO 29464:2024; 3.1.20]
3.24
gas
substance whose vapour pressure is greater than the ambient pressure at ambient temperature
[SOURCE: ISO 29464:2024; 3.1.34]
3.25
gas-phase air cleaning device
GPACD
assembly of a fixed size enabling the removal of specific gas- or vapour-phase contaminants
Note 1 to entry: It is normally box shaped or fits into a box of dimensions between 300 × 300 × 300 mm up to
approximately 610 × 610 × 610 mm or 2 × 2 × 2 feet.
[SOURCE: ISO 29464:2024; 3.5.34, modified – Note 1 to entry has been modified.]
3.26
GPAC media or device face area
cross-sectional area of the GPAC media or device also including a header frame if so equipped when viewed
from the direction of air flow using exact dimensions
[SOURCE: ISO 29464:2024; 3.5.36]
3.27
gas-phase air cleaning medium
GPACM
media or media configuration used for filtering a contaminant
EXAMPLE a porous film or fibrous layer; a bead shaped, granular or pelletized adsorbent (or chemisorbent); a
support structure of fabric, foam or monoliths containing adsorbent in the form of small sized particles, granules,
spheres or powder; a woven or nonwoven fabric completely made from an adsorbent material
[SOURCE: ISO 29464:2024; 3.5.37]

ISO/DIS 10121-2:2025(en)
3.28
initial removal efficiency
efficiency of an unexposed filter or GPACD calculated as soon after the start of a test as is possible
Note 1 to entry: For gas-phase, this should be calculated as soon as a steady reading can be obtained.
3.29
molecular contamination
contamination present in gas or vapour phase in an air stream and excluding compounds in particulate
(solid) phase regardless of their chemical nature
[SOURCE: ISO 29464:2024; 3.5.43]
3.30
ppb(v)
parts per billion by volume concentration measure normally used to record ambient levels of outdoor
pollution
3 3
Note 1 to entry: Units are mm /m .
[SOURCE: ISO 29464:2024; 3.5.46]
3.31
ppm(v)
parts per million by volume concentration measure normally used to record ambient levels of outdoor
pollution
3 3 3
Note 1 to entry: Units are cm /m and ml/m .
[SOURCE: ISO 29464:2024; 3.5.47]
3.32
penetration
P
ratio of contaminant concentration downstream of an air cleaner to the upstream (challenge) concentration
Note 1 to entry: sometimes expressed as a percentage
Note 2 to entry: Penetration (P) related to efficiency (E) by the expression: E = (1 – P) × 100 %.
Note 3 to entry: Penetration is related to the decontamination factor (DF) by the expression, DF = 1/penetration
[SOURCE: ISO 29464:2024; 3.1.41]
3.33
physisorption
physical adsorption
attraction of an adsorbate to the surface, both outer surface and inner pore surface, of an adsorbent by
physical forces (Van der Waals forces)
[SOURCE: ISO 29464:2024; 3.5.48]
3.34
pore
minute passageways through which fluid may pass or that expose to the fluid stream the internal surfaces
of an adsorbent media
[SOURCE: ISO 29464:2024; 3.5.49]

ISO/DIS 10121-2:2025(en)
3.35
pressure drop
Δp
difference in pressure between two points in an air flow system at specified conditions, especially when
measured across a GPACD
3.36
removal efficiency
E
fraction or percentage of a challenge contaminant that is removed by an air cleaner
[SOURCE: ISO 29464:2024; 3.1.17]
3.37
retentivity
m
r
measure of the ability of an adsorbent or GPACD to resist desorption of an adsorbate
Note 1 to entry: Computed as the residual capacity (fraction remaining) after purging the adsorbent with clean,
conditioned air only, following challenge breakthrough.
[SOURCE: ISO 29464:2024; 3.5.63]
3.38
residence time
t
r
relative time that an increment of fluid (or contaminant) is within the boundaries of the medium volume
Note 1 to entry: An example of the medium volume is a bed of granules or a non-woven sheet.
