Measurement of radioactivity in the environment - Air: radon-222 - Part 6: Spot measurement methods of the activity concentration (ISO 11665-6:2020)

This document describes radon-222 spot measurement methods. It gives indications for carrying out spot measurements, at the scale of a few minutes at a given place, of the radon activity concentration in open and confined atmospheres.
This measurement method is intended for rapid assessment of the radon activity concentration in the air. The result cannot be extrapolated to an annual estimate of the radon activity concentration. This type of measurement is therefore not applicable for assessment of the annual exposure or for determining whether or not to mitigate citizen exposures to radon or radon decay products.
The measurement method described is applicable to air samples with radon activity concentration greater than 50 Bq·m−3.
NOTE    For example, using an appropriate device, the radon activity concentration can be spot measured in the soil and at the interface of a material with the atmosphere (see also ISO 11665-7[8]).

Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 6: Punktmessverfahren für die Aktivitätskonzentration (ISO 11665-6:2020)

Dieses Dokument beschreibt Punktmessverfahren für 222Rn. Er gibt Hinweise zur Durchführung einer Punktmessung der Radon-Aktivitätskonzentration innerhalb weniger Minuten an einem vorgegebenen Ort in offenen und umschlossenen Atmosphären.
Dieses Messverfahren wird verwendet für die schnelle Bestimmung der Radon-Aktivitätskonzentration in der Luft. Das Ergebnis kann nicht zur Prognose des Jahreswerts der Radon-Aktivitätskonzentration verwendet werden. Diese Art der Messung ist deshalb nicht anwendbar für die Bewertung der Ganzjahresexposition oder zur Bestimmung, ob die Belastung der Bevölkerung durch Radon oder Radon-Folgeprodukte verringert werden muss.
Das beschriebene Messverfahren ist auf Luftproben mit Radon-Aktivitätskonzentrationen von mehr als 50 Bq·m–3 anwendbar.
ANMERKUNG Bei Verwendung eines geeigneten Geräts kann die Radon-Aktivitätskonzentration beispielsweise im Erdboden und an der Grenzfläche zwischen einem Material und der Atmosphäre mittels Punktmessung bestimmt werden (siehe auch ISO 11665-7 [8]).

Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 6: Méthodes de mesure ponctuelle de l'activité volumique (ISO 11665-6:2020)

Le présent document décrit les méthodes de mesure ponctuelle du radon-222. Il donne des indications pour réaliser des mesures ponctuelles, à l'échelle de quelques minutes et en un point donné, de l'activité volumique du radon dans des atmosphères libres et confinées.
Cette méthode de mesure est destinée à une évaluation rapide de l'activité volumique du radon dans l'air. Le résultat ne peut pas être extrapolé à une estimation annuelle de l'activité volumique du radon. Par conséquent, ce type de mesurage ne s'applique pas à l'évaluation de l'exposition annuelle ni à la détermination de l'opportunité de réduire ou non l'exposition des citoyens au radon ou aux descendants du radon.
La méthode de mesure décrite s'applique à des échantillons d'air dont l'activité volumique du radon est supérieure à 50 Bq·m−3.
NOTE    À titre d'exemple, le mesurage ponctuel de l'activité volumique du radon dans le sol et au niveau de l'interface entre un matériau et l'atmosphère peut être réalisé en utilisant un dispositif approprié (voir également ISO 11665-7[8]).

