Chapter 7
Mechanical Ventilation & Smoke Control Systems
Chapter 7 governs the design, installation and maintenance of air-conditioning, mechanical ventilation, pressurisation and smoke control systems in buildings to limit fire and smoke spread and to maintain tenable conditions for evacuation and firefighting. It sets out ductwork construction rules, fire damper requirements, special ventilation requirements for exits and protected spaces, pressurisation performance criteria, smoke extraction and purging system designs, and mandatory redundancy provisions for all critical life-safety ventilation systems.
Scope: All buildings (except PG I where explicitly exempted) that incorporate air-conditioning or mechanical ventilation systems, pressurised exit staircases or corridors, or engineered smoke control systems. Specific clauses apply to hotels, car parks, kitchens, battery rooms, and buildings with large or basement compartments.
Source: SCDF Code of Practice for Fire Precautions in Buildings 2023. This is a guidance summary — always verify against the full Fire Code clause text.
Critical points
The internal corridor pressure must exceed the guest room pressure by 12.5 Pa. This corridor pressurisation activates for the fire floor and two floors above only.
CriticalClause 7.3.1aThe smoke-free/fire lift lobby pressure must exceed the internal corridor pressure by a further 12.5 Pa. The lobby pressurisation fans shall activate on ALL floors during a fire.
CriticalClause 7.3.1bExit staircase pressure must comply with Clause 7.2.2a (≥50 Pa above occupied area). The staircase pressure must always remain higher than the lobby pressure.
CriticalClauses 7.3.1c, 7.2.2a–bRedundancy (N+1 standby fan) is required for the hotel internal corridor pressurisation system per Clause 7.5.
ImportantClause 7.5.1a(4)
Compliance thresholds
| Parameter | Value | Condition | Clause |
|---|---|---|---|
| Internal corridor pressure above guest room pressure | 12.5 Pa | Hotel internal corridors where pressurisation is required | Clause 7.3.1a |
| Smoke-free/fire lift lobby pressure above internal corridor pressure | 12.5 Pa | Lobby serving pressurised hotel internal corridors | Clause 7.3.1b |
| Exit staircase minimum pressure differential | ≥50 Pa above occupied area | Exit staircase serving pressurised hotel | Clause 7.2.2a |
| Corridor pressurisation activation floors | Fire floor + 2 floors above | Corridor pressurisation fans | Clause 7.3.1a |
| Lobby pressurisation fan activation | All floors during fire | Smoke-free/fire lift lobby fans serving hotel corridors | Clause 7.3.1b |
Interactive decision tree
Is this a hotel building with internal guestroom corridors required to be pressurised?