The traditional compartment fire framework has been the safety standard in fire engineering codes and design standards. Incorporating potentially combustible materials has led to reevaluating the foundations of this science. A simplified compartment fire model is proposed, modifying Semenov's model to quantify the fuel contribution of an exposed timber element to the compartment fire and determine the impact of this variable on the occurrence of a flashover. By involving a time-dependent component, the proposed model behavior approaches experimental observations. The overall results show that the larger the fuel surface area, the more certain flashover will occur.