1、BSI Standards PublicationBS EN ISO 844:2014Rigid cellular plastics Determination of compressionpropertiesBS EN ISO 844:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO 844:2014. Itsupersedes BS EN ISO 844:2009 which is withdrawn.The UK participation in i
2、ts preparation was entrusted to TechnicalCommittee PRI/24, Testing of rigid and flexible cellular materials.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users a
3、re responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 69484 4ICS 83.100Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStand
4、ards Policy and Strategy Committee on 31 August 2014.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 844 August 2014 ICS 83.100 Supersedes EN ISO 844:2009English Version Rigid cellular plastics - Determination of compression properties (I
5、SO 844:2014) Plastiques alvolaires rigides - Dtermination des caractristiques de compression (ISO 844:2014) Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO 844:2014) This European Standard was approved by CEN on 7 July 2014. CEN members are bound to comply with the CEN/CENELEC Internal R
6、egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN m
7、ember. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions
8、. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pola
9、nd, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rights of exploitation
10、in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 844:2014 EBS EN ISO 844:2014EN ISO 844:2014 (E) 3 Foreword This document (EN ISO 844:2014) has been prepared by Technical Committee ISO/TC 61 “Plastics” in collaboration with Technical Committee CEN/TC 249 “Pla
11、stics” 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 latest by February 2015, and conflicting national standards shall be withdrawn at the latest by February 2015.
12、 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 ISO 844:2009. According to the CEN-CENELEC Internal Regul
13、ations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, It
14、aly, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 844:2014 has been approved by CEN as EN ISO 844:2014 without any modification. BS EN ISO 844:20
15、14ISO 844:2014(E) ISO 2014 All rights reserved iiiContents PageForeword iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and abbreviated terms . 25 Principle 26 Apparatus . 26.1 Compression-testing machine . 26.2 Devices for measuring displacement and force 36.3 Instruments
16、for measuring the dimensions of the test specimens . 37 Test specimens 37.1 Dimensions . 37.2 Preparation 47.3 Number 47.4 Conditioning 48 Procedure. 49 Expression of results 59.1 General . 59.2 Compressive strength and corresponding relative deformation . 69.3 Compressive stress at 10 % relative de
17、formation 79.4 Compressive modulus of elasticity 710 Precision . 811 Test report . 8Bibliography .10BS EN ISO 844:2014ISO 844:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Inte
18、rnational 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, governmental and non-governmental, in liaison wi
19、th ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives
20、, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of
21、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. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations
22、 received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO
23、s adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 10, Cellular plastics.This sixth edition cancels and replaces the fifth edition (I
24、SO 844:2007), which has been technically revised to specify the choice of the procedure for the determination of the compressive strength and corresponding relative deformation, the compressive stress at 10 % relative deformation and the compressive modulus of rigid cellular plastics.iv ISO 2014 All
25、 rights reservedBS EN ISO 844:2014INTERNATIONAL STANDARD ISO 844:2014(E)Rigid cellular plastics Determination of compression properties1 ScopeThis International Standard specifies a method of determining:a) the compressive strength and corresponding relative deformation,orb) the compressive stress a
26、t 10 % relative deformation,andc) when desired, the compressive modulus of rigid cellular plastics.There are two procedures: Procedure A employs crosshead motion for determination of compressive properties. Procedure A is intended to be used when compressive stress at 10 % relative deformation has t
27、o be determined. Procedure B employs strain measuring devices mounted on the specimen (contact extensometer) or similar device which measures directly sample deformation. Procedure B is intended to be used when compressive modulus has to be determined.NOTE Compressive strength (at maximum load) can
28、be determined either with Procedure A and B.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 t
29、he referenced document (including any amendments) applies.ISO 1923, Cellular plastics and rubbers Determination of linear dimensions3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1relative deformationratio of the reduction (in relation to its in
30、itial value) in thickness of the test specimen (Procedure A) or of extensometer gauge length (Procedure B)Note 1 to entry: It is expressed as a percentage.Note 2 to entry: mis the relative deformation corresponding to m(see 3.2).3.2compressive strengthmmaximum compressive force Fmdivided by the init
31、ial cross-sectional area of the test specimen when the relative deformation is 10 % ISO 2014 All rights reserved 1BS EN ISO 844:2014ISO 844:2014(E)3.3compressive stress at 10 % relative deformation10ratio of the compressive force F10at 10 % relative deformation 10to the initial cross-sectional area
