SIST EN ISO 11665-2:2020

SLOVENSKI STANDARD
oSIST prEN ISO 11665-2:2019
01-julij-2019
Merjenje radioaktivnosti v okolju - Zrak: radon Rn-222 - 2. del: Integrirana merilna
metoda za ugotavljanje povprečne potencialne koncentracije alfa energije
njegovih kratkoživih razpadnih produktov (ISO/FDIS 11665-2:2019)
Measurement of radioactivity in the environment - Air: radon-222 - Part 2: Integrated
measurement method for determining average potential alpha energy concentration of its
short-lived decay products (ISO/FDIS 11665-2:2019)
Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 2: Integrierendes
Messverfahren für die Bestimmung des Durchschnittswertes der potenziellen Alpha-
Energiekonzentration der kurzlebigen Radon-Folgeprodukte (ISO/FDIS 11665-2:2019)
Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 2: Méthode
de mesure intégrée pour la détermination de l'énergie alpha potentielle volumique
moyenne de ses descendants à vie courte (ISO/FDIS 11665-2:2019)
Ta slovenski standard je istoveten z: prEN ISO 11665-2
ICS:
13.040.99 Drugi standardi v zvezi s Other standards related to air
kakovostjo zraka quality
17.240 Merjenje sevanja Radiation measurements
oSIST prEN ISO 11665-2:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 11665-2:2019

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oSIST prEN ISO 11665-2:2019
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 11665-2
ISO/TC 85/SC 2
Measurement of radioactivity in the
Secretariat: AFNOR
environment — Air: radon-222 —
Voting begins on:
2019-05-13
Part 2:
Voting terminates on:
Integrated measurement method for
2019-08-05
determining average potential alpha
energy concentration of its short-lived
decay products
Mesurage de la radioactivité dans l'environnement — Air: radon 222 —
Partie 2: Méthode de mesure intégrée pour la détermination de
l'énergie alpha potentielle volumique moyenne de ses descendants à
vie courte
ISO/CEN PARALLEL PROCESSING
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 11665-2:2019(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2019

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oSIST prEN ISO 11665-2:2019
ISO/FDIS 11665-2:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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
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Phone: +41 22 749 01 11
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2019 – All rights reserved

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oSIST prEN ISO 11665-2:2019
ISO/FDIS 11665-2:2019(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 . 3
5 Equipment . 3
5.1 General . 3
5.2 Measuring device . 3
5.2.1 Sampling system . 3
5.2.2 Detection system. 3
5.3 Counting system . 4
6 Sampling . 4
6.1 Sampling objective . 4
6.2 Sampling characteristics . . 4
6.3 Sampling conditions . 5
6.3.1 General. 5
6.3.2 Installation of sampling system . 5
6.3.3 Sampling duration . 5
6.3.4 Volume of air sampled . . . 5
7 Detection method . 6
8 Measurement . 6
8.1 Procedure . 6
8.2 Influence quantities . 6
8.3 Calibration . 7
9 Expression of results . 7
9.1 Average potential alpha energy concentration . 7
9.2 Standard uncertainty . 8
9.3 Decision threshold and detection limit . 9
9.4 Limits of the confidence interval . 9
10 Test report . 9
Annex A (informative) Example of a method meeting the requirements of this document .11
Bibliography .13
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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 11665-2:2012), 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.
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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 Annex A for further information). Solid elements,
[1]
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 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
[58].
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.
−3
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.
Variations of a few nanojoules per cubic metre to several thousand nanojoules per cubic metre are
observed in the potential alpha energy concentration of short-lived radon decay products.
The potential alpha energy concentration of short-lived radon-222 decay products in the atmosphere
can be measured by spot and integrated measurement methods (see ISO 11665-1). This document deals
with integrated measurement methods. Integrated measuring methods are applicable in assessing
[4]
human exposure to radiation .
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.
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oSIST prEN ISO 11665-2:2019
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 11665-2:2019(E)
Measurement of radioactivity in the environment — Air:
radon-222 —
Part 2:
Integrated measurement method for determining average
potential alpha energy concentration of its short-lived
decay products
1 Scope
[4]
This document describes integrated measurement methods for short-lived radon-222 decay products .
It gives indications for measuring the average potential alpha energy concentration of short-lived
radon-222 decay products in the air and the conditions of use for the measuring devices.
This document covers samples taken over periods varying from a few weeks to one year. This document
is not applicable to systems with a maximum sampling duration of less than one week.
The measurement method described is applicable to air samples with potential alpha energy concentration
3 3
of short-lived radon-222 decay products greater than 10 nJ/m and lower than 1 000 nJ/m .
NOTE For informative purposes only, this document also addresses the case of radon-220 decay products,
given the similarity in behaviour of the radon isotopes 222 and 220.
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/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 61577-3, Radiation protection instrumentation — Radon and radon decay product measuring
instruments — Part 3: Specific requirements for radon decay product 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 http: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
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3.2 Symbols
For the purposes of this document, the symbols given in ISO 11665-1 and the following apply.
222
a attenuation coefficient relating to the Rn found in the collimators corresponding to the
range P (established theoretically and provided by the manufacturer)
1
222
b attenuation coefficient relating to the Rn found in the collimators corresponding to the
range P (established theoretically and provided by the manufacturer)
2
alpha particle energy produced by the disintegration of the nuclide i, in joules
E
AE,i
average potential alpha energy concentration of the nuclide i, in joules per cubic metre
E
PAEC,i
decision threshold of the average potential alpha energy concentration of the nuclide i, in
*
E
PAEC,i
joules per cubic metre
detection limit of the average potential alpha energy concentration of the nuclide i, in
#
E
PAEC,i
joules per cubic metre
 lower limit of the confidence interval of the average potential alpha energy concentration
E
PAEC,i
of the nuclide i, in joules per cubic metre
upper limit of the confidence interval of the average potential alpha energy concentration

