IEC 61577-2:2014

IEC 61577-2 ®
Edition 2.0 2014-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Radon and radon decay product
measuring instruments –
222 220
Part 2: Specific requirements for Rn and Rn measuring instruments

Instrumentation pour la radioprotection – Instruments de mesure du radon et
des descendants du radon –
Partie 2: Exigences spécifiques pour les instruments de mesure du Rn et
du Rn
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 55 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 61577-2 ®
Edition 2.0 2014-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Radon and radon decay product

measuring instruments –
222 220
Part 2: Specific requirements for Rn and Rn measuring instruments

Instrumentation pour la radioprotection – Instruments de mesure du radon et

des descendants du radon –
Partie 2: Exigences spécifiques pour les instruments de mesure du Rn et
du Rn
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 13.280 ISBN 978-2-8322-1675-0

– 2 – IEC 61577-2:2014 © IEC 2014
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 General design considerations. 9
4.1 Design considerations for the measurements . 9
4.1.1 General . 9
222 220
4.1.2 Effects caused by physical properties of Rn and Rn . 10
4.2 Design considerations for handling and maintenance . 10
4.2.1 Portability . 10
4.2.2 Application under harsh environmental conditions . 10
4.2.3 Automatic operation . 11
4.2.4 Reliability . 11
4.2.5 Capability for operational testing . 11
4.2.6 Adjustment and maintenance facilities . 11
4.2.7 Acoustic noise level . 11
4.2.8 Electromagnetic interference . 11
4.2.9 Storage . 12
5 Technical components . 12
5.1 Sampling assembly . 12
5.2 Radiation detection assembly . 12
5.3 Data processing and recording . 13
5.4 Measurement display . 13
5.5 Power supply . 13
6 Test conditions . 14
6.1 General . 14
6.2 Standard test conditions . 14
6.3 Execution of tests . 14
6.4 Reference atmospheres . 14
7 Requirements and tests concerning radiation detection performance . 15
7.1 Reference response to a test source . 15
7.1.1 Requirements . 15
7.1.2 Test method . 15
7.2 Cross-interference to other radon isotopes . 15
7.2.1 Requirements . 15
7.2.2 Test method . 15
7.3 Linearity of indication . 15
7.3.1 Requirements . 15
7.3.2 Test method . 16
7.4 Instrument statistical fluctuation . 16
7.4.1 Requirements . 16
7.4.2 Test method . 16
7.5 Response time . 17
7.5.1 Requirements . 17

7.5.2 Test method . 17
7.6 Signal accumulation . 17
7.6.1 Requirements . 17
7.6.2 Test method . 17
8 Requirements and tests concerning air circuit performance . 17
8.1 General . 17
8.2 Flow-rate stability . 18
8.2.1 Requirements . 18
8.2.2 Test method . 18
8.3 Accuracy of the air flow-rate measurement . 18
8.3.1 Requirements . 18
8.3.2 Test method . 18
8.4 Effect of filter pressure drop . 18
8.4.1 Requirements . 18
8.4.2 Test method . 18
8.5 Indication of low sampling flow-rate . 19
8.5.1 Requirements . 19
8.5.2 Test method . 19
9 Requirements and tests concerning environmental performance . 19
9.1 Response to ambient gamma radiation . 19
9.1.1 Requirements . 19
9.1.2 Test method . 19
9.2 Ambient temperature . 19
9.2.1 Requirements . 19
9.2.2 Test method . 19
9.3 Relative humidity and condensed moisture . 20
9.3.1 Requirements . 20
9.3.2 Test method . 20
9.4 Atmospheric pressure . 20
10 Requirements and tests concerning electrical performance . 20
10.1 Power supply variations . 20
10.1.1 Requirements . 20
10.1.2 Test method . 20
10.2 Battery test . 21
10.2.1 Requirements . 21
10.2.2 Test method . 21
11 Requirements and tests concerning mechanical performance . 21
11.1 Requirements . 21
11.2 Test method . 21
12 Operation and maintenance manual . 21
13 Type test report and certificate . 22

Table 1 – Reference conditions and standard test conditions (unless otherwise
indicated by the manufacturer) . 23
Table 2 – Tests of the radiation detection performance . 23
Table 3 – Tests of the air circuit performance . 24
Table 4 – Tests performed with variation of influence quantities. 24

