BS ISO 11665-4-2012 Measurement of radioactivity in the environment Air radon-222 Integrated measurement method for determining average activity concentration using passive samplin.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 11665-4:2012Measurement of radioactivityin the environment Air:radon-222Part 4: Integrated measurement method fordetermining average activity concentrationusing passive sa

2、mpling and delayed analysisBS ISO 11665-4:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11665-4:2012.The UK participation in its preparation was entrusted to TechnicalCommittee NCE/2, Radiation protection and measurement.A list of organizations represent

3、ed on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 63932

4、 6ICS 13.040.01; 17.240Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2012.Amendments issued since publicationDate Text affectedBS ISO 11665-4:2012 ISO 20

5、12Measurement of radioactivity in the environment Air: radon-222 Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysisMesurage de la radioactivit dans lenvironnement Air: radon 222 Partie 4: Mthode de mesure intgre pour la dt

6、ermination de lactivit volumique moyenne du radon avec un prlvement passif et une analyse en diffrINTERNATIONAL STANDARDISO11665-4First edition2012-07-15Reference numberISO 11665-4:2012(E)BS ISO 11665-4:2012ISO 11665-4:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All ri

7、ghts 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 ISO at the address below or ISOs member body in the country of t

8、he requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 11665-4:2012ISO 11665-4:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative

9、 references . 13 Terms, definitions and symbols 13.1 Terms and definitions . 13.2 Symbols . 14 Principle . 25 Equipment . 36 Sampling 36.1 Sampling objective . 36.2 Sampling characteristics . 36.3 Sampling conditions . 37 Detection 48 Measurement 48.1 Procedure 48.2 Influence quantities 48.3 Calibra

10、tion . 59 Expression of results . 59.1 Average radon activity concentration 59.2 Standard uncertainty 59.3 Decision threshold and detection limit . 59.4 Limits of the confidence interval . 510 Test report . 6Annex A (normative) Measurement method using a solid-state nuclear track detector (SSNTD) .

11、7Annex B (normative) Measurement method using an electret detector 12Annex C (normative) Measurement method using activated charcoal 20Bibliography .28BS ISO 11665-4:2012ISO 11665-4:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standard

12、s 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 organiz

13、ations, 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.International Standards are drafted in accordance with the rules given in t

14、he ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of

15、the member bodies casting a vote.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.ISO 11665-4 was prepared by Technical Committee ISO/TC 85, Nuclear en

16、ergy, nuclear technologies, and radiological protection, Subcommittee SC 2, Radiological protection.ISO 11665 consists of the following parts, under the general title Measurement of radioactivity in the environment Air: radon-222: Part 1: Origins of radon and its short-lived decay products and assoc

17、iated measurement methods Part 2: Integrated measurement method for determining average potential alpha energy concentration of its short-lived decay products Part 3: Spot measurement method of the potential alpha energy concentration of its short-lived decay products Part 4: Integrated measurement

18、method for determining average activity concentration using passive sampling and delayed analysis Part 5: Continuous measurement method of the activity concentration Part 6: Spot measurement method of the activity concentration Part 7: Accumulation method for estimating surface exhalation rate Part

19、8: Methodologies for initial and additional investigations in buildingsThe following parts are under preparation: Part 9: Method for determining exhalation rate of dense building materials Part 10: Determination of diffusion coefficient in waterproof materials using activity concentration measuremen

20、tiv ISO 2012 All rights reservedBS ISO 11665-4:2012ISO 11665-4:2012(E)IntroductionRadon isotopes 222, 220 and 219 are radioactive gases produced by the disintegration of radium isotopes 226, 224 and 223, which are decay products of uranium-238, thorium-232 and uranium-235 respectively, and are all f

21、ound in the earths crust. Solid elements, also radioactive, followed by stable lead are produced by radon disintegration1.When disintegrating, radon emits alpha particles and generates solid decay products, which are also radioactive (polonium, bismuth, lead, etc.). The potential effects on human he

22、alth 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.Radon is today considered to be the main source

23、 of human exposure to natural radiation. The UNSCEAR (2006) report2suggests 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

24、 considered negligible. For this reason, references to radon in this part of ISO 11665 refer only to radon-222.Radon activity concentration can vary by one to multiple orders of magnitude over time and space. Exposure to radon and its decay products varies tremendously from one area to another, as i

25、t depends firstly on the amount of radon emitted by the soil and the building materials in each area and, secondly, on the degree of containment and weather conditions in the areas where individuals are exposed. Human exposure to radon is mainly linked to habitat and workplace. Long-term integrated

26、measurement methods are applicable in assessing human exposure to radiation3. For reasons of cost and ease of use, long-term measurements (over a period of several months) are only performed with passive sampling45.The values commonly found in the continental environment are usually between a few be

27、cquerels per cubic metre and several thousand becquerels per cubic metre. Activity concentrations of one becquerel per cubic metre or less can be observed in the oceanic environment. Mean annual values of radon activity concentrations inside houses can vary from several tens of becquerels per cubic

28、metre to several thousands of becquerels per cubic metre2. Activity concentrations can reach several thousands of becquerels per cubic metre in very confined spaces.The activity concentration of radon-222 in the atmosphere can be measured by spot, continuous and integrated measurement methods with a

