Prediction of CO evolution from small-scale polymer fires

The concentrations of decomposition products of polyethylene (PE), polypropylene (PP), polystyrene (PS), poly(methyl methacrylate) (PMMA) and 19% and 26% vinyl acetate–ethylene copolymers (19% EVA and 26% EVA, respectively) have been studied at equivalence ratios ϕ varying from 0.5 to 1.5 using a Purser furnace. The CO yield of the fire gases increased with increase in fuel/air ratio. For PE, PP, PMMA and 19% EVA and 26% EVA, the CO evolution was independent of the polymer and depended only on ϕ. PS gave higher CO yields at low fuel/air ratios, and lower CO yields at high fuel/air ratios in comparison with the other polymers studied. The CO yield translates to a fractional effective dose, showing a threefold increase in the fire toxicity in going from fuel lean (ϕ = 0.5) to fuel rich (ϕ = 1.5) conditions.