EN 61577-4:2014

Radiation protection instrumentation - Radon and radon decay product measuring instruments - Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)

IEC 61577-4:2009 concerns the System for Test Atmospheres with Radon (STAR) needed for testing, in a reference atmosphere, the instruments measuring radon and RnDP. Provides guidance for those facing problems associated with the production of equipment for setting up reference atmospheres for radon and its decay products.

Strahlenschutz-Messgeräte - Geräte für die Messung von Radon und Radon-Folgeprodukten - Teil 4: Einrichtungen für die Herstellung von Referenzatmosphären mit Radonisotopen und ihren Folgeprodukten (STAR)

Instrumentation pour la radioprotection - Instruments de mesure du radon et des descendants du radon - Partie 4: Dispositif pour la réalisation d’atmosphères de référence contenant des isotopes du radon et leurs descendants (STAR)

La CEI 61577-4:2009 concerne le Système de Test en Atmosphères contenant du Radon (STAR) servant à tester, dans une atmosphère de référence, les instruments mesurant le radon et les RnDP. Est un guide à l'attention de ceux qui se trouvent confrontés aux problèmes associés à la mise en place du matériel nécessaire pour la création des atmosphères de référence pour le radon et ses descendants.

Instrumenti za zaščito pred sevanjem - Instrumenti za merjenje radona in njegovih razpadnih produktov - 4. del: Oprema za proizvodnjo referenčnih atmosfer, ki vsebujejo radonove izotope in njihove razpadne produkte (STAR)

Standard IEC 61577-4:2009 obravnava sistem za preskusne atmosfere z radonom (STAR), potreben za preskušanje instrumentov za merjenje radona in njegovih razpadnih produktov v referenčni atmosferi. Zagotavlja navodila za subjekte, ki se soočajo s težavami, povezanimi s proizvodnjo opreme za vzpostavljanje referenčnih atmosfer za radon in njegove razpadne produkte.

General Information

• Status: Published
• Publication Date: 04-Dec-2014
• Withdrawal Date: 16-Nov-2017
• ICS: 13.280 - Radiation protection
• Technical Committee: CLC/TC 45B - Radiation protection instrumentation
• Drafting Committee: IEC/SC 45B - IEC_SC_45B
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 05-Dec-2014
• Completion Date: 05-Dec-2014
• Ref Project: SIST EN 61577-4:2015 - Radiation protection instrumentation - Radon and radon decay product measuring instruments -- Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Radiation protection instrumentation - Radon and radon decay product measuring instruments - Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)Instrumentation pour la radioprotection - Instruments de mesure du radon et des descendants du radon -- Partie 4: Dispositif pour la réalisation d’atmosphères de référence contenant des isotopes du radon et leurs descendants (STAR)Radiation protection instrumentation - Radon and radon decay product measuring instruments -- Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)17.240Merjenje sevanjaRadiation measurements13.280Varstvo pred sevanjemRadiation protectionICS:Ta slovenski standard je istoveten z:EN 61577-4:2014SIST EN 61577-4:2015en01-september-2015SIST EN 61577-4:2015SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 61577-4
December 2014 ICS 13.280
English Version
Radiation protection instrumentation - Radon and radon decay product measuring instruments - Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR) (IEC 61577-4:2009 , modified)
Instrumentation pour la radioprotection - Instruments de mesure du radon et des descendants du radon - Partie 4: Dispositif pour la réalisation d'atmosphères de référence contenant des isotopes du radon et leurs descendants (STAR) (CEI 61577-4:2009 , modifiée)
Strahlenschutz-Messgeräte - Geräte für die Messung von Radon und Radon-Folgeprodukten - Teil 4: Einrichtungen für die Herstellung von Referenzatmosphären mit Radonisotopen und ihren Folgeprodukten (STAR) (IEC 61577-4:2009 , modifiziert) This European Standard was approved by CENELEC on 2014-11-17. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung CEN-CENELEC Management Centre: Avenue Marnix 17,
B-1000 Brussels © 2014 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61577-4:2014 E SIST EN 61577-4:2015

