When the fire-fighting water in the building is stored separately (that is, a dedicated fire-fighting water tank), and a dedicated fire-fighting water tank replenishment pump is used, in order to ensure the storage capacity of the fire-fighting water, the start-up of the replenishment pump must be The water level should be the lowest water level of the fire water storage capacity in the water tank, and when the fire water in the building supervising the fire water storage is stored separately (that is, a dedicated fire water tank), and there is no domestic drinking water tank in the building, When water is replenished by variable frequency water supply equipment, an electric valve with the same diameter as the water inlet pipe of the fire water tank should be installed in accordance with the requirements of the specification. The electric valve cooperates with the variable frequency pump to replenish water for the special fire water tank. The high and low water level signals in the fire water tank are The opening signal of the electric valve of the water inlet pipe. When a fire-fighting water supply system of a building adopts a special fire-fighting water tank, in order to ensure the fire-fighting water storage capacity and water level control requirements in the water tank, it must be set on the visual alarm water level. The water level setting of the water replenishing pump depends on the requirements for the operation of the water pump (including the number of times the pump is started and stopped within an hour and the impact of water surface fluctuations). The water storage capacity of the fire-fighting water tank should be slightly larger than the various types of fire-fighting water consumption required by the specifications, leaving a certain adjustment buffer volume so that the water replenishment pump can operate normally. The determination of the overflow water level alarm signal in the fire water tank should refer to the interpretation of Article 3.7.7 of GB 50015?2003?Code for Design of Building Water Supply and Drainage:! ##The difference between the alarm water level, the highest water level and the overflow water level Relationship: The alarm water level should be about 50 mm higher than the maximum water level. Small water tanks can be smaller, and large water tanks can be larger. The distance between the alarm water level and the overflow water level is generally about 50 mm. If the diameter of the water inlet pipe is large and the flow of water is large, and manual or electric shutdown is required after the alarm, emergency shutdown time should be given. The distance between the alarm water level and the overflow water level is 250~300 mm. mm? requirements are set between the maximum water level and the overflow level, and are determined based on various factors such as the size of the water tank volume, the diameter of the water inlet pipe, the flow rate of the water inlet pipe, and the closing method of the water inlet valve. At the same time, the distance between the highest water level and the overflow port should also be higher than the 50 mm height requirement required for drinking water tanks to meet the requirements for the setting distance of the overflow water level alarm signal.