E
PAEC,i
of the nuclide i, in joules per cubic metre
n counting number of each range P
i
P range recording alpha particles for i = 1, 2, 3, 4
i
th
j number of net count of range P with deduced background for i = 1, 2, 3, 4
i
R
Pj,
i
mean number of net count of range P with deduced background for i = 1, 2, 3, 4
i
R
P
i
mean number of count due to background
R
0
212
r ratio between the number of alpha particles emitted by Bi (α emitter at 36 %) and
212
the number of alpha particles emitted by Po (produced by β disintegration at 64 %
212
of Bi); 0,56
U expanded uncertainty calculated by U = k⋅u( ) with k = 2
u( ) standard uncertainty associated with the measurement result
u ( ) relative standard uncertainty
rel
V sampled volume, in cubic metres
ε geometric detection efficiency (established theoretically), i.e. the ratio between the num-
gd
ber of tracks counted and the number of alpha particles emitted by the deposit collected
on the filter
ε collection efficiency (established experimentally), i.e. the ratio between the number of
hc
atoms of short-lived decay products collected per unit of sampled volume of air and the
number of atoms per unit of volume of air present in the detection system environment
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4 Principle
Integrated measurement of potential alpha energy concentration of short-lived radon decay products is
based on the following elements:
a) continuous sampling of short-lived radon decay products contained in an air volume representative
of the atmosphere under investigation, using a high-efficiency filtering membrane;
b) counting, and discriminating over four energy ranges, the alpha particles emitted by the collected
short-lived radon-222 decay products (alpha particles with an energy E and E
AE,218 AE,214
Po Po
218 214 214 214
produced by the disintegration of Po and Po, and the disintegration of Pb and Bi
potential emitters of alpha particles of this type), using a solid-state nuclear track detector;
c) calculation of the potential alpha energy concentration of the short-lived radon-222 decay products.
NOTE For the radon-220 decay products, this involves distinguishing between, and counting, the alpha
216 212
particles, with an energy E and E , released through disintegration of Po and Po, and
AE,212 AE,212
Bi Po
212 212
disintegration of Pb and Bi potential emitters of alpha particles of this type.
5 Equipment
5.1 General
The apparatus shall include a measuring device, composed of a sampling system and a detection system
(see Figure 1), and a counting system. The measuring device shall be in accordance with IEC 61577-1
and IEC 61577-3.
5.2 Measuring device
5.2.1 Sampling system
The sampling system shall include the following components:
a) a high-efficiency filtering membrane in cellulose acetate to collect the radon decay products;
b) a sampling pump which provides a volume rate compatible with the air and metrological
characteristics of the detection system;
c) a mass flow-meter which measures the flow-rate of air sampled throughout the sampling duration.
The sampling system is located downstream of the detection system.
5.2.2 Detection system
The detection system shall include the following components:
a) three boPET screens of different thickness placed at one end of the collimators are used to
discriminate between the particles over three energy ranges. This geometry is used to mitigate
the initial energy of each alpha particle emitted by the collected radionuclides in an energy range
compatible with the characteristics of the sensor (SSNTD) used;
b) a solid-state nuclear track detector (SSNTD).
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Key
1 solid state nuclear track detector (SSNTD)
2 air inlet
3 mass flow-meter
4 air outlet
5 vacuum pump
6 high-efficiency filter
7 baffles (diffusion barrier)
8 collimator
9 boPET (biaxially oriented polyethylene teraphthalate) screen
10 scanning range
a
Front view.
b
Side view.
