BS EN ISO 4589-3:2017规定了测定含氮混合物中氧气最小体积分数的方法，在规定的试验条件下，在25°C和150°C之间的温度范围内支持小型垂直试样的燃烧。温度范围通常在40°C和150°C之间。结果定义为试验温度下的温度指数值，这是塑料材料在过热情况下可能经历的典型实际温度。提供了在试验温度下以垂直杆或厚度不超过10.5mm的薄板形式自支撑材料的试验方法。 然而，它们不适用于需要ISO 4589-2:2017表2中定义的支撑架的形式V。这些方法适用于表观密度为100 kg/m3或更高的固体、层压或多孔材料。这些方法也适用于表观密度小于100 kg/m3的一些多孔材料。本发明提供了一种在垂直支撑的情况下测试柔性薄板或薄膜材料的方法。本文件还包括一种方法（见附录a），用于确定在规定试验条件下，空气中小型垂直试样的OI为20.9%时的温度。 发生这种情况的温度被定义为可燃性温度（FT），该方法仅限于测定低于400°C的温度。该方法不适用于OI小于20.9%的材料。注1:这些方法可能无法令人满意地应用于加热时表现出高收缩率的材料，例如高取向薄膜。注2:为了评估密度<100 kg/m3的多孔材料的火焰传播特性，请注意ISO 3582中描述的方法。交叉引用:ISO 4589-2:2017ISO 13943:2008 Ed 2ISO 4589-1:2017 ISO 3582: 2000年版2购买本文件时，所有当前可用的修订版均包含在购买本文件中。

BS EN ISO 4589-3:2017 specifies methods for determining the minimum volume fraction of oxygen, in a mixture with nitrogen, that will support combustion of small vertical test specimens under specified test conditions over a range of temperatures between 25 °C and 150 °C. The range of temperatures is typically between 40 °C and 150 °C. The results are defined as temperature index values at the test temperature, which is typical of the practical temperature that a plastic material can experience in an overheated service situation.Methods are provided for testing materials that are self-supporting at the test temperature in the form of vertical bars or sheet up to 10,5 mm thick. However, they are not applicable to form V which requires a supporting frame as defined in ISO 4589-2:2017, Table 2. These methods are suitable for solid, laminated or cellular materials characterized by an apparent density 100 kg/m3 or higher. The methods are also 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.This document also includes a method (see Annex A) for determining the temperature at which the OI of small vertical test specimens in air is 20,9 % under specified test conditions. The temperature at which this occurs is defined as the flammability temperature (FT) and the method is limited to the determination of temperatures less than 400 °C. The method is not applicable to materials having an OI of <20,9 %.NOTE 1 It might not be possible to apply these methods satisfactorily to materials that exhibit high levels of shrinkage when heated, e.g. highly oriented thin film.NOTE 2 For assessing the flame propagation properties of cellular materials of density <100 kg/m3, attention is drawn to the method described in ISO 3582.Cross References:ISO 4589-2:2017ISO 13943:2008 Ed 2ISO 4589-1:2017 ISO 3582:2000 Ed 2All current amendments available at time of purchase are included with the purchase of this document.