ISO/TS 11665-12:2018

Measurement of radioactivity in the environment — Air: radon-222 — Part 12: Determination of the diffusion coefficient in waterproof materials: membrane one-side activity concentration measurement method

This document specifies the method 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 which will be met during the test. The test method described in this document allows to estimate the radon diffusion coefficient in the range of 10-5 m2/s to 10-12 m2/s[8][9] with an associated uncertainty from 10 % to 40 %.

Mesurage de la radioactivité dans l'environnement — Air : radon 222 — Partie 12: Détermination du coefficient de diffusion des matériaux imperméables: méthode de mesure de l'activité volumique d'un côté de la membrane

General Information

• Status: Published
• Publication Date: 18-Oct-2018
• ICS: 13.040.01 - Air quality in general
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85/SC 2 - Radiological protection
• Drafting Committee: ISO/TC 85/SC 2 - Radiological protection
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 26-Apr-2022

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 11665-12
First edition
2018-10
Measurement of radioactivity in the
environment — Air: radon-222 —
Part 12:
Determination of the diffusion
coefficient in waterproof materials:
membrane one-side activity
concentration measurement method
Mesurage de la radioactivité dans l'environnement — Air : radon
222 —
Partie 12: Détermination du coefficient de diffusion des matériaux
imperméables: méthode de mesure de l'activité volumique d'un côté
de la membrane
Reference number
ISO/TS 11665-12:2018(E)
©
ISO 2018

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ISO/TS 11665-12:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO/TS 11665-12:2018(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 . 5
6 Sample preparation . 6
6.1 General consideration . 6
6.2 Fixing the sample in the holder . 7
6.3 Connection of the holder (cap) with the chamber . 7
7 Control measurements . 8
7.1 Verification of radon-tightness . 8
7.2 Calibration . 9
7.3 Detector background . 9
7.4 Instrument statistical fluctuation . 9
8 Measurement of radon activity concentration .10
9 Processing and expression of the results for the sample .11
9.1 Determination of the radon diffusion coefficient in the sample .11
9.2 Characteristics of measurement limits .11
9.3 Estimation of confidence interval and uncertainty .13
9.4 Expression of the results .13
10 Requirements for the test .14
11 Influencing factors .15
12 Expression of the results and assessment of the standard uncertainty for the material .16
13 Quality management and calibration of the test device .17
14 Test report .17
14.1 The test report for material .17
14.2 The test report for each sample .18
14.3 Archived material .18
Annex A (informative) Determination of the radon diffusion coefficient of the sample .19
Bibliography .27
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ISO/TS 11665-12:2018(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 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.
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.
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ISO/TS 11665-12:2018(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
[4]
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.
[5]
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 a diffusion mechanism caused by the all-time existing difference
between radon activity concentrations in the underlying soil and inside the building, and via a
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
[6]
World Health Organization . Wherever this is not possible, this reference level should not exceed
-3
300 Bq·m . This recommendation that was endorsed by the European community member states
establishes national reference levels for indoor radon activity concentrations. The reference levels for
-3[8]
the annual average activity concentration in air cannot be higher than 300 Bq·m .
To reduce the risk to the overall population, building codes which require radon prevention measures
in buildings under construction and radon mitigating measures in existing buildings should be
implemented. 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.
The 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
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ISO/TS 11665-12:2018(E)

design of value of the radon diffusion coefficient can also be prescribed by national building standards
and codes.
As no reference standards and no reference materials are currently available for these types of
materials, and related values of the radon diffusion coefficient, the metrological requirement regarding
the determination of the performance of the different methods described in ISO/TS 11665-13 and in
[3]
this document, as required by ISO 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.
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TECHNICAL SPECIFICATION ISO/TS 11665-12:2018(E)
Measurement of radioactivity in the environment — Air:
radon-222 —
Part 12:
Determination of the diffusion coefficient in waterproof
materials: membrane one-side activity concentration
measurement method
1 Scope
This document specifies the method 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 which will be met during the test.
The test method described in this document allows to estimate the radon diffusion coefficient in the
-5 2 -12 2 [8][9]
range of 10 m /s to 10 m /s with an associated uncertainty from 10 % to 40 %.
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 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
me a s ur ement (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, ISO 80000-10 and
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1.1
material
material produced according to certain technical specifications which is the object of the test
3.1.2
sample
certain amount of material (3.1.1) chosen from the production batch for determination of the radon
diffusion coefficient (3.1.3)
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ISO/TS 11665-12:2018(E)

