Certified Fire Investigator Practice Exam

What characterizes a low order explosive?

1. An explosion that causes minimal damage

2. An explosion where the material is completely consumed

3. An explosion that is only partially consumed

4. An explosion that occurs without any flame

The correct answer is: An explosion that is only partially consumed

A low order explosive is characterized by an explosion where the material is only partially consumed. This definition is fundamental to understanding how different types of explosives function. Low order explosives do not produce a shock wave of the same intensity as high order explosives; instead, they tend to burn rapidly and can produce a loud report or deflagration that results in a visible fireball and creates a less destructive force. Such explosions typically involve materials that can be ignited and will burn or degrade through chemical reactions at a slower rate. The energy released is insufficient to create a complete detonation of the entire mass of explosive material, hence leading to a condition where a significant portion remains as unreacted material after the explosion. In contrast, low order explosives can include substances such as certain types of pyrotechnics or propellants that function through combustion rather than detonation. This characteristic distinguishes them from high order explosives, which sustain a supersonic reaction, resulting in a uniformly rapid conversion of the explosive into gases and energy. This detailed understanding is crucial for fire investigators as it aids in analyzing scenarios involving various types of explosives, helping to determine the nature of an explosion and the materials involved.