Dry Wet Risers

What are dry & wet risers

Dry/wet risers are often called dry/wet rising mains.  They are intended for the use of the Fire Service to provide a readily available means of delivering considerable quantities of water to extinguish or to prevent the spread of fire.

Before installation of a dry/wet riser, the local Fire Service must be consulted to ascertain their exact requirements.

If, having completed your risk assessment, you conclude that the Fire Service would need to use this equipment during a fire, you must maintain it.

What is the difference between dry & wet risers

Dry riser: A system of valves and pipe work which enables the Fire Service to pump water onto upper floors of a building.

Wet riser: A system of valves and pip work which are kept permanently charged with water, generally utilising pumps and tanks.

Where are dry/wet risers found?

Dry risers will be found:

  • In buildings over 18 metres above ground level.
  • In low level buildings where there are excessive distances from entrances

Wet risers will be found in buildings over 60 metres above ground level.

What does a dry/wet riser look like?

Typical dry/wet risers contain the following components:

  • Large vertical pipe of 100mm or 150 metres diameter that can run internally or externally to the building.
  • Twin/four way inlet connection at street level boxed in a steel cabinet with glazed door for the dry riser only.
  • Outlet valves at each landing
  • Automatic air release valve at the highest point to provide bleeding of air from the system when it is filled with water
  • Pump and tanks for wet risers only
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