Disclosed is a fire protection system. The fire protection system comprises a firewall; and a waterway buried in a space below the firewall. The waterway comprises a first horizontal pipe; a bent pipe connected to the first horizontal pipe to be bent downwards; and a second horizontal pipe connected to the bent pipe. The inner bottoms of the first and second horizontal pipes are higher than the lowest part of the inner top of the bent pipe on the basis of the longitudinal cross section of the fire protection system.
