International ISo Standard IS04266-3 Petroleum and liquid petroleum Second edition products Measurement of level 2024-10 and temperature in storage tanks by automatic methods - Part 3: Measurement of level in pressurized storage tanks (non-refrigerated) Petroleet produits pétroliers liquides-Mesurageduniveau et delatemperaturedansles reservoirs de stockageparmethodes automatiques- Partie 3: Mesurage du niveau dans les réservoirs de stockage sous pression (nonrefrigérés) Referencenumber ISO 4266-3:2024(en) @ISO2024 IS0 4266-3:2024(en) COPYRIGHTPROTECTEDDOCUMENT @IS02024 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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. ISO copyright office CP 40i: Ch.de Blandonnet 8 CH-1214 Vernier,Geneva Phone: +41 22 749 01 11 Email: copyright@iso.org Website: www.iso.org Published in Switzerland @IS0 2024-All rights reserved ii IS0 4266-3:2024(en) Contents Page Foreword. .V 1 Scope .1 2 Normative reference. .1 3 Terms and definitions .1 4 Precautions. .2 .2 4.1 Safety precautions 4.2 Equipment precautions 4.3 Generalprecautions. ..3 5 Accuracy. 5.1 Intrinsic error of ALGs .3 5.2 Calibrationpriorto installation 5.3 Error caused byinstallation and operating conditions .4 5.4 Overall accuracy ..4 5.4.1 General ..4 5.4.2 Use of ALGs forfiscal/custody transferapplications .4 Installationof ALGs .5 6 .5 6.1 General. 6.2 Mounting location .5 6.3 Manufacturer's requirements ..5 6.4 Installation. .6 6.4.1 InstallationofintrusiveullageALGsmountedonstill-wells ..6 6.4.2 Installation of intrusive ullage ALGs using guide wires .7 6.4.3 Installation of non-intrusiveullage ALGs (e.g.microwave or radar)mounted on still-wells 6.4.4 Location of ALG .10 6.4.5 InstallationofALGsotherthanthosedescribed inthisdocument .10 6.5 Still-well design. ..10 7 Initial setting and initial verification of ALGs in the field .10 7.1 Preparation ..10 7.1.1 Checkingfor critical distances ..10 7.1.2 Checkingforfreemovementoflevel-sensingelementofintrusiveALGs .11 7.1.3 Checking for influences of changes in physical and electrical properties of the product (vapour/liquid). .11 7.2 Initial setting. ..11 7.2.1 General .11 7.2.2 Setting of intrusive ullage ALGs .11 7.2.3 Setting of non-intrusive ALGs. .12 7.2.4 OtherALGsnotdescribed inthisdocument .12 7.3 Initial field verification .12 7.3.1 General 12 7.3.2 Verificationprocedure ..13 7.3.3 Tolerance of initial field verification .13 7.4 Record keeping. ..13 8 Subsequent verification of ALGs ..13 .13 8.1 General. 8.2 Frequency of subsequent verification. .13 8.3 ..14 Procedure 8.4 Tolerance for subsequent verification of ALGs in fiscal/custody transfer application .14 8.5 Comparison of theALGreadingsfrom currentand previousverifications .14 8.6 Adjustmentinsubsequentverification... .15 9 Data communication and receiving .15 IS0 2024-All rights reserved iii