Class A, B, C, D, and K. Class A Fires are the most common fire classification. These fires involve common combustible materials, such as wood, paper, and cloth. Class B Fires are fueled by flammable liquids and gasses like propane, oil, or gasoline. Class C Fires involve electrical equipment such as power systems, lighting, computers, and appliances. Class D Fires involve combustible metals, such as magnesium or potassium. Lastly, Class K Fires involve cooking oils and fats typically found in kitchens.