ISO INTERNATIONAL STANDARD 8973 ANSl Internat Doe Sec First edition 1997-07-15 Liguefied petroleumgases--Calculation method for density and vapour pressure Gaz depeétrole liquéfies -Methode de calcul de la masse volumique etde lapressiondevapeur ISo Referencenumber ISO 8973:1997(E) ISO8973:1997(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, governmental and non- governmental, in liaison with iSO, also take part in the work. Iso collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 8973 was prepared by Technical Committee iSo/Tc28,Petroleumproductsand lubricants. Annex A forms an integral part of this International Standard. Annex B is for information only. ISO1997 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced orutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingand microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56.CH-1211Geneve 20.Switzerland Internet central@iso.ch X.400 C=ch; a=400net; p=iso; O=isocs; S=central Printed in Switzerland ii ISO 8973:1997(E) INTERNATIONALSTANDARDISO Liquefied petroleum gases - Calculation method for density and vapour pressure 1 Scope liquefied petroleum gases (LPG) based on compositional data and density and vapour pressure factors for individual'LPG components. A list of factors is provided in this International Standard. This method is intended for application in specifications of product quality and is not intended for application to quantity measurement in custody transfer (see ISO 6578). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and Iso maintain registersofcurrentlyvalid International Standards. IsO6578:1991, Refrigerated hydrocarbon liquids-Static measurement --- Calculation procedure. 3Definitions For the purpose of this International Standard the following definitions apply 3.1 liquefied petroleum gas (LPG): Hydrocarbon gas that can be stored and/or handled in the liquid phase under moderate conditions of pressure and at ambient temperature. It consists essentially of C3 and C4 alkanes or alkenes, or a mixture of these, contains generally less than 5 % by liquid volume of material of higher carbon number, and has a gauge vapour pressure not exceeding approximately 1 600 kPa at 40 °C. 3.2 density factor: Density, expressed in kilograms per cubic metre, of a component in the liquid phase under its own vapour pressure at a temperature of 15 °c. 3.3 vapour pressure: Vapour pressure, expressed in kilopascals on an absolute basis, i.e. the gauge pressure plus local ambient pressure. 3.4 vapour pressure factor: Absolute vapour pressure, expressed in kilopascals, of a component of the liquid at temperature of 37,8 °C, 40 C, 50 °℃ or 70 C.