1、BS EN ISO7326:2008ICS 23.040.70NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDRubber and plasticshoses Assessment ofozone resistance understatic conditionsCopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo re
2、production or networking permitted without license from IHS-,-,-This British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 August2008 BSI 2008ISBN 978 0 580 54857 4Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 7326:2008National for
3、ewordThis British Standard is the UK implementation of EN ISO 7326:2008. Itis identical to ISO 7326:2006. It supersedes BS EN 27326:1993 which iswithdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PRI/66, Rubber and plastics tubing, hoses and hoseassemblies.A list o
4、f organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityfrom legal oblig
5、ations.Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 7326February 2008ICS 23.040.70 Supersedes EN 27326:1993 English Versi
6、onRubber and plastics hoses - Assessment of ozone resistanceunder static conditions (ISO 7326:2006)Tuyaux en caoutchouc et en plastique - valuation de larsistance lozone dans des conditions statiques (ISO7326:2006)Gummi- und Kunststoffschluche - Bestimmung derOzonbestndigkeit unter statischen Beding
7、ungen (ISO7326:2006)This European Standard was approved by CEN on 7 February 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and b
8、ibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility
9、 of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Irela
10、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B
11、-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 7326:2008: ECopyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without
12、license from IHS-,-,-BS EN ISO 7326:2008EN ISO 7326:2008 (E) 3 Foreword The text of ISO 7326:2006 has been prepared by Technical Committee ISO/TC 45 “Rubber and rubber products” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 7326:2008 by Technical Commi
13、ttee CEN/TC 218 “Rubber and plastics hoses and hose assemblies” the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 2008, and conflicting national stand
14、ards shall be withdrawn at the latest by August 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 2732
15、6:1993. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
16、 Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 7326:2006 has been approved by CEN as a EN ISO 7326:2008 without any modification. Copyright Europea
17、n Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008ISO 7326:2006(E) ISO 2006 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1
18、 3 General considerations 1 4 Apparatus 2 5 Test pieces 2 5.1 Type of test piece 2 5.2 Number of test pieces 3 6 Conditioning of test pieces 3 7 Test conditions . 3 8 Procedure 3 8.1 Method 1 3 8.2 Method 2 4 8.3 Method 3 4 8.4 Method 4 5 8.5 Method 5 6 9 Test report . 7 Copyright European Committee
19、 for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008ISO 7326:2006(E) iv ISO 2006 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation
20、 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.
21、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. International Standards are drafted in accordance wit
22、h 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 by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approv
23、al 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 rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7326 was prepared by Technical Committee
24、 ISO/TC 45, Rubber and rubber products, Subcommittee SC 1, Hoses (rubber and plastics). This third edition cancels and replaces the second edition (ISO 7326:1991), which has been technically revised. Copyright European Committee for Standardization Provided by IHS under license with CENNot for Resal
25、eNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008ISO 7326:2006(E) ISO 2006 All rights reserved vIntroduction The methods described in this International Standard provide a means of assessing the resistance of hoses to the deleterious effects of atmospheric ozo
26、ne under static conditions. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008Copyright European Committee for Standardization Provided by IHS under license with
27、 CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008INTERNATIONAL STANDARD ISO 7326:2006(E) ISO 2006 All rights reserved 1Rubber and plastics hoses Assessment of ozone resistance under static conditions 1 Scope This International Standard specifi
28、es five methods for determining the ozone resistance of the outer covers of hoses: method 1, for bore sizes up to and including 25 mm, carried out on the hose itself; method 2, for bore sizes greater than 25 mm, carried out on a test piece from the hose wall; method 3, for bore sizes greater than 25
29、 mm, carried out on a test piece from the cover; method 4, for all bore sizes, carried out on the hose itself; method 5, for all bore sizes, carried out on hoses that are expandable, for example textile-reinforced hoses. NOTE For hoses with built-in fittings from which it is not possible to take tes
30、t pieces, the ozone resistance may be assessed on slabs in accordance with ISO 1431-1, using test sheets of the appropriate polymeric compound vulcanized to the same degree. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated re