Note 2 to entry: In typical use and in this document, this value neglects the fact that the media and possible support
structures occupy a significant portion of the volume of the bed (residence time is calculated as total bed volume/air
flow rate)
[SOURCE: ISO 29464:2024; 3.5.62]
3.39
rise time
t
Rn
time between initial injection of contaminant and reaching 95 % of the challenge concentration for an empty
duct (t – t ) measured at the downstream sampling
0 VO
Note 1 to entry: Rise time is specific to a particular test, challenge gas and gas flow rate
[SOURCE: ISO 29464:2024; 3.5.42]
3.40
sorbate
molecular compounds that are retained in the adsorbent of the device
Note 1 to entry: The sorbate will refer to both intended compounds like the selected challenge gas in a test or pollution
in real service but also any other compound present in the air stream e.g. gases and vapours.
[SOURCE: ISO 29464:2024; 3.5.66]
3.41
sorption
process in which gas or liquid molecules are removed by a GPACD media by absorption or adsorption
[SOURCE: ISO 29464:2024; 3.5.67]

ISO/DIS 10121-2:2025(en)
3.42
vapour
substance whose vapour pressure is less than the ambient pressure at ambient temperature, but is present
in the gas phase through evaporation or sublimation
[SOURCE: ISO 29464:2024; 3.5.72]
4 Symbols and abbreviated terms
4.1 Symbols
C upstream concentration [ppb, ppm] measured at a position X mm before the device
U
C downstream concentration [ppb, ppm] measured at a position Y mm after the device
D
Δp pressure drop measured over the tested device [Pa]
E initial removal efficiency [%] for the device measured at a low (< 1 ppm) challenge concentration during
I
the initial efficiency test in 6.3
E removal efficiency [%] for the device measured at the challenge concentration selected during the
C
capacity test in 6.4
E removal efficiency recorded at stop test time or value agreed between user and supplier [%]
END
m retentivity [g], [mol]; the amount withheld by the device after ventilating with clean air at the same
r
flow selected during the capacity test until C reaches a specified value close to zero.
D
m the integrated amount in moles or grams of challenge compound accumulated during the initial effi-
sEI
ciency test in Formula (2)
m the integrated amount in moles or gram of challenge compound accumulated during measurement at
sU
the upstream position in Formula (3)
m the integrated amount in moles or grams of challenge compound accumulated during measurement at
sD
the downstream position in Formula (3)
m the total integrated amount [g], [mol] of challenge compound accumulated during the whole challenge test
s
p upstream pressure [Pa] measured at a position X mm before the device
U
p downstream pressure [Pa] measured at a position Y mm after the device
D
Q flow used in test (normally the rated flow for the tested device) [m /h] measured at a position Z mm
after the device
RH upstream relative humidity [%] measured at a position X mm before the device
U
RH downstream relative humidity [%] measured at a position Y mm after the device
D
t start time. The time when C (contamination concentration upstream) equals the selected challenge
0 U
concentration for an empty duct
t time when a test is stopped. The time when a desired concentration or other termination criteria have
END
been met in any of the prescribed test procedures (agreed between user and supplier)
t decay time for challenge concentration
DC
t decay time for initial efficiency concentration
DE
ISO/DIS 10121-2:2025(en)
t rise time for challenge concentration
RC
t rise time for initial efficiency concentration
RE
t time noted at challenge gas valve closure
VC
t time noted at challenge gas valve opening
VO
T upstream temperature [°C] measured at a position X mm before the device
U
T downstream temperature [°C] measured at a position Y mm after the device
D
v face velocity [m/s] calculated from flow and cross sectional area of device
f
X a position X positioned sufficiently far ahead of the device to allow undisturbed measurements, de-
termined in the validation, Annex A. At the distance X, the concentration of challenge compound is
sufficiently mixed and uniform over the cross sectional area of the duct while not being so close to the
device that the device itself obscures the flow, pressure drop or concentration.
Y a position Y positioned sufficiently far after the device to allow undisturbed measurements, determined
in the validation section, Annex A. At the distance Y the concentration of penetrating challenge com-
pound is sufficiently mixed and uniform to represent the average of the device and not being so close
to the device that the device itself obscures the flow, pressure drop or concentration.
