1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Non-destructive testing - Leak testing - Calibration of reference leaks for gases (ISO 20486:2017)BS EN ISO 20486:2018National forewordThis British Standard is the UK implementation of EN ISO 20486:2018. It is identical
2、 to ISO 20486:2017. It supersedes BS EN 13192:2002, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does
3、not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 94918 0ICS 19.100Compliance with a British Standard cannot confer immunity from legal obl
4、igations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 20486:2018EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 20486February 20
5、18ICS 19.100 Supersedes EN 13192:2001EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 20486:2018: EAll rights of exploitation in any form and by any means reserv
6、ed worldwide for CEN national MembersNon-destructive testing - Leak testing - Calibration of reference leaks for gases (ISO 20486:2017)Essais non destructifs - Contrle dtanchit - talonnage des fuites de rfrence des gaz (ISO 20486:2017)Zerstrungsfreie Prfung - Dichtheitsprfung - Kalibrieren von Refer
7、enzlecks fr Gase (ISO 20486:2017)This European Standard was approved by CEN on 23 December 2017.CEN 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-d
8、ate lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
9、 under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Form
10、er Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionEN ISO 20486:2018 (E)Eu
11、ropean forewordThis document (EN ISO 20486:2018) has been prepared by Technical Committee ISO/TC 135 “Non-destructive testing“ in collaboration with Technical Committee CEN/TC 138 “Non-destructive testing”, the secretariat of which is held by AFNOR.This European Standard shall be given the status of
12、 a national standard, either by publication of an identical text or by endorsement, at the latest by August 2018, and conflicting national standards shall be withdrawn at the latest by August 2018.Attention is drawn to the possibility that some of the elements of this document may be the subject of
13、patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document supersedes EN 13192:2001.According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Aust
14、ria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spai
15、n, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 20486:2017 has been approved by CEN as EN ISO 20486:2018 without any modification.2BS EN ISO 20486:2018ISO 20486:2017Foreword v1 Scope . 12 Normative references 23 Terms and definitions . 24 Nominal leakage rates
16、 35 Classification of leaks 35.1 Permeation leak . 35.2 Conductance leaks . 35.2.1 Capillary leak 35.2.2 Aperture leak (orifice) 45.2.3 Compressed powder leak . 46 Calibration by comparison . 46.1 Methods A, As, B and Bs. 46.2 Applicability of comparison methods . 46.3 Preparation of leaks and appar
17、atus 56.3.1 Leak detector 56.3.2 Connection to the leak detector 56.3.3 Temperature accommodation 76.4 Measurement 76.4.1 Set-up . 76.4.2 General measurement sequence 76.5 Evaluation for methods A, As, B and Bs(Comparison) . 86.5.1 Determination of leakage rate 86.5.2 Influence factors to measuremen
18、t uncertainty . 97 Volumetric calibration.107.1 Direct flow (Method C) 107.1.1 General. 107.1.2 Equipment 107.1.3 Preparation of leaks and apparatus .107.1.4 Measurement . 117.1.5 Evaluation for Method C (direct flow measurement) .137.2 Leak measurement under water (Method D) 147.2.1 General. 147.2.
19、2 Equipment 147.2.3 Preparation of leaks and apparatus .147.2.4 Measurement . 157.2.5 Evaluation for Method D 167.2.6 Influence factors to measurement uncertainty 177.3 Calibration by (volumetric) gas meter (Method E) 177.3.1 General. 177.3.2 Equipment 187.3.3 Preparation of leaks and apparatus .187
20、.3.4 Measurement . 187.3.5 Evaluation for Method E (gas meter) 187.3.6 Influence factors to measurement uncertainty 197.4 Calibration by pressure change in a known volume (Method F) 197.4.1 General. 197.4.2 Preparation of leaks and apparatus .207.4.3 Measurement . 227.4.4 Special situation in vacuum
21、 chambers 237.4.5 Evaluation for Method F (pressure change) 247.4.6 Influence factors to measurement uncertainty 25 ISO 2017 All rights reserved iiiContents PageBS EN ISO 20486:2018ISO 20486:20177.5 Calibration by volume change at constant pressure (Method G) .257.5.1 Equipment 257.5.2 Preparation o
22、f leaks and apparatus .267.5.3 Measurement . 267.5.4 Evaluation for Method G (volume change at constant pressure)278 General influences .289 Report .2810 Labelling of reference leaks .2911 Handling of reference leaks .2911.1 General 2911.2 Permeation leaks (normally with reservoir fitted the leak ou
23、tlet) .2911.3 Conductance leaks (normally without reservoir) 29Annex A (informative) Calculation of leakage rate decrease due to tracer gas depletion in the reservoir 30Bibliography .32iv ISO 2017 All rights reservedBS EN ISO 20486:2018ISO 20486:2017ForewordISO (the International Organization for St
24、andardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the rig
25、ht to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedure
26、s used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial ru
27、les of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights ident
28、ified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation
29、on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/forew
30、ord.html.This document was prepared by Technical Committee ISO/TC 135, Non-destructive testing, Subcommittee SC 6, Leak testing. ISO 2017 All rights reserved vBS EN ISO 20486:2018This page deliberately left blankNon-destructive testing - Leak testing - Calibration of reference leaks for gases (ISO 2