– 4 – IEC 61577-2:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RADIATION PROTECTION INSTRUMENTATION –
RADON AND RADON DECAY PRODUCT
MEASURING INSTRUMENTS –
222 220
Part 2: Specific requirements for Rn and Rn
measuring instruments
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61577-2 has been prepared by sub-committee 45B: Radiation
protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.
This second edition cancels and replaces the first edition issued in 2000. This edition
constitutes a technical revision.
This second edition includes the following significant technical changes with respect to the
previous edition:
a) Addition of new requirements and tests concerning radiation detection performance.
b) Addition of new requirements and tests concerning environmental performance.

c) Harmonization of the requirements and tests concerning electrical and mechanical
performance with other standards in the area of radon and radon decay product
instrumentation.
The text of this standard is based on the following documents:
FDIS Report on voting
45B/793/FDIS 45B/798/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of IEC 61577 series, under the general title Radiation protection
instrumentation – Radon and radon decay product measuring instruments, can be found on
the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 61577-2:2014 © IEC 2014
INTRODUCTION
226 223 224
Radon is a radioactive trace gas produced by the decay of Ra, Ra and Ra,
238 235 232
respectively decay products of U, U and Th which are present in the earth's crust. By
222 219 220
decay, radon isotopes (i.e. Rn, Rn, Rn) produce three decay chains, each ending in
a stable lead isotope. The radon isotope Rn is generally known as thoron .
219 2
NOTE In normal conditions, due to the very short half-life of Rn, its activity and the activity of its RnDP are
considered negligible compared to the activity of the other two series. Its health effects are therefore not important.
Thus in this standard Rn and its decay products are not considered.
In order to facilitate its use, the IEC 61577 series is divided into the following different parts:
IEC 61577-1: This part emphasizes the terminology and units used in the specific field of
radon and radon decay products (RnDP) measurement techniques and describes briefly the
concept of System for Test Atmospheres with Radon (STAR) used for test and calibration of
radon and RnDP measuring devices.
222 220
IEC 61577-2: This part is dedicated to the tests of Rn and Rn measuring instruments.
IEC 61577-3: This part is dedicated to the tests of RnDP and RnDP measuring
222 220
instruments.
IEC 61577-4: This part is dedicated to the construction of a STAR and its use for testing.
IEC/TR 61577-5 (informative): This is a technical report (to be developed) concerning special
features of radon and/or RnDP measurement.
—————————
1 220
The term thoron is not used in this standard. Instead, the term radon is used to denote the radionuclides Rn
and Rn. In the case that one of these radionuclides is to be explicitly specified, the atomic mass number and
the chemical symbol are given.
RnDP is the acronym for Radon Decay Products, which are sometimes called radon progeny. The term Radon
Decay Products or its abbreviation (RnDP) denotes the whole set of short-lived decay products that becomes
the focus of this standard. A particular isotope is indicated by its chemical symbol preceded by its mass number.
The subscripts , added to the symbol RnDP refer to the whole set of short-lived decay products of the
222 220
218 214 214 214 216 212 212 212
corresponding radon isotope (RnDP : Po, Pb, Bi, Po, and RnDP : Po, Pb, Bi, Po,
222 220
Tl).
RADIATION PROTECTION INSTRUMENTATION –
RADON AND RADON DECAY PRODUCT
MEASURING INSTRUMENTS –
222 220
Part 2: Specific requirements for Rn and Rn
measuring instruments
1 Scope
This part of IEC 61577 describes the specific requirements for instruments measuring the
222 220
activity concentration of airborne Rn and Rn outdoors, in dwellings, and in workplaces
including underground mines.
This standard applies practically to all types of electronic measuring instruments that are
based on either spot or continuous measurements. The activity concentration can be
222 220
measured by pumping or by diffusing the air containing Rn and/or Rn into the sensitive
volume of the detection unit or at a particular moment by taking an air sample (grab sampling).
The different types of instrumentation used for measurements are stated in IEC 61577-1.
The standard does not apply to instruments using charcoal adsorption, electrets or solid state
nuclear track detectors.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-2-27, Environmental testing – Part 2-27: Tests – Test Ea and guidance: Shock
IEC 61000-6-4, Electromagnetic compatibility (EMC) – Part 6-4: Generic standards –
Emission standard for industrial environments
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
IEC 61187, Electrical and electronic measuring equipment – Documentation
IEC 61577-1, Radiation protection instrumentation – Radon and radon decay product
measuring instruments – Part 1: General principles
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM:1995)
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

