kSIST FprEN 13725:2021

Stationary source emissions - Determination of odour concentration by dynamic olfactometry and odour emission rate

This document specifies a method for the objective determination of the odour concentration of a gaseous sample using dynamic olfactometry with human assessors. The standard also specifies a method for the determination of the emission rate of odours from stationary sources, in particular:
-   point sources (conveyed or ducted emissions);
-   active area sources (e.g. biofilters);
-   passive sources.
The primary application of this standard is to provide a common basis for evaluation of odour emissions.
When this document is used for the determination of the odour concentration or the odour emission rate of stationary source emissions, the other relevant European Standards concerning stationary source emissions apply, in particular EN 15259 and EN 16911-1, especially when measurements have to be in compliance with the relevant European Directives concerning industrial air emissions.
Even so, the analysis/quantification step of the measurement method described in this document (i.e. the determination of the odour concentration of an odorous gas sample, without respect to the origin of the sample itself) can be fully applied in many cases not related with industrial emission sources (e.g. the measurement of the mass concentration at the detection threshold of pure odorous substances, the determination of effectiveness of deodorizing systems for indoor air). In those latter cases, the requirements in this document concerning the measurement planning and the sampling of stationary sources  can be ignored or adapted.
This document is applicable to the measurement of odour concentration of pure substances, defined odorant compounds and undefined mixtures of odorant volatiles in air or nitrogen, using dynamic olfactometry with a panel of human assessors being the sensor. The unit of measurement is the European odour unit per cubic metre: ouE/m3. The odour concentration is measured by determining the dilution factor required to reach the detection threshold. The odour concentration at the detection threshold is by definition 1 ouE/m3. The odour concentration is then expressed in terms of multiples of the detection threshold. The range of measurement is typically from 101 ouE/m3 to 107 ouE/m3 (including pre dilution).
The field of application of this document includes:
-   the measurement of the mass concentration at the detection threshold of pure odorous substances in g/m3;
-   the determination of the EROM value of odorants, in mol;
-   the measurement of the odour concentration of mixtures of odorants in ouE/m3;
-   the measurement of the emission rate of odorous emissions from point sources, active area sources and passive area sources, including pre dilution during sampling;
-   the sampling of odorous gases from emissions of high humidity and temperature (up to 200 °C);
-   the determination of effectiveness of end-of-pipe mitigation techniques used to reduce odour emissions.
The determination of odour emissions requires measurement of gas velocityto determine the gas volume flow rate.
The field of application of this document does not include:
-   the measurement of odours potentially released by particles of odorous solids or droplets of odorous fluids suspended in emissions;
-   the measuring strategy to be applied in case of variable emission rates;
-   the measurement of the relationship between odour stimulus and assessor response above detection threshold (perceived intensity);
-   measurement of hedonic tone (or (un)pleasantness) or assessment of annoyance potential;
-   direct measurement of odour exposure in ambient air. For this measurement purpose, field panel methods exist which are the subject of CEN standard EN 16841-1, Ambient Air - Determination of odour in ambient air by using field inspection - Grid method;
-   direct olfactometry, including field olfactometry;
-   static olfactometry;
-   measurement of odour recognition thresholds;
-   measurement of odour identification thresholds.
.....

Emissionen aus stationären Quellen - Bestimmung der Geruchsstoffkonzentration durch dynamische Olfaktometrie und die Geruchsstoffemissionsrate

