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Corridor smoke exhaust: fan flow and intakes
Enter the largest door from the corridor to the stair or outside and the corridor length. The tool gives the smoke mass flow, fan m³/h, number of intakes and damper area.
Quick answer
The corridor needs 12,562 kg/h smoke exhaust, fan about 20,391 m³/h; 2 intakes, damper area 0.35–0.50 m² each.
Preliminary results
Smoke mass flow12,562kg/h
Fan flow20,391m³/h
Intakes2pcs
Damper area0.35–0.50m²
| Step | Result | Basis |
|---|---|---|
| Coefficient n by door widthB = 1.20 m | n = 0.800 | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
| Smoke flow G4300 × 1.20 × 0.800 × 2.10^1,5 × 1.0 | 12,562 kg/h | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
| Smoke density353 / (273 + 300) | 0.616 kg/m³ | — |
| Convert to m³/h12,562 / 0.616 | 20,391 m³/h | — |
| Number of intakes⌈60 / 45⌉ | 2 pcs | QCVN 06:2022/BXD ⚠ |
| Damper area (7–10 kg/s·m²)3.490 kg/s ÷ (7…10 kg/s·m²) | 0.35–0.50 m² | МДС 41-1.99 ⚠ |
- Intakes at corridor ceiling, lower edge not below the top of the doors.
- Normally closed smoke dampers open on fire alarm; fans and ducts heat-rated per design.
- Provide replacement air to the corridor per QCVN 06:2022/BXD Annex D ⚠.
Sources and assumptions. Corridor smoke exhaust method from Posobie 4.91 (SNiP 2.04.05-91), the basis of TCVN 5687 and QCVN 06:2022/BXD Annex D: G = 3420·B·n·H^1.5 (residential), G = 4300·B·n·H^1.5·Kd (others), kg/h; smoke 300 °C ρ = 0.616 kg/m³; fan +10 % duct leakage. Corridor length per intake and damper velocity ⚠. ⚠ = code table value to be checked against the original standard. Preliminary results for material selection and budgeting; not a substitute for an approved fire protection design.
Suggested materials
Heat-rated smoke exhaust fan ≥ 22,431 m³/h1
Normally closed smoke damper (corridor intake)2 pcs
Fire-rated galvanised smoke ductper drawing
Coefficient n by door width B
| B, m | 0.6 | 0.9 | 1.2 | 1.8 | 2.4 |
|---|---|---|---|---|---|
| Residential, apartments | 1.00 | 0.82 | 0.70 | 0.51 | 0.41 |
| Public, administrative, industrial | 1.05 | 0.91 | 0.80 | 0.62 | 0.50 |
Frequently asked questions
What fan does a hotel corridor need?
Stair door 1.2 × 2.1 m, public building, ≥ 25 people: G = 4300 × 1.2 × 0.8 × 2.1^1.5 ≈ 12,600 kg/h, about 20,400 m³/h at 300 °C.
Why is flow based on the door, not the corridor area?
The aim is to stop smoke spilling through the open stair door during evacuation, so the flow depends on door size and the number of people using it.