SIST EN ISO 11665-11:2019

SLOVENSKI STANDARD
oSIST prEN ISO 11665-11:2019
01-januar-2019
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Measurement of radioactivity in the environment - Air: radon-222 - Part 11: Test method
for soil gas with sampling at depth (ISO 11665-11:2016)
Ermittlung der Radioaktivität in der Umwelt - Luft: Radon-222 - Teil 11: Verfahren zur
Probenahme und Prüfung von Bodenluft (ISO 11665-11:2016)
Mesurage de la radioactivité dans l'environnement - Air: radon 222 - Partie 11: Méthode
d'essai pour le gaz du sol avec un prélèvement en profondeur (ISO 11665-11:2016)
Ta slovenski standard je istoveten z: prEN ISO 11665-11
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 11665-11:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 11665-11:2019

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oSIST prEN ISO 11665-11:2019
INTERNATIONAL ISO
STANDARD 11665-11
First edition
2016-04-15
Measurement of radioactivity in the
environment — Air: radon-222 —
Part 11:
Test method for soil gas with sampling
at depth
Mesurage de la radioactivité dans l’environnement — Air: radon 222 —
Partie 11: Méthode d’essai pour le gaz du sol avec un prélèvement en
profondeur
Reference number
ISO 11665-11:2016(E)
©
ISO 2016

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oSIST prEN ISO 11665-11:2019
ISO 11665-11:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
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the requester.
ISO copyright office
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CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 2
3.1 Terms and definitions . 2
3.2 Symbols . 2
4 Principle . 3
5 Equipment . 3
6 Sampling . 4
6.1 Sampling objective . 4
6.2 Sampling characteristics . . 4
6.3 Sampling conditions . 4
6.3.1 General. 4
6.3.2 Location of sampling place . . 5
6.3.3 Sampling duration . 5
6.3.4 Volume of air sampled . . . 5
6.3.5 Minimal depth of sampling . 5
7 Detection . 6
8 Measurement . 6
8.1 Procedure . 6
8.2 Influence quantities . 6
8.3 Calibration . 7
9 Expression of results . 7
9.1 Radon activity concentration. 7
9.2 Standard uncertainty . 7
9.3 Decision threshold and detection limit . 7
9.4 Limits of the confidence interval . 8
10 Test report . 8
Annex A (informative) Values of soil-gas volumes available for extraction .10
Annex B (normative) Measurement method using an active sampling .11
Annex C (normative) Measurement method using a passive sampling .18
Annex D (informative) Examples of soil-gas sampling probes for active sampling .21
Bibliography .24
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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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information.
The committee responsible for this document is Technical Committee ISO/TC 85, Nuclear energy, nuclear
technologies, and radiological protection, Subcommittee SC 2, Radiological protection.
ISO 11665 consists of the following parts, under the general title Measurement of radioactivity in the
environment — Air: radon-222:
— Part 1: Origins of radon and its short-lived decay products and associated measurement methods
— Part 2: Integrated measurement method for determining average potential alpha energy concentration
of its short-lived decay products
— Part 3: Spot measurement method of the potential alpha energy concentration of its short-lived decay
products
— Part 4: Integrated measurement method for determining average activity concentration using passive
sampling and delayed analysis
— Part 5: Continuous measurement method of the activity concentration
— Part 6: Spot measurement method of the activity concentration
— Part 7: Accumulation method for estimating surface exhalation rate
— Part 8: Methodologies for initial and additional investigations in buildings
— Part 9: Test methods for exhalation rate of building materials
— Part 11: Test method for soil gas with sampling at depth
The following part is under preparation:
— Part 10: Determination of the diffusion coefficient in waterproof materials using activity concentration
measurement
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Introduction
Radon isotopes 222, 220 and 219 are radioactive gases produced by the disintegration of radium
isotopes 226, 224 and 223, which are decay products of uranium-238, thorium-232 and uranium-235,
respectively, and are all found in the Earth’s crust. Solid elements, also radioactive, followed by stable
[1]
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
according to their size.
