ISO/TS 11665-13:2025
(Main)Measurement of radioactivity in the environment — Air: radon 222 — Part 13: Determination of the diffusion coefficient in waterproof materials: membrane two-side activity concentration test method
Measurement of radioactivity in the environment — Air: radon 222 — Part 13: Determination of the diffusion coefficient in waterproof materials: membrane two-side activity concentration test method
This document specifies the different methods intended for assessing the radon diffusion coefficient in waterproofing materials such as bitumen or polymeric membranes, coatings or paints, as well as assumptions and boundary conditions that shall be met during the test. This document is not applicable for porous materials, where radon diffusion depends on porosity and moisture content.
Mesurage de la radioactivité dans l'environnement — Air: radon 222 — Partie 13: Détermination du coefficient de diffusion des matériaux imperméables: méthode de mesurage de l'activité volumique des deux côtés de la membrane
General Information
Relations
Standards Content (Sample)
Technical
Specification
ISO/TS 11665-13
Second edition
Measurement of radioactivity in the
2025-12
environment — Air: radon 222 —
Part 13:
Determination of the diffusion
coefficient in waterproof materials:
membrane two-side activity
concentration test method
Mesurage de la radioactivité dans l'environnement — Air: radon
222 —
Partie 13: Détermination du coefficient de diffusion des
matériaux imperméables: méthode de mesurage de l'activité
volumique des deux côtés de la membrane
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Principle of the test method . 5
6 Measuring system . 5
6.1 Components of the measuring system .5
6.2 Configuration of the measuring system .6
7 Test methods . 9
7.1 General information.9
7.2 Method A — Determining the radon diffusion coefficient during the phase of non-
stationary radon diffusion .10
7.3 Method B — Determining the radon diffusion coefficient during the phase of stationary
radon diffusion .10
7.4 Method C — Determining the radon diffusion coefficient during the phase of stationary
radon diffusion established during ventilation of the receiver container .11
7.5 Method D — Determining the radon diffusion coefficient during stationary radon
activity concentrations in the source and receiver containers . 12
8 General application procedures .12
8.1 Preparation of samples . 12
8.2 Fixing the samples in the measuring device . 13
8.3 Test of radon-tightness, assessment of the radon leakage rate of the receiver container . 13
8.4 Determining the radon diffusion coefficient according to method A . 13
8.5 Determining the radon diffusion coefficient according to method B .14
8.6 Determining the radon diffusion coefficient according to method C . 15
8.7 Determining the radon diffusion coefficient according to method D.17
8.8 General requirements for performing the tests .17
9 Influence quantities . 19
10 Expression of results . 19
10.1 Relative uncertainty .19
10.2 Decision threshold and detection limit . 20
10.3 Limits of the confidence interval . 20
11 Quality management and calibration of the test device .20
12 Test report .20
Annex A (informative) Determining the radon diffusion coefficient during the phase of
stationary radon diffusion according to method C .22
Annex B (informative) Determining the radon diffusion coefficient during the phase of non-
stationary radon diffusion .27
Bibliography .35
iii
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of 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 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/TS 11665-13:2017), which has been
technically revised.
The main changes are as follows:
— 6.2: configuration of the measuring system has been revised and supplemented with new figures to
show different configuration options with different types of radon sources and radon detectors;
— new 7.5: Method D (determining the radon diffusion coefficient from the stationary radon activity
concentrations in receiver and source containers) has been introduced;
— 8.4: a new procedure for determining the minimum duration of decisive measurement has been
established for method A;
— 8.5: a revised procedure for determining the minimum duration of decisive measurement has been
established for method B;
— new 8.7 has been inserted describing the measurement procedure according to method D;
— 8.8: the procedures for determining the minimum radon activity concentration in the source container
and for situations when the growth curve is not clearly determined, or when no radon penetrates the
receiver container were specified.
A list of all 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
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. 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 according to
their size.
[2]
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. 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, 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
[3]
pathways. Other sources are described in other parts of ISO 11665 series and ISO 13164 series for 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 Health
[8] −3
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 average activity
−3[4]
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.