– 8 – IEC 61577-2:2014 © IEC 2014
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
conventionally true value of a quantity
ν
c
value attributed to a particular quantity and accepted, sometimes by convention, as having an
uncertainty appropriate for a given purpose
Note 1 to entry: "Conventionally true value of a quantity" is sometimes called assigned value, best estimate of the
value, conventional value or reference value.
[SOURCE: IEC 60050-394:2007, 394-40-10]
3.2
rated range
range of a quantity to be measured, observed, supplied, set, or assigned to the instrument
[SOURCE: IEC 60050-394:2007, 394-39-42]
3.3
error
error of measurement
result of a measurement minus a true value of the measurand
Note 1 to entry: Since a true value cannot be determined, a conventional true value is used in practice.
Note 2 to entry: When it is necessary to distinguish “error” from “relative error”, the former is sometimes called
“absolute error of measurement”. This should not be confused with “absolute value of error”, which is the modulus
of the error.
[SOURCE: IEC 60050-394:2007, 394-40-13]
3.4
relative error
e
r
error of measurement divided by a true value of the measurand
Note 1 to entry: Since a true value cannot be determined, in practice a conventional true value is used.
[SOURCE: IEC 60050-394:2007, 394-40-11]
3.5
intrinsic error
e
i
error of a measuring instrument, determined under reference conditions
[SOURCE: IEC 60050-394:2007, 394-40-12]
3.6
response (of a radiation measuring assembly)
ratio, under specified conditions, given by the relation:
v
,
R=
v
c
where v is the value measured by the equipment or assembly under test and v is the
c
conventionally true value of this quantity

Note 1 to entry: The input signal to a measuring system may be called the stimulus; the output signal may be
called the response (IVM).
Note 2 to entry: Response can have several definitions. As an example, the definition of the response of a
radiation measuring assembly is given.
[SOURCE: IEC 60050-394:2007, 394-40-21]
3.7
reference response
response of the assembly under reference conditions to a reference dose rate or activity
expressed as:
v
R = ,
ref
v
c
where v is the value measured by the equipment or assembly under test and v is the
c
conventionally true value of the reference source
Note 1 to entry: The background value may be automatically taken in account by an algorithm included in the
measurement system.
[SOURCE: IEC 60050-394:2007, 394-40-22]
3.8
cross-interference
ratio of the response of the instrument to the radiation from interfering radionuclide to the
response of the radiation from the radionuclide of interest
3.9
coefficient of variation
of a set of n measurements x given
ratio of the standard deviation s to the arithmetic mean x
i
by the following formula:
(x − x)
s 1 i
∑
V = =
x x n− 1
,
Note 1 to entry: The coefficient of variation can be expressed in percent (%) of the arithmetic mean.
[SOURCE: IEC 60050-394:2007, 394-40-14]
3.10
response time
response time of a measuring assembly
duration between the instant of a step change in the measured quantity and the instant when
the output signal reaches for the first time a specified percentage, usually 90 %, of its final
value
[SOURCE: IEC 60050-394:2007, 394-39-09]
4 General design considerations
4.1 Design considerations for the measurements
4.1.1 General
222 220
To measure the activity concentration of Rn/ Rn, several methods of measurement can
be used. General aspects of the physical principles involved and the performance of the
instruments have been summarized in IEC 61577-1 and ISO 11665-1.