Dieses Dokument legt ein objektives Verfahren zur Bestimmung der Geruchsstoffkonzentration einer gasförmigen Probe durch dynamische Olfaktometrie mit Hilfe menschlicher Prüfpersonen fest. Das Dokument legt darüber hinaus ein Verfahren zur Bestimmung der Geruchsstoffemissionsrate aus stationären Quellen fest, und zwar insbesondere aus:
a)   Punktquellen (geförderte oder geführte Emissionen);
b)   aktiven Flächenquellen (z. B. Biofilter).
Der Hauptzweck dieses Dokuments besteht darin, eine allgemeine Grundlage für die Bewertung von Geruchsstoffemissionen zu liefern.
Wenn dieses Dokument zur Bestimmung der Geruchsstoffkonzentration oder der Geruchsstoffemissionsrate aus stationären Quellen verwendet wird, gelten die anderen relevanten Europäischen Normen in Bezug auf Emissionen aus stationären Quellen, insbesondere EN 15259 und EN ISO 16911 1, vor allem wenn Messungen die Anforderungen der relevanten Europäischen Richtlinien in Bezug auf Industrieemissionen in die Außenluft erfüllen müssen.
Desgleichen kann der in diesem Dokument beschriebene Analyse-/Quantifizierungsschritt des Messverfahrens (d. h. die Bestimmung der Geruchsstoffkonzentration einer gasförmigen Geruchsstoffprobe ungeachtet der Herkunft der Probe) in vielen Fällen unabhängig von industriellen Emissionsquellen uneingeschränkt angewendet werden (z. B. zur Messung der Massenkonzentration von Geruchsstoffen an der Wahrnehmungsschwelle, zur Bestimmung der Wirksamkeit von deodorierenden Systemen für Innenraumluft). In den letztgenannten Fällen können die Anforderungen in diesem Dokument in Bezug auf Messplanung und Probenahme aus stationären Quellen ignoriert oder angepasst werden.
Dieses Dokument ist anwendbar auf die Messung der Geruchsstoffkonzentration eines riechbaren Gases, definiert zusammengesetzter Geruchsstoffgemische und undefinierter Mischungen von Geruchsstoffen in Luft oder Stickstoff mit Hilfe der dynamischen Olfaktometrie durch ein Kollektiv menschlicher Prüfpersonen als Sensoren. Die Maßeinheit ist die Europäische Geruchseinheit je Kubikmeter: GEE/m3. Die Geruchsstoffkonzentration wird durch Bestimmung des zum Erreichen der Wahrnehmungsschwelle erforderlichen Verdünnungsfaktors gemessen. Die Geruchsstoffkonzentration an der Wahrnehmungsschwelle ist per Definition 1 GEE/m3. Die Geruchsstoffkonzentration wird dann als Vielfaches der Wahrnehmungsschwelle angegeben. Der Messbereich liegt üblicherweise zwischen 101 GEE/m3 und 107 GEE/m3 (einschließlich Vorverdünnung).

Émissions de sources fixes - Détermination de la concentration d'odeur par olfactométrie dynamique et du taux d'émission d'odeurs émanant de sources fixes

Le présent document définit une méthode objective pour déterminer la concentration d'odeur d'un échantillon gazeux par olfactométrie dynamique avec des sujets humains. Il spécifie également une méthode de détermination du taux d'émission d'odeurs provenant de sources fixes, notamment de :
a)   sources ponctuelles (émissions rejetées dans l'atmosphère ou canalisées) ;
b)   sources surfaciques actives (par exemple, biofiltres).
L'application principale du présent document est de fournir une base commune pour l'évaluation des émissions odorantes.
Lorsque le présent document est utilisé pour déterminer la concentration d'odeur ou le taux d'émission d'odeurs dans des émissions de sources fixes, les autres Normes européennes pertinentes concernant les émissions de sources fixes s'appliquent, en particulier l'EN 15259 et l'EN ISO 16911 1, notamment lorsque les mesures doivent être conformes aux Directives européennes applicables, relatives aux émissions atmosphériques industrielles.
Néanmoins, l'étape d'analyse/de quantification de la méthode de mesure décrite dans le présent document (c'est-à-dire la détermination de la concentration d'odeur d'un échantillon de gaz olfactivement actif, indépendamment de l'origine de l'échantillon lui-même) peut être pleinement appliquée dans de nombreux cas non liés aux sources d'émissions industrielles (par exemple, le mesurage de la concentration massique au seuil de détection de substances odorantes, la détermination de l'efficacité des systèmes de désodorisation de l'air intérieur). Dans ces derniers cas, les exigences du présent document concernant la planification des mesures et l'échantillonnage des sources fixes peuvent être ignorées ou adaptées.
Le domaine d'application du présent document concerne le mesurage de la concentration d'odeur du gaz odorant, de mélanges de substances odorantes d'une composition définie et de mélanges non définis de substances odorantes dans l'air ou l'azote, en utilisant l'olfactométrie dynamique avec un jury de sujets humains comme détecteurs. L'unité de mesure est l'unité d'odeur européenne par mètre cube, dont le symbole est : ouE/m3. La concentration d'odeur se mesure en déterminant le facteur de dilution requis pour atteindre le seuil de détection. La concentration d'odeur au seuil de détection est par définition de 1 ouE/m3. La concentration d'odeur s'exprime ensuite en termes de multiples du seuil de détection. L'étendue de mesure va en général de 101 ouE/m3 à 107 ouE/m3 (y compris la prédilution).
[...]

