What is the primary function of a fire helmet's inner liner?

The primary function of a fire helmet's inner liner is to provide thermal protection. This layer is designed to shield the firefighter from extreme heat and flames they might encounter during firefighting operations. The materials used in the inner liner are specifically chosen for their ability to resist high temperatures and prevent heat transfer, which is crucial in ensuring the safety of firefighters in hazardous environments.

While other aspects of a fire helmet contribute to its overall effectiveness—such as structural support to maintain the helmet's shape and design, and impact absorption to protect from falling objects—the inner liner's main purpose is specifically focused on thermal protection. This is vital as it helps to mitigate the risk of heat-related injuries, allowing firefighters to perform their duties more safely in intense situations.