BS 903-0:2012 pdf download – Physical testing of rubber Part 0: General
For the testing of rubber, the use of BS 903 and BS ISO test methods should always be considered before resorting to other methods or procedures. These methods are intended for use with small, laboratory test pieces taken either from specially prepared samples or test sheets or from fnished rubber products. In most instances, these test pieces are cut by dies or knives from a representative sample.
In these cases attention is drawn to the procedures specifed in BS ISO 23529 as the method of preparation can affect test performance, especially where strength measurements are involved.
For some tests, directly moulded test pieces are necessary or most appropriate. The test methods are applicable to unvulcanized and vulcanized rubber prepared from dry rubber or latex. Most, although not all, of the test methods described for vulcanized rubber are suitable for use with thermoplastic rubbers and their products. The scopes of many of the test methods have already been extended to include thermoplastic rubbers. The test methods are not intended for use with cellular rubber or with rubber-coated fabrics except where specifed, although several standards may be applied to some cellular rubber materials and products. Dedicated test methods for fexible cellular materials are given in BS 4443 and in several BS ISO and BS EN standards, whilst dedicated methods for coated fabrics are given in BS 3424 (all parts) and several BS ISO and BS EN standards.
6.2 Selection of test method Detailed guidance on the selection and use of laboratory-scale tests is given in BS 903-1. Many of the methods give options for test piece size and shape, test procedure, test environment and, where appropriate, test duration. For example, heat ageing tests conducted in accordance with BS ISO 188 may be carried out at one or more of several standard or recommended test temperatures and times. Such options should be selected to suit the particular application, and in all cases the conditions used should be specifed and reported. The size of sample or product, the overall test time, the anticipated service environment and, for example, whether or not the test is for quality control or type approval purposes should be considered. Attention is drawn to BS ISO 24453 and BS ISO 24454 on the acquisition and presentation of comparable test data.
These standards specify test procedures, test pieces and conditions from the options given in test methods in order to assist a meaningful comparison of materials and reduce unnecessary testing. BS ISO 24453 addresses single-point data, whilst BS ISO 24454 is concerned with multi-point data, for example the results of accelerated ageing for several test times.
A guide to the application of rubber testing to fnite element analysis is given in BS 903-5. The following are also useful when selecting test methods and choosing test conditions:
a) BS 6716;
b) Physical Testing of Rubber ; and
c) Handbook of Polymer Testing: Physical Methods .
6.3 Expression of test results At present, not all of the test methods specify the number of signifcant fgures to which the test results should be expressed. For comparative purposes it is desirable that the precision should be the same irrespective of the means by which the individual results of the appropriate measure of central tendency is calculated. Thus results need to be rounded off to an accuracy representative of the test method and the number of test pieces specifed.
6.4 Calibration of test equipment It is important that the test equipment specifed in test methods is suitably calibrated for consistent and reproducible test results. Attention is therefore drawn to the specifcation, procedures and schedules for the calibration of rubber and plastic test equipment described in BS 7825. The calibration of hardness meters is specifed in BS ISO 18898. Specifcations for testing machines for rubber and plastics are given in BS ISO 5893. Calibration schedules for individual tests are being included in the revision of various standards.
7 Statistical analysis Attention is drawn to BS ISO 19003, which provides examples of statistical techniques, applied to particular rubber testing situations. Attention is also drawn to PD ISO/TR 12134 for the estimation of uncertainty for rubber test methods. 8 Analysis of graphical traces Graphical traces of test results are sometimes interpreted automatically by software packages that might not use the same basis of analysis, which can lead to to differences in interpretation and in test results. BS ISO 6133 provides a means of avoiding this.