Use of a Radiant Furnace Fire Model to Evaluate Acute Toxicity of Smoke

Abstract

The design and construction of a radiant furnace are described. Acute toxicity experiments were conducted using the radiant furnace as a fire model to produce smoke from Douglas fir (D. fir), southern yellow pine (SYP), and tempered hard- board (THB). The correlation of blood carboxyhemoglobin (COHb) and mortality to irradiation time, smoke concentration, mass loss, carbon monoxide (CO) con centrations, and carbon dioxide (CO2) concentrations is reported. At 2.5 w/cm 2, toxicity was characterized by post-exposure lethality with sublethal COHb ex posure levels. LC 50's (median lethal concentrations) were 59.5 (D. fir), 66.6 (SYP), and 86.5 mg/L (THB) and the IT50's (median lethal irradiation times) were 6.8 (D. fir), 6.9 (SYP), and 9.3 minutes (THB). For 5.0 w/cm 2, most deaths occurred dur ing the 30 minute exposure and COHb levels were in a lethal range. LC50's at 5.0 w/cm2 were 101.6 (D. fir), 100.1 (SYP), and 58.1 mg/L (THB), and the IT50's were 2.7 (D. fir, SYP) and 2.6 minutes (THB). Data were compared to those produced in other combustion toxicity test methods, and the advantages of the radiant furnace with continuous sample mass-loss monitoring are discussed.

Use of an Approximate Lethal Exposure Method for Examining the Acute Inhalation Toxicity of Combustion Products

“…Since the flaming experiments did not exhibit this variability, it is most likely due to slight differences in the combustion conditions of the test material. The production of toxic gases during sample combustion has been previously shown to be dependent on temperature [4,12,20], presence of flame [2,12], and oxygen availability at the site of combustion [21,22]. However, since those conditions were unlikely to vary substantially under the prespecified heating conditions, it is possible that sample heterogenity may have been a factor.…”

“…The purpose of combustion toxicity testing has been suggested as a screen for unusually hazardous smokes that may be present in fires [4]. Smoke hazard has on occasion been expressed relative to solid wood due to our society's familiarity with it.…”

“…First, the general classification of smoke from materials into broad categories of relative toxic potency may be sufficient. Second, slopes of concentration-response curves of decomposition products have been reported to be extremely steep [4]; suggesting that any smoke exposure concentration producing a partial response group would lie close to and could serve as a reasonable approximation of the L(Ct)so. Third, differences in LCCt)50's of less than a factor of four are unlikely to be of practical importance [3].…”

The Combustion Toxicology of Polyvinylchloride Revisited

“…Combustion products exert their effects by becoming airborne and entering the body by the respiratory tract which means that not only will the amount in the air influence the toxicity which results from exposure, but the duration of the exposure will determine how much of the toxicants are inhaled and the toxicity which results. The dose in an inhalation toxicity study is proportional to the arithmetical product of the exposure concentration and the duration of exposure (MacFarland, 1976) to give the Exposure Intensity (Alexeef and Packham, 1984). This value has proved useful in comparing the results of different experimental systems and is finding growing acceptance in hazard estimation.…”

Evaluation of Smoke Toxicity Using Concentration-Time Products

“…The principle demonstrated in this paper for converting smoke toxicity data to Ct products could effectively be applied to other test methods in addition to the UPT [e.g. 4,15] using smoke concentration estimates.…”