NFPA 22, Edition 2018, Section 188.8.131.52 states that "The water supply shall be capable of filling the minimum
required fire protection volume within the tank in a maximum of 8 hours" and at the same time Section 14.4.3 states that "The tank shall be kept filled, and the water level shall never be more than 4 in. (102 mm) below the designated fire service level".
Both sections, if i understand correctly, In Fire Case, As soon as water level goes below 4" from normal filled level (HHL), makeup water supply shall initiate to replenish water, This means, tanks will never gets empty out to refill. In what scenario tank shall be filled in 8 hrs except maintenance?
What if the required fire water stored in two tanks to allow maintenances, in this case do we still need to comply 8hrs?