wet riser – Connexxity

A wet-riser system must be installed in the types of buildings listed in Table 1. This system includes one or more pipes, depending on the building’s area and height, which are continuously charged with water under pressure. Each floor should have landing valves, hose reels, hoses, and branch pipes. A pressure differential switch should be included to automatically start the pump when water is drawn from the landing valves, ensuring that water is available for hydrants and hose reels. Additionally, a standby pump must activate automatically if the main power supply fails.
The distribution of the wet-riser system should ensure that no point within the area covered by the hydrant is more than 30 meters away from the nearest riser. The risers should be positioned between 0.75 meters and 1 meter above the floor, and should not be spaced more than 50 meters apart horizontally.
A fire service inlet with a gate and non-return valve must be provided on the wet-riser system to allow for charging from a mobile fire service pump in case of failure of the static pump. For a 100 mm diameter rising main, the fire service inlet should include a collecting head with two 63 mm inlets. For a 150 mm diameter rising main, it should have a collecting head with four 63 mm inlets.