558 International Standard (ISO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAA OPrAHW3AUMA IO CTAHAAPTW3AUWMORGANISATION INTE RNATIONALE DE NORMALISATION Conditioning and testing - Standard atmospheres Definitions Conditionnementetessais-Atmospheresnormales-Definitions First edition - 1980-09-15 UDC 620.1:551.584.6 Ref.No.ISO 558-1980 (E) ISO558-1980 Price based on2pages No reproduction or networking permitted without license from IHS Not for Resale Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO member bodies). The work of developing Inter- national 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, 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 558 was developed by Technical Committee ISO/TC 125, Enclosures and conditions for testing. It was submitted directly to the Iso Council, in accordance with clause 5.10.1 of part 1 of the Directives for the technical work of ISO. It cancels and replaces ISo Recommen- dation R 558-1967, which had been approved by the member bodies of the following countries : Australia Hungary Portugal Belgium India Romania Brazil Indonesia Sweden Chile Iran Switzerland Czechoslovakia Italy United Kingdom Egypt, Arab Rep. of Japan USA France Mexico USSR Germany, F. R. Netherlands Yugoslavia Greece Norway No member body had expressed disapproval of the document InternationalOrganizationforStandardization,1980 Printed in Switzerland Copyright Internatioal Organizatin for Standadization No reproduction or networking permitted without license from IHS Not for Resale ISO 558-1980 (E) INTERNATIONALSTANDARD Conditioning and testing - Standard atmospheres Definitions 0 Introduction 2 Definitions The determined value of the characteristics of many materials, 2.1 atmosphere : Ambient conditions defined by one or components or equipment is often dependent on the external more of the parameters : influences to which the sample or test piece is exposed. In par- ticular, the influence of temperature, relative humidity and temperature; pressure is important. In case there is a need to obtain results which are significant and, above all, reproducible, i.e. suitable relative humidity: for comparing the characteristics of the material, the compo- nent or the equipment considered,it becomes necessaryto re- pressure. establish identical ambient conditions and hence to control theseparameters. If it is desired either to classify different materials, components or equipment, by quality, or to compare the results of tests 2.2 conditioning atmosphere : The atmosphere in which a carried out on them in different laboratories, it is essential : sample or test piece is kept before being subjected to test. It is a) to bring the samples or test pieces into contact with a parameters temperature, relative humidity and pressure, which standard conditioning atmosphere, i.e. an environment are kept within the prescribed tolerances for a given period of having agreed characteristics (as exactly reproducible as time. possible) of temperature, relative humidity and pressure, for a specified period of time or,if specified, until the samples NOTES or test pieces have reached equilibrium with the condition- ing atmosphere; The term "conditioning" refers to the operation as a whole de- signed to bring a sample or test piece, before testing, into a specified b) to carry out specified tests in a standard test at- condition in relation to temperature and humidity, by keeping it for a given period of time in the conditioning atmosph