ISO INTERNATIONAL STANDARD 20486 First edition 2017-12 Non-destructive testing -Leak testing -Calibration of reference leaks for gases Essais non destructifs-Controle d'étancheite -Etalonnage des fuites deréference des gaz Reference number ISO 20486:2017(E) O ISO 2017 Cagao Not for Resale,12/26/201720:35:53MST ISO20486:2017(E) COPYRIGHTPROTECTEDDOCUMENT O ISO 2017,Published in Switzerland Allrights reserved.Unless otherwise specified,no part of this publication may be reproduced or utilized otherwise in any form written permission.Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester: ISO copyright office Ch.de Blandonnet_8-CP 401 CH-1214.Vernier,Geneva,Switzerland Tel.+41227490111 Fax+41227490947 [email protected] wwwiso.org CoyiniansOrganatdo to Standardaton O ISO 2017-All rights reserved Provided by IHS Markit under licensewihANSl No reproduction or networking permited without licensefrom IHS Not for Resale,12/26/201720:35:53 MST 20486:2017(E) ISO Contents Page Foreword 1 Scope 2 Normative references 3 Terms and definitions 4 Nominal leakage rates 5 Classification of leaks 5.1 Permeation leak 5.2 Conductance leaks 5.2.1 Capillary leak 5.2.2 Aperture leak (orifice) 5.2.3 Compressed powder leak 6 Calibration by comparison 6.1 Methods A. As, Band Bs 6.2 Applicability ofcomparison methods 6.3 of leaks and apparatus Preparation 6.3.1 Leak detector 6.3.2 Connection to the leak detector 6.3.3 Temperature accommodation 6.4 Measurement 6.4.1 Set -ll p .... 6.4.2 General measurement sequence 6.5 Evaluation for methods A, As, Band Bs(Comparison) 6.5.1 Determination of leakage rate 6.5.2 Influence factors to measurement uncertainty 9 Volumetric 7 calibration 7.1 C) 10 Direct flow (Method 7.1.1 General .10 7.1.2 Equipment 10 7.1.3 Preparation of leaks and apparatus 10 7.1.4 Measurement +......+..+..+..++..+....+.+.+.++. 7.1.5 Evaluation for Method C(direct flow measurement) .13 7.2 Leak measurement under water (Method D) 14 7.2.1 General 14 7.2.2 Equipment 7.2.3 Preparation of leaks and apparatus 14 7.2.4 Measurement 15 7.2.5 Evaluation for Method D... 16 7.2.6 Influence factorstomeasurement uncertainty 17 7.3 Calibration by (volumetric )gas meter (Method E) 17 7.3.1 General 7.3.2 Equipment 18 7.3.3 Preparation of leaks and apparatus 18 7.3.4 Measurement 18 7.3.5 Evaluation for Method E (gas meter) 18 7.3.6 Influence factors tomeasurement uncertainty 19 7.4 Calibration by pressure change in aknown volume (Method F). 19 7.4.1 General .19 7.4.2 Preparation of leaks and apparatus .20 7.4.3 Measurement 7.4.4 Special situation in vacuum chambers 23 7.4.5 Evaluation for Method F (pressure change) 25 25 7.4.6 Influence factors to measurement uncertainty Copri HLintematigna 1OnOISO.2017- A Ilrightsreserved ii rp "soSu s tomHs Not for Resale, 12/26/2017 20:35:53MST