What characteristic is true of thermoplastics when exposed to fire?

Thermoplastics are known for their ability to melt and flow when exposed to heat. This characteristic is particularly relevant in a fire scenario, as when thermoplastics reach their melting point, they transition from a solid state to a liquid state. This behavior can lead to the material dripping or flowing away from the heat source, which can pose additional challenges during firefighting efforts, such as creating hazardous runoff or increasing fire spread.

The melting and flowing property of thermoplastics under thermal stress distinguishes them from other materials that may not react in the same way, either by remaining rigid or sustaining combustion. Understanding this behavior is critical for firefighters to effectively anticipate and manage the risks associated with burning thermoplastics in a fire situation.