Figure 1 — Example set-up of a measuring device for determination over four energy ranges of
average potential alpha energy concentration of short-lived radon-222 decay products
5.3 Counting system
The counting system shall include the following components:
a) equipment and suitable chemical reagents for etching the detector (SSNTD);
b) an optical microscope and associated equipment for scanning and counting the etched tracks.
6 Sampling
6.1 Sampling objective
The sampling objective is to collect, without interruption, all the aerosols carrying short-lived radon
decay products, regardless of size (unattached and attached fractions), that are contained in the
ambient air during a given sampling duration (at least one week).
6.2 Sampling characteristics
Sampling shall be carried out under the conditions specified in ISO 11665-1.
The short-lived radon decay products shall be sampled continuously and directly in the atmosphere
under investigation by pumping and filtering a known volume of air through a high-efficiency collection
membrane. The air sample shall be omni-directional.
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The filtering membrane shall be as close as possible to the sampler inlet section, so as to collect the
ambient decay products with the maximum efficiency.
In order to count the emitted alpha particles correctly, the sampling system shall conduct to the surface
deposit of the radionuclides on the filter and shall prevent the aerosols from being buried.
The sampling system shall be used in conditions that preclude clogging of the filtering membrane, which
would cause self-absorption of the alpha emissions of particles collected on the filter or a reduction in
the sampling flow-rate over time.
The sampling flow-rate shall be stable (no more than 10 % variation from the average value) in order
for the sampling to remain representative throughout the sampling duration. This can be achieved by
using a flow-rate controller (sonic throat, servo-controlled valve, etc.).
6.3 Sampling conditions
6.3.1 General
Sampling shall be carried out as specified in ISO 11665-1.
6.3.2 Installation of sampling system
Installation of the sampling system shall be carried out as specified in ISO 11665-1.
In the specific case of an indoor measurement, the sampling system shall be installed as follows:
a) in an area not directly exposed to solar radiation;
b) away from a heat source (radiator, picture windows, electrical equipment, etc.);
c) away from traffic areas, doors and windows, walls and ventilation sources (it could, for example, be
sited on an item of furniture like a shelf or sideboard).
6.3.3 Sampling duration
The sampling duration is equal to the time interval between installation and removal of the sampling
system at a given point.
Time (date and hour) of installation and time of removal of the sampling system shall be recorded.
Sampling duration shall be determined according to the intended use of the measurement results and
the phenomenon under investigation.
A sampling duration of at least one week is required in order to obtain a measurement result above the
detection limit.
It is recommended that measurements be performed with a sampling duration of several months when
assessing the annual human exposure.
Users should be aware of the saturation characteristics of the sensor (SSNTD) and should perform their
sampling regime so as to ensure that saturation does not occur.
6.3.4 Volume of air sampled
The volume of air sampled shall be ascertained by measuring the flow-rate or volume during sampling
with a calibrated system (for example a sonic nozzle) (see IEC 61577-3).
The total volume of air sampled throughout the sampling duration shall be recorded.
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7 Detection method
Detection shall be carried out using solid-state nuclear track detectors (SSNTD), as described
in ISO 11665-1.
8 Measurement
8.1 Procedure
Measurement shall be carried out as follows.
a) Select and locate the m
...