When a building requires protection against radon from the soil, radon-proof insulation (based on
membranes, coatings or paints) placed between the soil and the indoors may be used as a stand-alone radon
prevention/remediation strategy or in combination with other techniques such as passive or active soil
depressurization. Radon-proof insulation functions at the same time as the waterproof insulation.
Radon diffusion coefficient is a parameter that determines the barrier properties of waterproof materials
against the diffusive transport of radon. Applicability of the radon diffusion coefficient for radon-proof
insulation can be prescribed by national building standards and codes. Requirements for radon-proof
insulation as regards the durability, mechanical and physical properties and the maximum design value of
the radon diffusion coefficient can also be prescribed by national building standards and codes.
As no reference standards and reference materials are currently available for these types of materials and
related values of radon diffusion coefficient, the metrological requirement regarding the determination of
v
[9]
the performance of the different methods described in ISO/TS 11665-12 and this document, as required
[5]
by ISO/IEC 17025 , cannot be directly met.
NOTE The origin of radon-222 and its short-lived decay products in the atmospheric environment and the
measurement methods are described in ISO 11665 1.
vi
Technical Specification ISO/TS 11665-13:2025(en)
Measurement of radioactivity in the environment — Air:
radon 222 —
Part 13:
Determination of the diffusion coefficient in waterproof
materials: membrane two-side activity concentration test
method
1 Scope
This document specifies the different methods intended for assessing the radon diffusion coefficient
in waterproofing materials such as bitumen or polymeric membranes, coatings or paints, as well as
assumptions and boundary conditions that shall be met during the test.
This document is not applicable for porous materials, where radon diffusion depends on porosity and
moisture content.
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 11665-5, Measurement of radioactivity in the environment — Air: radon-222 — Part 5: Continuous
measurement methods of the activity concentration
ISO 11665-6, Measurement of radioactivity in the environment — Air: radon-222 — Part 6: Spot measurement
methods of the activity concentration
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 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM: 1995)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11665-1 and ISO 80000-10 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
material
product according to a certain technical specifications which is the object of the test
3.2
sample (of material)
certain amount of material (3.1) chosen from the production batch for determination of the radon diffusion
coefficient (3.3)
3.3
radon diffusion coefficient
D
radon activity permeating due to molecular diffusion through unit area of a monolayer material (3.1) of unit
thickness per unit time at unit radon activity concentration gradient on the boundaries of this material
3.4
equivalent radon diffusion coefficient
D
eqv
radon diffusion coefficient (3.3) of the multilayer material (3.1) that numerically equals to the radon diffusion
coefficient of a homogeneous material of the same thickness as the layered material through which radon
penetrates in the same amount as through the layered material
3.5
radon diffusion length
l
distance crossed by radon due to diffusion in which activity is reduced by “e” times because of decay
Note 1 to entry: Numeric “е” is the natural logarithm, equal to about 2,72.
Note 2 to entry: Radon diffusion length is expressed by the relationship given in the following formula:
1/2
l = (D/λ) (1)
where
l is the radon diffusion length, in metres;
D is the radon diffusion coefficient (3.3) of the sample, in square metres per second;
λ is the radon decay constant, in per second.
3.6
diffusive radon surface exhalation rate
E
value of the activity concentration of radon atoms that leave a material (3.1) per unit surface per unit time
Note 1 to entry: For the purpose of this document, only the diffusion transport through the sample is taken into
account. The diffusive radon exhalation rate is given by the following formula (Fick's law):
Cx()
Ex() D (2)
x
where
E(x) is the distribution function along the axis "X" of the radon exhalation rate in the sample, in
Becquerel per square metre per second;
C(x) is the distribution function along the axis "X" of the radon activity concentration in the sample,
in Becquerel per cubic metre;
D is the radon diffusion coefficient (3.3) of the sample, in square metre per second;
x is the coordinate on axis "X" (the axis is directed along radon transport and perpendicular to
the sample surface), in metre.
