IEC 60695-11-20:2015 describes a test method consisting of two small-scale laboratory test procedures which is intended to compare the burning behaviour of different materials used in electrotechnical products. Vertically oriented bar specimens or horizontally oriented plate test specimens are exposed to a small flame ignition source with a nominal thermal power of 500 W. The test method uses two test specimen configurations to classify material performance. Rectangular bar-shaped test specimens are used to assess ignitability and burning behaviour, and square plate test specimens are used to assess the resistance of the test specimen to burn-through, as defined in 8.3.3. This test method only applies to materials that have been classified as V-0 or V-1 according to IEC 60695-11-10. This test method is only applicable to solid and cellular materials that have an apparent density of more than 250 kg/m3, determined in accordance with ISO 845. The method does not apply to materials that shrink away from the applied flame without igniting due to their thinness. The test method described provides classifications which may be used for quality assurance, the pre-selection of component materials of products, or to verify the required minimum flammability classification of materials used in end products. If used for pre-selection, then positive results shall be obtained at a test specimen thickness which equals the smallest thickness used in the product application. The results obtained provide some information about the behaviour of materials in service, but cannot by themselves assure safe performance in service. This second edition cancels and replaces the consolidated version of IEC 60695-11-20 published in 2003. This edition constitutes a technical revision. The main changes with respect to the first edition are as follows:
- The Part title has been modified to the singular - 500 W flame test method;
- Editorial changes have been made throughout the document for the purpose of aligning IEC 60695-11-10 with IEC 60695-11-20;
- The Introduction has been modified to clarify the description of the test method;
- The Scope has been modified for clarification;
- All occurrences of the term "fixture" have been deleted from the document;
- Preferred thickness values have been added to 7.2 and 7.3;
- 7.4.4: 'Thickness measurement' is now numbered 7.5 to which a new Table 1 - Thickness tolerances has been added;
- New Subclause 8.1.4 'Conditioning of the cotton pad' has been added;
- 8.2.3 clarifies the application of the test flame to distorted specimens;
- Explanatory notes have been added to Figures 5 and 6 and the Bibliography has been updated and references added. This basic safety publication is intended for use by technical committees in the preparation of standards in accordance with IEC Guide 104 and ISO/IEC Guide 51. Key words: Test flames,Fire Hazard, Fire Test Method

This publication is to be read in conjunction with IEC 60695-11-3:2012. The contents of the corrigendum of January 2016 have been included in this copy.