Methodology for small-scale toxic hazard assessment of burning cables

The IEC 60695-7-50 tube furnace method using the Purser furnace was used to create three fire conditions and study the fire toxicity of four typical whole cables replicating the protective behaviour of the sheathing found in a real fire. The results for the plasticized PVC cables show some HCl and traces of CO and CO2 and significant smoke under smouldering conditions, CO, CO2 and HCl and copious quantities of smoke under well-ventilated flaming conditions, and large quantities of CO and organic materials under fully developed flaming conditions The results for the polyolefin (Casico) sheathed cables show very little pyrolysis, with only slight smoke and CO and little CO2 or oxygen depletion during smouldering, and quite high levels of CO and CO2 under well-ventilated and fully developed flaming conditions. The fire toxicity of these cables has been quantified through he calculation of the fractional effective dose calculated using the Purser and N-Gas models, and the rank order of toxicity is shown to be the same for each case.