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Room and factory smoke exhaust: zones and flow
Enter the room area, height and the clear layer height to keep. The tool splits smoke zones, estimates fire perimeter, fan flow per zone and how fast smoke fills down to the danger level.
Quick answer
1 smoke zones, about 52,111 m³/h fan per zone (Pf = 12.0 m), 52,111 m³/h if all run together; without exhaust smoke reaches the danger level in about 178 s.
Preliminary results
Smoke zones1zones
Fan per zone52,111m³/h
Total if all52,111m³/h
Smoke reaches Y after178s
| Step | Result | Basis |
|---|---|---|
| Smoke zones ≤ 1,600 m²⌈1,200 / 1600⌉ | 1 × 1,200 m² | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
| Fire perimeter Pf0,38 × √1,000 | 12.00 m | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
| Smoke flow G676,8 × 12.00 × 2.5^1,5 | 32,103 kg/h | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
| Convert to m³/h32,103 / 0.616 | 52,111 m³/h | — |
| Time for smoke to reach Y6,39 × 1,200 × (2.5^-0,5 − 8.0^-0,5) / 12.00 | 178 s | Пособие 4.91 · QCVN 06:2022 PL D ⚠ |
- Rooms over 1,600 m² are split by non-combustible smoke curtains reaching down to at least 2.5 m above floor.
- Usually only the fire zone is exhausted; the all-zones total is for reference.
- Provide replacement air of about 70–90 % of exhaust through low-level doors or louvres ⚠.
Sources and assumptions. Posobie 4.91 (SNiP 2.04.05-91) section 2, the basis of QCVN 06:2022/BXD Annex D: G = 676.8·Pf·Y^1.5·Ks (kg/h, Ks = 1 mechanical); Pf = 0.38·√A (A 100–1,000 m², Pf 4–12 m), sprinklered Pf = 12 m; t = 6.39·A·(Y^-0.5 − H^-0.5)/Pf; smoke zone ≤ 1,600 m² ⚠. ⚠ = 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 ≥ 57,322 m³/h (per zone)1
Ducts, smoke dampers, exhaust grillesper drawing
Frequently asked questions
How many smoke fans for a 5,000 m² factory?
At least 4 smoke zones ≤ 1,600 m²; each zone has its own fan or exhaust branch sized as above, and usually only the fire zone runs.
Do sprinklers reduce the exhaust rate?
In this method a sprinklered fire is taken as a fixed 12 m perimeter (controlled fire), so the flow no longer depends on area.