31、ferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1431-1:2004, Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 1: Static and dynamic strain testing ISO 23529, Rubber General pr
32、ocedures for preparing and conditioning test pieces for physical test methods 3 General considerations Methods 1 and 2 are the methods normally used, method 3 being for use only if it is not possible to carry out the test in accordance with method 2. Method 4 is suitable for all bore sizes. Method 5
33、 is specifically for testing expandable hoses in the expanded state. The results of tests carried out in accordance with method 1 may not be comparable with the results obtained when tests are carried out in accordance with method 2 or 3, even if the cover compounds of the hoses under test are ident
34、ical in composition and are cured to the same degree. The test method to be used shall be as specified in the product standard. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS
35、 EN ISO 7326:2008ISO 7326:2006(E) 2 ISO 2006 All rights reserved4 Apparatus All apparatus placed in the test cabinet shall be fabricated from materials which do not absorb or decompose ozone. 4.1 Ozone cabinet, with apparatus for generating ozone and monitoring and controlling the ozone concentratio
36、n, as described in ISO 1431-1. 4.2 Test piece holder, as shown in Figure 1 (for method 1). 4.3 Test piece holder, as shown in Figure 2, made, for example, of wood coated with paint or aluminium (for method 2). 4.4 Jig, for elongation of test pieces (for method 3). Details given in ISO 1431-1:2004, S
37、ubclause 5.6, shall be followed. 4.5 Cylinder, as shown in Figure 3, with an outside diameter eight times that of the hose being tested (for method 4). 4.6 Round rod, as shown in Figure 4, with an outside diameter 1,2 times the inside diameter of the hose being tested (for method 5). 5 Test pieces 5
38、.1 Type of test piece 5.1.1 Method 1 The test piece shall consist of a hose sample. The length shall be calculated by the equation L = (rb+ dext) + 2dextwhere L is the length of the test piece; rbis the bend radius of the hose under test, as specified in 8.1.1; dextis the outside diameter of the hos
39、e under test. 5.1.2 Method 2 The test piece shall consist of a strip cut longitudinally from the hose. The strip shall be 150 mm long and 25 mm wide. 5.1.3 Method 3 The test piece shall consist of a strip of the hose cover, 25 mm in width, removed longitudinally from the hose. Lightly buff the under
40、side of the strip in accordance with ISO 23529 to remove any reinforcement impressions and thus ensure uniformity of strain along the length of the strip. 5.1.4 Method 4 The test piece shall consist of a hose sample long enough to be wound at least once round the cylinder which will be used for the
41、test. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008ISO 7326:2006(E) ISO 2006 All rights reserved 35.1.5 Method 5 The test piece shall consist of a straight
42、length of hose approximately 50 mm long. 5.2 Number of test pieces Three test pieces shall be tested. 6 Conditioning of test pieces No test shall be carried out within 24 h of manufacture. The time interval between manufacture and testing shall be as specified in ISO 23529. For evaluations which are
43、 intended to be comparable, the test shall, as far as possible, be carried out after the same time interval after manufacture. The test pieces, mounted as described for the appropriate procedure, shall be conditioned for 48 h in a substantially ozone-free atmosphere at standard temperature (see ISO
44、23529), in darkness or subdued light. 7 Test conditions Unless other conditions are specified in the relevant hose specification, the test pieces shall be exposed in the ozone cabinet to an ozone concentration of (50 5) parts per hundred million (pphm) by volume at (40 2) C for ( )0272h. NOTE It has
45、 been found that differences in atmospheric pressure can influence ozone cracking when test pieces are exposed to constant ozone concentrations expressed in parts per hundred million. This effect may be taken into account by expressing the ozone content in the ozonized air in terms of the partial pr
46、essure, i.e. in millipascals, and making comparisons at constant ozone partial pressure. At standard conditions of atmospheric pressure and temperature (101 kPa, 273 K), a concentration of 1 pphm is equivalent to a partial pressure of 1,01 mPa. 8 Procedure 8.1 Method 1 8.1.1 Mount each test piece on
47、 a test piece holder (4.2), as shown in Figure 1. The radius, rb, shall be equal to the specified minimum bend radius for the hose under test or, if not specified, six times the internal diameter. 8.1.2 Seal the ends of the test pieces with caps to prevent absorption of ozone by the inner lining and
48、 reinforcement. 8.1.3 After periods of exposure of 2 h, 4 h, 24 h, 48 h and 72 h, examine the test pieces, whilst still in the extended condition, under 2 magnification, ignoring the area adjacent to the fixing points. If cracks are discovered, record their nature and the time at which they were first observed. Copyright European Committee for Standardization Provided by IHS under license with CENNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-BS EN ISO 7326:2008ISO 73