Emisije nepremičnih virov - Določevanje koncentracije vonjav z dinamično olfaktometrijo in stopnja emisije vonjav

General Information

• Status: Not Published
• Public Enquiry End Date: 03-Jul-2019
• ICS: 13.040.40 - Stationary source emissions
• Technical Committee: KAZ - Air quality
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 11-Oct-2021
• Due Date: 29-Nov-2021
• Completion Date: 02-Nov-2021
• Ref Project: EN 13725:2022 - Stationary source emissions - Determination of odour concentration by dynamic olfactometry and odour emission rate

RELATIONS

• Revised: SIST EN 13725:2003 - Air quality - Determination of odour concentration by dynamic olfactometry
• Effective Date: 01-Jun-2019
• Replaces: SIST EN 13725:2003 - Air quality - Determination of odour concentration by dynamic olfactometry
• Effective Date: 02-Mar-2022
• Replaces: SIST EN 13725:2003/AC:2006 - Air quality - Determination of odour concentration by dynamic olfactometry
• Effective Date: 02-Mar-2022

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 13725:2019
01-junij-2019
[Not translated]
Stationary source emissions - Determination of odour concentration by dynamic
olfactometry and odour emission rate from stationary sources
Emissionen aus stationären Quellen - Dynamische Olfaktometrie zur Bestimmung von
Geruchskonzentrationen
Ta slovenski standard je istoveten z: prEN 13725
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
oSIST prEN 13725:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 13725:2019
DRAFT
EUROPEAN STANDARD
prEN 13725
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2019
ICS 13.040.99 Will supersede EN 13725:2003
English Version
Stationary source emissions - Determination of odour
concentration by dynamic olfactometry and odour
emission rate from stationary sources
Emissionen aus stationären Quellen - Dynamische
Olfaktometrie zur Bestimmung von
Geruchskonzentrationen

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 264.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.

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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 13725:2019 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 7

3 Terms and definitions ................................................................................................................................... 7

3.1 Terms and definitions for olfactometry .................................................................................................. 8

3.2 Terms and definitions for sampling ...................................................................................................... 14

3.3 Terms and definitions for metrology and statistics ........................................................................ 17

4 Symbols and abbreviated terms ............................................................................................................. 22

5 Principle of method ..................................................................................................................................... 24

5.1 Odour measurement: odorant gas sampling and odour analysis ............................................... 24

5.2 Odorant gas sampling ................................................................................................................................. 25

5.3 Determination of odour concentration ................................................................................................ 25

6 Apparatus and materials ........................................................................................................................... 28

6.1 General properties of materials ............................................................................................................. 28

6.2 Sampling equipment ................................................................................................................................... 29

6.2.1 General ............................................................................................................................................................. 29

6.2.2 Materials for sample equipment ............................................................................................................ 29

6.2.3 Cleaning and re-use of sampling equipment ...................................................................................... 30

6.3 Sample container ......................................................................................................................................... 30

6.3.1 Materials for sample container (bags) ................................................................................................. 30

6.3.2 Testing of sample containers ................................................................................................................... 30

6.3.3 Cleaning and re-use of sample containers .......................................................................................... 31

6.4 Gases ................................................................................................................................................................. 31

6.4.1 Neutral gas ...................................................................................................................................................... 31

6.4.2 Primary reference material for the EROM: odorant (n-butanol) ............................................... 32

6.4.3 Reference material for calibration of dilution equipment............................................................ 32

6.5 Dilution apparatus ....................................................................................................................................... 32

6.5.1 Construction of the olfactometer............................................................................................................ 32

6.5.2 Dilution range of olfactometer ................................................................................................................ 33

6.5.3 Interface between nose and olfactometer .......................................................................................... 33

6.5.4 Calibration procedure ................................................................................................................................ 34

6.6 Environment for observations by assessors ...................................................................................... 34

6.6.1 Olfactometry room ...................................................................................................................................... 34

6.6.2 Air conditioning for the olfactometry room ....................................................................................... 35

6.7 Panel ................................................................................................................................................................. 36

