NFPA 921: Guide for Fire and Explosion Investigations Practice Exam

A combustible gas indicator is specifically designed to measure the presence of ignitable vapors or gases in the atmosphere. This tool is essential during fire investigations, as it helps determine whether there are flammable substances that could pose a risk of ignition. By evaluating the concentration of these gases, investigators can better assess fire dynamics, potential ignition sources, and fire spread.

The function of this instrument is crucial because understanding the presence and concentration of ignitable vapors is key to determining the causes of a fire or explosion. It plays a significant role in safety assessments during investigations, ensuring that the environment is safe for personnel and helping to identify potential hazards.

In contrast, measuring the temperature of combustibles, the flash point of liquids, or the overall fire intensity involves different methods and instruments that do not focus on detecting gaseous substances in the environment, which makes those options irrelevant in relation to what a combustible gas indicator is designed to measure.