This part of IEC 61034 provides details of the test apparatus to be used for measuring smokeemission when electric or optical fibre cables are burnt under defined conditions, for example,a few cables burnt horizontally. The light transmittance (lt) under flaming combustion andsmouldering conditions can be used as a means of comparing different cables or complyingwith specific requirements.NOTE For the purposes of this standard, the term "electric cable" covers all insulated metallic conductor cablesused for the conveyance of energy or signals.