It consists of a central water main and outlet valves on each level, known as landing valves.
Wet Riser System Water Pressure
A wet riser system is so called because it is permanently charged with pressurized water from a pumped source. This is usually a holding tank fed by municipal water supplies to ensure there is sufficient water for fighting large fires.
A wet riser system is a vital safeguard against fire intended mainly for the use of fire fighters who can connect their hoses to any of the landing valve outlets.
For redundancy and safety in the case of pump failure, these systems are typically designed with two automatic pumps, one for primary duty and a second standby pump ensuring that there will be water pumped through the riser if the primary pump breaks down. The system also generally includes a ground level inlet for hooking in a firetruck’s pump in case the water level gets dangerously low.
This is in contrast to a dry riser system which is similar, but in the dry system the central main is not filled with water- it’s left dry when not used and filled and pressurized by the fire fighter equipment when necessary. Thus it is not suitable for taller buildings as there will not be enough pressure at higher floors.
Installation and Design
Wet riser systems are installed as a main vertical shaft usually 100mm in diameter that may be located inside the building or on an external wall.
The landing valves are at specified points on each floor and an air bleed valve is installed at the highest point of the main line.
The advantage of this is that fire fighters don’t need to create their own pumping system or use long hose systems as there is adequate water flow immediately available at each valve.
Wet risers are normally designed to be within fire fighting shafts or protected stairways meant as fire escape routes. The landing valves may be within these stairs, protected lobbies, or other enclosures where the fire fighting crews will have open access. A wet riser system fits the compartmentalization concept of building design, which involves sealing off buildings as much as possible into sections to contain the spread of fire and smoke.
Maintenance and Inspection
Our technicians are experienced at inspecting and maintaining wet riser systems. These fire protection systems should be tested and inspected regularly to ensure all valves and equipment are functioning correctly, water pressure and water supply is adequate, and the system is ready for use as needed.
Malaysian property owners are typically responsible for maintaining wet riser systems and could face heavy fines if they fail to operate in an emergency. Water leaks could also lead to structural damage.