Foreword This document (EN 61577-4:2014) consists of the text of IEC 61577-4:2009 prepared by IEC/SC 45B "Radiation protection instrumentation" of IEC/TC 45 "Nuclear instrumentation", together with the common modifications prepared by CLC/TC 45B "Radiation protection instrumentation". The following dates are fixed: • latest date by which this document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2015-11-17 • latest date by which the national standards conflicting with this document have to be withdrawn (dow) 2017-11-17 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights. SIST EN 61577-4:2015

- 3 - EN 61577-4:2014 Endorsement notice The text of the International Standard IEC 61577-4:2009 was approved by CENELEC as a European Standard with agreed common modifications.
COMMON MODIFICATIONS
2 Normative references Replace the title indicated for IEC 61577 (all parts) with “Radiation protection instrumentation – Radon and radon decay product measuring instruments”.
3 Terms, definitions and units 3.2 Specific terms and definitions 3.2.11 unattached fraction of PAEC Delete the note. Add a new note below the entry: NOTE Z1
The particle size concerned is below 10 nm. 3.2.12 attached fraction Replace in the note 0,3 µm with 0,5 µm.
6 Requirements for the reference atmosphere provided by STAR 6.3 Influence quantities 6.3.1 General Add to the paragraph “According to Clause 4, only those influence quantities relevant to the kind of STAR under test need to be considered.”
6.3.2 Temperature In the second paragraph, replace “+18 °C to +22 °C” with “+18 °C to +24 °C”.
6.3.3 Relative humidity In the second paragraph, replace “50 % RH” with “65 % RH” and “40 % RH to 60 % RH” with “40 % RH to 75 % RH”.
Table 1 – Reference and standard test conditions Replace the line for temperature as follows: Temperature 20 °C 18 °C to 24 °C Replace the line for relative humidity as follows: Relative humidity 65 % 40 % to 75 % SIST EN 61577-4:2015

Replace the line for ambient gamma dose rate as follows: Ambient γ dose rate Negligible <0,25 µSv{h–1 Replace the line for unattached fraction as follows: Unattached fraction Negligible <0,25 Replace the line for aerosol size (AMTD or AMAD) as follows: Aerosol size (AMTD or AMAD)* 0,2 µm 0,1 µm to 0,5 µm
Table A.1 – Atmosphere characteristic ranges (typical values) Delete the line of the unattached fraction of RnDP222.
- 5 - EN 61577-4:2014 Annex ZA (normative)
Normative references to international publications with their corresponding European publications 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. NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here: www.cenelec.eu.
Publication Year Title EN/HD Year IEC 60050-111 1996
International Electrotechnical Vocabulary - Chapter 111: Physics and chemistry - -
IEC 60050-393 2003
International Electrotechnical Vocabulary - Part 393: Nuclear instrumentation - Physical phenomena and basic concepts - -
IEC 60050-394 2007
International Electrotechnical Vocabulary - Part 394: Nuclear instrumentation - Instruments, systems, equipment and detectors - -
IEC 61577 series
Radiation protection instrumentation - Radon and radon decay product measuring instruments
EN 61577 series
ISO/IEC 17025 -
General requirements for the competence of testing and calibration laboratories EN ISO/IEC 17025 -
ISO/IEC Guide 99 2007
International vocabulary of metrology - Basic and general concepts and associated terms (VIM) - -
ICRP 32 - Annals of the ICRP, Publication N° 32, Limits for inhalation of Radon Daughters by Workers, Vol. 6, N°1, 1981, Pergamon Press - - ICRP 38 - Annals of the ICRP, Publication N° 38, Radionuclide transformations, Energy and Intensity of Emissions, Vol. 11 – 13, 1983, Pergamon Press - - ICRP 65 - Annals of the ICRP, Publication N° 65, ICRP Publication 65: Protection against Radon-222 at Home and at Work, Vol. 23/2, 1994, Pergamon Press - -
IEC 61577-4Edition 1.0 2009-02INTERNATIONAL STANDARD NORME INTERNATIONALERadiation protection instrumentation – Radon and radon decay product measuring instruments –
Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)
Instrumentation pour la radioprotection – Instruments de mesure du radon et des descendants du radon –
Partie 4: Dispositif pour la réalisation d’atmosphères de référence contenant des isotopes du radon et leurs descendants (STAR)
INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE UICS 13.280 PRICE CODECODE PRIXISBN 978-2-88910-545-8
– 2 – 61577-4 © IEC:2009 CONTENTS FOREWORD.4 INTRODUCTION.6 1 Scope and object.7 2 Normative references.7 3 Terms, definitions and units.8 3.1 General terms and definitions.8 3.2 Specific terms and definitions.9 3.3 Units and conversion factors.12 4 General description of a System for Test Atmospheres with Radon (STAR).13 4.1 General.13 4.2 Mode of operation of a STAR.14 4.2.1 Static mode of operation.14 4.2.2 Dynamic mode of operation.14 5 Characteristics of a STAR.15 5.1 General.15 5.2 STAR for radon.16 5.2.1 General.16 5.2.2 Technical characteristics of STAR containers.16 5.2.3 Radon sources.16 5.2.4 222Rn
and 220Rn analysis and control.17 5.2.5 Analysis and control of climatic parameters.18 5.3 STAR for radon and RnDP.18 5.3.1 General.18 5.3.2 Technical characteristics of STAR containers.18 5.3.3 RnDP sources.18 5.3.4 RnDP analysis and control.19 5.3.5 Sampling flow rate of equipment under test.19 5.3.6 Analysis and control of climatic parameters.20 6 Requirements for the reference atmosphere provided by STAR.20 6.1 General.20 6.2 Reference conditions.20 6.3 Influence quantities.21 6.3.1 General.21 6.3.2 Temperature.22 6.3.3 Relative humidity.22 6.3.4 Atmospheric pressure.22 6.3.5 Ambient gamma field.23 6.3.6 Working range for exposure to RnDP.23 6.3.7 Working range for aerosols.23 6.3.8 Exposure time for the instrument under test.23 7 Calibration and traceability of measurement methods and instruments used in a STAR.23 7.1 Traceability chains.23 7.2 Quality assurance.24 Annex A (informative)
Characteristics of atmospheres that can be simulated in a STAR.25 SIST EN 61577-4:2015