3.7
non-stationary radon diffusion
time-dependent radon diffusion through the sample when the radon activity concentration within the
sample is changing (in dependence on time, distance from the surface exposed to radon and the radon
activity concentration in the source container) and the radon surface exhalation rate from the sample into
the receiver container is also changing
Note 1 to entry: One-dimensional non-stationary radon diffusion is described by the partial differential equation:
Cx( ,t) Cx( ,t)
D Cx( ,t) (3)
t
x
where
D is the radon diffusion coefficient (3.3) of the sample, in square metre per second;
C(x,t) is the function changing in time along the axis "X" of radon activity concentration in the sample,
in Becquerel per cubic metre;
x is the coordinate on axis "X" (the axis is directed along radon transport and perpendicular to
the sample surface), in metre;
λ is the radon decay constant, in per second.
Note 2 to entry: Non-stationary radon diffusion occurs during the time when radon activity concentration in the source
container is not steady and in the time interval that immediately follows the moment when the steady concentration in
the source container is established.
3.8
stationary radon diffusion
time-independent radon diffusion through the sample; stationary radon diffusion is characterized by a
stable (time-independent) radon distribution within the sample and consequently by a stable radon surface
exhalation rate from the sample into the receiver container (long term test methods)
Note 1 to entry: One-dimensional stationary radon diffusion is described by the differential equation:
Cx()
D Cx() 0 (4)
x
where
D is the radon diffusion coefficient (3.3) of the sample, in square metre per second;
C(x) is the distribution function along the axis "X" of the radon activity concentration in the sample,
in Becquerel per cubic metre;
x is the coordinate on axis "X" (the axis is directed along radon transport and perpendicular to
the sample surface), in metre;
λ is the radon decay constant, in per second.
3.9
decisive measurement of radon activity concentrations
measurement of the time courses of radon activity concentrations in the source and receiver containers
used for calculating the radon diffusion coefficient (3.3)
Note 1 to entry: The duration of the decisive measurement can be shorter or the same as the duration of the test.
3.10
decisive volume of the receiver container
V
volume of the container used to calculate the radon diffusion coefficient (3.3)
3.11
decisive sample area
S
s
material (3.1) sample area used to calculate the radon diffusion coefficient (3.3)
3.12
minimum duration of the decisive measurement for non-stationary radon diffusion
period of time in the frame of the decisive measurement of radon activity concentrations (3.9) in the source
and receiver containers taken during the phase of non-stationary diffusion ensuring the uncertainty of the
radon diffusion coefficient (3.3) assessment lower than ±20 %
3.13
minimum duration of the decisive measurement for stationary radon diffusion
period of time in the frame of the decisive measurement of radon activity concentrations (3.9) in the source
and receiver containers taken during the phase of stationary diffusion ensuring the uncertainty of the radon
diffusion coefficient (3.3) assessment lower than ±20 %
3.14
minimum radon activity concentration in the source container
concentration of radon in the source container which for the particular sample characterized by the d/l ratio
ensures values of radon activity concentration in the receiver container measurable with uncertainty lower
than 10 %
3.15
radon transfer coefficient
radon transport in thin boundary layer of air near the surface of the sample
Note 1 to entry: In this boundary, layer radon activity concentration on the surface of the sample equalizes with radon
activity concentration in the surrounding air.
−1
Note 2 to entry: For waterproof materials (3.1), the default value of the radon transfer coefficient is 0,1 m·s
3.16
standard uncertainty of a variable
s(X)
standard deviation of a variable X
3.17
relative uncertainty of a variable X
u(X) = k·s(X)/E(X)
where
E(X) is the expected value of a variable X
k is the shrinkage factor (k = 1,96 by default for 95 % confidence interval)
4 Symbols
−1
λ radon decay constant s
−1
λ radon leakage rate characterizing the ventilation of the receiver container s
V
-3
C radon activity concentration in the sample Bq·m
-3
C radon activity concentration in a particular container of the measuring device Bq·m
a
-3
C radon activity concentration in the receiver container Bq·m
rc
-3
C radon activity concentration in the source container Bq·m
sc
2 -1
D radon diffusion coefficient of the monolayer sample m ·s
2 -1
D equivalent radon diffusion coefficient of the multilayer sample m ·s
eqv
d thickness of the sample m
2 -1
E diffusive radon surface exhalation rate Bq·m ·s
-1
h radon transfer coefficient m·s
l radon diffusion length m
3 -1
p slope of the linear regression straight line Bq·m ·s
R correlation coefficient
S decisive sample area m
s
t time s
Δt duration of the considered time step between time t and t s
i−1 i
V decisive volume of the receiver container m
x
distance within the tested sample measured from the surface of the sample exposed
m
to radon
u(X) relative uncertainty of a variable X, in relative units
s(X) standard uncertainty of a variable X, in same units as variable X
5 Principle of the test method
The sample of the tested material is placed between the air-tight source and the receiver containers, and the
joint is carefully sealed.
