What is the term for the layer of smoke and gases building up at the ceiling level of a structure fire?

The term for the layer of smoke and gases that accumulates at the ceiling level during a structure fire is commonly referred to as the smoke layer. This layer forms as a result of rising hot gases, smoke, and other combustion products, which are lighter than the surrounding cooler air. As these products rise, they can create a hazardous environment, restricting visibility and introducing toxic gases that can be dangerous to both occupants and firefighters. Recognizing the presence and characteristics of the smoke layer is crucial for effective fire suppression and for ensuring the safety of personnel during firefighting operations. Understanding this phenomenon aids firefighters in making informed decisions about search and rescue operations and the strategies they employ to combat the fire effectively.