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Dry and Wet Riser System
"Dry Riser" is a system of pipe work and valves that enables water to be delivered for firefighting purposes to all floors in buildings over 18 metres high.
Dry Risers
A dry riser is a system of empty pipework within the building. It comprises a two-way breeching inlet at ground level. The two way breeching inlet enables connection to a fire appliance via a hose for the water supply. It consists of a vertical pipe with landing valves fitted inside cabinets on each floor that provides outlets, enabling the fire service to connect into the water supply.
Wet Risers
Wet risers are used to supply water within buildings for fire-fighting purposes. The provision of a built-in water distribution system means that fire fighters do not need to create their own distribution system in order to fight a fire and avoids the breaching of fire compartments by running hose lines between them.
Wet risers are permanently charged with water. This is as opposed to dry risers which do not contain water when they are not being used, but are charged with water by fire service pumping appliances when necessary.Where there are floors higher than 50 m above fire service access level, wet fire mains should be installed owing to the pressures required to provide adequate fire-fighting water supplies at the landing valves at upper floors and also to ensure that water is immediately available at all floor levels.