3.1.3
radon diffusion coefficient
D
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 (3.1.1)
[SOURCE: ISO/TS 11665-13:2017, 3.1.3, modified — “” has been added as the domain of the
definition.]
3.1.4
decisive measurements
measurement results used to calculate the radon diffusion coefficient (3.1.3)
3.1.5
decisive volume of the chamber
volume of the chamber used to calculate the radon diffusion coefficient (3.1.3)
3.1.6
decisive area of the sample
material (3.1.1) sample (3.1.2) area used to calculate the radon diffusion coefficient (3.1.3)
3.1.7
radon transfer coefficient
radon transport in thin boundary layer of air near the surface of the sample (3.1.2)
Note 1 to entry: The default value of the radon transfer coefficient is 0,001 m/s to 0,1 m/s.
[SOURCE: ISO/TS 11665-13:2017, 3.1.15, modified — Note 1 to entry has been removed. Note 2 to entry
has become Note 1 to entry and has been slightly rephrased.]
3.2 Symbols
For the purposes of this document, the symbols given in ISO 11665-1 and the following apply.
D Radon diffusion coefficient of the sample, in square metre per second
< Lower limit of the confidence interval of the radon diffusion coefficient of the sample, in
D
square metre per second
> Upper limit of the confidence interval of the radon diffusion coefficient of the sample, in
D
square metre per second
D Radon diffusion coefficient of the material, in square metre per second
M
λ Radon decay constant, in per second
λ Radon leakage rate, in per second
L
ˆ
Best estimate of the radon leakage rate, in per second
λ
L
C Radon activity concentration in the sample, in becquerel per cubic metre
C Radon activity concentration in a source-detect chamber, in becquerel per cubic metre
sd
C Radon activity concentration in a source-detect chamber at the initial time after injection of
0
radon, in becquerel per cubic metre
C Radon activity concentration in the ambient air, in becquerel per cubic metre
amb
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ISO/TS 11665-12:2018(E)

C Measured radon activity concentration in a source-detect chamber, in becquerel per
m
cubic metre
d Thickness of the sample, in metre
S Decisive area of the sample, in square metre
s
V Decisive volume of the source-detect chamber, in cubic metre
sd
h Radon transfer coefficient, in metre per second
t Time, in second
τ Time of start of measurement period, in second (or hour)
i i
r Gross count rate, in counts per second
g
α
Gross count rate from alpha-source, in counts per second
r
g
r Background count rate, in counts per second
0
R Measured rate of decrease of radon activity concentration in the chamber (of pulse count rate)
m
R Calculated rate of decrease of radon activity concentration in the chamber
c
R Calculated rate of decrease of radon activity concentration in the chamber at verification of
L
radon-tightness
R Function of the minimum measured rate of decrease in the chamber
min
R Function of the maximum measured rate of decrease in the chamber
max
u(y) Standard uncertainty of the value of y
s(y) Standard deviation of the value of y
u (D) Relative uncertainty of the radon diffusion coefficient in the sample
rel
k Coverage factor
N Number of samples of the test material
4 Principle
The one-side method is based on the measurement of the decrease over time of the radon activity
concentration in a source-detect chamber in contact with one side of the tested membrane. The test
is performed in a non-stationary mode. This test method can be used for single-layer waterproof
materials when testing results are needed rapidly. They are not applicable for multi-layer waterproof
materials that do not meet the requirements of Figure 7.
A sample of the tested material is installed in the sealed end of the cylindrical chamber (Figure 1). The
detector of radon activity is located at the other end of the chamber.
In the beginning of the test, a highly active portion of radon is injected into the chamber through a
special valve. Since then, radon activity concentration in the chamber begins to decline because of
a) diffusion of radon through the sample towards the ambient air,
b) radon decay, and
c) leakage of radon from the chamber.
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The chamber serves as a source radon and also allows to measure radon activity in the chamber.
Key
1 source-detect chamber
2 tested sample
3 ambient air
Figure 1 — Measurement scheme
The process of radon transfer from the chamber through the sample is described by Formulae (1) and (2):
∂Ct() S
sd s
 
=−λ ⋅−Ct() ⋅⋅hC ()tC− (,0 t) (1)
sd 1 sd
 
∂t V
sd
2
∂Cx(,t)(∂ Cx,)t
= D −⋅λ Cx(,t) , 0≤≤xd , 0≤ 2
∂t
∂x
with the following boundary conditions in Formulae (3) to (5):
C (t = 0) = C , C(x, 0) = 0 (3)
sd 0
∂Ct(0, )
 
−D =⋅hC ()tC− (0,t) (4)
1sd
 
∂x
∂Cd(,t)
 
 
−D =⋅hC(,dt)−C , Ct() =0 (5)
2amb  amb 
 
∂x
Formulae (1) to (5) with respect to the values of radon activity concentration in the chamber are solved
as the function expressed by Formula (6):
C (t) = C ·f(t, D, λ, V , S , d) (6)
sd 0 sd s
which is calculated as in Formula (7):
t
 
