This paper addresses fire protection issues with a focus on hydraulic calculation and design of fire hydrant systems. The introductory chapter provides basic information on fire and its classification, along with preventive measures. The development of fire protection systems is outlined through a historical overview and contemporary methods. Firefighting systems are extensively examined, including stable fire suppression systems such as sprinkler systems, drencher systems, and systems using foam, halon, carbon dioxide (CO2), dry powder, and steam. The fire hydrant network is discussed in terms of its historical evolution, types of external and internal networks, pressure boosting systems, and pumping stations. Methods for testing systems and the advantages and disadvantages of hydrant networks are also presented. The final chapter focuses on a practical example of fire hydrant network calculation, covering technical descriptions of water supply installations, pressure reports, water quantity calculations, fire water tanks, pressure boosting pump stations, and pressure drop calculations in hydrant pipelines.