Cooperative Personnel Services Firefighter (CPS) Practice Exam

The factor that can lead to the self-heating of powders is exothermic decomposition reactions. These reactions occur when certain substances break down and release heat as part of the chemical process. When powders undergo exothermic decomposition, the heat generated can lead to an increase in temperature, potentially resulting in self-heating. This is particularly concerning in a firefighting context, as it can create conditions conducive to combustion if the temperatures reach a sufficient level.

In contrast, insufficient moisture typically means that the powders are less likely to clump together or undergo reactions that require water, which does not contribute to self-heating. High ambient pressure can affect the behavior of substances but does not directly cause self-heating; rather, it may influence the rate of reactions or the physical state of materials. Low temperature storage, by definition, would not promote self-heating because it typically reduces the energy available for reactions, thus decreasing the likelihood of temperature increases associated with exothermic processes.