# A Deep-Learning-Based Approach to the Classification of Fire Types
## 1 Introduction
Fire exhibits various features contingent upon its classification, yet firefighters routinely assess several overarching attributes:  
1. Flames: characteristics including colour, shape, and intensity are pivotal indicators. For instance, a blue flame may denote a gas-fueled fire, whereas yellow or orange flames typically signify combustible material combustion. 2. Smoke: Attributes encompassing colour, density, and odour contribute to material identification. Dense, black smoke commonly signifies synthetic-material combustion, while lighter, greyish smoke suggests natural-material involvement. 3. Heat: fire intensity and temperature give firefighters insights into potential propagation rates and associated hazards. 4. Behavior: Fire dynamics, such as the spread rate, auditory cues, or the presence of crackling noises, furnish supplementary information to firefighters. It is imperative to note that these characteristics are general, with specific fire types potentially presenting unique attributes. Firefighters undergo training to discern these traits effectively, facilitating appropriate action. Furthermore, fire types/classes should be recognized. The categorization of fires is fundamental in fire science and emergency response protocols. Fires are typically classified based on the materials fueling their combustion, with each type exhibiting distinct characteristics and posing unique challenges to containment and extinguishment [8]. According to [9], four primary classifications commonly referenced in fire science literature are as follows:  
1. Class A fires: Class A fires involve combustible and solid materials such as wood, paper, cloth, and plastics. They are characterized by glowing embers and typically produce ash upon combustion. Class A fires are extinguished using water or other agents that cool the burning material and remove the heat source. 2. Class B fires: Class B fires involve chemical materials such as magnesium, titanium, potassium, and sodium. These fires can burn extremely high temperatures and produce intense, blinding light. Extinguishing Class B fires often requires specialized dry powders or sand-based agents that react with the metal to form a crust, cutting off the oxygen supply. 3. Class C fires: Class C fires involve energized electrical equipment or wiring. These fires pose unique challenges due to the risk of electric shock and the potential for re-ignition if the power source is not adequately de-energized. Extinguishing Class C fires requires non-conductive, specialized agents that do not create a conductive path to the electrical source, such as dry chemical powders or carbon dioxide. 4. Class D fires: Class D fires involve flammable liquids or gases, including gasoline, oil, grease, and solvents. They often produce visible flames and may spread rapidly, making them particularly hazardous. Extinguishing Class D fires typically involves smothering the flames with foam, dry chemical agents, or carbon dioxide to deprive them of oxygen. Understanding the characteristics and appropriate extinguishing methods for each fire class is essential for firefighters and emergency responders to effectively mitigate the risks of various fire incidents. Additionally, ongoing research and advancements in fire science contribute to developing improved strategies and technologies for fire prevention, suppression, and safety. For instance, water-based suppression systems effectively extinguished Class A fires, particularly those involving combustible solids like wood or paper. Conversely, foam or carbon dioxide suppression systems proved more productive for Class B fires involving flammable liquids or gases. The response time plays a critical role in the operational effectiveness of firefighting systems. Systems with automatic detection mechanisms exhibited significantly reduced response times compared to manually activated systems. The evaluation of the existing firefighting systems yielded several noteworthy findings. It was observed that the efficacy varied depending on the type and scale of the fire.