61577-4 © IEC:2009 – 3 – Bibliography.27
Figure 1 – Components of a STAR: general case.13 Figure 2 – Minimum requirements for a STAR.14 Figure 3 – Dynamic mode of operation of a STAR.15
Table 1 – Reference and standard test conditions.21 Table 2 – Tests with variation of the influence quantities.21 Table A.1 – Atmosphere characteristic ranges (typical values).26
– 4 – 61577-4 © IEC:2009 INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
RADIATION PROTECTION INSTRUMENTATION –
RADON AND RADON DECAY PRODUCT MEASURING INSTRUMENTS –
Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 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 61577-4 has been prepared by subcommittee 45B: Radiation protection instrumentation, of IEC technical committee 45: Nuclear instrumentation. The text of this standard is based on the following documents: FDIS Report on voting 45B/598/FDIS 45B/606/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. SIST EN 61577-4:2015

61577-4 © IEC:2009 – 5 – A list of all parts of the 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 maintenance result 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 – 61577-4 © IEC:2009 INTRODUCTION Radon is a radioactive gas produced by the decay of 226Ra, 223Ra and 224Ra, respectively decay products of 238U, 235U and 232Th which are present in the earth's crust. By decay, radon isotopes (i.e. 222Rn, 219Rn, 220Rn) produce three decay chains, each ending in a stable lead isotope.
NOTE In normal conditions, due to the very short half-life of 219Rn, its activity and the activity of its RnDP1 are considered negligible compared to the activity of the two other series. Its health effects are therefore not important. Thus in this standard 219Rn and its decay products are not considered. Radon isotopes and their corresponding short-lived Radon Decay Products (RnDP) (i.e. 218Po, 214Pb, 214Bi, 214Po for 222Rn, and 216Po, 212Pb, 212Bi, 212Po, 208Tl for 220Rn) are of considerable importance, as they constitute the major part of the radiological exposure to natural radioactivity for the general public and workers. In some workplaces, for instance in underground mines, spas and waterworks, the workers are exposed to very significant levels of RnDP. These radionuclides are present in variable quantities in the air, in a gaseous form for the radon isotopes, and as very fine particles for the decay products. It is worthwhile for health physicists to be able to measure with a great accuracy the level of this kind of natural radioactivity in the atmosphere. Because the very particular behaviour of these radioactive elements in the atmosphere and in the corresponding measuring instruments, it is necessary to formalize the way such instruments could be tested. Remark: In order to facilitate its use, the IEC 61577 series is divided into the following different parts: IEC 61577-1: This emphasizes the terminology and units of the specific field of radon and radon decay products (RnDP) measurement techniques and presents briefly the concept of System for Test Atmospheres with Radon (STAR) used for test and calibration of radon and RnDP measuring devices.
IEC 61577-2: This part is dedicated to the tests of 222Rn and 220Rn measuring instruments. IEC 61577-3: This part is dedicated to the tests of RnDP222 and RnDP220 measuring instruments. IEC 61577-4: Details how a STAR is constructed and how it can be used for testing.
——————— 1
RnDP is the acronym of Radon Decay Products and it is equivalent to Radon Progeny (see
[1] in the Bibliography). SIST EN 61577-4:2015

