Indoor fire water tanks for low-rise buildings (including water towers and air pressure tanks) are water storage equipment for storing fire-fighting water in the initial stage of fire fighting.

     The requirements for setting fire water tanks are as follows:

     1. Setting conditions: For buildings whose outdoor fire water supply system is a normal high pressure water supply system, if the water volume and water pressure of fire hydrants and automatic sprinkler systems are unfavorable in the building, fire water tanks may not be installed. For buildings with temporary high-pressure water supply systems, fire water tanks should be installed.

     2. Fire-fighting water storage capacity of the water tank: the indoor fire-fighting water tank should store 10 minutes of fire-fighting water (the same is true for pneumatic water tanks and water towers). When the indoor fire-fighting water consumption does not exceed 25L/s, 12min can still be used when the calculated water storage capacity of the indoor fire-fighting water tank exceeds 12min. 18min can be used.

     3. Setting height requirements: The fire water tank should be set at the high part of the building, and it should be a gravity self-flowing water tank. For buildings with an indoor fire-fighting water consumption exceeding 15L/s, if the fire-fighting water tank cannot meet the water pressure of the fire-fighting equipment at unfavorable points, pressurization facilities such as air-pressure water tanks shall be installed.

     4. Requirements for shared water tanks: For water tanks that share fire water with domestic and production water, there should be technical measures to prevent fire water from being used by others.

     5. After a fire occurs, the fire-fighting water supplied by the fire-fighting water pump should not enter the fire-fighting water tank, and the indoor fire hydrants and automatic sprinkler systems must have sufficient water pressure and water volume. The fire water tank shall be fed by the production or domestic water pipe network. A one-way valve should be installed on the fire water outlet pipe of the fire water tank to only allow the water in the water tank to enter the fire pipe network to prevent the water from the fire pipe network from entering the water tank.