29、ctive or passive air sampling (see ISO 11665-1). This part of ISO 11665 deals with radon-222 integrated measurement techniques with passive sampling.NOTE The origin of radon-222 and its short-lived decay products in the atmospheric environment and other measurement methods are described generally in

30、 ISO 11665-1. ISO 2012 All rights reserved vBS ISO 11665-4:2012BS ISO 11665-4:2012Measurement of radioactivity in the environment Air: radon-222 Part 4: Integrated measurement method for determining average activity concentration using passive sampling and delayed analysis1 ScopeThis part of ISO 116

31、65 describes radon-222 integrated measurement techniques with passive sampling. It gives indications for determining the average activity concentration of the radon-222 in the air from measurements based on easy-to-use and low-cost passive sampling, and the conditions of use for the sensors.This par

32、t of ISO 11665 covers samples taken without interruption over periods varying from a few days to one year.This measurement method is applicable to air samples with radon activity concentrations greater than 5 Bq/m3.2 Normative referencesThe following referenced documents are indispensable for the ap

33、plication 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 shor

34、t-lived decay products and associated measurement methodsISO 11929, Determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measurements of ionizing radiation Fundamentals and applicationISO/IEC 17025, General requirements for the co

35、mpetence of testing and calibration laboratoriesIEC 61577-1, Radiation protection instrumentation Radon and radon decay product measuring instruments Part 1: General principles3 Terms, definitions and symbols3.1 Terms and definitionsFor the purposes of this document, the terms and definitions given

36、in ISO 11665-1 apply.3.2 SymbolsFor the purposes of this document, the symbols given in ISO 11665-1 and the following apply.C average activity concentration, in becquerels per cubic metreCdecision threshold of the average activity concentration, in becquerels per cubic metreC#detection limit of the

37、average activity concentration, in becquerels per cubic metre INTERNATIONAL STANDARD ISO 11665-4:2012(E) ISO 2012 All rights reserved 1BS ISO 11665-4:2012ISO 11665-4:2012(E)Clower limit of the confidence interval of the average activity concentration, in becquerels per cubic metreCupper limit of the

38、 confidence interval of the average activity concentration, in becquerels per cubic metretsampling duration, in hoursUexpanded uncertainty calculated by Uku=() with k = 2u()standard uncertainty associated with the measurement resulturel() relative standard uncertainty quantity to be measured0backgro

39、und level correction factor linked to the calibration factor and the sampling duration4 PrincipleIntegrated measurement of the average radon activity concentration is based on the following elements:a) continuous, passive sampling of an air sample representative of the atmosphere under investigation

40、, by free convection and natural diffusion for a sensor in an open configuration (open to the air) or by natural diffusion for a sensor in a closed configuration (with an accumulation chamber);b) simultaneous accumulation of a measurable physical quantity (etched tracks, electric charges, radioactiv

41、e atoms, etc.) on a suitable sensor;c) measurement of the accumulated physical quantity with a direct link to the average radon activity concentration over the sampling period in question.Several measurement methods meet the requirements of this part of ISO 11665. They are basically distinguished by

42、 the type of accumulated physical quantity and how it is measured. The physical quantity and its related measurement may be as follows, for example: “latent tracks” produced in a polymer solid-state nuclear track detector (SSNTD) by ionization from alpha particles of the radon and its decay products

43、; these latent tracks are detected and counted (see Annex A); charges produced in a solid semi-conductor medium (silicon) by ionisation from alpha particles of the radon and its decay products; they are detected by related electronics; discharge of an electret (non-rechargeable, positively charged e

44、lement) by ionisation of the air due to the radioactive disintegration of radon and its decay products; the voltage variation relating to this discharge is measured (see Annex B); atoms of 222Rn adsorbed on charcoal; the gamma emission rates of the decay products 214Pb and 214Bi are measured with a

45、gamma spectrometer (see Annex C).NOTE Analysis of the physical quantity might not be immediate and might require laboratory operations.The result of integrated measurement is the exposure of a sensor to radon over the sampling duration in question. The average radon activity concentration is calcula

46、ted by dividing the exposure result by the sampling duration.2 ISO 2012 All rights reservedBS ISO 11665-4:2012ISO 11665-4:2012(E)5 EquipmentThe apparatus shall include the following:a) a sensor which collects the physical quantity (SSNTD, silicon detector, electret detector, activated charcoal, etc.

47、), either alone or with an accumulation chamber made from a conductive plastic material with a known detection volume; in closed configuration, the sensor is placed in a closed accumulation chamber with a filter and in open configuration, the sensor is in direct relation with the atmosphere (no accu

48、mulation chamber);b) a detection system adapted to the accumulated physical quantity.The necessary equipment for each measurement method is specified in Annexes A, B and C respectively.6 Sampling6.1 Sampling objectiveThe sampling objective is to place, without interruption, an air sample representat

49、ive of the atmospheric medium under investigation in contact with the sensor (SSNTD, silicon detector, electret detector, activated charcoal, etc.).6.2 Sampling characteristicsSampling is passive.In the closed configuration, sampling is performed through a filtering medium, thus only radon alpha particles are detected by the sensor (see Clause 5). Sampling shall be performed in conditions that preclude clogging of the filtering medium, which would result in modified measuring conditions. Clogg