61577-4 © IEC:2009 – 7 – RADIATION PROTECTION INSTRUMENTATION –
RADON AND RADON DECAY PRODUCT MEASURING INSTRUMENTS –
Part 4: Equipment for the production of reference atmospheres containing radon isotopes and their decay products (STAR)
1 Scope and object The IEC 61577 series covers the general features concerning test and calibration of radon and radon decay products measuring instruments. It is also intended to help define type tests, which have to be conducted in order to qualify these instruments. These type tests are described in IEC 61577-2 and IEC 61577-3. This standard addresses only the instruments and associated methods for measuring isotopes 220 and 222 of radon and their subsequent short-lived decay products in gases. IEC 61577-4 concerns the System for Test Atmospheres with Radon (STAR) needed for testing, in a reference atmosphere, the instruments measuring radon and RnDP. The clauses that follow do neither claim to solve all the problems involved in the production of equipment for setting up reference atmospheres for radon and its decay products, nor to describe all the methods for doing so. They do however set out to be a guide enabling those faced with such problems to choose the best methods for adoption in full knowledge of the facts. 2 Normative references
The following referenced documents are indispensable for the application 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. IEC 60050-111:1996, International Electrotechnical Vocabulary (IEV) – Chapter 111: Physics and chemistry
IEC 60050-393:2003, International Electrotechnical Vocabulary (IEV) – Part 393: Nuclear instrumentation – Physical phenomena and basic concepts IEC 60050-394:2007, International Electrotechnical Vocabulary (IEV) – Part 394: Nuclear instrumentation – Instruments, systems, equipment and detectors IEC 61577 (all parts), Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. – Equipment for testing, measuring or monitoring of protective measures ISO/IEC Guide 99:2007, International vocabulary of metrology – Basic and general concepts and associated terms (VIM) ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories ICRP 32: Annals of the ICRP, Publication N° 32, Limits for inhalation of Radon Daughters by Workers, Vol. 6, N°1, 1981, Pergamon Press ICRP 38: Annals of the ICRP, Publication N° 38, Radionuclides transformations, Energy and Intensity of Emissions, Vol. 11 - 13, 1983, Pergamon Press SIST EN 61577-4:2015

– 8 – 61577-4 © IEC:2009 ICRP 65: Annals of the ICRP, Publication N° 65, ICRP Publication 65: Protection Against Radon-222 at Home and at Work, Vol. 23/2, 1994, Pergamon Press 3 Terms, definitions and units For the purposes of this document, the following terms, definitions and units apply. Throughout the whole standard, the term RADON is used to denote all the radon isotopes, which are covered by this standard. When a particular isotope is to be referred to, it will be indicated by its chemical symbol preceded by its mass number (e.g. 220Rn, 222Rn). For historical reasons, 220Rn is also called thoron. The term RADON DECAY PRODUCTS or its abbreviation (RnDP) denotes the whole set of short-lived decay products, which are concerned by this standard. A particular isotope is indicated by its chemical symbol preceded by its mass number. The subscripts 222, 220 added to the symbol RnDP refer to the whole set of short-lived decay products of the corresponding radon isotope (218Po, 214Pb, 214Bi, 214Po), (216Po, 212Pb, 212Bi, 212Po, 208Tl). All the nuclear data used in this standard refers to ICRP 38, as this standard applies mainly to instruments used for radiation protection purposes. 3.1 General terms and definitions 3.1.1
activity
A
quotient, for an amount of radionuclide in a particular energy state at a given time, of dN by dt, where dN is the expectation value of the number of spontaneous nuclear transitions from this energy state in the time interval of duration dt:
tNAdd=
NOTE This quantity is expressed in becquerels (Bq). [IEV 393-14-12] 3.1.2
volumic activity activity concentration CA
quotient of the activity by the total volume of the sample NOTE 1 For a gas, it is necessary to indicate the temperature and pressure conditions for which the volumic activity, expressed in becquerel per cubic metre, is measured, for example standard temperature and pressure (STP). NOTE 2 This quantity is expressed in becquerels per cubic metre (Bq·m–3). [IEV 393-14-16] 3.1.3
primary standard
standard that is designed or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity NOTE The concept of primary standard is equally valid for base quantities and derived quantities. [VIM, 5.4, modified] SIST EN 61577-4:2015

