PVC-Based Copper Electric Wires under Various Fire Conditions: Toxicity of Fire Effluents

Abstract

Ventilation-controlled fires tend to be the worst for toxicity, because they produce large amounts of fire effluent containing high yields of toxic products. In order to examine the dependence of the amount of chosen few main combustion gases under ventilation-controlled conditions, a PVC-insulated copper electric wire with unknown composition (PVC filled with chalk) was studied by mean of a steady state tube furnace. For the tested wire, lower values of CO2 yields at different ventilation conditions were obtained than for the reference pure polymer unplasticized PVC and additionally tested pure LDPE, the yields were higher three times in the case of PVC and two times in the case of LDPE than those received for wire at the same ventilation conditions, which pointed out decreasing contribution of hyperventilation effect to human during cable fire. In contrast, higher values of toxic CO yields, four times higher, were obtained for the PVC-insulated electric wire rather than for the pure polymers. The maximum value of CO yield (0.57 g/g) was determined in the case of 5 L/min of primary airflow and decreased with increasing ventilation. The measured yields of hydrocarbons were similar to the reference values except for the equivalence ratio ϕ = 0.27, where hydrocarbon yield was equal to 0.45 g/g. The HCl yield of fire effluents from the PVC-insulated wire was shown to be independent of ventilation conditions. The corrosive reaction between copper and the HCl species and the flame-retardant mechanisms of the additives, caused the lower values of HCl in the fire effluent of the PVC-insulated copper wire than for pure polymer.

Calorimetric Behaviour of Electric Cables

“…A large amount of volatile saturated, unsaturated, and aromatic hydrocarbons, as well as char, was then formed during the combustion processes. Mostly, cyclisation and chain scission radical reactions are responsible for the production of visible smoke species [17][18][19]. The toxicity of cables is discussed in detail in another publication by the authors [20].…”

Importance of Recycling the Waste-Cables Containing Copper and PVC

“…Among the most interesting properties of PVC materials are processability, resistance to temperature, resistance to hydrocarbons, self-extinguish properties, fire resistance, insulating properties, flexibility, transparency, recyclability and it is light and easy to reuse [25,26]. The properties of PVC can be significantly influenced by using a combination of plasticizers, fillers, stabilizers and other additives [25,27]. For example, plasticizers make PVC soft and bendable, which is an essential characteristic to produce cables and to ensure their durability for decades (PVC cables can last up to 80 years under normal conditions of use) [24,28].…”

Some Aspects of the Thermochemical Route for the Valorization of Plastic Wastes, Part I: Reduction of Iron Oxides by Polyvinyl Chloride (PVC)

“…Note that other potentially polluting substances contained in plastic are the bromine-containing flame retardants still used widely to meet the flammability standards of products [ 9 ]. Several recent scientific studies addressing the diverse aspects of plastics containing PVC and halogenated flame retardants were reported in the scientific journal Materials [ 10 , 11 , 12 , 13 , 14 , 15 ].…”