7258 (iSo International Standard INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAA OPTAHW3ALMH HO CTAHAAPTM3AUWM ORGANISATION INTERNATIONALE DE NORMALISATION Polytetrafluoroethylene (PTFE) tubing for aerospace applications - Methods for the determination of the density and relative density de la densité First edition - 1984-06-15 UDC 621.643.29 : 629.7 : 531.75 Ref. No. ISO 7258-1984 (E) ISO 7258-1984 (E) Descriptors : aircraft industry, plastic tubes, tests, determination, density (mass/volume). Price based on 6 pages Copyright International Organization for Standardization Not for Resale Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of developing International interested in a subject for which a technical committee has been authorized 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. 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. International Standard ISO 7258 was developed by Technical Committee ISO/TC 20, Aircraft and space vehicles, and was circulated to the member bodies in December 1981. It has been approved by the member bodies of the foilowing countries : Australia Czechoslovakia Romania Austria Egypt, Arab Rep. of South Africa, Rep. of Belgium France ueds Brazil Germany, F.R. Sweden Canada United Kingdom Italy China Netherlands USA No member body expressed disapproval of the document. @ International Organization for Standardization, 1984 Printed in Switzerland anadz itted without licensefromIHS Not for Resale 1SO 7258-1984 (E) INTERNATIONAL STANDARD Polytetrafluoroethylene (PTFE) tubing for aerospace applications - Methods for the determination of the density and relative density O Introduction 2.2 relative density : The ratio of the mass in air of a given volume of material to the mass in air of an equal volume of a reference material at the same temperature; it is expressed as variations in the physical structure of specimens and in calcula- relative density, t/t C : dt tions of the amount of materiat necessary to fill a given volume. Density is the preferred property relating the mass and volume of an object, specimen or material. These properties may also where t is the temperature in degrees Celsius. For the purpose be useful in determining uniformity among samples or of this International Standard, t is equal to 25 oC. specimens. NOTES Throughout this International Standard, the term "relative density" Scope and field of application 1 should be taken as meaning relative density with respect to water. in This International Standard specifies three methods for the "relative density" when the reference material (see 2.2) is water. determination of the density and relative density of 2 Density in grams per cubic centimetre may be converted to relative polytetrafluoroethyiene (PTFE) tubing used in the manufacture density with respect to water as follows : of medium and high pressure, high temperature, PTFE hose assemblies for aerospace applications : t Method A - Density gradient column method without a preconditioning heating and cooling cycle. where Method B - Displacement of water and determination of d is the relative density: change of weight method. t is the density of the specimen; Method C - Density gradient column method with a d't is the density of water, at temperature t. preconditioning heating and cooling cycle. At a temperature of 25 °C, 0t = 0,997 1 g/cm3. PTFE hose industry for the density or relative density determined by methods A and B. The term "Relative Specific Gravity" is similarly used for the results of method c. Apparatus 3 2 Definitions 3.1 Methods A and C density : The mass per unit volume of material at t oC 2.1 3.1.1 D