61577-4 © IEC:2009 – 9 – 3.1.4
secondary standard
standard whose value is assigned by comparison with a primary standard of the same quantity
[VIM, 5.5, modified] 3.1.5
reference standard
standard generally having the highest metrological quality available at a given location or in a given organization, from which measurements made there are derived
[VIM, 5.6, modified] 3.1.6
mass flow rate (kg·s–1) mass of a gas flowing in a conduit during a unit time
3.1.7
volume flow rate
(m3·s–1) volume of gas flowing in a conduit during a unit time
3.1.8
aerosol
set of solid or liquid particles in suspension in a gaseous medium
NOTE The range of particle diameter is generally from a few nanometres up to 10 m.
[IEV 393-11-37]
3.1.9
homogeneous
qualifies a physical medium in which the relevant properties are independent of the position in the medium
[IEV 111-13-08] 3.1.10
conventionally true value of a quantity
vc value attributed to a particular quantity and accepted, sometimes by convention, as having an uncertainty appropriate for a given purpose
NOTE "Conventionally true value of a quantity" is sometimes called assigned value, best estimate of the value, conventional value or reference value.
[IEV 394-40-10] 3.2 Specific terms and definitions 3.2.1
Potential Alpha Energy
PAE or
εp
total alpha energy emitted during the decay of RnDP atoms along the decay chain through to 210Pb or 208Pb respectively for the decay chains of the 222Rn and 220Rn εp 222 =[(6,003 + 7,687)×N218Po+7,687×(N214Pb+N214Bi)+7,687 × N214Po]×1,602×10–13 (J) εp 220 =[(6,779 + 7,804)×N216Po+7,804×(N212Pb+N212Bi)+8,785 × N212Po]×1,602×10–13 (J) SIST EN 61577-4:2015

– 10 – 61577-4 © IEC:2009 where N is the number of atoms NOTE 1 The 7,804 MeV alpha energy corresponds to a virtual alpha emission due to the branching ratio of 212Bi. NOTE 2 Annual Limits of Intake (ALI) can be expressed in the term of PAE222 and PAE220. For this reason, PAE222 and PAE220 are used as health risk indicator. [ICRP 32] 3.2.2
Potential Alpha Energy Concentration PAEC or cp
concentration of any mixture of short-lived radon decay products in air in terms of the alpha energy released during decay through 210Pb or 208Pb NOTE This quantity is expressed in the SI unit J·m–3. [ICRP 32] 3.2.3
Potential alpha energy exposure Pp(T)
time integral of the potential alpha energy concentration in air, cp, to which an individual is exposed over a given time period T, e.g. one year ∫=TdttcTP).()(pp NOTE This quantity is expressed in the SI unit J·m–3·h. [ICRP 65] 3.2.4
equilibrium equivalent concentration ceq
activity concentration of radon, in radioactive equilibrium with its short-lived decay products that has the same potential alpha energy concentration as the non-equilibrium mixture to which the ceq refers
NOTE This quantity is expressed in the SI unit Bq·m–3. [ICRP 32] 3.2.5
equilibrium factor F
ratio of equilibrium equivalent concentration to the radon gas concentration CcFRneq= [ICRP 65] 3.2.6
emanating power (or emanation coefficient) ratio between the number of radon atoms (n) transferred to the pore space of the material and the number (N) of radon atoms present in the material itself, including the pores’ space SIST EN 61577-4:2015

