Interior coverings contribute to fire behavior in four significant ways. First, they affect flame spread, as wall and ceiling finishes with high flame-spread characteristics allow fire to move rapidly across surfaces and involve a larger area. Second, interior coverings influence the heat release rate; many synthetic or plastic materials release large amounts of energy when burning, which can accelerate fire growth and lead to flashover. Third, they contribute to smoke production, often generating dense, toxic smoke that reduces visibility, complicates evacuation, and increases the risk of injury or death. Fourth, interior coverings add to the overall fire load of a compartment, increasing the amount of combustible material available and extending fire intensity and duration. Because these factors directly impact fire development and life safety, building and fire codes strictly regulate interior finish materials and their use.