– 10 – IEC 61577-2:2014 © IEC 2014
222 220
The air sample shall be filtered to remove Rn/ Rn decay products before entering the
sensitive volume of the detection unit. For the determination of Rn volumetric activity, its
very short half life shall be taken into account.
222 220
For spot measurement of the activity concentration of Rn/ Rn, grab sampling methods
are used. A sample of the air to be measured may be collected by filling a container, either a
previously evacuated or flow-through type one, and sealing the container afterwards.
222 220
To measure the variation of the activity concentration of Rn/ Rn, continuous
measurement methods are used. There are two sampling methods: flow-through and diffusion
sampling.
The air humidity may also affect the efficiency of some detectors and the instruments can be
provided with air drying systems.
Instrumentation that is intended to be used in field monitoring shall be portable and protected
against hostile environmental conditions.
The response time of the instrument shall be adequate for the variability of the phenomenon
measured.
222 220
4.1.2 Effects caused by physical properties of Rn and Rn
222 220
There is a large difference in the half lives of Rn (3,8 d) and Rn (55,4 s). Special
attention shall be paid to the half life of Rn when air samples are taken and measurements
are made.
222 220
In the case of the simultaneous determination for Rn and Rn activity concentration,
separation techniques using their different physical properties such as their half lives, the
alpha-particle energies emitted, and their decay products shall be introduced.
222 220
The determination of the activity concentration for Rn/ Rn may be affected by changes in
the flow-rate. In particular the influence on Rn measurement is significant because of its
very short half life. The flow-rate shall be measured when the activity concentration of Rn
is being determined.
4.2 Design considerations for handling and maintenance
4.2.1 Portability
The instrument shall be portable in order to perform in-situ measurements. This requires, in
particular, robustness against mechanical shock.
4.2.2 Application under harsh environmental conditions
If the instrument is applied under harsh environmental conditions occurring mostly outdoors or
at workplaces, in particular in mines, the instrument shall be of rugged construction. Where
applicable appropriate measures shall be met to protect the instrument and its components
against external influences or conditions such as
a) mechanical impacts;
b) corrosion and corrosive solvents;
c) solar radiation;
d) ice formation;
e) moisture and spraying water;
f) explosive atmospheres.
In cases where the impact of external influences cannot be eliminated totally, the influences
shall not affect the satisfactory operation of the instrument or compromise safety. Spray water
shall have no harmful effects.
The manufacturer shall specify the minimum ranges of environmental conditions or external
influences within which satisfactory operation of the instrument is ensured. The manufacturer
shall state influences or conditions that significantly reduce the measurement capability of the
instrument.
The manufacturer shall explicitly state whether the instrument can be used in explosive
atmospheres (e.g., in mines) or not.
4.2.3 Automatic operation
The instrument shall be such that the measurement cycle can be carried out either manually
or with programming so that automatic operation will be achievable.
4.2.4 Reliability
The instrument shall be designed to provide reliable performance with unrevealed failures
kept to a minimum.
4.2.5 Capability for operational testing
Capability should be provided to allow the purchaser to carry out periodic checks on the
operation of the instrument.
These checks shall be carried out using one or more suitable radioactive sources as
necessary.
4.2.6 Adjustment and maintenance facilities
The instrument shall be provided with a sufficient number of accessible and identifiable test
points to facilitate adjustments and fault location. Any special maintenance tools and
appropriate maintenance manuals shall be supplied.
The design of the instrument shall be such as to facilitate ease of repair and maintenance.
4.2.7 Acoustic noise level
Acoustic noise level of the instrument shall arise mainly from the sampling assembly and its
resultant vibration.
The manufacturer shall select the components and design the instrument so that the noise
level is not excessive. In particular, for instruments which are used indoors, the reduction of
the acoustic noise level shall be taken into consideration.
4.2.8 Electromagnetic interference
All necessary precautions shall be taken against detrimental effects of electromagnetic
interference on or by the instrument.
The manufacturer shall quantify the electromagnetic emission of the equipment. The emission
limits applicable to the instrument covered by this standard are given in IEC 61000-6-4.
Moreover, the manufacturer shall comply with current registration on the influence of cellular
phones and walkie-talkies on the instrument at a given distance and give appropriate warning.

– 12 – IEC 61577-2:2014 © IEC 2014
4.2.9 Storage
The instrument shall remain operable within the specified requirements of this standard after
storage without batteries and transportation in the manufacturer’s packaging at any
temperature between –25 °C and +60 °C. In some cases, more severe requirements may be
stated such as capability to withstand air transportation at low atmospheric pressure.
5 Technical components
5.1 Sampling assembly
The sampling assembly can include but is not limited by the following components and
functional units:
a) air pump;
b) aerosol retention device;
c) air-drying device;
d) flow-rate control and measurement system.
The air pump circuit shall provide a total air flow adequate for the measurement method. The
air pump shall be capable of withstanding the variations of pressure induced by operating
conditions, sampling time, filter types, and atmospheric dust-mass blockage. Pipes and
connections shall be sufficiently tight to maintain a stable flow rate and prevent leaks. Where
an air pump is an integral part of the assembly it is recommended that the air pump shall be
capable of continuous operation between scheduled maintenance operations. The flow-rate
should be stabilized or measured.
222 220
Most instruments use a filter to prevent Rn/ Rn decay products from entering the
detector active volume. The manufacturer shall state the type of filter.
If the response is dependent on the humidity of the sampled air, the instrument may be
equipped with an air-drying device (for example chemical drying agents or electrically
operated Peltier-elements). Care should be taken to choose a drying agent which does not
222 220
Rn/ Rn. When chemical drying agents are used, the life-time of the drying agent
adsorb
shall be clearly stated.
If the measurements are influenced by flow-rate, particularly in the determination of Rn
activity concentration, a flow-rate control device shall be provided that has a flow-rate
adjustment range sufficient to allow for variation in the intrinsic characteristics of the air pump
and any filters used. If the flow-rate is to be measured and indicated, the pressure and the
temperature, at which the flow-rate meter is calibrated, shall be provided.
5.2 Radiation detection assembly
Rn,
The radiation detection assembly transforms the radiation emitted by the sampled
Rn and their decay products into an electronic signal. In this case, the response shall be
optimized.
Contamination of the detector may increase the background. Precautions should be taken for
the protection against airborne contamination, when the instrument is not in use.
NOTE The contamination can be caused by:
– deposition of air-borne decay products;
– radioactive materials inside the relevant components of the instrument.

