ISO INTERNATIONAL STANDARD 3171 Second edition 1988-12-01 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAA OPIAHW3ALM NO CTAHAAPTM3ALMM Petroleum liquids - Automatic pipeline sampling Produits petroliers liquides -- Echantillonnage automatique en oleoduc Reference number ISO 3171 : 1988 (E) ISO 3171 : 1988 (E) Foreword Iso (the International Organization for Standardization) 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 right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IsO collaborates closely with the International Electrotechnical Commission (lEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 3171 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants. This second edition cancels and replaces the first edition (ISO 3171 : 1975) of which it constitutes a technical revision. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. International Organization for Standardization, 1988 ? Printed in Switzerland ii ISO 3171 : 1988 (E) Contents Page Introductior Scopeandfieldof application References 2 2 Definitions 2 3 Principles 4 Selection of sampling point (including stream conditioning) 6 5 6 Profile testing. 7 Sampling probe design. 9 Sampler design and installatiom? 9 8 Control equipment 10 9 Flow measurement 10 11 Sample receivers and containers . 12 11 13 12 Sample handling Safety precautions 15 13 Operating procedures 15 14 15 Proving the sampling system . 17 Estimation of overall sampling system uncertainty . 20 16 17 Bibliography. 23 Annexes Estimating water-in-oil dispersion . 32 A Example of water concentration profile:tests at a crude oil terminal , 51 B Guide for initial screening of potential sampling locations . 54 C