Measurement of radioactivity in the environment -- Air: radon 222

ISO/TS 11665-13:2017 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. ISO/TS 11665-13:2017 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

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Published
Publication Date
12-Oct-2017
Current Stage
6060 - International Standard published
Start Date
09-Sep-2017
Completion Date
13-Oct-2017
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TECHNICAL ISO/TS
SPECIFICATION 11665-13
First edition
2017-10
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
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/TS 11665-13:2017(E)
ISO 2017
---------------------- Page: 1 ----------------------
ISO/TS 11665-13:2017(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

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ii © ISO 2017 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 11665-13:2017(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 ......................................................................................................................................................................................................... 5

4 Principle of the test method ..................................................................................................................................................................... 6

5 Measuring system ................................................................................................................................................................................................ 6

5.1 Components of the measuring system ............................................................................................................................... 6

5.2 Configuration of the measuring system ............................................................................................................................ 7

6 Test methods ............................................................................................................................................................................................................. 9

6.1 General information ........................................................................................................................................................................... 9

6.2 Method A — Determining the radon diffusion coefficient during the phase of non-

stationary radon diffusion ............................................................................................................................................................ 9

6.3 Method B — Determining the radon diffusion coefficient during the phase of

stationary radon diffusion .........................................................................................................................................................10

6.4 Method C — Determining the radon diffusion coefficient during the phase of

stationary radon diffusion established during ventilation of the receiver container .............11

7 General application procedures ........................................................................................................................................................12

7.1 Preparation of samples .................................................................................................................................................................12

7.2 Fixing the samples in the measuring device...............................................................................................................13

7.3 Test of radon-tightness, assessment of the radon leakage rate of the receiver container ..13

7.4 Determining the radon diffusion coefficient according to method A ...................................................13

7.5 Determining the radon diffusion coefficient according to method B ...................................................14

7.6 Determining the radon diffusion coefficient according to method C ....................................................15

7.7 General requirements for performing the tests ......................................................................................................16

8 Influence quantities .......................................................................................................................................................................................18

9 Expression of results .....................................................................................................................................................................................18

9.1 Relative uncertainty ........................................................................................................................................................................18

9.2 Decision threshold and detection limit ...........................................................................................................................19

9.3 Limits of the confidence interval ..........................................................................................................................................19

10 Quality management and calibration of the test device ...........................................................................................19

11 Test report ................................................................................................................................................................................................................20

Annex A (informative) Determining the radon diffusion coefficient during the phase of

stationary radon diffusion according to method C ........................................................................................................21

Annex B (informative) Determining the radon diffusion coefficient during the phase of non-

stationary radon diffusion ......................................................................................................................................................................27

Bibliography .............................................................................................................................................................................................................................36

© ISO 2017 – All rights reserved iii
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ISO/TS 11665-13:2017(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.
A list of all parts in the ISO 11665 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved
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ISO/TS 11665-13:2017(E)
Introduction

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

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

respectively, and are all found in the earth's crust. Solid elements, also radioactive, followed by stable

[5]
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.
[7]

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

[2]
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

[8] −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[9]
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.

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

© ISO 2017 – All rights reserved v
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ISO/TS 11665-13:2017(E)

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 the performance of the different methods described in ISO/TS 11665-12 and this

[3]
document, as required 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 © ISO 2017 – All rights reserved
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TECHNICAL SPECIFICATION ISO/TS 11665-13:2017(E)
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 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 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, definitions and symbols
3.1 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 terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
© ISO 2017 – All rights reserved 1
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ISO/TS 11665-13:2017(E)
3.1.1
material

product according to a certain technical specifications which is the object of the test

3.1.2
sample (of material)

certain amount of material chosen from the production batch for determination of the radon diffusion

coefficient
3.1.3
radon diffusion coefficient

radon activity permeating due to molecular diffusion through unit area of a monolayer material of unit

thickness per unit time at unit radon activity concentration gradient on the boundaries of this material

3.1.4
equivalent radon diffusion coefficient
eqv

radon diffusion coefficient of the multilayer material 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
3.1.5
radon diffusion length

