The topic of this final assignment is maintenance of stable wet fire sprinkler systems. Fire sprinkler systems are the most efficient systems for the prevention of fire especially in its initial phase. In order to reduce the consequences and damage caused by fire to the minimum and to protect people's lives, their property and the environment we are living in, fire protection must be taken into consideration already during the designing phase. While choosing the fire protection system it is necessary to make sure that the selected system is highly efficient in both detecting and extinguishing fire, that it is easy to maintain and has no false alarms. The sprinkler system provides all the above. The sprinkler system is the most widely used stable automatic device used to detect and extinguish fire. The device is activated as the temperature reaches certain limits at places where the sprinkler nozzles are located, which open at that temperature and discharge water on the protected facility or zone. Wet sprinkler systems are used in facilities in which no freezing occurs, i.e. at places where temperatures do not drop below +5 °C. In order for the fire sprinkler systems to function properly and meet the conditions they were designed for and to be installed in protected facilities, the legal regulations require that they are tested and serviced in accordance with the manufacturer's instructions, keeping records of such activities.