Wet Riser
A wet riser is a vertical fire-water main that stays permanently full and pressurised, feeding a landing valve on every floor, so firefighting water is instantly available at height without waiting for pumps to charge empty pipe.
Why it matters on an MEPF project
Once a building crosses the height thresholds in NBC 2016 Part 4, dry arrangements stop being acceptable: the code wants water already at the landing valve when the hose connects. The wet riser, backed by the jockey pump holding system pressure, is how that instant availability is engineered.
Riser sizing, the number of risers (driven by floor area and travel distance), air-release at the top, and drain arrangements at the bottom are all inspectable details. So is the fire-brigade inlet that lets the brigade pump into your riser from their appliance if your pumps fail.
How it's specified in practice
| Parameter | Typical / working position | Governing reference |
|---|---|---|
| When required | Height/occupancy thresholds per code — most buildings above low-rise | NBC 2016 Part 4 |
| State | Permanently charged, pressure held by jockey pump | NBC 2016 Part 4 |
| Per-floor provision | Landing valve (single/double outlet) with hose | IS 3844 practice |
| Brigade connection | Fire-service inlet at ground level to charge the riser externally | NBC 2016 Part 4 |
Common mistakes
- No air-release valve at the riser top — airlocks give false pressure readings and spitting outlets.
- Landing valves painted shut or hidden behind later fit-outs.
- Brigade inlet missing, inaccessible, or unlabelled.
- Riser isolation valves left unsupervised — a closed valve is invisible until the fire.
Related on this site
Frequently asked
Wet riser vs dry riser — what is the difference?
A wet riser is permanently full and pressurised; a dry riser stands empty and is charged by the fire brigade through the ground-level inlet when needed. NBC 2016 Part 4 decides which your building height and class requires — taller buildings get wet risers.
Why does my riser pressure keep dropping overnight?
Small leaks or a passing valve — the jockey pump cycles to hold pressure, and its start frequency is your leak indicator. Frequent jockey starts deserve investigation, not tolerance.
Standards referenced: NBC 2016 Part 4 · IS 3844