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 of the sample, in square metres per second;

 λ is the radon decay constant, in per second.
3.1.6
diffusive radon surface exhalation rate

value of the activity concentration of radon atoms that leave a material 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)
2 © ISO 2017 – All rights reserved
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ISO/TS 11665-13:2017(E)
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 sam-

ple, in Becquerel per cubic metre;
D is the radon diffusion coefficient 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.
3.1.7
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⋅ −⋅λ Cx( ,t)= (3)
∂x ∂t
where
D is the radon diffusion coefficient 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.
3.1.8
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⋅ −⋅λ Cx()=0 (4)
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ISO/TS 11665-13:2017(E)
where
D is the radon diffusion coefficient 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 sam-

ple, 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.
3.1.9
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

Note 1 to entry: The duration of the decisive measurement can be shorter or the same as the duration of the test.

3.1.10
decisive volume of the container
volume of the container used to calculate the radon diffusion coefficient
3.1.11
decisive sample area
material sample area used to calculate the radon diffusion coefficient
3.1.12
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 in the source

and receiver containers taken during the phase of non-stationary diffusion ensuring the uncertainty of

the radon diffusion coefficient assessment lower than ±20 %
3.1.13
minimum duration of the decisive measurement for stationary radon diffusion

period of time in the frame of the decisive measurement of radon activity concentrations in the source

and receiver containers taken during the phase of stationary diffusion ensuring the uncertainty of the

radon diffusion coefficient assessment lower than ±20 %
3.1.14
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 %
3.1.15
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.

Note 2 to entry: For waterproof materials, the default value of the radon transfer coefficient is 0,1 m·s

3.1.16
standard uncertainty of a variable
standard deviation of a variable X
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ISO/TS 11665-13:2017(E)
3.1.17
relative uncertainty of a variable X
u(X) = k·s(X)/EX
where
EX is the expected value of a variable X;
k is the shrinkage factor (k = 1,96 by default for 95 % confidence interval).
3.2 Symbols

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

λ radon decay constant, in per second

λ radon leakage rate characterizing the ventilation of the receiver container, in per second

C radon activity concentration in the sample, in Becquerel per cubic metre

C radon activity concentration in a particular container of the measuring device, in Becquerel per

cubic metre

C radon activity concentration on the surface of the sample, in Becquerel per cubic metre

C radon activity concentration in the receiver container, in Becquerel per cubic metre

C radon activity concentration in the source container, in Becquerel per cubic metre

D radon diffusion coefficient of the monolayer sample, in square metre per second

D equivalent radon diffusion coefficient of the multilayer sample, in square metre per second

eqv
d thickness of the sample, in metre

E diffusive radon surface exhalation rate, in Becquerel per square metre per second

E diffusive radon surface exhalation rate from the sample to the receiver container, in Becquerel

per square metre per second
h radon transfer coefficient, in metre per second
l radon diffusion length, in metre
S decisive area of the sample, in square metre
t time, in second
Δt duration of the considered time step between time t and t , in second
i−1 i
V decisive volume of the receiver container, in cubic metre

x distance within the tested sample measured from the surface of the sample exposed to radon,

in metre
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
© ISO 2017 – All rights reserved 5
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ISO/TS 11665-13:2017(E)
4 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

−3 −3

the 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
5 Measuring system
5.1 Components of the measuring system

The measuring system for determining the radon diffusion coefficient in the waterproof materials shall

comprise the following components:

a) at least two air-tight containers (source and receiver), each with a minimum air volume of

−3 3

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 (for

example, aluminium, 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

−3 2

with a test area of at least 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

−3 −3
concentration in the source container within the range 1 MBq·m to 100 MBq·m ;
−3 3 −3 3

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

container with standard relative uncertainty 10 % and a dynamic measuring range from

−3 −3
500 Bq·m to 1,0 MBq·m ;

f) a calibrated measuring device for monitoring the radon activity concentration in the source

container with standard relative uncertainty 10 % and a dynamic measuring range from

−3 −3
10 kBq·m to 100,0 MBq·m ;
g) a measuring instrument for determining the relative pressu
...

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