λτ ()−t −⋅λ t
 
Ct() =+Ce Fe()ττd (7)
sd 0 ∫
 
0
 
The calculation by Formula (7) is carried out by the algorithm described in Annex A.
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During the test, the ratios between current radon activity concentrations in the chamber to radon
activity concentration at the beginning of the decisive measurements are registered. These ratios
determine the rate of radon activity concentration decrease in the chamber (Clause 8).
The radon diffusion coefficient in the sample is calculated according to 9.1, taking into account the
effect of radon leakage from the chamber.
5 Equipment
The scheme of the test installation is shown in Figure 2.
Key
1 chamber 10 computer
2 bolt (with washer) 11 micro-fan
3 holder 12 power supply of the micro-fan
4 sample 13 valve
5 insert 14 syringe
6 scintillation plate 15 radon source
7 light-transmissive window 16 thermometer
8 photomultiplier unit 17 cap
9 signal converter
Figure 2 — The scheme of the test installation
The installation includes an aluminium cylindrical chamber (1). The lower end of the chamber is a
flange with a sealing gasket which is hermetically connected to the aluminium holders (3) with a test
sample (4) by bolts (2).
Aluminium cylindrical inserts (5) are used to reduce the decisive volume of the chamber.
Scintillation plate (6) with sensitive ZnS(Ag) layer and light-transmissive window (7) made of
polymethyl methacrylate are hermetically embedded in the upper end of the chamber.
The alpha radiation of radon and its progeny, interacting with the sensitive layer of the scintillator plate,
causes light flashes (scintillations) which are converted into electrical pulses by the photomultiplier
unit (8). These pulses are converted by the device (9) and transmitted to the computer (10). The
computer software registers the average count rate at predetermined time intervals.
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ISO/TS 11665-12:2018(E)

[8]
The micro-fan (11) provides stability in registering radon activity inside the chamber . The micro-
fan is equipped with a brushless motor and a consumption current of less than 20 mA at a voltage not
exceeding 5 V. The power of the micro-fan is provided by a power supply of stable voltage (12).
The sealed valve (13) for injecting radon inside the chamber with the syringe (14) is located on the
sidewall of the chamber. The radon portion in the syringe is introduced from the radon source (15). The
activity and the volume of the radon source should be 10 kBq to 100 kBq and 0,2 l to 0,5 l, respectively.
The thermometer (16) is connected to the computer.
The test installation is equipped with at least 3 holders and one aluminium cap (17).
To register the activity concentration, a semiconductor or another type of detector, located inside the
chamber and meeting the requirements of Clauses 7 and 10, can be also used.
The installation kit also includes
a) a torque wrench with predetermined torque between 1 Nm and 10 Nm,
b) a measuring instrument capable of determining the thickness of the tested sample with accuracy of
±0,01 mm (maximum standard relative measurement uncertainty of 5 %),
c) an epoxy adhesive,
d) alcohol, acetone, or another degreasing agent.
The chamber is set upright and the flange downwards (Figure 2) to avoid problems for radon exhalation
from the sample.
Light shall not enter the chamber when the photomultiplier is on.
6 Sample preparation
6.1 General consideration
If the condition of Formula (29) is not satisfied after testing 3 samples, additional samples of the
material should be prepared and tested until this condition is fulfilled.
The samples are cut out from the prefabricated membranes at a minimum distance of 20 mm from the
edges of the membrane.
In the case of coatings, paints, sealants or other waterproof materials prepared on site, at least 3
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.
2
The thickness of each sample is measured at 4 points per 0,01 m placed uniformly along the surface of
the sample. The resulting thickness of each sample is the arithmetic mean of all measurements on the
sample. If a radon-permeable surface coating is part of the tested material, its thickness is not included
in the thickness of the tested sample. This type of surface coating can be removed from the sample
before performing the test.
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6.2 Fixing the sample in the holder
The sample is cut into a disk and fixed in the holder (Figure 3) so that the direction of the radon flow
through the sample during the test corresponds to the real flow direction through the material in
operational conditions.
The sample is fixed in the holder without slack via an epoxy adhesive that is first applied to the shelf of
the holder, and then poured into the annular gap (1 mm to 2 mm) between the sample and the sidewall
of the holder.
The surfaces of the sample and the holder to which the adhesive is applied, should be pre-treated by the
degreasing agent.
During the preparation of the epoxy adhesive, the hardener is added to the epoxy resin in an amount
which provides elasticity to the adhesive composition in order to avoid excessive hardness and
brittleness after solidification. The prepared glue fixes the sample holder reliably for at least one week.
Before reuse, the holder is purified from the epoxy adhesive by using a solvent of epoxy resin, or by
immersion in boiling water, or by a lathe.
The holder is attached to the chamber not earlier than 24 h after fixing the sample.
Dimensions in millimetres
Key
1 holder
2 shelf of the holder of 4 mm to 5 mm width
3 sidewall of the holder
4 sample
5 epoxy adhesive
ØА decisive diameter of the sample, equal to the inner diameter of the chamber
ØB diameter of the sample
ØC diameter of the mating part of the holder
Figure
...