61577-4 © IEC:2009 – 11 – τ=nN 3.2.7
emanation rate value of the activity of radon atoms leaving a material per unit mass per unit time NOTE This is expressed in Bq·kg–1·s–1. 3.2.8
deconvolution mathematical treatment of a set of data resulting from a measurement (i.e. counted events) allowing, through the use of a particular set of equations, to get the value of the original quantity to be measured 3.2.9
Activity Median Aerodynamic Diameter
AMAD [2]2 median of the activity distribution of diameters of the unit density (kg·m–3) spheres that have the same settling velocity as the aerosol particle concerned 3.2.10
Activity Median Thermodynamic Diameter
AMTD median of the activity distribution of diameters of the unit density (kg·m–3) spheres that have the same thermodynamic properties as the aerosol particle concerned 3.2.11
unattached fraction of PAEC
fraction of the potential alpha energy concentration of short-lived RnDP that is not attached to the ambient aerosol NOTE The particle size concerned is in the order of magnitude of nm. [ICRP 65] 3.2.12
attached fraction fraction of the potential alpha energy concentration of short-lived RnDP that is attached to the ambient aerosol. NOTE The sizes of the carrier aerosol, to which most of RnDP are attached, are generally in the 0,1 μm to 0,3 μm range. 3.2.13
grab sampling
collection of a sample (e.g. of air containing radon or aerosol particles) during a period considered short compared with the fluctuations of the quantity under study (e.g. volumic activity of the air) 3.2.14
continuous method
method which ensures a continuous recording of the parameter to be measured, over a defined period of time, and with a time resolution adapted to the phenomenon to be studied ——————— 2
Numbers in brackets refer to the bibliography. SIST EN 61577-4:2015

– 12 – 61577-4 © IEC:2009 3.2.15
integrating method method that relies on the measurement of the integral over a defined sampling and measurement time of the quantity under study 3.2.16
passive sampling sampling that applies to instruments using no active device like pumps for sampling the atmosphere NOTE In this case, the sampling is in most instruments mainly made by diffusion. 3.2.17
active sampling sampling applies to instruments using active devices like pumps for sampling the atmosphere 3.2.18
reference source
radioactive secondary standard source for use in the calibration of the measuring instrument
[IEV 394-40-19] 3.2.19
reference atmosphere radioactive atmosphere in which the influencing parameters (aerosols, radioactivity, climatic conditions, etc.) are sufficiently well-known or controlled to allow its use in a testing procedure for radon or RnDP measuring instruments. The parameter values concerned are traceable to recognized standards 3.2.20
System for Test Atmospheres with Radon STAR
system that designates the equipment needed for the creation and the use of a reference atmosphere 3.2.21
High Efficiency Particulate Air filters (HEPA filters) filters used for the aerosol collection, with a minimum efficiency of 99,97 % for particle size of 0,3 μm 3.3 Units and conversion factors This standard uses the International System of Units (SI).
NOTE The following "non-standard" units are still sometimes used: Curie (Ci), a unit of activity: 1 Ci = 3,7 × 1010 Bq MeV·l–1, a unit of potential alpha energy concentration 1 MeV·l–1 = 1,6 × 10–4 μJ·m–3 The following conversion factors are given for information: Working Level (WL), a quantity of volume potential alpha energy 1 WL = 20,8 μJ·m–3 Working Level Month (WLM), a quantity of exposure to potential alpha energy 1 WLM = 3,6 mJ·h·m–3 - A 222Rn activity concentration of 1 Bq·m–3
in equilibrium with its RnDP222, is equivalent to a Potential Alpha Energy,Concentration, PAEC222 of 5,62 × 10–9 J⋅m–3 . - A 220Rn activity concentration of 1 Bq.m–3
in equilibrium with its RnDP220, is equivalent to a Potential Alpha Energy,Concentration, PAEC220 of
75,8 × 10–9 J⋅m–3 .
61577-4 © IEC:2009 – 13 – 4 General description of a System for Test Atmospheres with Radon (STAR) 4.1 General
The need for a reference atmosphere arises from the necessity for a complete and standardized testing, under controlled conditions, of the measuring instruments concerned. The various examples illustrated indicate a need for a test facility related directly to the elements to be measured. Such a facility will consist of four inseparable parts: – the equipment for producing the atmosphere; – the equipment for containing the atmosphere; – the reference atmosphere thus created; – the equipment and methods for monitoring this atmosphere. Equipment used to characterise the atmosphere shall be traceable to a primary standard. In order to simplify the text of this standard, such a system is referred to as a "STAR" (an acronym for System for Test Atmospheres with Radon).
The Figure 1 shows the general components of a complete STAR. It is also called “Radon Chamber”; however, this term does not imply the same integrated concept.
STARContainer Reference
atmosphere Instrument under test Reference radon measuring instruments Reference RnDP measuring instruments Reference aerosol measuring instruments Reference climatic parameter measuring instruments Reference flow rates measuring instrument Aerosol generation system Climatic conditioning system Radon source
Traceability to a reference standard For RnDP tests Not always necessary IEC
270/09
Figure 1 – Components of a STAR: general case In some cases, a STAR may comprise only parts of the complete scheme. As an example, STAR used only for testing radon instruments, which are not affected by aerosols and RnDP in the atmosphere, do not need special equipment for controlling quantities relating to these effects. Figure 2 illustrates this minimum configuration. SIST EN 61577-4:2015

