2796 International Standard (ISO INTE RNATIONAL ORGANIZATION FOR STANDARDIZATION+MEXAYHAPOAHAA OPrAHM3ALWA NO CTAHAAPTW3AUWW+ORGANISATION INTE RNATIONALE DE NORMALISATION Cellular plastics, rigid --- Test for dimensional stability Plastiques alveolaires rigides -- Essai de stabilite dimensionnelle Third edition - ‘1986-08-15 UDC 678-405.8 : 531.71 Ref. No. ISO 2796-1986 (E) ISO 2796-1986 (E) Descriptors : plastics, cellular plastics, rigid plastics, tests, dimensional stability tests. Price based on 3 pages Copyright International Organization for Standardization itted without license from IHS Not for Resale 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, aiso 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. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 2796 was prepared by Technical Committee ISO/TC 61, Plastics. This third edition cancels and replaces the second edition (ISO 2796-1980), of which it constitutes a minor 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, 1986 Printed in Switzerland itted withoutlicense from IHS Not for Resale ISO 2796-1986 (E) INTERNATIONAL STANDARD Cellular plastics, rigid -- Test for dimensional stability Scope and field of application Apparatus This International Standard specifies a method for the deter- Temperature or temperature and humidity con- 4.1 mination of dimensional stability of rigid cellular plastics when trolled chamber, capable of maintaining the test specimens subjected to specific conditions of temperature and relative within the specified conditions and within the limits specified in humidity. the procedure (7.2). The method suggests a range of conditions from which one or 4.2 Measuring instruments, capable of measuring linear more of the desired test conditions can be selected. dimensions in accordance with iso 1923. Additional conditions may be used as agreed upon by the pur. chaser and the supplier. Test specimens The term "dimensional stability of a rigid cellular plastic" im- plies the absence of irreversible change in dimensions in each 5.1 Test specimens shall be machined or sawn from the sam- of three directions perpendicular to each other when a test ple so as to have a smooth surface free of cracks. Foam skins specimen of specified size is exposed to stated conditions for a shall be removed, unless otherwise specified. specified period. In practice, such irreversible changes do occur and are measured by the method described in this International Standard. 5.2 The dimensions of the test specimens shall be not less than the following values: 2 References length: 100 ± 1 mm width: 100 ± 1 mm Iso 291, Plastics -- Standard atmospheres for conditioning and testing. 25 ± 0,5 mm thickness: Iso 1923, Cellular plastics and rubbers - Determination of 5.3 A minimum of three test specimens for each sample shall linear dimensions. be used under each set of chosen conditions. 3 Principle Conditioning 6 Determination of the changes of linear dimensions which occur when the test specimens have been subjected to specified en- The test specimens shall be conditioned in one of the standard atmosph