Certified Fire Investigator Practice Exam

What occurs at temperatures greater than 932 F regarding wood pyrolisis?

1. Insufficient heat to ignite

2. Beginning of char formation

3. Rapid pyrolysis

4. Free burning

The correct answer is: Free burning

When wood is exposed to temperatures greater than 932°F, a state known as rapid pyrolysis occurs. During this phase, the thermal decomposition of wood accelerates significantly. The heat causes the organic materials in the wood to break down more rapidly, releasing volatile gases. This process not only produces flammable gases but also generates a considerable amount of heat, which can lead to a substantial and rapid combustion process, often referred to as free burning. In this context, free burning describes a condition where the material ignites and burns at a fast rate due to the high temperature and abundant volatile materials being released. As the wood continues to undergo pyrolysis at these elevated temperatures, it can lead to intense flames and a vigorous fire situation. Understanding this phase in wood pyrolysis is crucial for fire investigators as it defines the behavior of wood during combustion and can impact fire dynamics and spread in a fire scenario.