Radon is today considered to be the main source of human exposure to natural radiation. Reference [2]
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. For this reason, references to radon in this part of
ISO 11665 refer only to radon-222.
Radon activity concentration can vary from one to multiple orders of magnitude over time and space.
Exposure to radon and its decay products varies tremendously from one area to another, as it depends
firstly on the amount of radon emitted by the soil and the building materials in each area and, secondly,
on the degree of containment and weather conditions 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 (building materials) and
ISO 13164 (water).
Measurements of radon in the soil gas are performed for several applications dealing with radon
risk management (drawing up of radon potential maps, defining radon-prone areas, characterization
of radon potential of building sites, characterization of soil contaminated with radium-226, defining
mitigation techniques to be applied in a building, verification of applied mitigation techniques, etc.), and
phenomenological observation (understanding radon transport mechanisms in the soil and from the
soil into the building, identification and analysis of radon entry parameters, gas activity measurement
for survey of CO , volcanic eruption prediction, earthquake prediction, etc.).
2
The radon activity concentrations in the soil gas not only vary substantially at the season scale but also
from day to day and even from hour to hour. It also varies in space in the horizontal, as well as the
[3][4][5][19]
vertical dimension, depending on the following parameters characterizing the soil properties :
— geochemical parameters of soils (mainly distribution of uranium and radium in soils and rocks and
their localization influencing the radon emanation);
— physical parameters of all present layers of soils (grain size, permeability, porosity and effective
porosity, soil moisture and water saturation, density);
— geological situation (thickness of Quaternary cover, weathering character of the bedrock,
stratification, modification of layers by various antropogeneous activities);
— soil structure (deformation, presence of cracks);
— hydrological and geodynamic processes (transport of gaseous and liquid substances in porous and
fractured environment, radium and radon in underground/fissure water);
— geomorphological situation (location of the area in a valley, on the slopes, or on the top of a hill);
— exogenous/meteorological factors (temperature, pressure, precipitation).
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Because of these fluctuations, standardized measurement protocols are needed in order to ensure
accurate and consistent measurement results of radon in the soils to ensure that they can be compared
in time and space.
Depending on the depth, the values usually found in the soil gas are normally between a few hundred
becquerels per cubic metre and several hundred of thousand becquerels per cubic metre. Activity
concentrations can reach several billions of becquerels per cubic metre in radium-rich soils.
Theoretically, the radon activity concentration in the soil gas can be defined for any variable depth below
the ground surface and it generally increases with depth below the surface in an ideal homogeneous
[6]
soil . But there is a minimal depth below the ground surface, at which the parameter can be really
measured. The minimal depth depends on the soil properties at a given place and on the measurement
method used. In particular, it depends on the volume of the soil gas sample. When the depth below the
ground surface is lower than the above mentioned minimal depth, the soil gas sample is diluted with
atmospheric air and the real value of radon activity concentration in the soil gas is underestimated (see
Annex A).
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 11665-11:2019
INTERNATIONAL STANDARD ISO 11665-11:2016(E)
Measurement of radioactivity in the environment — Air:
radon-222 —
Part 11:
Test method for soil gas with sampling at depth
1 Scope
This part of ISO 11665 describes radon-222 test methods for soil gas using passive and active in-situ
sampling at depth comprised between surface and 2 m.
This part of ISO 11665 gives general requirements for the sampling techniques, either passive or active
and grab or continuous, for in-situ radon-222 activity concentrations measurement in soil gas.
The radon-222 activity concentration in the soil can be measured by spot or continuous measurement
methods (see ISO 11665-1). In case of spot measurement methods (ISO 11665-6), the soil gas sampling
is active only. On the other hand, the continuous methods (ISO 11665-5) are typically associated with
passive soil gas sampling.
The measurement methods are applicable to all types of soil and are determined according to the end
use of the measurement results (phenomenological observation, definition or verification of mitigation
techniques, etc.) taking into account the expected level of the radon-222 activity concentration.