6.7.1 Code of behaviour for assessors and panel members..................................................................... 36

6.7.2 Selection of assessors on individual variability and sensitivity ................................................. 36

6.7.3 Monitoring of panel members of assessors on individual variability and sensitivity ........ 37

6.7.4 Panel size ......................................................................................................................................................... 38

7 Performance and determination of the performance characteristics ...................................... 38

7.1 General ............................................................................................................................................................. 38

7.2 Accuracy - statistical model ...................................................................................................................... 39

7.3 Overall sensory quality requirements ................................................................................................. 40

7.3.1 General ............................................................................................................................................................. 40

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7.3.2 Quality criteria for the performance within one laboratory on reference material

(odorant) ......................................................................................................................................................... 41

7.3.3 Assessment of precision between laboratories (reproducibility) using

environmental samples .............................................................................................................................. 43

7.4 Quality requirements for dilution apparatus ..................................................................................... 44

7.4.1 General ............................................................................................................................................................. 44

7.4.2 Quality criteria for the performance of dilution apparatus .......................................................... 44

7.4.3 Quality criterion for instability of dilution apparatus .................................................................... 46

8 Measurement objective and measurement plan ............................................................................... 47

8.1 General ............................................................................................................................................................. 47

8.2 Preliminary investigation .......................................................................................................................... 47

8.3 Measurement plan........................................................................................................................................ 48

9 Measurement procedure ........................................................................................................................... 49

9.1 Sampling .......................................................................................................................................................... 49

9.1.1 Health and safety issues during sampling ........................................................................................... 49

9.1.2 Sample collection method ......................................................................................................................... 49

9.1.3 Pre-dilution during sampling ................................................................................................................... 50

9.1.4 Transport and storage of odorant gas samples before analysis .................................................. 52

9.2 Sampling of a point source ........................................................................................................................ 54

9.2.1 Sampling equipment .................................................................................................................................... 54

9.3 Sampling of area sources .......................................................................................................................... 55

9.3.1 Sampling of active area sources .............................................................................................................. 55

9.3.2 Sampling of passive area sources ........................................................................................................... 60

9.4 Olfactometric analysis ................................................................................................................................ 62

9.4.1 Modes of presentation and choice .......................................................................................................... 62

9.4.2 Evaluation time and inter-stimulus time ............................................................................................. 63

9.4.3 Number and order of presentations ...................................................................................................... 63

9.4.4 Initial determination of presentation series at the start of the measurement ...................... 64

9.5 Occupational safety for sampling personnel, assessors and analysis operators .................. 64

9.5.1 General ............................................................................................................................................................. 64

9.5.2 Toxicity ............................................................................................................................................................. 65

9.5.3 The panel members ..................................................................................................................................... 66

9.5.4 The test leaders ............................................................................................................................................. 66

9.5.5 The sampling technicians .......................................................................................................................... 66

9.6 Validation and calculation of results ..................................................................................................... 68

9.6.1 Calculation of odour concentration of a sample from a set of panel member

responses ......................................................................................................................................................... 68

9.6.2 Calculation of odour flow from odour concentration and volume flow rate .......................... 70

9.6.3 Calculation of odour abatement efficiency .......................................................................................... 70

10 Quality assurance and quality control procedures .......................................................................... 70

10.1 Field blank ....................................................................................................................................................... 70

10.2 Measurement uncertainty ......................................................................................................................... 72

10.2.1 General ............................................................................................................................................................. 72

10.2.2 Estimation of the within laboratory uncertainty .............................................................................. 73

10.3 Determination of the limit of detection (LoD) and the limit of quantification (LoQ) .......... 77

11 Measurement report ................................................................................................................................... 79

Annex A (informative) Physiological principles ............................................................................................. 82

Annex B (informative) Example of calculation of instrumental accuracy and instability ............... 87

Annex C (informative) Example of calculation of odour measurements within one

laboratory ........................................................................................................................................................ 90

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Annex D (informative) Example of calculations for panel selection....................................................... 92

Annex E (informative) Example of the calculation of the odour concentration from a set of

panel member responses .......................................................................................................................... 93

Annex F (informative) Example of the calculation used to determine the number of odour

concentration measurements required to achieve a defined precision .................................. 97

