ISO INTERNATIONAL STANDARD 20657 First edition 2017-03 Glass in building Heat soaked tempered soda lime silicate safety glass Verre dans la construction - Verre de sécurité de silicate sodocalciquetrempéettraite Reference number IS0 20657:2017(E) International Organization for Standardization @ IS0 2017 =ZHEJIANG INST OF STANDARDIZATION C15956617 vided by IHS under I itted without license from IHS IS0 20657:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org Intenationaibr PrganizationforStandardization icensee-ZHEJIANG INST.OF STANDARDIZRoISQ s1.7 - All rights reserved Not for Resale, 2017/5/16 00:42:41 etworking permitted without license from IHS IS0 20657:2017(E) Contents Page Foreword ..V Introduction. ...vi 1 Scope 2 Normative references 3 Terms and definitions 4 Glass products. 3 5 Manufacturing processes .3 5.1 General. .3 5.2 Tempering process. ? 5.3 Heat soak process cycles .4 5.3.1 Off-line process 5.3.2 In-line process. > 6 Fracture characteristics .8 6.1 General 6.2 Accidental human impact ..8 6.3 Fragmentation. ..8 Dimensions and tolerances ..9 7.1 Nominal thickness and thickness tolerances 9 7.2 Width and length (sizes) ..9 7.2.1 General. .9 7.2.2 Maximum and minimum sizes. .10 7.2.3 Tolerances and squareness .10 7.2.4 Edge deformation produced by vertical tempering .11 7.3 Flatness. .11 7.3.1 General. .11 7.3.2 Measurement of overall bow. ..13 7.3.3 Measurement of wave or roller wave distortion ..14 7.3.4 Measurement of edge lift (only for heat soaked tempered safety glass which was horizontally tempered) .15 7.3.5 Measurement of perimeter deformation of glass produced by air cushion tempering process. .16 7.3.6 Measurement of local distortion (only for heat soaked tempered safety glass which was vertically tempered) ..16 7.3.7 Limitation on overall bow, roller waves and edge lift for heat soaked tempered safety glass which was horizontally tempered. .. 17 7.3.8 Limitation on overall bow, wave and perimeter deformation for heat soaked tempered safety glass manufactured by air cushion process.. ..18 7.3.9 Limitation on overall bow and local distortion for heat soaked tempered safety glass which was vertically tempered .18 7.3.10 Other distortions.. ..18 8 Edge work, holes, notches and cut-outs. ..19 8.1 General .19 8.2 Edge working of glass for tempering .19 8.3 Profiled edges. 20 8.4 Round holes 20 8.4.1 General 20 8.4.2 Diameter of holes. 20 8.4.3 Limitations on position of holes. 20 8.4.4 Tolerances on hole diameters.. 21 8.4.5 Tolerances on position of holes. .22 8.5 Holes/others .23 iii ee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 ed without license from IHS Not for Resale, 2017/5/16 00:42:41