32、of the test specimen3.4compressive modulus of elasticityEcompressive stress divided by the corresponding relative deformation below the proportional limit, i.e. when the relation is linear4 Symbols and abbreviated termsA0initial cross-sectional area, in square millimetresE compressive modulus of ela
33、sticity, in megapascalsFeforce corresponding to xe(conventional proportional limit), in newtonsFmmaximum force, in newtonsF10force at 10 % relative deformation, in newtonsh0initial thickness of test specimen (Procedure A) or extensometer gauge length (Procedure B), in millimetresmrelative deformatio
34、n corresponding to compressive strength m, in percentmcompressive strength, in megapascals10compressive stress at 10 % relative deformation, in magapascalsxedisplacement at Fein the conventional elastic zone, in millimetresxmdisplacement at maximum force, in millimetresx10displacement at 10 % relati
35、ve deformation, in millimetres5 PrincipleA compressive force is applied in an axial direction to the faces of test specimen.The maximum stress supported by the test specimen is calculated.If the value of the maximum stress corresponds to a relative deformation of less than 10 %, it is noted as the “
36、compressive strength”. Otherwise, the compressive stress at 10 % relative deformation is calculated and its value noted as the “compressive stress at 10 % relative deformation”.6 Apparatus6.1 Compression-testing machineUse a compression-testing machine suited to the range of force and displacement i
37、nvolved and having two square or circular plane, parallel plates which are polished and cannot be deformed and of which the length of one side (or the diameter) is at least 10 cm. One of the plates shall be fixed and the other 2 ISO 2014 All rights reservedBS EN ISO 844:2014ISO 844:2014(E)movable; t
38、he latter shall be capable of moving at a constant rate of displacement in accordance with the conditions laid down in Clause 8. Neither plate shall be self-aligning.6.2 Devices for measuring displacement and force6.2.1 Measurement of displacementProcedure A The compression-testing machine shall be
39、fitted with a system allowing continuous measurement of the displacement x of the movable plate with an accuracy of 5 % or 0,1 mm if this latter value is a more accurate measurement (see second paragraph in 6.2.2).Procedure B The measure of displacement shall be obtained by attaching an extensometer
40、 to the sample or by using similar devices that measure directly the sample deformation, with an accuracy of 1 %.6.2.2 Measurement of forceA force sensor shall be fixed to one of the machine plates in order to measure the force F produced by the reaction of the test specimen upon the plates during t
41、he test. This sensor shall be such that its own deformation during the course of the measurement operation is negligible compared with that being measured and, in addition, it shall allow the continuous measurement of the force at any point in time with an accuracy of 1 %.It is recommended that a de
42、vice be used for the simultaneous recording of the force F and the displacement x that allows, by obtaining a curve of F = f(x), the graphical determination of the pair of values F, x required in Clause 9 with the accuracy laid down in 6.2.1 and this subclause, and provides additional information on
43、 the behaviour of the product.6.2.3 CalibrationDevices for measuring and, if applicable, recording graphically the force and displacement produced by the test machine shall be checked periodically. The devices shall be checked by using a series of standard weights, the masses of which are known to a
44、ccuracies better than 1 % and which correspond to the forces applied during the test. To check the devices, spacers shall be used which have thicknesses known to accuracies better than either 0,5 % or 0,1 mm, whichever is more restrictive.6.3 Instruments for measuring the dimensions of the test spec
45、imensThese instruments shall be in accordance with ISO 1923.7 Test specimens7.1 DimensionsThe test specimens shall be (50 1) mm in thickness except for products with moulded skins which are intended to remain integral with the product in use. With such products, the specimens shall be the full thick
46、ness, provided that the minimum thickness is 10 mm or greater and that the maximum thickness is not greater than the width or diameter of the specimen.The test specimen base shall be either square or circular, with a minimum area of 25 cm2and maximum of 230 cm2. The preferred geometry and dimensions
47、 are a right prism with a base of (100 1) mm (100 1) mm.The distance between two faces shall not vary by more than 1 % (tolerance on parallelism).Under no circumstances may several test specimens be piled up to produce a greater thickness for testing. ISO 2014 All rights reserved 3BS EN ISO 844:2014
48、ISO 844:2014(E)Since sample geometry and dimensions may have an influence on results, it is recommended to compare results only if obtained by testing samples having the same geometry and dimensions.7.2 PreparationTest specimens shall be cut so that the specimen base is normal to the direction of co
49、mpression of the product in its intended use. In some cases with anisotropic materials where a more complete characterization is desired or where the principal direction of anisotropy is unknown, it may be necessary to prepare additional sets of specimens.Cutting of the test specimens shall be accomplished by methods that do not change the structure of the cellular material. Moulding skins that do not remain with the product in use shall be removed.In general, any anisotropy is characterized by a plane and the directi