Merjenje radioaktivnosti v okolju - Zrak: radon Rn-222 - 6. del: Točkovna metoda za merjenje koncentracije aktivnosti (ISO 11665-6:2020)

General Information

Status
Published
Publication Date
04-Feb-2020
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
05-Feb-2020
Completion Date
05-Feb-2020

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SLOVENSKI STANDARD
SIST EN ISO 11665-6:2020
01-april-2020
Nadomešča:
SIST EN ISO 11665-6:2015
Merjenje radioaktivnosti v okolju - Zrak: radon Rn-222 - 6. del: Točkovna metoda
za merjenje koncentracije aktivnosti (ISO 11665-6:2020)
Measurement of radioactivity in the environment - Air: radon-222 - Part 6: Spot
measurement methods of the activity concentration (ISO 11665-6:2020)
Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 6:
Punktmessverfahren für die Aktivitätskonzentration (ISO 11665-6:2020)

Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 6: Méthodes

de mesure ponctuelle de l'activité volumique (ISO 11665-6:2020)
Ta slovenski standard je istoveten z: EN ISO 11665-6:2020
ICS:
13.040.01 Kakovost zraka na splošno Air quality in general
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 11665-6:2020 en,fr,de

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

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SIST EN ISO 11665-6:2020
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SIST EN ISO 11665-6:2020
EN ISO 11665-6
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 17.240; 13.040.01 Supersedes EN ISO 11665-6:2015
English Version
Measurement of radioactivity in the environment - Air:
radon-222 - Part 6: Spot measurement methods of the
activity concentration (ISO 11665-6:2020)

Mesurage de la radioactivité dans l'environnement - Ermittlung der Radioaktivität in der Umwelt - Luft:

Air: radon 222 - Partie 6: Méthodes de mesure Radon-222 - Teil 6: Punktmessverfahren für die

ponctuelle de l'activité volumique (ISO 11665-6:2020) Aktivitätskonzentration (ISO 11665-6:2020)

This European Standard was approved by CEN on 21 January 2020.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11665-6:2020 E

worldwide for CEN national Members.
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SIST EN ISO 11665-6:2020
EN ISO 11665-6:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 11665-6:2020
EN ISO 11665-6:2020 (E)
European foreword

This document (EN ISO 11665-6:2020) has been prepared by Technical Committee ISO/TC 85 "Nuclear

energy, nuclear technologies, and radiological protection" in collaboration with Technical Committee

CEN/TC 430 “Nuclear energy, nuclear technologies, and radiological protection” the secretariat of

which is held by AFNOR.

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 August 2020, and conflicting national standards shall

be withdrawn at the latest by August 2020.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN ISO 11665-6:2015.

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, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 11665-6:2020 has been approved by CEN as EN ISO 11665-6:2020 without any

modification.
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SIST EN ISO 11665-6:2020
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SIST EN ISO 11665-6:2020
INTERNATIONAL ISO
STANDARD 11665-6
Second edition
2020-01
Measurement of radioactivity in the
environment — Air: radon-222 —
Part 6:
Spot measurement methods of the
activity concentration
Mesurage de la radioactivité dans l'environnement — Air: radon 222 —
Partie 6: Méthodes de mesure ponctuelle de l'activité volumique
Reference number
ISO 11665-6:2020(E)
ISO 2020
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and symbols ............................................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Symbols ......................................................................................................................................................................................................... 2

4 Principle ........................................................................................................................................................................................................................ 2

5 Equipment ................................................................................................................................................................................................................... 3

6 Sampling ........................................................................................................................................................................................................................ 3

6.1 Sampling objective ............................................................................................................................................................................... 3

6.2 Sampling characteristics ......... ........................................................................................................................................................ 3

6.3 Sampling conditions ........................................................................................................................................................................... 3

6.3.1 General...................................................................................................................................................................................... 3

6.3.2 Location of sampling place .................. .................................................................................................................... 3

6.3.3 Sampling duration .......................................................................................................................................................... 3

6.3.4 Volume of air sampled .................. ......................................................................................................................... ...... 3

7 Detection ....................................................................................................................................................................................................................... 4

8 Measurement ........................................................................................................................................................................................................... 4

8.1 Procedure .................................................................................................................................................................................................... 4

8.2 Influence quantities ............................................................................................................................................................................ 4

8.3 Calibration .................................................................................................................................................................................................. 4

9 Expression of results ........................................................................................................................................................................................ 5

9.1 Radon activity concentration...................................................................................................................................................... 5

9.2 Standard uncertainty ......................................................................................................................................................................... 5

9.3 Decision threshold and detection limit .............................................................................................................................. 5

9.4 Limits of the confidence interval ............................................................................................................................................. 5

10 Test report ................................................................................................................................................................................................................... 5

Annex A (informative) Measurement method using scintillation cells ............................................................................ 7

Bibliography .............................................................................................................................................................................................................................13

© ISO 2020 – All rights reserved iii
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(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.

