Operating room fires continue to be reported in the medical literature. To simulate operating room conditions, a high pressure spontaneous ignition apparatus was redesigned to allow for the determination of spontaneous ignition temperature of trachea! tubes in 100% oxygen at atmospheric pressure. Pure oxygen flowed through a test chamber at 100 cm³/min, and a temperature ramp rate of 10°C/min was used. Sample temperature, chamber temperature, chamber pressure and elapsed time were stored on-line by computer. The experimental ignition temperature was observed as a spike in sample temperature-time plot.

Five samples each of poly (vinyl chloride), red rubber and silicone rubber tracheal tubes were analyzed for spontaneous ignition temperature, which were determined to be 428°C, 371°C, 381°C, respectively.

It was concluded that the small differences in spontaneous ignition temperature for the various tracheal tube materials has little clinical relevance to the tubes chosen for the particular surgical procedure.