1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 18925:2013Imaging materials Opticaldisc media Storage practicesBS ISO 18925:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 189
2、25:2013. It supersedes BS ISO 18925:2008, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include
3、 all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013.ISBN 978 0 580 80502 8 ICS 35.220.30; 37.040.99 Compliance with a British Standard cannot confer immunityfrom legal obligati
4、ons.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2013.Amendments issued since publicationDate Text affectedBS ISO 18925:2013 ISO 2013Imaging materials Optical disc media Storage practicesMatriaux pour limage Milieux pour disque
5、 optique Pratiques de stockageINTERNATIONAL STANDARDISO18925Third edition2013-02-01Reference numberISO 18925:2013(E)BS ISO 18925:2013ISO 18925:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may b
6、e reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the re
7、quester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 18925:2013ISO 18925:2013(E) ISO 2013 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative refere
8、nces 13 Terms and definitions . 14 Environmental conditions 34.1 Humidity and temperature limits . 34.2 Contaminants and gaseous impurities . 44.3 Magnetic fields 45 Materials . 46 Enclosures . 46.1 General requirements . 46.2 Labelling . 57 Preparation 57.1 General . 57.2 Acclimatization . 58 Stora
9、ge housing . 59 Storage rooms 610 Fire-protective storage . 611 Identification, inspection, and cleaning . 711.1 Identification 711.2 Inspection 711.3 Cleaning . 7Annex A (informative) Temperature-relative humidity relationship 8Annex B (informative) Temperature and humidity acclimatization . 9Bibli
10、ography .10BS ISO 18925:2013ISO 18925:2013(E)ForewordISO (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 membe
11、r 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 Elec
12、trotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted
13、 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.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent r
14、ights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 18925 was prepared by Technical Committee ISO/TC 42, Photography.This third edition cancels and replaces the second edition (ISO 18925:2008), of which it constitutes a minor revision.The following change has b
15、een made to the second edition: an update of the bibliographical references.iv ISO 2013 All rights reservedBS ISO 18925:2013ISO 18925:2013(E)IntroductionUse of optical disc material is becoming widespread in audio, video, and computer applications. Preservation of this information is becoming of inc
16、reasing concern to society, particularly as the recorded information becomes older and frequently of greater value to libraries, archives, museums, government agencies, and commercial organizations.The stability of optical discs is dependent upon that of the complete system. This includes the stabil
17、ity of the material itself, the equipment on which it is run and, in systems, upon the necessary software. ISO 18921 specifies a methodology for estimating the life expectancy of the CD-ROM. Other optical discs will be addressed in future International Standards. These standards consider only the ef
18、fects of temperature and humidity and do not include other factors such as light, corrosive gases, and particulates. International Standards are not available on the life expectancy of hardware and the problems associated with hardware wearing out or becoming obsolete.It is advisable that optical di
19、sc users store discs under conditions that will extend their life and handle the material so that it will not be subjected to stress and undergo physical breakdown during use. This International Standard addresses the concerns of long-term storage.A major component of a large number of optical discs
20、 is the polycarbonate substrate. Polycarbonate is a very durable material, but it does absorb moisture and there is always an equilibrium between the ambient humidity and the moisture content of the disc. Polycarbonate is susceptible to decomposition under certain conditions and given a suitable cat
21、alyst.The second component of most optical discs is the reflective layer. This layer is usually some highly reflective metal such as aluminium, silver, or gold. Each of these materials is subject to reaction with various chemicals that can be found in the environment. Aluminium, for example, combine
22、s readily with oxygen to form aluminium oxide. Silver combines with sulfur to tarnish and form silver sulfides. Gold is known to react with chlorine to form gold chlorides.A third component of these discs is some type of seal coat. This is typically a UV-cured polymer whose purpose is to protect the
23、 reflective layer and any other material layers in the disc.A fourth component, in the case of some recordable optical discs, is the dye layer. For magneto-optic or phase change discs, additional layers are also included.Regardless of the inherent stability of the various disc layers, it is known th
24、at good storage conditions will extend the life of all optical discs. While a good storage environment cannot reverse any degradation that has already occurred, it can slow down additional deterioration.A single storage condition is described in this International Standard. This condition is intende
25、d for discs that contain recorded information of long-term value. Various manufacturers studies indicate that the life expectancy of well-manufactured optical discs is in excess of 50 years under typical room ambient conditions (see References 1 and2). ISO 2013 All rights reserved vBS ISO 18925:2013
26、BS ISO 18925:2013Imaging materials Optical disc media Storage practices1 ScopeThis International Standard establishes extended-term storage conditions for optical discs and provides recommendations concerning the storage conditions, storage facilities, enclosures, and inspection for optical discs. I
27、t is applicable to discs made for audio, video, instrumentation, and computer use.Recommendations are general in nature and it is advisable that the manufacturers cautions for specific material be considered. Relaxation from these recommendations, whether before or after recording, will generally re
28、sult in shortened life expectancy.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referen
