ISO 4589-2: Oxygen Index Test
ISO 4589-2: Plastics – Determination of burning behaviour by oxygen index – Part 2: Ambient- temperature test.
ISO 4589-2: Burning test for Oxygen Index test - Principle
A small test specimen is supported vertically in a mixture of oxygen and nitrogen flowing upwards through a transparent chimney. The upper end of the specimen is ignited and the subsequent burning behaviour of the specimen is observed to compare the period for which burning continues, or the length of specimen burnt, with specified limits for such burning. By testing a series of specimens in different oxygen concentrations, the minimum oxygen concentration is estimated. Alternatively, for comparison with a specified minimum oxygen index value, three test specimens are tested using the relevant oxygen concentration, at least two of which are required to extinguish before any relevant burning criterion is exceeded.
ISO 4589-2: Burning test for Oxygen Index test - Scope
This part of ISO 4589 specifies methods for determining the minimum concentration of oxygen,
in admixture with nitrogen, that will support combustion of small vertical test specimens under
specified test conditions. The results are defined as oxygen index values.
Methods are provided for testing materials that are self-supporting in the form of vertical bars or sheet up to 10,5 mm thick. These methods are suitable for solid, laminated or celluar materials characterized by an apparent density greater than 100 kg/m3.
The methods may also be applicable to some cellular materials 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.
Oxygen index results obtained using the methods described in this part of ISO 4589 can provide a sensitive measure of the burning characteristics of materials under certain controlled laboratory conditions, and hence may be useful for quality control purposes. The results obtained are dependent upon the shape, orientation and isolation of the test specimen and the conditions of ignition. For particular materials or applications, it may be necessary or appropriate to specify different test conditions. Results obtained from test specimens of
differing thickness or by using different ignition procedures may not be comparable and no
correlation with flammability behaviour under other fire conditions is implied.
Results obtained in accordance with this part of ISO 4589-2 must not be used to describe or appraise the fire hazard presented by a particular material or shape under actual fire conditions, unless used as one element of a fire risk assessment that takes into account all of the factors pertinent to the assessment of the fire hazard of a particular application for the material.
ISO 4589-2: Specimen Requirements: 25 specimens for each of the above two tests.
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Test specimen form *1
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Dimensions (mm)
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Typical Use
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Length
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Width
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Thickness
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l
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80 to 150
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10 ± 0.5
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4 ± 0.25
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For Moulding materials
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ll
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80 to 150
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10 ± 0.5
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10 ± 0.5
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For Cellular materials
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lll *2
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80 to 150
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10 ± 0.5
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£ 10.5
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For Sheet materials as “received”
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lV
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70 to 150
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6.5 ± 0.5
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3 ± 0.25
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Alternative size for self supporting moulding or sheet materials, for electrical purposes
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V *2
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140
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52 ± 0.5
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£ 10.5
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For flexible film or sheet
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Vl *3
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140 to 200
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20
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0.02 to 0.10 *4
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For thin film “as received” ; limited to the film that can be rolled by the specified rod *4
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*NOTE*
*1 Test specimen of forms l, ll, lll and lV are suitable for materials that are self supporting at these dimensions, test specimens of form V are suitable for materials that require support during testing.
*2 Results obtained using form lll or form V test specimens may only be comparable for specimens of the same form and thickness, it is assumed that the amount of variation in thickness for such materials will be controlled by other standards.
*3 The test specimen of form Vl is suitable for thin film that is self supporting when it is rolled. Dimensions in the table are of an original film from which the rolled form is made.
*4 The film is limited to thicknesses that can be rolled by the specified rod. If the film is very thin, it may be necessary to combine two or more films together in the preparation of the rolled film so as to obtain results similar to those nominally obtained with the specimen form Vl.
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