Cooperative Personnel Services Firefighter (CPS) Practice Exam 2026 - Free Firefighter Exam Questions and Study Guide

The influence of temperature on flammable mixtures is significant, particularly regarding the Upper Flammable Limit (UFL) and Lower Flammable Limit (LFL). As temperature increases, the kinetic energy of the molecules in the mixture also increases. This heightened energy can allow more molecules to escape from the liquid phase into the vapor phase, potentially increasing the concentration of the vapor in the air.

Specifically, an increase in temperature can elevate the UFL. The UFL is the maximum concentration of flammable vapor in the air that can ignite and sustain combustion. When the temperature rises, the vapor can achieve higher concentrations before reaching the point at which additional vapor will no longer support combustion. As a result, the UFL increases, allowing the mixture to accommodate a wider range of flammable conditions.

Understanding this interaction between temperature and flammable mixtures is crucial for safety in handling and storing flammable materials, as it influences the conditions under which those materials pose a risk of fire or explosion.