These measurement methods are applicable to soil gas samples with radon activity concentrations
3
greater than 100 Bq/m .
NOTE This part of ISO 11665 is complementary with ISO 11665-7 for characterization of the radon soil
potential.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 10381-7, Soil quality — Sampling — Part 7: Guidance on sampling of soil gas
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 11665-5, Measurement of radioactivity in the environment — Air: radon-222 — Part 5: Continuous
measurement method of the activity concentration
ISO 11665-6, Measurement of radioactivity in the environment — Air: radon-222 — Part 6: Spot
measurement method of the activity concentration
ISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the
confidence interval) for ionizing radiation measurements — Fundamentals and application
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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 and the following apply.
3.1.1
water saturation of soil
part of soil pores filled with water
3.1.2
effective soil porosity
ratio of the volume of soil pores, which is available for transport, and the volume of soil
3.1.3
effective air porosity
ratio of the volume of soil pores filled with air, which is available for transport, and the volume of soil
3.1.4
activity concentration in soil air
activity per unit volume of soil air
3.1.5
active soil-gas sampling
sampling by extracting a certain volume of soil-gas
[SOURCE: ISO 10381-7:2005]
3.1.6
passive soil-gas sampling
sampling performed without employing negative pressure or suction
3.1.7
dead volume
volume which is present between suction opening of the soil-gas probe and the sampling vial or the
detection chamber
3.1.8
soil-gas sampling probe
probe, generally a tube, which is installed directly in soil (one-stage soil-gas sampling), to take soil-
gas samples
3.1.9
one-stage soil-gas sampling
sampling of soil-gas directly from a soil-gas probe placed in soil, without pre-drilling
[SOURCE: ISO 10381-7:2005]
3.2 Symbols
For the purposes of this document, the symbols given in ISO 11665-1 and the following apply.
C Activity concentration, in becquerel per cubic metre
µ Quantity to be measured
µ Background level
0
ε Correction factor linked to the calibration factor
V Volume of the soil gas extracted from the soil during the soil gas sampling, in cubic metre
s
V Volume of a sphere of an homogeneous soil, which contains the volume, V , of soil gas available for
soil s
extraction, in cubic metre
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r Radius of the sphere of an homogeneous soil in metre
,
s Water saturation of soil
n Effective soil porosity
eff
n Effective air porosity
a
u( ) Standard uncertainty associated with the measurement result
u ( ) Relative uncertainty associated with the measurement result
rel
U Expanded uncertainty calculated by U = k ∙ u( ) with k = 2
C* Decision threshold of the activity concentration, in becquerel per cubic metre
#
C Detection limit of the activity concentration, in becquerel per cubic metre
Lower and upper limit of the confidence interval, respectively, of the activity concentration, in bec-

C ,C
querel per cubic metre
4 Principle
When the active soil gas sampling is used, the measurement of the radon activity concentration in the
soil gas is based on the following:
— sampling of a volume of soil gas representative of the soil under investigation at time, t, or during
time interval Δt;
— transfer of the soil gas sample into the detection chamber;
— measurement of the physical variable (photons, pulse counts and amplitude, etc.) linked to the
radiation emitted by radon and/or its decay products present in the detection chamber after the
transfer of the soil gas sample.
When the passive soil gas sampling is used, the measurement of the radon activity concentration in the
soil gas is based on the following:
— placing of the detection chamber to the place below the ground surface representative of the soil
under investigation during time interval Δt;
— passive transfer of the soil gas sample into the detection chamber by diffusion;
— measurement of the physical variable linked to the radiation emitted by radon and/or its decay
products present in the detection chamber after the transfer of the soil gas sample.
Several measurement methods meet the requirements of this part of ISO 11665. They are basically
distinguished by the type of the sampling and measurement of the physical quantity.
5 Equipment
The apparatus includes the following:
a) soil-gas sampling probe installed directly in soil if an active sampling is performed;
b) device for placing the detection chamber to the chosen place below the ground surface if a passive
sampling is used;
c) detection chamber;
d) measuring system adapted to the physical quantity.