Annex G (informative) Example of the calculation used to determine the number of odour

concentration measurements required to determine a difference between two

means ............................................................................................................................................................... 99

Annex H (informative) Example of the calculation of the odour flow rate (standard

conditions) for a wet emission .............................................................................................................. 102

Annex I (informative) Example of the calculation of an EROM value for a new defined

odorant from an EROM comparison .................................................................................................... 103

Annex J (informative) Example of the calculation of measurement uncertainty ............................. 114

Annex K (informative) Significant technical changes ................................................................................ 122

Bibliography ............................................................................................................................................................... 123

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European foreword

This document (prEN 13725:2019) has been prepared by Technical Committee CEN/TC 264 “Air quality”,

the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 13725:2003.

This document is the first revised edition of the standard that was first published as EN 13725:2003. The

method defined in this first edition and its quality criteria have been validated in numerous proficiency

tests. This first revision contains modified and additional clauses on health and safety, sampling and

emissions measurement, the use of additional reference materials and the assessment of overall

uncertainty.
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1 Scope

This document specifies a method for the objective determination of the odour concentration of a gaseous

sample using dynamic olfactometry with human assessors. The standard also specifies a method for the

determination of the emission rate of odours from stationary sources, in particular:

— point sources (conveyed or ducted emissions);
— active area sources (e.g. biofilters);
— passive sources.

The primary application of this standard is to provide a common basis for evaluation of odour emissions.

When this document is used for the determination of the odour concentration or the odour emission rate

of stationary source emissions, the other relevant European Standards concerning stationary source

emissions apply, in particular EN 15259 and EN 16911-1, especially when measurements have to be in

compliance with the relevant European Directives concerning industrial air emissions.

Even so, the analysis/quantification step of the measurement method described in this document (i.e. the

determination of the odour concentration of an odorous gas sample, without respect to the origin of the

sample itself) can be fully applied in many cases not related with industrial emission sources (e.g. the

measurement of the mass concentration at the detection threshold of pure odorous substances, the

determination of effectiveness of deodorizing systems for indoor air). In those latter cases, the

requirements in this document concerning the measurement planning and the sampling of stationary

sources can be ignored or adapted.

This document is applicable to the measurement of odour concentration of pure substances, defined

odorant compounds and undefined mixtures of odorant volatiles in air or nitrogen, using dynamic

olfactometry with a panel of human assessors being the sensor. The unit of measurement is the European

odour unit per cubic metre: ou /m . The odour concentration is measured by determining the dilution

factor required to reach the detection threshold. The odour concentration at the detection threshold is

by definition 1 ou /m . The odour concentration is then expressed in terms of multiples of the detection

1 3 7 3

threshold. The range of measurement is typically from 10 ou /m to 10 ou /m (including pre-dilution).

E E
The field of application of this document includes:

— the measurement of the mass concentration at the detection threshold of pure odorous substances

in g/m ;
— the determination of the EROM value of odorants, in mol;
/m ;
— the measurement of the odour concentration of mixtures of odorants in ouE

— the measurement of the emission rate of odorous emissions from point sources, active area sources

and passive area sources, including pre-dilution during sampling;

— the sampling of odorous gases from emissions of high humidity and temperature (up to 200 °C);

— the determination of effectiveness of end-of-pipe mitigation techniques used to reduce odour

emissions.

The determination of odour emissions requires measurement of gas velocityto determine the gas volume

flow rate.
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The field of application of this document does not include:

— the measurement of odours potentially released by particles of odorous solids or droplets of odorous

fluids suspended in emissions;
— the measuring strategy to be applied in case of variable emission rates;

— the measurement of the relationship between odour stimulus and assessor response above detection

threshold (perceived intensity);

— measurement of hedonic tone (or (un)pleasantness) or assessment of annoyance potential;

— direct measurement of odour exposure in ambient air. For this measurement purpose, field panel

methods exist which are the subject of CEN standard EN 16841-1, Ambient Air - Determination of

odour in ambient air by using field inspection - Grid method;
— direct olfactometry, including field olfactometry;
— static olfactometry;
— measurement of odour recognition thresholds;
— measurement of odour identification thresholds.