Z a position Z positioned sufficiently far after the device to permit a reliable flow measurement using an
orifice device, determined in the validation, Annex A
4.2 Abbreviated terms
ASHRAE American Society of Heating Refrigerating and Air-conditioning Engineers
ASTM ASTM International, formerly known as the American Society for Testing and Materials (ASTM)
HEPA High Efficiency Particulate Air (filter)
JIS Japanese Industrial Standards
JSA Japanese Standards Association
MSDS Material Safety Data Sheet
NMP n-Methyl −2-pyrrolidone
TLV threshold limit value. Amount of a chemical substance is a level to which it is believed a worker
can be exposed day after day for a working lifetime without adverse health effects.
VOC Volatile Organic Compound
5 Testing of GPACDs
5.1 General
This document shows how to measure four key parameters that reflect the performance of a GPACD. The
four parameters are:
— pressure drop, Δp
— capacity, m
s
— removal efficiency, E
ISO/DIS 10121-2:2025(en)
— retentivity, m
r
These parameters are:
— linked to each other;
— different for different challenge compounds (exception: Δp is not affected);
— different for different concentrations of the same challenge compound (exception: Δp is not affected);
— affected by other gases present, by temperature, by humidity and by the air flow.
The ideal case would be to test at the exact parameter values and concentration present in the intended
application, but then the test time would be as long as the real service life, e.g. years. One way to accelerate
the test is to increase the concentration. In this part of ISO 10121 an increased concentration should be
agreed between user and supplier. Alternatively, for general benchmark purposes three concentrations
are used, one mildly increased for determination of the removal efficiency and two strongly increased for
determination of capacity. Besides the key performance parameters other important factors shall also be
considered. Particles may be emitted downstream, at least during initial start-up, for GPACDs employing
loose fill granular and pelletized adsorbents or adsorbent fibres and possibly for other media types as well.
This may pose a problem depending on the sensitivity of the specific application and on available particle
filtration after the GPACD. Other factors that may be considered are gaseous emissions, corrosion resistance,
weight and depth requirements.
This clause will describe the normative part of the test stand, normative parameters for generation
of the challenge air stream and suggest test compounds for benchmark purposes and for the case when
the pollution in the real application is not yet defined. Clause 6 describes in detail the test sequence for
conditioning and for determination of pressure drop, initial removal efficiency, capacity and retentivity in
this order.
5.2 Test setup and normative section of test stand
The test equipment can be designed in various ways and it is not the purpose of this document to enforce a
particular engineering solution or analysis technique. Several designs and analysis techniques are described
in the informative annexes. It is the user of this document that should select the solution best fitted with
regard to equipment availability and other concerns. There are some key parameters that will severely skew
the data or make benchmark testing impossible unless they are controlled within specified limits. These
parameters are displayed in the normative test section in Figure 1 and Table 1. The adherence to these levels
shall be demonstrated by the tests provided in the validation section.
The GPACD shall be installed without leakages or bypass. The air stream should be uniformly mixed and with
equal velocity and upstream concentration over the cross section. Recorded parameters are concentration
C, pressure p, temperature T and relative humidity RH in two positions. The air flow is recorded at a third
position that may be upstream or downstream of the GPACD.
The inner dimension (ID) of the duct, width and height as indicated in Figure 1, should be 610 × 610 mm
along the whole GPACD section. Devices in actual (full) size shall always be tested. Flat adaptor plates are
used for GPACD < 610 × 610 mm. In addition, a duct with internal dimension (ID) 300 × 300 mm is permitted
for testing of a full size 300 × 300 mm GPACD. Acceptable sizes of GPACD for testing are 300 × 300 mm to
610 × 610 mm. The length of the GPACD section shall be greater that the inner dimension (ID) of the duct,
ideally 1–3 × ID. Any changes in duct diameter before and after the GPACD section should be designed so that
the flow is uniform over the entire GPACD cross section.

ISO/DIS 10121-2:2025(en)
Key
1 diffusor and Δp device
2 sampling points – should be of “fork” type or similar with multiple inlet points to make a compounded sample over
the whole cross section
3 GPACD under test
4 GPACD section of test duct, starting at 1 and ending at 7.
5 upstream sampling point for T , RH , p and C at X mm before the GPACD
...