NTERNATIONAL STANDARD (ISO) 2975/ VI Measurement of water flow in closed conduits - Tracer methods - Part VI : Transit time method using non-radioactive tracers Mesure de debit de I'eau dans les conduites fermees -- Methodes par traceurs - Partie VI : Methode du temps de transit utilisant des traceurs non radioactifs First edition -- 1977-02-15 UDC 532.574.87 Ref. No. ISO 2975/VI-1977 (E) Descriptors:flowmeasurement,waterflow,pipeflow,tracermethods. Price based on 13 pages Copyright International Organization for Standardization Not for Resale FOREWORD IsO (the International Organization for Standardization) is a worldwide federation of nationai standards institutes (ISO member bodies). The work of developing International Standards is carried out through ISO technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standardsby theIsOCouncil. International Standard ISO 2975/VI was drawn up by Technical Committee ISO/TC 30, Measurement of fluid flow in closed conduits, and was circulated to the member bodies in January 1976. It has been approved by the member bodies of the following countries : Australia Germany Romania Belgium India Turkey Chile Italy United Kingdom Finland Mexico Yugoslavia France Netherlands No member body expressed disapproval of the document. @ International Organization for Standardization, 1977 Printed in Switzerland Not for Resale ted without license from IHS INTERNATIONAL STANDARD ISO 2975/VI-1977 (E) Measurement of water flow in closed conduits -- Tracer methods Part Vl : Transit time method using non-radioactive tracers 0 INTRODUCTION where V is the volume of the conduit between the detector This International Standard is the sixth of a series of positions; standards covering tracer methods of water flow measure- ment in closed conduits. t is the transit time of the labelled fluid particles. The complete series of standards will be as follows : In general, the theoretical condition for the validity of the Part I : General. formula is that the measuring section be "closed to diffusion' : i.e. that the ratio of the local velocity to the -- Part Il : Constant rate injection method using non- longitudinal dispersion coefficient be equal at both ends of radioactive tracers. the measuring section. Part I!! : Constant rate injection method using radio In practice this condition is fulfilled when the conduit has active tracers. a constant cross-section. Part IV : Integration (sudden injection) method The value of t is obtained by measuring the difference in using non-radioactive tracers. abscissae of characteristic points (in theory : centre of gravity, but in practice other characteristic points may be Part V : Integration (sudden injection) method using found, see 5.6) of recorded distributions, corresponding to radioactive tracers. concentration/time distributions or their integrals, obtained - Part VI : Transit time method using non-radioactive at each detection cross-section. The signal from the detec- tracers. tors shall be proportional to the tracer concentration. The value of the proportionality coefficient and hence the - Part Vll : Transit time method using radioactive absolute concentration value need not, however, be known tracers. exactly. 1 SCOPE AND FIELD OF APPLICATION 3 REQUIRED CONDITIONS This Internationa! Standard specifies the transit time 3.1 Tracer of water flow rate in closed conduits. The tracer shall meet the general requirements defined in clause 5 of part 1. 2 PRINCIPLE Sodium chloride is commoniy used as the tracer, mainiy because of the linear relationship between the conductivity Flow-rate measurement by the transit time method of its solutions and concentration over a wide range of concentra