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).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,

and radiological protection, Subcommittee SC 2, Radiological protection.

This second edition cancels and replaces the first edition (ISO 11665-6:2012), of which it constitutes a

minor revision. The changes compared to the previous edition are as follows:
— update of the Introduction;
— update of the Bibliography.
A list of all the parts in the ISO 11665 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.
iv © ISO 2020 – All rights reserved
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
Introduction

Radon isotopes 222, 219 and 220 are radioactive gases produced by the disintegration of radium isotopes

226, 223 and 224, which are decay products of uranium-238, uranium-235 and thorium-232 respectively,

and are all found in the earth's crust (see ISO 11665-1:2019, Annex A, for further information). Solid

[1]

elements, also radioactive, followed by stable lead are produced by radon disintegration .

When disintegrating, radon emits alpha particles and generates solid decay products, which are also

radioactive (polonium, bismuth, lead, etc.). The potential effects on human health of radon lie in its solid

decay products rather than the gas itself. Whether or not they are attached to atmospheric aerosols,

radon decay products can be inhaled and deposited in the bronchopulmonary tree to varying depths

[2][3][4][5]
according to their size .
[6]

Radon is today considered to be the main source of human exposure to natural radiation. UNSCEAR

suggests that, at the worldwide level, radon accounts for around 52 % of global average exposure to

natural radiation. The radiological impact of isotope 222 (48 %) is far more significant than isotope

220 (4 %), while isotope 219 is considered negligible (see ISO 11665-1:2019, Annex A). For this reason,

references to radon in this document refer only to radon-222.

Radon activity concentration can vary from one to more orders of magnitude over time and space.

Exposure to radon and its decay products varies tremendously from one area to another, as it depends

on the amount of radon emitted by the soil and building materials, weather conditions, and on the

degree of containment in the areas where individuals are exposed.

As radon tends to concentrate in enclosed spaces like houses, the main part of the population exposure

is due to indoor radon. Soil gas is recognized as the most important source of residential radon through

infiltration pathways. Other sources are described in other parts of ISO 11665 and ISO 13164 series for

[7]
water .

Radon enters into buildings via diffusion mechanism caused by the all-time existing difference between

radon activity concentrations in the underlying soil and inside the building, and via convection

mechanism inconstantly generated by a difference in pressure between the air in the building and the

air contained in the underlying soil. Indoor radon activity concentration depends on radon activity

concentration in the underlying soil, the building structure, the equipment (chimney, ventilation

systems, among others), the environmental parameters of the building (temperature, pressure, etc.)

and the occupants’ lifestyle.

To limit the risk to individuals, a national reference level of 100 Bq·m is recommended by the World

[5] -3

Health Organization . Wherever this is not possible, this reference level should not exceed 300 Bq·m .

This recommendation was endorsed by the European Community Member States that shall establish

national reference levels for indoor radon activity concentrations. The reference levels for the annual

-3[5]
average activity concentration in air shall not be higher than 300 Bq·m .

To reduce the risk to the overall population, building codes should be implemented that require radon

prevention measures in buildings under construction and radon mitigating measures in existing

buildings. Radon measurements are needed because building codes alone cannot guarantee that radon

concentrations are below the reference level.

The activity concentration of radon-222 in the atmosphere can be measured by spot, continuous and

integrated measurement methods with active or passive air sampling (see ISO 11665-1). This document

deals with radon-222 spot measurement methods.