5.3 Data processing and recording
This assembly comprises the functional units for acquiring and processing signals supplied by
the detector.
The manufacturer shall publish the measurement principles and procedures for yielding a
measurement result and its uncertainties. The detail of information shall facilitate the
verification of measurement results by the purchaser.
The electronic data recording system shall have a capacity sufficient for recording all
measurement data generated during a long automatic data-acquisition period. The data shall
be retained on a medium that ensures protection and availability of the data, especially in the
event of malfunction and interruption of operation or failure of power supply. The
manufacturer shall specify the capacity of the data recording system.
5.4 Measurement display
The display shall be easily readable in different ambient conditions. The measurement units
shall be clearly marked on the display. If needed by the measurement method, flow-rate
indication shall be provided.
222 220
The display shall show the activity concentration of Rn/ Rn.
The quantities shall be given in combined SI-units. Appropriate submultiples should be used.
The display should show the uncertainty of the measurement.
The result of the measurement shall comprise both the value attributed to the quantity to be
measured and the uncertainty of the measurement associated with that value when possible.
The uncertainty given should be based on the requirements of ISO/IEC Guide 98-3 to the
expression of uncertainty in measurement.
Data outputs should be provided permitting remote indications and the use of one or more of
the following devices:
a) display;
b) data recorder;
c) printer;
d) computer;
e) or other devices via data port.
The instrument should be equipped with a preset threshold level to give a warning that
222 220
relevant radiation quantity (e.g., the activity concentration of Rn/ Rn) exceeds a
predetermined value. The preset threshold level should be adjustable.
5.5 Power supply
The power supply subassembly shall fulfil the requirements on the protection of persons
against electric shock as specified in IEC 61140.
Some instruments may be equipped with batteries. The batteries shall be individually
replaceable. The correct polarity shall be clearly indicated. The manufacturer shall specify the
type(s) of batteries.
Rechargeable batteries shall be fully charged by line power within 16 h. A device that turns off
the charger upon complete charging of a battery should be provided. A minimum load
indication shall be clearly displayed before the display malfunctions.

– 14 – IEC 61577-2:2014 © IEC 2014
6 Test conditions
6.1 General
General test procedures covered in this part of IEC 61577 concern instruments with different
technical characteristics. Except where otherwise specified, these are considered type tests.
The stated requirements are minimum requirements and may be extended for any particular
equipment or function unit. Certain tests may be considered acceptance tests by agreement
between manufacturer and purchaser.
A test quantity is one with which the metrological characteristics of the instrument are tested.
The specification of the test quantity can also be agreed upon between the manufacturer and
the purchaser.
6.2 Standard test conditions
Unless otherwise specified, the tests described in this standard shall be executed under
222 220
standard test conditions which are established in a Rn/ Rn reference atmosphere.
The standard test conditions listed in Table 1 shall be kept constant within the specified limits
during a test.
6.3 Execution of tests
222 220
The activity concentration of Rn/ Rn in the test atmosphere shall induce an indication
within the rated range. Unless otherwise specified the indication shall lie within the lower third
of the rated range.
Statistical fluctuation of the measurements caused by the random nature of radioactivity shall
be minimized by taking a sufficient number of measurements to yield a sufficiently precise
average value in the assessment of the instrument conformity against relevant requirements.
In order to test the instrument for a specific influence quantity, this quantity shall be varied
over the range specified in Table 4 while the other influence quantities shall be kept constant
within the tolerances of the standard test conditions specified in Table 2. The relative error in
the instrument indication under
...