Radon activity concentration in both containers shall be measured using continuous or spot measurement
methods as specified in ISO 11665-5 and ISO 11665-6.
By means of the radon source with stable radon production rate, the radon activity concentration in the
−3 −3
source container is kept on a high level (usually within the range 1 MBq·m to 100 MBq·m ). The radon
that diffuses through the sample is monitored using calibrated radon monitor in the receiver container.
Using an appropriate mathematical process (either analytical or numerical), the radon diffusion coefficient
is afterwards calculated from the time-dependent courses of the radon activity concentrations measured
in the source and receiver containers, and the area and thickness of the tested sample. In case of multilayer
samples, the above-described principle results in determination of the equivalent radon diffusion coefficient
D .
eqv
6 Measuring system
6.1 Components of the measuring system
The measuring system for determining the radon diffusion coefficient in the waterproof materials shall
comprise the following components:
−3 3
a) at least two air-tight containers (source and receiver), each with a minimum air volume of 0,5 × 10 m
or when the spot measurement method for radon activity concentration is going to be used, the
minimum air volume should be at least 10 times larger than the total volume of spot samples taken from
each of the containers during the test performance, and made from metal materials (e.g. aluminium,
−4
stainless steel, etc.) of a thickness at least 5 × 10 m that effectively eliminates radon transport between
the air inside and outside the containers; each container shall be equipped with a test area of at least
−3 2
5 × 10 m surrounded by flanges for fixing the tested material; the minimum width of the flanges shall
be 0,01 m and their arrangement shall eliminate the transport of radon from the source container to
the receiver container; each container shall be further equipped with an appropriate number of valves
intended for ventilating the containers, for measuring the pressure differences between the containers,
for extracting air samples for control measurements of radon activity concentration and for connecting
to the radon source;
b) a measuring instrument capable of determining the thickness of the tested sample with accuracy
±0,01 mm (maximum standard relative uncertainty of measurement 5 %);
c) a source of radon with stable radon production rate capable of creating a radon activity concentration in
−3 −3
the source container within the range 1 MBq·m to 100 MBq·m ;
−3 3 -1 −3 3 -1
d) an air-tight flow pump with the range of air flow rates 6 × 10 m ·h to 30 × 10 m ·h that is used in
some measurement methods in a closed circuit with a radon source and a source container;
e) a calibrated measuring device for monitoring the radon activity concentration in the receiver
−3
container with standard relative uncertainty 10 % and a dynamic measuring range from 100 Bq·m to
−3
200 kBq·m ;
f) a calibrated measuring device for monitoring the radon activity concentration in the source container
−3
with standard relative uncertainty 10 % and a dynamic measuring range from 10 kBq·m to
−3
100,0 MBq·m ;
g) a measuring instrument for determining the relative pressure difference between the air volume in the
source container and the air volume in the receiver container with standard relative uncertainty of 10 %
and a dynamic measuring range from 1 Pa to 150 Pa; it is only used if the measuring systems includes a
flow pump, which can cause a pressure difference between the source and receiver containers;
h) suitable sensors and a data storage system capable of continuously monitoring the temperature and
relative humidity of air, atmospheric pressure and radon activity concentration in the place where the
measuring device is positioned.
