Wet rising mains are fitted in tall buildings due to the excessive pressures required to pump water to high levels. A Wet riser is a supply system intended to distribute water to multiple levels or compartments of a building, as a component of its fire fighting systems. They are advantageous to the fire service in two respects. Firstly they provide a fixed distribution system within the building that requires no fire service resources or equipment. Secondly it is designed as part of, and to maintain, the compartmentalization of the building.
Wet rising mains consist of vertical pipes similar to the dry rising main system with landing valves at each floor except the ground. The pipe system is connected to a permanent water supply normally a tank fed from the town mains. Duplicate automatic pumps, one duty and one standby supply this water to the pipe system.
