MEP / Plumbing / Fire Shaft Sizing
Vertical riser shafts are set by the core layout very early and are painful to enlarge later. These indicative sizes help you reserve enough core space for each service group before the detailed riser design.
| Shaft | Carries | Indicative clear size |
|---|---|---|
| Electrical riser | Bus-ducts / cable risers, LT & ELV (segregated) | ~1.0–2.0 m² per riser group |
| Plumbing/PHE shaft | Water supply, soil, waste & vent stacks | ~0.6–1.2 m wide, depth by stack count |
| Fire shaft | Wet-riser, sprinkler main, hydrant standpipe | Sized to risers + valve access |
| HVAC shaft | Supply, return, fresh-air & exhaust ducts | Largest where vertical ducts run |
Reserve separate, stacked, accessible shafts for electrical, plumbing, fire and HVAC in the core — keep electrical segregated from wet services, and allow door/access to valves and dampers on each floor.
Verify — Rule of thumb only. Shaft sizes follow the actual riser count and diameters, fire-compartmentation and access requirements — confirm against the MEP riser schedule and NBC 2016 (Parts 4, 8 and 9).
Want this coordinated against your structure?
Send us your schematic and we'll mark up a coordinated services section — so your ceiling height and shafts survive detailed design.