Although the ultimate application of odour concentration measurement is aimed at reducing odour

nuisance, the relation between emissions, dispersion, exposure and annoyance is not within the scope of

this document. The relation between measured odour concentrations and odour emissions according to

this standard and the occurrence of odour nuisance is highly complex. It is profoundly influenced by the

atmospheric processes determining the dispersion of odours, the quality of the odour (hedonic tone) and

finally by the receptor characteristics of those exposed to the odour. These receptor characteristics not

only vary strongly between individuals, but also in time within one individual.
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.

EN 15259, Air quality — Measurement of stationary source emissions - Requirements for measurement

sections and sites and for the measurement objective, plan and report

EN ISO 16911-1, Stationary source emissions — Manual and automatic determination of velocity and

volume flow rate in ducts - Part 1: Manual reference method

EN ISO 20988:2007, Air quality — Guidelines for estimating measurement uncertainty

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
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— ISO Online browsing platform: available at https://www.iso.org/obp
The terms and definitions are categorized according to:
a) term and definitions for metrology and statistics;
b) terms and definitions for olfactometry;
c) terms and definitions for sampling.
3.1 Terms and definitions for olfactometry
3.1.1
anosmia
lack of sensitivity to olfactory stimuli
[SOURCE: EN ISO 5492:2008, 2.32]
3.1.2
assessor
somebody who participates in odour testing
3.1.3
delayed olfactometry
measurement of an odour with a time-lag between sampling and analysis
Note 1 to entry: The odour sample is preserved in an appropriate container.
3.1.4
detection threshold

odorant concentration which has a probability of 0,5 of being detected under

the conditions of the test
3.1.5
detection threshold

dilution factor at which the odorant gas has a probability of 0,5 of being

detected under the conditions of the test
3.1.6
dilution factor

ratio between flow or volume after dilution and the flow or volume of the odorous gas

3.1.7
dilution series

presentation of a sequence of dilutions to one panel member in order to obtain one Individual

Threshold Estimate
Note 1 to entry: See Figure 1.

Note 2 to entry: One dilution series can consist of: one series of presentations, at odour concentrations where,

when sorted in order of descending dilution factors, a significant change from FALSE responses to consistently

TRUE responses occurs (see Figure 1).
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3.1.8
direct olfactometry
on-line olfactometry

measurement of odour concentrations without any time-lag between the sampling (operation) and the

analysis
3.1.9
dynamic dilution

dilution achieved by mixing two known flows of gas, odorous sample and neutral gas, respectively

Note 1 to entry: The rate of dilution is calculated from the flow rates.
3.1.10
dynamic olfactometer

equipment that delivers a flow of mixtures of odorous and neutral gas with known dilution factors in a

common outlet
3.1.11
dynamic olfactometry
olfactometry using a dynamic olfactometer
3.1.12
European Odour unit

amount of odorant(s) that, when evaporated into one cubic metre of neutral gas at standard conditions,

elicits a physiological response from a panel (detection threshold) equivalent to that elicited by one

European Reference Odour Mass (EROM), evaporated in 1 m of neutral gas at standard conditions

3.1.13
European Reference Odour Mass
EROM

conventional quantity value for the European odour unit, equal to a defined mass of reference odorant

Note 1 to entry: The primary reference odorant is n-butanol (CAS-Nr. 71-36-3). The conventional quantity value

for 1 EROM is 123 µg n-butanol. Evaporated in 1 m of neutral gas this produces a concentration of 0,040 µmol/mol.

Note 2 to entry: For each odorant a specific quantity for the EROM can be determined, according to the procedure

in 5.3. If an EROM quantity has been established for an odorant, it can serve as a secondary reference odorant.

3.1.14
forced choice method
procedure in which the response “no difference” is not permitted
[EN 5492:2009/A1:2017, 4.58
3.1.15
group threshold
detection threshold applying to a group of assessors
3.1.16
identification threshold
recognition threshold

odour concentration which has a probability of 0,5 of being recognised under the conditions of the test

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3.1.17
individual threshold
detection threshold applying to an individual
3.1.18
individual threshold estimate
ITE

detection threshold applying to an individual estimated on the basis of one dilution series

3.1.19
instrumental dilution range
range between the minimum and maximum dilution factor
3.1.20
intensity
magnitude of the perceived sensation
[SOURCE: ISO 5492:2008,2.8]
3.1.21
maximum dilution factor
highest settable dilution factor of the olfactometer
3.1.22
measurement report

report established by the testing laboratory according to the customer request and containing at least

the information required in the standar
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