This part of IEC 60695 describes the test methods for the determination of the specific optical density of smoke produced by materials used in electrotechnical products using the apparatus described in technical specification IEC/TS 60695-6-30. Test specimens are exposed vertically to a radiant heat source with or without the application of a pilot flame in a closed chamber (i.e. without air-change). The test methods are only applicable to flat, solid, non-metallic test specimens of materials used in electrotechnical products. This technical specification does not provide a classification system for the behaviour of materials. The test methods are not applicable to materials which melt and flow away from the direct impingement of heat flux. The test methods are not recommended for further development for electrotechnical products,nor are they recommended as the basis for regulation or other controls on smoke release due to the limitations of the physical fire model and the test specimen geometry – see Clause 4. WARNING: Appropriate safety measures are to be taken as toxic and harmful fire effluents may be produced by pyrolysis or combustion of test specimens. This basic safety publication is intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.