Abstract: In order to study the effects of different environmental pressures and temperatures on the characteristics of smoldering smoke and the alarm time of detectors, smoldering tests were conducted on corrugated cardboard in environments of 40 kPa to 101 kPa and 0 ℃ to 40 ℃. The changes in fuel quality, smoke morphology, smoke temperature, obscuration coefficient, smoke velocity, and the detection and alarm time of three different types of smoke detectors were measured during the smoldering process under different environmental conditions. The results indicate that a decrease in environmental pressure can lead to a reduction in the rate of fuel mass loss during smoldering, as well as a decrease in the peak smoke volume fraction after complete combustion of the cardboard, resulting in a delay in smoke alarm time or even no alarm under low pressure conditions; Due to air resistance and reduced air density, smoke under low pressure conditions will have higher temperature and faster spread speed. The decrease in ambient temperature will also reduce the rate of fuel mass loss during the smoldering process, as well as lower the smoke temperature and spread rate, resulting in a slight delay in the smoke alarm time under low temperature conditions, but almost no change in the peak smoke volume fraction after complete combustion.

Key words: smoldering, ambient pressure, ambient temperature, smoke velocity, volume fraction of smoke