A rising main is a system of pipework and valves, often found in high-rise buildings, which allows fire-fighting water to be easily delivered to all floors.
It consists of a vertical pipe with an inlet at ground level on an outside face of the building allowing fire and rescue service personnel to pressurise the main from their appliances and outlets (known as landing valves) usually fitted in cabinets on each floor that act as outlets, enabling the fire service to connect their fire hoses into the water supply. The installation of risers removes the need for fire fighters to have to drag charged fire hoses all the way up through tall buildings which could delay fire-fighting operations or create a hazard during evacuation. The current British Standard used for design, installation, testing and maintenance of Wet and Dry Risers is: BS9990:2015 Non-automatic fire-fighting systems in buildings Code of practice. It requires that all dry fire mains be checked every six months to ensure that all valves are fully serviceable, and a wet pressure test be carried out annually to ensure that there is no leakage.