NOTE The origin of radon-222 and its short-lived decay products in the atmospheric environment and other

measurement methods are described generally in ISO 11665-1.
© ISO 2020 – All rights reserved v
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SIST EN ISO 11665-6:2020
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SIST EN ISO 11665-6:2020
INTERNATIONAL STANDARD ISO 11665-6:2020(E)
Measurement of radioactivity in the environment — Air:
radon-222 —
Part 6:
Spot measurement methods of the activity concentration
1 Scope

This document describes radon-222 spot measurement methods. It gives indications for carrying out

spot measurements, at the scale of a few minutes at a given place, of the radon activity concentration in

open and confined atmospheres.

This measurement method is intended for rapid assessment of the radon activity concentration in

the air. The result cannot be extrapolated to an annual estimate of the radon activity concentration.

This type of measurement is therefore not applicable for assessment of the annual exposure or for

determining whether or not to mitigate citizen exposures to radon or radon decay products.

The measurement method described is applicable to air samples with radon activity concentration

greater than 50 Bq·m .

NOTE For example, using an appropriate device, the radon activity concentration can be spot measured in

[8]

the soil and at the interface of a material with the atmosphere (see also ISO 11665-7 ).

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 11665-1, Measurement of radioactivity in the environment — Air: radon-222 — Part 1: Origins of radon

and its short-lived decay products and associated measurement methods

ISO 11929 (all parts), Determination of the characteristic limits (decision threshold, detection limit and

limits of the confidence interval) for measurements of ionizing radiation — Fundamentals and application

ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in

measurement (GUM: 1995)

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

IEC 61577-1, Radiation protection instrumentation — Radon and radon decay product measuring

instruments — Part 1: General principles
3 Terms, definitions and symbols
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 11665-1 apply.

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

— ISO Online browsing platform: available at http:// www .iso .org/ obp
© ISO 2020 – All rights reserved 1
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
— IEC Electropedia: available at http:// www .electropedia .org/
3.2 Symbols

For the purposes of this document, the symbols given in ISO 11665-1 and the following apply.

C activity concentration, in becquerels per cubic metre
decision threshold of the activity concentration, in becquerels per cubic metre
detection limit of the activity concentration, in becquerels per cubic metre

lower limit of the confidence interval of the activity concentration, in becquerels per

cubic metre

upper limit of the confidence interval of the activity concentration, in becquerels per

cubic metre
U expanded uncertainty calculated by Uk=⋅u() with k = 2
u() standard uncertainty associated with the measurement result
u relative standard uncertainty
rel
μ quantity to be measured
μ background level
ω correction factor linked to the calibration factor
4 Principle

Spot measurement of the radon activity concentration is based on the following elements:

a) active grab sampling of a volume of air previously filtered and representative of the atmosphere

under investigation at time t; this pre-filtered sample is introduced into the detection chamber;

b) measurement of the physical variable (photons, pulse counts and amplitude, etc.) linked to the

radiation that is emitted by the radon and/or its decay products present in the detection chamber

after sampling.

Several measurement methods meet the requirements of this document. They are basically

distinguished by the type of physical quantity and how it is measured. The physical quantity and its

related measurement may be as follows, for example:

— photons emitted by a scintillating medium, such as ZnS(Ag), when excited by an alpha particle

(see Annex A);
214 214

— gamma emission rates of the decay products Pb and Bi produced by the radon that is present

in the sampled air volume.

The measurement results can be available immediately or after a certain period of time. Due to the

great variability of the radon activity concentration in time and space, the measurement result is

representative of the radon activity concentration at the sampling time and the sampling place only.

2 © ISO 2020 – All rights reserved
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
5 Equipment
The apparatus shall include the following:

a) a sampling device, including a filtering medium, for taking the air sample in the detection chamber;

the role of the filtering medium is to stop the aerosols present in the air at the time of sampling,

especially the solid radon decay products;
b) a device to pump the air for sampling if active sampling is required;
c) the detection chamber;
d) a measuring system adapted to the physical quantity.

The necessary equipment for a specific measurement method is specified in Annex A.

