Measurement of radioactivity in the environment - Air: radon-222 - Part 5: Continuous measurement methods of the activity concentration (ISO 11665-5:2020)

This document describes continuous measurement methods for radon-222. It gives indications for continuous measuring of the temporal variations of radon activity concentration in open or confined atmospheres.
This document is intended for assessing temporal changes in radon activity concentration in the environment, in public buildings, in homes and in work places, as a function of influence quantities such as ventilation and/or meteorological conditions.
The measurement method described is applicable to air samples with radon activity concentration greater than 5 Bq/m3.

Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 5: Kontinuierliche Messverfahren für die Aktivitätskonzentration (ISO 11665-5:2020)

Dieses Dokument beschreibt kontinuierliche Messverfahren für 222Rn. Es gibt Hinweise für die kontinuierliche Messung der zeitlichen Veränderung der Radon-Aktivitätskonzentration in offenen und umschlossenen Atmosphären.
Dieses Dokument dient der Bewertung der zeitlichen Schwankungen der Radon-Aktivitätskonzentration in der Umgebung, in öffentlichen Gebäuden, in Wohnhäusern und an Arbeitsplätzen in Abhängigkeit von Ein-fluss¬größen wie der Belüftung und/oder den meteorologischen Bedingungen.
Das beschriebene Messverfahren ist anwendbar auf Luftproben mit Radon-Aktivitätskonzentrationen größer als 5 Bq m–3.

Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 5: Méthodes de mesure en continu de l'activité volumique (ISO 11665-5:2020)

Le présent document décrit les méthodes de mesure en continu du radon-222. Il donne des indications pour le mesurage en continu des variations temporelles de l'activité volumique du radon dans des atmosphères libres ou confinées.
Le présent document est destiné à évaluer les variations temporelles de l'activité volumique du radon dans l'environnement, les bâtiments publics, les habitations et les lieux de travail en fonction de grandeurs d'influence telles que les conditions de ventilation et/ou météorologiques.
la méthode de mesure décrite s'applique à des échantillons d'air dont l'activité volumique du radon est supérieure à 5/m3.

Merjenje radioaktivnosti v okolju - Zrak: radon Rn-222 - 5. del: Neprekinjeno merjenje koncentracije aktivnosti (ISO 11665-5:2020)

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 11665-5:2020
01-april-2020
Nadomešča:
SIST EN ISO 11665-5:2015
Merjenje radioaktivnosti v okolju - Zrak: radon Rn-222 - 5. del: Neprekinjeno
merjenje koncentracije aktivnosti (ISO 11665-5:2020)

Measurement of radioactivity in the environment - Air: radon-222 - Part 5: Continuous

measurement methods of the activity concentration (ISO 11665-5:2020)

Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 5: Kontinuierliches

Messverfahren für die Aktivitätskonzentration (ISO 11665-5:2020)

Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 5: Méthodes

de mesure en continu de l'activité volumique (ISO 11665-5:2020)
Ta slovenski standard je istoveten z: EN ISO 11665-5:2020
ICS:
13.040.99 Drugi standardi v zvezi s Other standards related to air
kakovostjo zraka quality
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 11665-5:2020 en,fr,de

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

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SIST EN ISO 11665-5:2020
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SIST EN ISO 11665-5:2020
EN ISO 11665-5
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2020
EUROPÄISCHE NORM
ICS 17.240 Supersedes EN ISO 11665-5:2015
English Version
Measurement of radioactivity in the environment - Air:
radon-222 - Part 5: Continuous measurement methods of
the activity concentration (ISO 11665-5:2020)

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

Air: radon 222 - Partie 5: Méthodes de mesure en Radon-222 - Teil 5: Kontinuierliches Messverfahren für

continu de l'activité volumique (ISO 11665-5:2020) die Aktivitätskonzentration (ISO 11665-5:2020)

This European Standard was approved by CEN on 20 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 11665-5:2020 E

worldwide for CEN national Members.
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SIST EN ISO 11665-5:2020
EN ISO 11665-5:2020 (E)
Contents Page

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

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SIST EN ISO 11665-5:2020
EN ISO 11665-5:2020 (E)
European foreword

This document (EN ISO 11665-5:2020) 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 11665-5:2015.

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 11665-5:2020 has been approved by CEN as EN ISO 11665-5:2020 without any

modification.
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SIST EN ISO 11665-5:2020
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SIST EN ISO 11665-5:2020
INTERNATIONAL ISO
STANDARD 11665-5
Second edition
2020-01
Measurement of radioactivity in the
environment — Air: radon-222 —
Part 5:
Continuous measurement methods of
the activity concentration
Mesurage de la radioactivité dans l'environnement — Air: radon 222 —
Partie 5: Méthodes de mesure en continu de l'activité volumique
Reference number
ISO 11665-5:2020(E)
ISO 2020
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SIST EN ISO 11665-5:2020
ISO 11665-5:2020(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 11665-5:2020
ISO 11665-5:2020(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 Installation of sampling device ............................................................................................................................ 3

6.3.3 Sampling duration .......................................................................................................................................................... 4

6.3.4 Integration interval ........................................................................................................................................................ 4

6.3.5 Volume of air sampled .................. ......................................................................................................................... ...... 4

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

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

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

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

8.3 Calibration .................................................................................................................................................................................................. 5

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 ................................................................................................................................................................................................................... 6

Annex A (informative) Measurement method using a vented ionization chamber and a

current ionization chamber ...................................................................................................................................................................... 7

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

© ISO 2020 – All rights reserved iii
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SIST EN ISO 11665-5:2020
ISO 11665-5:2020(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 11665-5:2012), 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 11665-5:2020
ISO 11665-5:2020(E)
Introduction

Radon isotopes 222, 219 and 220 (also known as thoron) 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 elements, also radioactive, followed by stable lead are produced

[1]
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 continuous measurement methods for radon-222.

