ISO 4589-2:1996 pdf download – Plastics – Determination of burning behaviour by oxygen index
9.4.1 An interlaboratory study was conducted in 1 999 between IS0 and ASTM using IS0 4589-2: 1 996 and ASTM D 2863-97 as protocols for the test criteria. The precision data were determined from interlaboratory tests involving twelve laboratories, on eight polymeric materials, with two replicates of each material. The resulting data were analysed in accordance with IS0 5725-2, and are summarized in Table 5.
9.4.2 Repeatability, in the normal and correct operation of the method, is the difference between two averages, determined from two specimens, using identical test material and the same apparatus, by one operator within a short time interval. The value of the repeatability should not exceed those shown in Table 5.
9.4.3 Reproducibility, in the normal and correct operation of the method, is the difference between two independent averages determined from two specimens by two operators working in different laboratories on identical test material. The values of the reproducibility should not exceed those shown in Table 5.
9.4.4 Two averages (determined from two specimens) are to be considered suspect and not equivalent if they differ by more than the repeatability and reproducibility shown in Table 5. Any decision made in relation to 9.4.2 or 9.4.3 would have an approximately 95 % (0,95) probability of being correct.
NOTE 25 The explanations of “repeatability” and “reproducibility” given in 9.4.2 and 9.4.3 are only intended to present a meaningful way of considering the approximate precision of this test method. The test results and precision data in Table 5 should not be used for the acceptance or rejection of materials, as these data apply only to the materials tested in the interlaboratory study and are unlikely to be rigorously representative of other lots, formulations, conditions, materials or laboratories. Users of this test method should apply the principles outlined in IS0 4589-2 to generate data specific to their materials and laboratory (or between specific laboratories). The principles of 9.4.2 to 9.4.4 would then be valid for such data.
This part of ISO 4589 specifies methods for deter- mining the minimum concentration of oxygen, in ad- mixture with nitrogen, that will support combustion of small vertical test specimens under specified test conditions. The results are defined as oxygen index va lues. Methods are provided for testing materials that are self-supporting in the form of vertical bars or sheet up to 1 0,5 m m thick. These methods are suitable for solid, laminated or cellular materials characterized by an apparent density greater than 100 kg/m3. The methods may also be applicable to some cellular ma- terials having an apparent density of less than 100 kg/m3. A method is provided for testing flexible sheet or film materials while supported vertically. For comparative purposes, a procedure is provided for determining whether or not the oxygen index of a material lies above some specified minimum value.