Smoke Control Design: atrium_smoke_exhaust
Smoke control design parameters per NFPA 92-2021 and IBC 2021 Section 909 — stairwell and elevator pressurization differentials (0.05–0.10 in. w.g.), door opening force limits (30 lbf max), atrium exhaust prescriptive rates (4–6 ACH), axisymmetric and balcony/window plume mass flow equations (NFPA 92 Eq. 4.1, 4.10, 4.12), design fire heat release rates by occupancy (1000–5000 kW), building leakage areas by tightness class (tight/average/loose), door leakage areas, t² fire growth coefficients, tenability criteria (visibility 16–33 ft, temperature 120°C max, CO FED thresholds), and the smoke filling rate formula. Sources: NFPA 92-2021, IBC 2021 Sec. 909, ASHRAE Handbook HVAC Applications Ch. 54, Klote/Milke Handbook of Smoke Control Engineering.
| smoke control type | record id | description | formula or method | notes |
|---|---|---|---|---|
| atrium_smoke_exhaust | axisymmetric_plume_region1 | Axisymmetric Plume Mass Flow — Region 1 (z < z_l) | m_e = 0.032 * Qc^(3/5) * z - 0.024 * Qc^(1/2) | Region 1: z < limiting flame height z_l; use only when fire is at floor level; m_e in kg/s; Qc = convective HRR in kW; z = height above fuel base in m; z_l = 0.166 * Qc^(2/5); per NFPA 92-2021 Eq. 4.1a |
| atrium_smoke_exhaust | axisymmetric_plume_region2 | Axisymmetric Plume Mass Flow — Region 2 (z ≥ z_l) | m_e = 0.071 * Qc^(1/3) * z^(5/3) + 0.0018 * Qc | Region 2 (dominant): z ≥ z_l; most common case for tall atria; m_e in kg/s; Qc = convective HRR in kW; z = height above base of fuel in m; convective fraction typically assumed = 0.70 * Q_total; per NFPA 92-2021 Eq. 4.1b |
| atrium_smoke_exhaust | balcony_spill_plume | Balcony Spill Plume Mass Flow Formula | m_e = 0.36 * (Q_b * W^2)^(1/3) * (z_b + 0.25 * H_b) | Balcony spill plume; m_e in kg/s; Q_b = HRR reaching balcony edge (kW); W = width of plume at balcony edge (m); z_b = height above balcony edge to smoke layer (m); H_b = height of balcony above floor fire; per NFPA 92-2021 Eq. 4.10; Morgan (1997) |
This is a sample. Search the full smoke control design dataset and 300+ more by creating a free account and accessing the database.
Get started for FREE