Aging of solid insulators exposed to toxic fire byproducts

During fire accidents aggressive chemicals associated with the chemical decomposition of burning materials may be released. Fire by-products can be diffused and be adsorbed in to the volume of organic insulators. This is likely to initiate chemical attack leading to irreversible deterioration of the serviceability of an insulation system. The degassing in vacuum of the trapped contaminants may be practically utilized to provide information concerning fire by-product identification. The work presented investigates-as a case study-the induced ageing in polymeric cable insulation. The investigated materials were indirectly exposed in a fire accident that occurred in a fully automated margarine and olive oil production plant, where large quantities of PVC packing were burned. Toxic fire byproducts were detected in the cable insulation by means of quadrupole mass spectrometry. The electrical performance of cable insulation was examined by dc conductivity measurements in the uniform low field regime