31、0486:2017)1 ScopeThis document specifies the calibration of those leaks that are used for the adjustment of leak detectors for the determination of leakage rate in everyday use. One type of calibration method is a comparison with a reference leak. In this way, the leaks used for routine use become t
32、raceable to a primary standard. In other calibration methods, the value of vapour pressure was measured directly or calculated over a known volume.The comparison procedures are preferably applicable to helium leaks, because this test gas can be selectively measured by a mass spectrometer leak detect
33、or (MSLD) (the definition of MSLD is given in ISO 20484).Calibration by comparison (see methods A, As, B and Bsbelow) with known reference leaks is easily possible for leaks with reservoir and leakage rates below 107Pam3/s.Figure 1 gives an overview of the different recommended calibration methods.a
34、) Calibration by comparisonINTERNATIONAL STANDARD ISO 20486:2017 ISO 2017 All rights reserved 1BS EN ISO 20486:2018ISO 20486:2017b) Calibration by direct measurementKeyX leakage rate in Pam3/s C Method CA Method A D Method DB Method B E Method EAsMethod AsF Method FBsMethod BsG Method Gnormal range
35、possible rangeFigure 1 Calibration ranges2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest editi
36、on of the referenced document (including any amendments) applies.ISO 20484, Non-destructive testing Leak testing Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 20484 and the following apply.ISO and IEC maintain terminological databases for
37、use in standardization at the following addresses: ISO Online browsing platform: available at https:/www.iso.org/obp IEC Electropedia: available at http:/www.electropedia.org/2 ISO 2017 All rights reservedBS EN ISO 20486:2018ISO 20486:20173.1unknown leakleak having a stable and repeatable leakage ra
38、te of known order of magnitude that can be determined by calibration3.2reference leakcalibrated leak which may be used to calibrate another leakNote 1 to entry: The uncertainty of the reference leak is lower than the required uncertainty of the leak to be calibrated.3.3calibrationset of operations w
39、hich establish, under specified conditions, the relationship between leakage rate values represented by an unknown leak and the corresponding known values of the leakage rateNote 1 to entry: In the case of calibration by comparison, the known values of the leakage rate are represented by a reference
40、 leak.Note 2 to entry: Normally, the result of a calibration is given as the leakage rate value for the reference leak with a standard uncertainty.3.4nominal leakage rateleakage rate of a leak calculated for specified reference conditionsNote 1 to entry: In leak detection, leakage rates are commonly
41、 given in units of pV-throughput (Pam3/s, mbar l/s, Std cm3/min). These are only a precise measure of gas flow if the temperature is given and kept constant. Flow units such as mass flow (g/y) or molar flow (mol/s) are sometimes used to overcome this problem.4 Nominal leakage ratesCalibrated leaks a
42、re only comparable under the same reference conditions. Nominal leakage rates shall be used for comparison. Recommended reference conditions are: Ambient temperature: 20 C Atmospheric exhaust pressure: 1 000 mbar Vacuum exhaust pressure: 100 mbarThe reference inlet pressure is given by the leak rese
43、rvoir pressure or the application requirement.5 Classification of leaks5.1 Permeation leakThis type of leak is normally made with a tracer gas reservoir. It has the best long-term stability but an appreciable temperature coefficient (approximately 3,5 %/K). Typical leakage rates are in the range fro
44、m 1010Pam3/s to 104Pam3/s.5.2 Conductance leaks5.2.1 Capillary leakThis type of leak is available with or without a tracer gas reservoir. It has a low temperature coefficient (approximately 0,3 %/K) but easily blocks if not handled with care. Typical leakage rates are greater than 107Pam3/s. ISO 201
45、7 All rights reserved 3BS EN ISO 20486:2018ISO 20486:20175.2.2 Aperture leak (orifice)Orifices are seldom used as reference leaks in practice, as they are difficult to manufacture and even more prone to blocking than capillaries.NOTE Critical flow orifices are a form of aperture leak that is commonl
46、y found in industry, but are out of the scope of this document.5.2.3 Compressed powder leakThis type of leak uses metal powder compressed into a tube. They are usually offered without reservoir. They are used for routine check of the sensitivity of leak detectors but they are not stable enough to be
47、 used as calibrated leaks. Their suitability depends on how well controlled the storage and operating conditions are, and on the required uncertainty.6 Calibration by comparison6.1 Methods A, As, B and BsThere are two ways of calibrating leaks by comparison with known reference leaks. Both methods r
48、equire the knowledge of the order of magnitude of the leakage rate to be measured. The methods differ in using one or two reference leaks, resulting in different uncertainties of measurement. In the following, the two methods are designated as A and B: Method A: Comparison to one reference leak norm
49、ally with a leakage rate of the same order of magnitude, calibration with vacuum method. Method As: Comparison to one reference leak normally with a leakage rate of the same order of magnitude, calibration with sniffing method. Method B: Comparison to two reference leaks with leakage rates normally lying on either side of the unknown leakage rate, calibration with vacuum method. Method Bs: Comparison to two reference leaks with leakage rates normally lying on either side of the unknown leakage rate. Calibration with sniffin