– 14 – 61577-4 © IEC:2009
STARContainer Reference
atmosphere Instrument under test Reference radon measuring instruments Reference climatic parameter measuring instruments Radon source
Traceability to a reference standard IEC
271/09
Figure 2 – Minimum requirements for a STAR The equipment used for containing the reference atmosphere can be classified into two main categories: – large containers (internal volume of several m3), often designed as "walk in", allow the equipment to be handled inside it, by operators;
– small containers only for the equipment under test.
4.2 Mode of operation of a STAR 4.2.1 Static mode of operation
With the static mode of operation, the conditions inside the container are settled at the beginning of the operation.
The radon sources are placed inside or outside the container. The static mode of operation may include the use of an internal fan for the purpose of homogenisation of the atmosphere. NOTE Containers for static mode of operation are relatively simple to set up and to use, and they enable a diverse set of atmospheres to be created and manipulated. However, there are only limited possibilities when it comes to controlling the internal conditions (atmospheres, aerosols, etc.). 4.2.2 Dynamic mode of operation With the dynamic mode of operation, atmosphere conditions in the container can be controlled and modified during the exposition of the apparatus to be tested. Dynamic mode of operation always incorporates some method of renewing, totally or partially, the internal atmosphere (Figure 3). Dynamic mode can be used in two ways (Figure 3): – with a closed loop (recirculation of the atmosphere), – with an open loop (partial or total evacuation). SIST EN 61577-4:2015

61577-4 © IEC:2009 – 15 –
Instruments under testExhaust Open loop Closed loop ContainerFlow ratemeter Aerosol source 222Rn and/or 220Rn source
Air inlet Flow ratemeter IEC
272/09
Figure 3 – Dynamic mode of operation of a STAR
The radon sources are generally located outside the container, thus allowing some control, or at least a continuous monitoring, of the internal conditions. The aerosol source is located inside or outside the container. The use of an open-air circuit may have influence on the radioactive releases to the environment. The closed loop is used to control the aerosol concentration or the equilibrium factor in the container. The different modes of operation of a STAR may involve various air-flow conditions that influence the homogeneity or the behaviour of RnDP: a) Convection
Convection shall be taken into account in static or very low air exchange rate conditions. This phenomenon may, in these experimental conditions, modify the homogeneity of the STAR atmosphere. b) Forced air movement Forced air movement may have an influence on aerosol behaviour, mainly by turbulent diffusion and impaction phenomena, leading to changes in the deposition of RnDP on surfaces (walls, instrument, etc.). It may also be important for the homogeneity of the atmosphere. Air exchange rates have a strong influence on the RnDP concentration in the reference atmosphere. 5 Characteristics of a STAR 5.1 General This clause describes the characteristics for STARs dedicated to radon reference atmosphere and, for STARs dedicated to radon and RnDP reference atmosphere. SIST EN 61577-4:2015

