A Method to Determine the Potential Toxicity of Smoke from Burning Polymers: I. Experiments with Douglas Fir

Abstract

A small scale apparatus has been developed using a radiant source to burn Douglas fir specimens. Three irradiance levels were selected: 21, 35 and 50 kW/m2. Burning took place within an enclosure which was ventilated under known airflows, from levels just sufficient to maintain flaming combus tion to higher levels providing for more efficient flaming combustion. For each experiment flaming combustion was maintained for 30 minutes. The following variables were measured in each experiment: time to ignition, mass loss rate, flame height, O2 consumed, CO2 and CO produced and heat release. From CO measurements potential lethal conditions for mice or humans were evaluated using either CO production in ppm-min or using an equation to calculate COHb levels in blood. Within the range of irradiance levels and airflow levels evaluated the smoke produced by Douglas fir under flaming conditions can be below lethal potential to rapidly incapacitating and lethal. This new small- scale combustion module/animal exposure chamber system, termed the University of Pittsburgh II method (UPitt II) is a significant departure from previous attempts to evaluate toxicity of smoke from burning polymeric mate rials. It is also a significant improvement over previous systems because well defined burning conditions can be established over a wide range of irradiance and ventilation levels, not possible to examine with previous methods. Further more, performance of the specimens can be given in terms of time to ignition, flame height and heat release.