Analysis of toxic effluents released from PVC carpet under different fire conditions

Abstract

A large number of investigations have been reported on minimising the PAH and PCDD/F yields during controlled combustion, such as incineration. This study is an attempt to quantify acute and chronic toxicants including PAH and PCDD/F in conditions relating to unwanted fires. This paper investigates distribution patterns of fire effluents between gas and aerosol phase, and the different particle size-ranges produced under different fire conditions. PVC carpet was selected as the fuel as a precursor for both PAH and PCDD/F. In order to generate fire effluents under controlled fire conditions, the steady-state tube furnace, was chosen as the physical fire model. Fire scenarios included oxidative pyrolysis, well-ventilated and under-ventilated fires. Fire effluent measurements included: carbon monoxide, carbon dioxide, hydrogen chloride, polycyclic aromatic hydrocarbons, chlorinated dibenzo-dioxins and furans and soot. The distribution patterns between gas and particle phase, and the size-ranges of the particles produced in these fires together with their chemical composition is also reported. Significant quantities of respirable submicron particles were detected, together with a range of PAHs. Lower levels of halogenated dioxins were detected in the fire residue compared with those found in other studies. Nevertheless, the findings do have implications for the health and safety of fire and rescue personnel, fire investigators, and other individuals exposed to the residue from unwanted fires.

Fig. 1

Fire effluents mass loss yields (A) CO, HCl, CO₂ and (B) total soot.

Fig. 2

(A) Soot size distribution and (B) chlorine content from cascade impactor plates under different fire conditions (for clarity smoothed curves have been used to associate the points to the fire condition).

Fig. 3

Chlorine content from cascade impactor plates and gravimetry filter under different fire conditions.

Fig. 4

Chlorine content of residues as a function of sample position in furnace.

Fig. 5

Concentration of PCDD/F in PVC carpet residues under different fire conditions.

Fig. 6

Individual PAHs yields for (A) oxidative pyrolysis, (B) well-ventilated and (C) under-ventilated tests.