1、BS EN 15702:2008ICS 83.100NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDCellular Plastics Cell count procedurefor flexible and rigidpolyurethaneThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 January2009
2、 BSI 2009ISBN 978 0 580 58983 6Amendments/corrigenda issued since publicationDate CommentsBS EN 15702:2008National forewordThis British Standard is the UK implementation of EN 15702:2008. Itsupersedes BS4443-1:1988 which is withdrawn.The UK participation in its preparation was entrusted to Technical
3、Committee PRI/24, Testing of rigid and flexible cellular materials.A list of 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 applicatio
4、n.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 15702:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15702December 2008ICS 83.100English VersionCellular Plastics - Cell count procedure for flexible and rigidpolyurethanePlastiques alvolaires - Mode oprat
5、oire de dnombrementdes alvoles des polyurthanes souples et rigidesSchaumstoffe - Verfahren zur Zellenzhlung fr weich-elastische und harte Schaumstoffe aus PolyurethanThis European Standard was approved by CEN on 15 November 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulatio
6、ns which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This Europea
7、n Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility 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
8、 standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
9、 Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15702:2008: EBS EN
10、 15702:2008EN 15702:2008 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Terms and Definitions .4 3 Apparatus .4 4 Test specimens 4 4.1 Preparation .4 4.2 Shape and dimensions 4 4.3 Number of test specimens 4 5 Procedure .4 6 Precision .5 6.1 General 5 6.2 Results 5 7 Test report 5 BS EN 15702:2008EN 157
11、02:2008 (E) 3 Foreword This document (EN 15702:2008) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the
12、latest by June 2009, and conflicting national standards shall be withdrawn at the latest by June 2009. 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 suc
13、h patent rights. 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,
14、 Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15702:2008EN 15702:2008 (E) 4 1 Scope This European Standard specifies a method for determining the cell count of flexib
15、le and rigid cellular polyurethane. 2 Terms and Definitions For the purposes of this document, the following term and definition applies: cell count number of cells per 25 mm in the cellular polyurethane under specified conditions 3 Apparatus 3.1 The apparatus shall consist of a magnifying device (o
16、f sufficient power to allow identification of each cell) with a scale, calibrated in millimetres, capable of measuring a length of 25 mm to an accuracy of at least 0,1 mm. A 25 mm cloth-counting glass is normally adequate. 3.2 In the case of very fine celled foams optical fatigue may be experienced
17、and in this event the use of a smaller glass (10 mm or 15 mm) and arithmetic conversion is permitted. 3.3 A X10 magnifying device is adequate for a cell count of 40 or less. 4 Test specimens 4.1 Preparation If the material shows a predominant direction of the cellular structure (orientation of the c
18、ells), the test specimens shall be cut in such a way that both axes of the cells can be measured. 4.2 Shape and dimensions The test specimen may consist of any sample which is free of skin and has a plane surface large enough to accommodate the counting glass. A 50 mm x 50 mm x 3 mm sample is recomm
19、ended. Samples shall be cut with a sharp blade in such a manner that the cells are not damaged. Specimen surfaces showing marked variation in the cellular structure from place to place shall not be measured unless specifically required. 4.3 Number of test specimens Five test specimens shall be used.
20、 If there is a noticeable difference in the cell count in specimens taken from different locations in the sample, the specimen location shall be as agreed upon by the interested parties. 5 Procedure 5.1 Lay the test specimens on a flat horizontal surface, without strain. Place the counting device on
21、 the surface of the test specimen and count the actual number of cells against the counting edge of the glass. BS EN 15702:2008EN 15702:2008 (E) 5 5.2 Where there is marked anisotropy in the cell dimensions, at least two counts shall be made. The directions shall be chosen such that the maximum and
22、minimum dimensions of the cells are used to perform this test. 5.3 Some individuals can find it difficult to count very fine celled foams. Therefore the top surface of the cellular structure may be lightly shaded. For un-pigmented or pale coloured materials, a black felt-tipped marker should be used
23、. The top surface of dark coloured foams may be lightly coated with white typewriter correction fluid. Such fluids do not normally cause swelling or distortion of the cellular structure but should be left to dry thoroughly before the counting procedure is performed. 6 Precision 6.1 General The preci
24、sion of CEN procedure was determined in accordance with ISO/TR 9272. The ITP (Interlaboratory test programme) was conducted in 2007. Six participants from UK laboratories tested two grades of flexible polyester urethane foam. Both grades were white (un-pigmented), Foam type “A” was of fine uniform c
25、ell structure and Foam type “B” had much larger cells. All samples were cut horizontally from commercially produced block and were counted in two directions parallel to the axis of the foaming conveyor and at right angles. Cell counts were performed on two separate days. All laboratories found it be
26、neficial to lightly shade the top layer of cells using a black felt-tipped marker. 6.2 Results The precision results for the two materials are given in Tables 1 and 2. The number of test pieces in each measurement was five. Table 1 Precision results Foam Type A Direction Mean Repeatability Reproduci
27、bility (Cells/25mm) Sr SR Along 55 1,12 5,33 Across 55 0,58 4,40 Table 2 Precision results Foam Type B Direction Mean Repeatability Reproducibility (Cells/25mm) Sr SR Along 15 0,87 1,01 Across 15 0,76 1,17 7 Test report The test report shall include the following information: a) direction(s) in whic
28、h the cell count was made; b) average number of cells per 25 mm; c) power of the magnifying device and size of counting glass; BS EN 15702:2008EN 15702:2008 (E) 6 d) whether surface shading was used to assist the counting; e) any deviation from the testing and conditioning procedures specified. BS E
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