BS EN ISO 178:2019 pdf free download – Plastics – Determination of flexural properties.
9.4 Statistical parameters
Calculate the arithmetic mean of the test results and, if required, the standard deviation and the 95 % confidence interval of the mean value using the procedure given in Iso 2602.
9.5 Significant figures
Calculate the stresses and the modulus to three significant figures. Calculate the deflections to two significant figures.
10 Precision See Annex A.
11 Test report
The test report shall include the following information:
a) a reference to this lnternat4onal-Standarddocument, i.e. ISO 178:20 19;
b) all the information necessary for identification of the material tested, including type, source, manufacturer’s code-number, form and previous history where these are known;
c) for sheets, the thickness of the sheet and, if applicable, the direction of the major axes of the specimens in relation to some feature of the sheet (for anisotropic material, the direction of testing shall be noted);
d) f the shape and dimensions of the test specimens and, if applicable, the dimensionsdimension of the Fneas’ gtips used;
e) the method of preparing the specimens;
f) the test conditions and conditioning procedures, if applicable;
g) the number of specimens tested;
h) the nominal span used;
i) the method (A or B) and the test speed(s) used;
j) the accuracy grading of the test machine (see 5.4) orce and deflection measurement system
k) the surface on which the force was applied;
l) the individual test results, if required;
m) the mean values of the individual results;
n) the standard deviations and the 95 % confidence intervals of these mean values, if required;
o) the date of the test.
A.1 Tables A,1 and Aare based on a round-robin test performed in accordance with ASTM E 691[8L All materials were sampled and distributed by one source. Each “test result” was the average of five
individual determinations. Each laboratory obtained and reported two test results for each material.
A.2 Table A.1 is based on a round robin involving nine laboratories and four materials and Table A.2 is based on a round robin involving elevenil laboratories and four materials.
The following explanations ofrand R (see Chuse A.3L) are only intended to present a meaningful way of considering the approximate precision of this test method. The data in Tables A. 1 and 42..should not be rigorously applied to acceptance or rejection of material, as those data are specific to the round robin and might not be representative of other lots, conditions, materials or laboratories. Users of this test method should apply the principles of ASTM E691 to generate data specific to their laboratory and materials, or between specific laboratories. The principles of Clause A.3 would then be valid for such data.
A.3 Concept of rand R in Tables A.1 and J lfsrand SR have been calculated from a large enough body of data, and for test results that were averages from testing five specimens for each test result, then:
a) Repeatability: Two test results obtained within one laboratory should be judged not equivalent if they differ by more than the r-value for that material, rbeing the interval representing the critical difference between two test results for the same material, obtained by the same operator using the same equipment in the same laboratory.
b) Reproducibility: Two test results obtained by different laboratories should be judged not equivalent if they differ by more than the R-value for that material, R being the interval
representing the critical difference between two test results for the same material, obtained by different operators using different equipment in different laboratories.