6.2 Configuration of the measuring system
The configuration of the measuring system shall be chosen according to the number of samples to be
measured, the type of radon source, the type of measuring device for monitoring the radon activity
concentration in containers, the size of the containers, etc. In the simplest case, the measuring system can
comprise one source container, one receiver container and a radon source connected to the source container
or inserted into the source container (see Figure 1). If more than one sample is to be measured under
equal conditions, it is convenient to use a measuring system comprising more than one receiver container
assembled on one source container, or a set of pair containers (source + receiver) connected to each other
and to the radon source through the source containers in a closed circuit (see Figure 2). The flexible tubing
used to connect the source containers, and the radon source should be as tight as possible. The tubing type is
chosen so that no electrostatic charge is created in the measuring system, which could negatively affect the
measuring devices for monitoring the radon activity concentration.
a) With a sealed radon source connected to the b) With an open source of radon placed in the
source container through a closed circuit source container
Key
1 receiver container
2 source container
3 tested sample
4 radon detector for the receiver container
5 radon detector for the source container
6 radon source
7 flow pump
Figure 1 — Measuring system comprising one receiver container and one source container
a) With three pair containers connected to a sealed radon source and a radon detector through the
closed circuit
b) With three receiver containers assembled on one source container into which the open source of
radon was placed
Key
1 receiver container
2 source container
3 tested sample
4 radon detector for the receiver container
5 radon detector for the source container
6 radon source
7 flow pump
Figure 2 — Measuring system for testing several samples
Key
1 receiver container
2 source container
3 tested sample
4 wireless radon detector for the receiver container
5 radon detector for the source container
6 radon source
7 flow pump
8 data logger
Figure 3 — Measuring system with wireless radon detectors inserted in the receiver containers
Radon can be transported from the radon source to the source container only by diffusion or with the help
of a flow pump. If a flow pump is used, the radon source, the source container and the flow pump shall be in
a single, closed circuit. A flow pump shall not be applied if the radon diffusion through the tested sample is
influenced by the pressure difference between the source and receiver containers (this can be seen as rapid
drop or rise of radon activity concentration in the receiver container after applying the pump). A measuring
instrument for determining the relative pressure difference between the source and receiver containers
shall be used before starting the decisive measurement. After determining the pressure difference, the
instrument shall be disconnected from the measuring system. This is because these instruments are not
radon-tight, so radon can penetrate through them from the source container to the receiver container.
If the measuring system is made up of a set of pair containers, the maximum number of pairs that can be
connected to one radon source in a single closed circuit is four. A flow pump shall be an indispensable part of
the circuit. Only samples of one material shall be tested in a single circuit at the same time.
If the measuring system is made up of more than one receiver container assembled on a single source
container, only samples of one material shall be tested in this system at the same time.
Open sources of radon producing radon from their surface shall be placed inside the source container. With
such an arrangement, there is no pressure difference between the source and receiver containers. This
arrangement is therefore suitable for testing samples through which the diffusion of radon can be affected
by a pressure difference.
It is recommended that the measuring device for monitoring the radon activity concentration in the receiver
container be part of the container or be inserted into the container (see Figure 3). This prevents the leakage
of radon from the receiver container through the pipes if the measuring device is connected to the receiver
container via a closed circuit. Measuring device for monitoring the radon activity concentration in the source
container can be part of a closed circuit together with a radon source and a flow pump. The sensitivity of
these detectors to the gamma radiation produced by the radon source should always be considered.
7 Test methods
7.1 General information
A suitable test method is selected from the following options in dependence on the measuring system,
sampling method and properties of the tested material (especially its thickness and the assumed radon
[6][7]
diffusion coefficient value ). Methods A, B and D are convenient for continuous monitoring of radon
activity concentrations and method C for spot measurements. Method A is the least demanding to comply with
the measurement conditions, does not require the achievement of stationary radon diffusion and provides
the result in the shortest possible time. Determining the radon diffusion coefficient according to method
A is possible only on the basis of the numerical solution of non-stationary radon diffusion as described in
8.4. Methods B and C are more demanding in terms of time and compliance with measurement conditions,
as they take place in two phases. The goal is that from the very beginning of the second phase, the increase
in the radon activity concentration in the receiver container is constant. This enables the calculation of the
radon diffusion coefficient by analytical solution of stationary radon diffusion if conditions described in 8.5
are satisfied. Method D is simple and easy to meet the measurement conditions, but it requires a lot of time
to achieve stationary radon activity concentrations in the receiver and source containers. The achievement
of stationary radon activity concentrations allows the diffusion coefficient to be calculated by analytical
solution of stationary radon diffusion.