– 16 – 61577-4 © IEC:2009 5.2 STAR for radon
5.2.1 General This type of STAR shall be used only for testing instruments that do not depend on aerosol parameters. Therefore, instruments measuring radon with an open detector cannot be tested with this STAR.
5.2.2 Technical characteristics of STAR containers A STAR container shall be sufficiently leak proof: – to ensure safety through the effective confinement of any radioactivity it might contain; – to prevent any unforeseen change due to leakage of the reference atmosphere. If, in addition, the container is to be provided with means for carrying out tests under pressure, it shall withstand the internal pressure required for such tests and be in conformity with all relevant regulations related to pressure vessels. The walls shall be thermally insulated (for example with Rth > 3 m2·K·W–1) when tests with variation of temperature and humidity, according to Table 2, are conducted. Where the atmosphere in the container is to be continuously renewed, its internal shape should be designed so as to avoid badly ventilated "dead" zones capable of leading to a non-uniform distribution of activities throughout the volume. Such a design might also facilitate the processes of evacuation and decontamination of the atmosphere. The internal walls of the container should be made of a smooth material which cannot corrode and is a good electrical conductor. These qualities not only facilitate decontamination and limit the trapping of aerosols by diffusion to a minimum, but they also prevent any stray collection of RnDPs through electrostatic effects. Whatever the type of container used, the manipulation of equipment during tests shall as far as possible be carried out from the outside, either by remote control or by the use of glove apertures so as to cause the least possible disturbance to the internal conditions. For the same reason, the largest containers should be fitted with an airlock, both for the introduction of instruments and for the entrance and exit of operators. The electricity supply should be stable both in voltage and frequency and should provide sufficient power. NOTE A suitable location shall be available to store passive integrating detectors where the radon level is minimal. 5.2.3 Radon sources 5.2.3.1 Solid sources Solid sources generally consist of a salt of 226Ra or 228Th to generate 222Rn and 220Rn, respectively. The salt may be pure or it may be mixed with, or trapped on a matrix. The nature of the material will determine the value of the emanating power and of emanation rate and thus the capacity of the source to supply large amounts of radon. The emanation rate should be constant. But, since the emanating power is highly dependent on certain physical parameters (relative humidity, etc), the use of such sources will require considerable precautions to be taken (control of temperature, humidity, etc). Nevertheless, these sources are very widely used because of easily handling. SIST EN 61577-4:2015

61577-4 © IEC:2009 – 17 – NOTE Some other solid sources are simply constructed using uranium or thorium ore or tailings packed in a closed container; although this kind of source may be cheap to build and easy to operate, its stability is difficult to obtain. 5.2.3.2 Liquid sources Liquid sources generally consist of an acid solution of a salt of 226Ra or 228Th in order to obtain 222Rn or 220Rn, respectively. After a time that depends on the half-life of the radon isotope in question, the daughters are in secular equilibrium with the parent nuclide forming the source. By careful degassing of the solution, it is then possible to recover the radon formed either: – in a single operation, or – continuously. In the latter case, a simple calculation enables the radon flow rate to be obtained in terms of the activity of the source and the flow rate of the carrier gas. The main application of these types of sources is the calibration of the reference instruments. Precaution shall be taken to avoid contamination risks. Permeation capsules containing 226Ra in solution with a certified emanation rate are also used for calibration purposes. 5.2.3.3 Gaseous sources Ampoules containing radon are also used as a gaseous source for generation of the STAR atmosphere. Properly calibrated radon sources in glass bulbs or stainless steel containers can be used for the standardisation of the STAR atmosphere [3, 4, 14].
NOTE Using this type of source, care shall be taken to ensure the complete transfer of the radon contained in the ampoule. Standard 222Rn gas sources are available to be used for calibration purposes. 5.2.4 222Rn
and 220Rn analysis and control
The radon activity concentration in a STAR is chosen according to the mode of operation. This radon activity concentration in the STAR container can be: – kept at a constant level; – modified in order to reach several constant levels; – allowed to decrease with radon decay constant after injection of the radon activity in the container; – allowed to increase until a plateau is reached.
The means used to analyse the radioactivity of the STAR will be chosen according to the tests that are planned. The conventionally true value of radon activity concentration of the reference atmosphere is traceable to national or international standards.
Auxiliary measuring equipment, if possible traceable to reference standards, will be added according to the tests to be carried out.
If, for example, a significant quantity to be investigated is the gamma radiation, an instrument for measuring this type of radiation will then be required. In order to compare the conventionally true value of the radon activity concentration with the v
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