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 11665-5:2020
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SIST EN ISO 11665-5:2020
INTERNATIONAL STANDARD ISO 11665-5:2020(E)
Measurement of radioactivity in the environment — Air:
radon-222 —
Part 5:
Continuous measurement methods of the activity
concentration
1 Scope

This document describes continuous measurement methods for radon-222. It gives indications for

continuous measuring of the temporal variations of radon activity concentration in open or confined

atmospheres.

This document is intended for assessing temporal changes in radon activity concentration in the

environment, in public buildings, in homes and in work places, as a function of influence quantities such

as ventilation and/or meteorological conditions.

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

greater than 5 Bq/m .
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 coverage 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

me a s ur ement (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

IEC 61577-2, Radiation protection instrumentation — Radon and radon decay product measuring

instruments — Part 2: Specific requirements for radon measuring instruments
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 https:// www .iso .org/ obp
© ISO 2020 – All rights reserved 1
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SIST EN ISO 11665-5:2020
ISO 11665-5:2020(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 U=ku⋅ () 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 and climatic correction factors

4 Principle

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

a) continuous in situ sampling of a volume of air previously filtered and representative of the

atmosphere under investigation;

b) continuous detection of radiations emitted by radon and its decay products accumulated in the

detection chamber.

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

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

related detection may be as follows, for example:

— ionization current produced by several tens of thousands of ion pairs created by each alpha particle

emitted by the radon that is present in the detection chamber and its decay products formed therein

(see Annex A);

— charges produced in a solid [semi-conductor medium (silicon)] by ionization from alpha particles of

radon and its decay products; the charges are detected by related electronics.

Measurement results are instantly available. A mean or integrated value can be obtained through

appropriate processing based on an integration interval compatible with the phenomenon studied but

in all cases less than or equal to one hour.

In order to monitor the temporal variation of radon activity concentration, the measurement period

shall be compatible with the dynamics of the phenomenon studied. For example, the minimum

significant period for detecting daily variations is approximately one week.
2 © ISO 2020 – All rights reserved
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SIST EN ISO 11665-5:2020
ISO 11665-5:2020(E)

Continuous monitoring allows for the assessment of temporal changes in radon activity concentration.

For measurements performed outdoors, the season and climatic conditions shall be taken into account.

For measurements performed inside a building, the lifestyles of its inhabitants, the level at which

the measurement place is located (basement, ground floor, upper levels) and the natural ventilation

characteristics (condition of doors and windows, open or closed) shall be taken into account.

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,

a device to pump the air for sampling if active sampling is necessary, and the detection chamber;

b) a measuring system adapted to the physical quantity to be measured.

The instrument used for measurement shall satisfy the requirements of IEC 61577-2.

An example of the equipment (ionization chamber) for a specific measurement method is given in

Annex A.
6 Sampling
6.1 Sampling objective

The sampling objective is to ensure air samples representative of the atmosphere under investigation

are in continuous contact with the detector.
6.2 Sampling characteristics
Sampling may be passive (natural diffusion) or active (pumping).

Sampling shall be performed through a filtering medium which prevents access of aerosol particles

present in the air at the time of sampling, especially radon decay products.
The filter shall not trap radon gas.

The sampling system shall be used under conditions that do not cause clogging of the filter (this would

result in a modification of the measurement conditions, e.g. decrease of gas quantity sampled due to

pressure drop in measurement chamber).

In case of clogging during sampling by pumping, the pressure drop might increase, leading to a

degradation in the performance of the measurement system, and possibly resulting in the perforation

of the filter.

Clogging during sampling by natural diffusion can lead to the non-renewal of air in the detection

chamber.
6.3 Sampling conditions
6.3.1 General

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

recorded.
6.3.2 Installation of sampling device

Installation of the sampling device shall be carried out as specified in ISO 11665-1.

© ISO 2020 – All rights reserved 3
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SIST EN ISO 11665-5:2020
ISO 11665-5:2020(E)
6.3.3 Sampling duration

For continuous sampling, the sampling duration corresponds to the measurement period, which shall

be compatible with the dynamics of the phenomenon studied.
6.3.4 Integration interval

The integration interval determines the time resolution of the measurement. Different parameters such

as the expected radon activity concentration or dynamics of radon level changes need to be taken into

account when selecting the appropriate integration interval.
6.3.5 Volume of air sampled

For active sampling, the volume of air sampled shall be measured by a flowmeter corrected for the

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

of 1,013 hPa and 0 °C respectively).

For passive sampling, direct measurement of the air volume sampled is not necessary; a calibration

factor (activity per unit volume) shall be used.
7 Detection

Detection shall be carried out using a suitable method as outlined in ISO 11665-1.

8 Measurement
8.1 Procedure
The measurement procedure is specific to the detection method used.

An example of a measurement procedure using an ionization chamber is given 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) temperature, humidity and atmospheric turbulence; these variables are taken into account when

choosing a location for the device;
b) background radiation;
c) instrumental background noise;
d) electromagnetic field;
e) increase in pressure drop due to clogging of the intake filter;

f) possible presence of other alpha emitters (radium, radon isotopes, actinides, etc.) in the detection

volume; if the presence of other radon isotopes is suspected, it shall be ruled out using an

appropriate system, e.g. ageing chamber;
g) possible presence of other gamma emitters in the detection volume.

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

followed.
4 © ISO 2020 – All rights reserved
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SIST EN ISO 1166
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