29、ced document (including any amendments) appliesISO/IEC 15486, Information technology Data interchange on 130 mm optical disk cartridges of type WORM (Write Once Read Many) using irreversible effects Capacity: 2,6 Gbytes per cartridgeNFPA 75, Standard for the Protection of Electronic Computer/Data Pr
30、ocessing Equipment3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1blisterlocalized delamination that looks like a bubble3.2compact discCDoptical disc format in which the information layer is located at one surface of a substrate and the data can
31、 be read by an optical beamNote 1 to entry: CD is the subject of IEC 60908.3.2.1compact disc-recordableCD-Rrecordable optical disc in which information can be recorded to certain areas in the compact disc formatNote 1 to entry: Information can be recorded once and read many times.3.2.2compact disc r
32、ead-only memoryCD-ROMoptical disc to which information is transferred during manufacture to certain areas in the compact disc formatNote 1 to entry: Information can be read many times.Note 2 to entry: CD-ROM is the subject of ISO/IEC 10149.INTERNATIONAL STANDARD ISO 18925:2013(E) ISO 2013 All rights
33、 reserved 1BS ISO 18925:2013ISO 18925:2013(E)3.2.3compact disc-rewritableCD-RWrecordable optical disc in which information can be recorded to certain areas in the compact disc formatNote 1 to entry: Information can be erased and new information recorded many times and read many times.3.3containerbox
34、, can, or carton used for storage and shipping of recording materials3.4digital versatile discDVDdigital video disc (deprecated)optical disc format in which one or more information layers are located between two substrates and the data can be read by an optical beam3.5delaminationseparation of a lam
35、inate into its constituent layers3.6dew pointtemperature at which moisture begins to condense on a surfaceNote 1 to entry: See relative humidity (3.16).EXAMPLE The more humid the air, the higher the dew point temperature.3.7enclosurefolder, envelope, sleeve, or clam shell intended for physical prote
36、ction against mechanical damage3.8extended-term storage conditionsstorage conditions suitable for the preservation of recorded information having permanent value3.9fire-protective storagefacilities designed to protect records against excessive temperatures, water and other fire-fighting agents, and
37、steam developed by insulation of safes or caused by the extinguishing of fires and collapsing structures3.10insulated record containerstorage box designed to withstand elevated temperatures and conforming to national standards and regulations3.11isoperm lineslines of constant life plotted as a funct
38、ion of temperature and relative humidity3.12life expectancyLElength of time that information is predicted to be retrieved in a system at 23 C and 50 % relative humidity (RH)3.13magnetic field intensitylevel of the magnetic field at a point in space2 ISO 2013 All rights reservedBS ISO 18925:2013ISO 1
39、8925:2013(E)3.14mediummaterial on which the information is recorded3.15MO discoptical disc in which the information is recorded using magneto-optical technology in some specified formatNote 1 to entry: Information can be recorded, read many times, and overwritten many times.3.16relative humidityRHra
40、tio, defined as a percentage, of the existing partial vapour pressure of water to the vapour pressure at saturationNote 1 to entry: It is usually, but not always, equal to the percentage of the amount of moisture in the air to that at saturation.3.17storage environmentconditions for storing material
41、s, i.e. temperature, relative humidity, cleanliness of facilities, and atmospheric pollutants3.18storage housingphysical structure supporting materials and their enclosuresNote 1 to entry: It can consist of drawers, racks, shelves, or cabinets.3.19systemcombination of material, hardware, software, a
42、nd documentation necessary for recording and/or retrieving information3.20WORM discoptical disc in which the data in specified areas can be written only once and read multiple times by an optical beam4 Environmental conditions4.1 Humidity and temperature limitsThe average relative humidity of an ext
43、ended-term storage environment shall be maintained between 20 % RH and 50 % RH. Cycling of relative humidity shall not be greater than 10 %. Ideally, the maximum temperature for extended periods should not exceed 25 C, and a temperature below 23 C is preferable. The peak temperature shall not exceed
44、 32 C. Generally, useful life will be increased by storing discs at low temperature and low relative humidity since chemical degradation is reduced at these conditions (see Annex A). Storage of discs below 10 C and below 10 % RH is not recommended.Specific manufacturers recommendations, when availab
45、le, should take precedence over the above general recommendations.For any facility, it is impossible to specify what the best relative humidity and storage temperature should be, since it depends upon the value of the material, the past storage history, the length of time the disc is to be kept, the
46、 size of the vault, the cost of various options, and the climate conditions where the facility is located. ISO 2013 All rights reserved 3BS ISO 18925:2013ISO 18925:2013(E)Lower temperatures within the specified relative humidity range can be difficult to achieve with normal humidity air-conditioning
47、 equipment and may require a specialized installation. Automatic control systems are recommended, and they shall be checked frequently enough to determine that the specified temperature and humidity limits are not being exceeded. A reliable hygrometer can be used for humidity measurements.Where air
48、conditioning is not practical, high humidities may be lowered by electrical refrigeration-type dehumidifiers controlled with a hygrostat. Inert desiccants, such as chemically pure silica gel, may be used, provided the dehumidifier is equipped with filters capable of removing dust particles down to 0
49、,3 m in size and is controlled to maintain the relative humidity within the specified range. Dehumidification may be required in storage areas such as basements and caves which have inherently low temperatures but which frequently exceed the upper humidity limit.The recommended humidity and temperature conditions can be maintained either within individual storage housings or within storage rooms containing such housings.4.2 Contaminants and gaseous impuritiesContaminants can pass through very small cracks or scratches in pr