The necessary equipment for specific measurement methods is specified in Annex B and Annex C.
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6 Sampling
6.1 Sampling objective
The sampling objective is to obtain an air sample representative of the soil without creating a
perturbation of the soil.
6.2 Sampling characteristics
The sampling is passive or active. The sampling is grab or continuous.
The sampling is representative of the radon activity concentration at a given place and at a given depth
(or at a given depth interval) below the ground surface.
Grab sampling is representative of the radon activity concentration in the soil at a given moment.
Continuous sampling is representative of the radon activity concentration in the soil at a given time
interval.
Active sampling is based on the extraction of the soil-gas sample by applying a negative pressure on the
gas-soil sampling probe (using a syringe, pump, etc.).
Passive sampling is based on the transport of the soil gas from the soil into the detection chamber by
diffusion.
6.3 Sampling conditions
6.3.1 General
Sampling shall be carried out as specified in ISO 11665-1 and ISO 10381-7. The sampling location, the
sampling depth (or depth interval) and the sampling time (or time interval) shall be recorded.
The sampling method shall enable that the sampling depth (or depth interval) is well-defined and
cannot be influenced by changes of other parameters (soil permeability, soil moisture, meteorological
conditions, and others).
Circumstances in cold conditions make soil-gas sampling difficult in many ways. Ground frost greatly
limits the mobility of gas in soil and should be considered in planning and carrying out sampling, as
well as interpreting the measurement results. Similarly, water saturated ground can limit mobility (see
ISO 10381-7).
When sampling soil gas close to the surface, the effect of ambient air penetration needs to be considered.
It is considered unlikely that useful samples can be collected at depth less than 0,5 m. To avoid dilution
of the soil-gas sample,
— a minimum depth of 1 m is recommended,
— the sampling method, especially the volume of the soil gas sample, shall correspond to the soil
properties at a given place and to the chosen sampling depth if an active sampling is used,
— all parts of the soil-gas sampling probe shall be perfectly sealed if an active sampling is used,
— a penetration of the ambient air through leakages along the soil-gas sampling probe shall be avoided
if an active sampling is used, and
— a penetration of the ambient air into the chamber of a passive sampling device shall be avoided.
If a passive sampling is used, the preparatory works before placing the detection chamber to the chosen
place below the ground surface shall be performed in order to limit perturbation of the soil. It should be
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considered that any invasive activity can affect migration patterns and acts as a pathway for the gas. A
hand-held auger may be used to bore into the ground.
If a measuring system is used in the field, check that the variations of meteorological conditions which
can be met in the field are in the range of operation conditions.
In case of some active sampling and measurement methods, the soil-gas sample shall be filtered before
the transfer of the sample into the detection chamber. The filtering medium shall stop the aerosol
particles present in the soil gas at the time of sampling, especially the radon decay products and the soil
moisture. When the delay between the soil-gas sampling and the beginning of measurement is longer
than three hours, the filtering of the radon decay products are not needed.
The soil-gas sampling probe shall not include components that trap the radon (desiccants, etc.).
Detailed requirements related to sampling conditions are specified in Annex B and Annex C.
6.3.2 Location of sampling place
Sampling may be carried out in any kind of soil.
The location and number of the sampling points should be planned in advance in accordance with
the aims of the site investigations (for example, verification of the homogeneity of the activity
concentrations in an environment or search for anomalies, etc.).
The spacing of the sampling points is dependent on the nature of the strata (see ISO 10381-7).
6.3.3 Sampling duration
Sampling duration depends on the objectives sought and on the sampling method used (spot, continuous,
or integrated).
6.3.4 Volume of air sampled
The volume of soil-gas sample can be determined accurately for example,
— with a part of the soil-gas sampling probe that enables to determine the volume of the soil-gas
sample directly (syringe),
3
— with a flow-meter corrected for the temperature and pressure variation (
...