When using methods B, C and D, the numerical solution of non-stationary radon diffusion can also be used
to determine the radon diffusion coefficient. In this case, the time position and duration of the decisive
measurement is determined by the method of numerical solution. Figures 5, 6 and 7 show the time position
of the decisive measurement for the analytical solution of stationary radon diffusion.
7.2 Method A — Determining the radon diffusion coefficient during the phase of non-
stationary radon diffusion
After placing the sample between the source and receiver containers, both containers are closed and radon
is admitted into the source container. The decisive measurement of radon activity concentrations in both
containers begins at this moment (see Figure 4).
Key
X time (without scale)
Y radon concentration (without scale)
1 source container
2 receiver container
3 decisive measurement
Figure 4 — Test procedure according to method A
7.3 Method B — Determining the radon diffusion coefficient during the phase of stationary
radon diffusion
After placing the sample between the source and receiver containers, both containers are closed and radon
is admitted into the source container. The time-dependent increase in radon activity concentrations in both
containers is monitored. After establishing stationary radon activity concentration in the source container
and stationary radon diffusion through the sample, the receiver container is flushed with radon-poor
ambient air. Flushing is stopped when the radon activity concentration in the receiver container decreases
−3
below the operational threshold (at least below 1 kBq·m ). The decisive measurement of radon activity
concentrations in both containers begins at this moment (see Figure 5).
X time (without scale)
Y radon concentration (without scale)
1 source container
2 receiver container
3 time position of the decisive measurement for the analytical solution
4 flushing
Figure 5 — Test procedure according to method B
7.4 Method C — Determining the radon diffusion coefficient during the phase of stationary
radon diffusion established during ventilation of the receiver container
After placing the sample between the source and receiver containers, radon is admitted into the source
container and the time-dependent increase in the radon activity concentrations in both containers is
monitored. The radon activity concentration in the receiver container is held at values below the operational
−3
threshold (at least below 1 kBq·m ) by means of continuous ventilation of the receiver container. After
establishing stationary radon activity concentration in the source container and the stationary radon
diffusion through the sample, the ventilation of the receiver container is stopped. The decisive measurement
of radon activity concentrations in both containers begins at this moment (see Figure 6).
Key
X time (without scale)
Y radon concentration (without scale)
1 source container
2 receiver container
3 time position of the decisive measurement for the analytical solution
4 flushing
Figure 6 — Test procedure according to method C
7.5 Method D — Determining the radon diffusion coefficient during stationary radon
activity concentrations in the source and receiver containers
After placing the sample between the source and receiver containers, both containers are closed, and radon
is admitted into the source container. The time-dependent increase in radon activity concentrations in both
containers is monitored. The decisive measurement of radon activity concentrations in both containers
begins at the moment when the stationary radon activity concentration in the source and receiver containers
is reached (see Figure 7).
Key
X time (without scale)
Y radon concentration (without scale)
1 source container
2 receiver container
3 time position of the decisive measurement for the analytical solution
Figure 7 — Test procedure according to method D
8 General application procedures
8.1 Preparation of samples
The diameter or the side of a rectangular sample shall be at least five times greater than the thickness of the
sample. The minimum effective area of the sample (the area exposed to radon) shall be 0,005 m at least.
The samples are cut out from the prefabricated membranes at a minimum distance of 100 mm from the
edges of the membrane. At least three samples are required for testing.
In the case of coatings, paints, sealants or other waterproof materials prepared on site, at least four samples
are required for testing. Samples can be produced by applying a coating, paint or sealant on a non-absorbing
flexible underlay material (for example, wax-paper, cellophane foil, etc.) that is removed from the sample after
the drying process is completed. The underlay shall not react with the applied coatings, paints or sealants.
Approximately uniform thickness of the samples can be achieved with the help of guide gibs (paint, coating
or sealant is poured or pasted between the gibs of uniform height and the excessive material is removed
by drawing the steel float over the gibs). The samples shall not be tested until the drying and hardening
processes are completed. The time between the sample preparation and the start of the measurement as
well as the storing conditions shall correspond to the recommendation of the producer.
The thickness of each sample is measured with accuracy of ±0,01 mm at four points per 0,05 m placed
uniformly along the surface of the sample. The resulting thickness of each sample is th
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