6 Sampling
6.1 Sampling objective

The sampling objective is to introduce an ambient air sample into the detection chamber of the device

during a short period of time of less than 1 h.
6.2 Sampling characteristics

Sampling is active and may be carried out via pumping or suction in a detection chamber under vacuum.

Grab sampling is representative of the radon activity concentration at a given moment and a given

place. An air sample adapted to the detection chamber of the measuring device used is taken directly in

the atmosphere by pumping and filtering.

The filtering medium shall stop the aerosol particles present in the air at the time of sampling, especially

the radon decay products.

The sampling device shall not include components that trap radon (desiccants, etc.).

6.3 Sampling conditions
6.3.1 General

Sampling shall be carried out as specified in ISO 11665-1. The sampling location and time (date and

hour) shall be recorded.
6.3.2 Location of sampling place

Grab sampling may be carried out in the atmosphere, inside a building, in the ground or at the interface

between a material and the atmosphere, etc.

The choice of each sampling location depends on the objectives sought (for example, verification of the

homogeneity of the activity concentrations in an environment or a search for anomalies, etc.).

6.3.3 Sampling duration

Sampling is carried out over a short period of time. The sampling duration shall be less than 1 h.

6.3.4 Volume of air sampled

The volume of air sampled shall be determined accurately with a flowmeter corrected for the

temperature and pressure variation (expressed in cubic metres at a standard pressure and temperature

© ISO 2020 – All rights reserved 3
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)

of 1,013 hPa and 0 °C respectively) or by deducing it from a pressure measurement when sampling is

carried out via suction (see Annex A).
7 Detection

Detection shall be carried out using silver-activated zinc sulphide ZnS(Ag) scintillation or gamma-ray

spectrometry, as described in ISO 11665-1.
8 Measurement
8.1 Procedure
Measurement shall be carried out as follows.
a) Determine the background of the detection chamber.
b) Select and locate the measuring place.

c) Using grab sampling, collect an air sample representative of the atmosphere under investigation.

d) Record the location and time (date and hour) of sampling.

e) Wait until short-lived decay products are in equilibrium with radon in the detection chamber (3 h).

f) Measure the physical quantity emitted in the detection chamber with a suitable measuring chain.

g) Record the time (date and hour) of measurement.
h) Determine the activity concentration by calculation.
The measurement procedure for the scintillation method is detailed in Annex A.
8.2 Influence quantities

Various quantities can lead to measurement bias that could induce non-representative results.

Depending on the measurement method and the control of usual influence quantities specified

in IEC 61577-1 and ISO 11665-1, the following quantities shall be considered in particular:

a) the instrumental background noise;

b) the presence of other gaseous radionuclide alpha-emitters or gamma-emitters in the detection

chamber, including other radon isotopes and their decay products.

Manufacturer recommendations in the operating instructions for the measuring devices shall be

followed.
8.3 Calibration

The entire measuring instrument (sampling system, detector and related electronics) shall be calibrated

as specified in ISO 11665-1.

The relationship between the physical quantity measured by the detection device (count rate, etc.) and

the activity concentration of the radon in the air sample shall be established based on the measurement

of a radon-222 reference atmosphere. The radon-222 activity concentration in the reference atmosphere

shall be traceable to a primary radon-222 gas standard.

An instrument calibration result shall allow traceability of the measurement result against a primary

standard.
4 © ISO 2020 – All rights reserved
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SIST EN ISO 11665-6:2020
ISO 11665-6:2020(E)
9 Expression of results
9.1 Radon activity concentration
The radon activity concentration shall be calculated as given in Formula (1):
C =−μμ ⋅ω (1)
9.2 Standard uncertainty

In accordance with ISO/IEC Guide 98-3, the standard uncertainty of C shall be calculated as given

in Formula (2):
22 2 22
 
uC()=⋅ωμuu()+ μω+⋅Cu () (2)
 0  rel
9.3 Decision threshold and detection limit

The characteristic limits associated with the measurand shall be calculated in ac

...

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